Digestive System and Nutrition Compendium Review

Table of Contents

Digestive System and Nutrition

• Overview of the Digestion
• First Part of the Digestive Tract
• The Stomach and Small Intestine
• Three Accessory Organs and Regulation of Secretions
• The Large Intestine and Defecation
• Nutrition and Weight Control

Digestive System and Nutrition

Overview of Digestion

The gastrointestinal tract holds all of the digestive system organs. Digestion takes the macromolecules and breaks them down to the unit molecules which can then cross the plasma membranes. There are four layers in a GI tract wall. The central space where the food is digested is known as the lumen. The firt layer after this is the mucosa (produces mucus to protect the wall from digestive enzymes). Submucosa is the second layer (loose connective tissue containing blood and lymphatic vessels, and nerves). Third layer is muscularis ( two layers of smooth muscle. Inner encircles the tract and outer lies same direction of tract. Contracti0n of these muscles moves digested food). Serosa is the last layer (secretes serous fluid and is part of the peritoneum)

• Ingestion- this is when food enters the mouth
• Digestion- Either mechanical (food broken into pieces that digestive enzymes can work on) or chemical (digestive enzymes.)
• Movement- Food passes from one organ to another through the digestive tract.
• Absorbtion- Unit molecules resulting from digestion are now able to move across the GI tract into the cells that line the GI tract, where they enter the blood for transportation.
• Elimination- Indigestible wastes are defecated through the anus

First Part of the Digestive Tract

Your mouth, pharynx, and esophagus make up the first section of the GI tract. The food enters through the mouth, and this is the beginning of mechanical and chemical digestion. The mouth is made up of your hard palate, soft palate, tonsils (lymphatic tissue), and salivary glands(send saliva containing salivary amylase to the mouth). Teeth (20 baby teeth, replaced by 32 adult teeth) function as a mechanical aspect. Your tongue helps in mechanical digestion along with taste buds that send nerve impulses to the brain.

Pharynx is the next stop after food enters the mouth. This is where the food and air passages intersect (trachea is front of the esophagus). Swallowing is voluntary until food reaches the pharynx, here it becomes automatic. The soft palate blocks off nasal passages, and the epiglottis covers the glottis, blocking food from going into the trachea. The only place left to go is down the esophagus. Peristalsis moves the food down the esophagus and sphinters allow the food to enter the stomach, but prevent stomach acids from entering the esophagus.

The Stomach and Small Intestine

The stomach sits on the left side of the body under the diaphragm. The esophagus conects to the top of the stomach and the duodenum of the small intestine connects on the bottom. In the stomach, food is stored, protein digested and chyme is moved into the small intestine. There are also four layers of the stomach wall: Three layers of smooth muscle(circular, longitudal and obliquely) and a mucosa layer on the inside in which rugae produce gastric juice that contains pepsin, HCl and mucus.

The small intestine completes the digestion process. Here there are many enzymes capable of digesting all types of food including carbohydrates, proteins, and fats. This wide array of enzymes is secreted in the pancreas and enters the duodenum along with bile to emulsify fat. Nutrients are absorbed here. The small intestine's large surface area is designed perfectly for this absorption. Mucosa contains villi which have extensions called microvilli. Each villus has a small lymphatic capillary (lacteal). The vessels in here allow the unit molecules to be carried to all the other cells in your body through the bleed stream.

Three Accessory Organs and Regulation of Secretions

Digestive secretions are regulated by the nervous system and digestive hormones.

1. Pancreas- located behind the stomach. Pancreatic cells produce pancreatic juice containing digestive enzymes for all the types of food.(amylase digests starch, trypsin is for protein, and lipase is for fat). This organ is also very important because it is responsible for producing insulin. When the bodies blood glucose level rises, this triggers an excess amount of insuling to be produced which in turn, brings the glucose level back to normal range. Diabetes type 2 occurs when a body's cells become resistant to the insulin. Type one diabetes occurs when the pancreas does not secrete insulin like it should, and thus blood sugar must be checked frequently and insulin injected when needed.

2. Liver- is the largest metabolic gland. Located in the upper right quadrant of abdominal cavity. Blood travels through the hepatic portal vein into the capillaries of the liver lobules where poisonous substances are removed. The liver also stores iron and vitamins. Glucose is stored as glycogen which is broken down when there is insulin, effectively keeping your blood glucose level constant. The liver also produces plasma proteins and regulates cholesterol and breads down hemoglobin, forming bile

Liver diseases can be life threatening. Two big diseases are hepatitis(inflammation) and cirrhosis(liver tissue replaced by scar tissue)

3. Gallbladder- located below the liver. Bile is stored here.

The Large Intestine and Defecation

The cecum, colon, and rectum all are part of the large intestine. The cecum is located behind the junction of the small intestine with the large intestine and has a projection known as the vermiform appendix. The colon is the ascending, transverse, descending and sigmoid. This leads into the rectum and opens at the anus.

The large intestine functions to absorb water and proteins produced by intestinal flora. The bacteria here break down the indigestible material to form feces. Diseases of the large intestine include: diarrhea, constipation, hemorrhoids, diverticulitis, irritable bowel syndrome, inflammatory bowel disease, polyps and cancer. Most of these can be prevented by exercising a good diet, and good bowel habits.

Nutrition and Weight Control

Obesity affects 33% of adults today. This is determined by your body mass index (BMI). A healthy BMI 19.1-26.4, overweight 26.5-31.1, obese 32.3-39.9 and morbidly obese 40+.

Nutrients are an important part of diet. They are classified into

1. Carbohydrates- either simple or complex. Glucose is preferred by the body for energy. As fatty acids cannot be converted to glucose, it is important to include carbohydrates in your diet. Unrefined products are best

2. Proteins- these are broken down into amino acids when digested and used to synthesize cellular proteins. 8 out of 20 amino acids are essential for children's growth. Absence of just one essential amino acid, and the other 19 will not function properly. Since amino acids are not stored, a daily intake is needed.

3. Lipids- these are the fats, oils and cholesterol. Unsaturated fats do not encourage cardiovascular disease. Polyunsaturated fats are actually needed since they contain linoleic and linolenic acids which the body does not produce on its own.

Minerals are either major( structural components of cells) or trace (part of a larger molecule). Exampels are: calcium, vitamin D, and sodium. Vitamins are organic compounds that the body cannot produce enough of, but is needed for metabolic reasons. There are 13 vitamins and they are either fat soluble or water soluble. Vitamins C, E, and A are antioxidants and can be found in fruits and vegetables.

A healthy diet consists of eating a variety of foods and being physically active. More fruits, vegatables and whole grains should be consumed, and less sugars, saturated fat, salt and cholesterol.

Anorexia, bulima, binge eating and muscle dysmorphia are all eating disorders that effect people everyday.

Works Cited

Mader, Sylvia. Human Biology 10th ed

Frolich Powerpoint

Website links for pictures

1.http://www.mc.vanderbilt.edu/histology/labmanual2002/labsection3/EsophagusandStomach03_files/image004.jpg 2. http://cache.eb.com/eb/image?id=1354&rendTypeId=4
3. http://www.acm.uiuc.edu/sigbio/project/digestive/middle/stomach2.jpg
4.http://a-s.clayton.edu/biology/biol1152l/digestive_system_anatomy/stomach_rugae.jpg
5. http://www.rivm.nl/interspeciesinfo/Images/small-intestine_tcm75-26441.gif
6. http://www.foxriverwatch.com/color_liver2a.jpg

Blood Pressure Online Lab

1.State a problem about the relationship of age and gender to blood pressure.
One problem is as people get older often times they will start smoking or drinking which can increase blood pressure. Also older people might not exercise as much which results in higher blood pressure

2.Use your knowledge about the heart and the circulatory system to make a hypothesis about how the average blood pressure for a group of people would be affected by manipulating the age and gender of the group members.
I hypothesize that as the age groups increase in age there will be more cases of individual hypertension, thus also bringing up the average blood pressures. By manipulating the gender, I hypothesize that males will have higher blood pressures due to obesity factors.

3.How will you use the investigation screen to test your hypothesis? What steps will you follow? What data will you record?
After all the blood pressures have been taken I will look to see if any individual shows hypertension. If so, the factors of their past medical history will be noted. Then I will go through everyone's history and note the factors, even if they are not hypertensive at this time.

4.Analyze the result of your experiment. Explain any patterns you observed.
Females were broken into 5 groups of 10. Group one is age 11-17, group two 18-24, group three 25-34, group four 35-44 and group five 45-54.
Group One- average BP 116/75. No cases of hypertension. Two of the subjects had a family history of hypertension, and one of these two also lacked exercise
Group Two- average BP 117/75. One case of hypertension. This person had family history, lacked exercise and was 30% overweight. Her BP was 140/91
Group Three-average BP 117/76. No cases of hypertension. Two subjects lacked exercise but did not exhibit hypertension due to this fact
Group Four- average BP 126/81. Three cases of hypertension. Of these three, one had family history and a BP of 140/91, one consumed alcohol and had a BP of 141/92 and the third had no history of any kind but a BP of 142/92
Group Five- average 131/80. Two cases of hypertension. Both of these subjects had high salt diets, lacked exercise, and were 30% overweight. BP's were 144/91 and 145/95. Two other subjects had family history of hypertension, but were not hypertensive themselves.
In the females, regardless of age, 6 out of 50 subjects showed hypertension. 1 of these 6 was 30%overweight with a family history, 1 had a family history only, 1 had no history of anything, 1 consumed alcohol only, and 2 had high salt diets and were obese.

Males Group One- average 117/76. No cases of hypertension. 2 subjects were obese
Group Two- average 127/79. One case of hypertension. This subject had a family history and was obese. BP was 141/91
Group Three- average 130/80. No cases of hypertension. Two subjects had a high salt diet
Group Four- average 130/81. One case of hypertension. This subject had a high salt diet, consumed alcohol and was obese. BP was 142/91.
Group Five- average 135/85. Four cases of hypertension. Of these four all had family history, three were obese, and one consumed alcohol on top of the other factors. BP's were 140/90, 144/91, 142/90, and 146/94
In the males 6 out of 50 subjects were hypertensive. 4 of them fell into the age group 45-54. 5 out of these six were obese and had a family history of hypertension.

5.Did the result of your experiment support your hypothesis? Why or why not? Based on your experiment what conclusion can you draw about the relationship of age and gender to group blood pressure averages?
For the most part these tests supported my hypothesis. To get a more accurate result, I feel that a larger number of subjects would need to be tested. From this experiment it shows there were 6 cases in both genders of hypertension, not just males. It also shows more cases of obesity in males in group 5 with hypertension verses females, whose hypertension was spread throughout the age groups, and not strictly related to obesity.

6.During the course of your experiment, did you obtain any blood pressure reading that were outside of the normal range for the group being tested? What did you notice on the medical charts for these individuals that might explain their high reading?
In both male and females there were 6 cases each of hypertesion. Of these 12 subjects only one (female) had no medical history. The other 11 had any combination of family history, high salt diet, lack of exercise, obesity, or alcohol consumption. More males then females were obese.

7.List risk factors associated with the hypertension. Based on your observation, which risk factor do you think is most closely associated with hypertension?
Risk factors of hypertension include smoking, drug abuse, weight gain, and also family history. In this particular study, weight gain was seen most frequently with hyptertension, along with family history. However, smoking and drug abuse were not listed in subjects history

8.What effect might obesity have on blood pressure? Does obesity alone cause a person to be at risk for high blood pressure? What other factors, in combination with obesity, might increase a
person's risk for high blood pressure?
When someone is obese they have more tissues for the blood to circulate through and take care of. To accompish this, the heart must increase the pressure when it pumps. Obesity alone can cause risk of high blood pressure, but other things such as diet, family history, drinking, can all play a part.
Graphs and charts for this lab

Topic Two Online Lab- Food

Online Food Lab

1. I think my day was pretty healthy. I didn't eat very much, but what I did I felt was healthy(minus the soda).

2. The thing I would change would be to have eaten some kind of lunch, and drinken more water, however I worked a busy shift on the ambulance, and that wasn't an option for that day.

3. This type of nutritional tracking is very beneficial in my opinion. The Balance Mind Body and Soul site was exceptional in entering all of my information and organizing it into a nutritional chart. I think if you have to note everything that goes into your body throughout the day it makes you more self concious of trying to eat healthier.

Compendium Review Oxygen, Microbes, Immunity

Table of Contents

Cardiovascular System: Heart and Blood Vessels

• Overview of the Cardiovascular System
• Types of Blood Vessels
• Heart is a Double Pump
• Features of the Cardiovascular System
• Two Cardiovascular Pathways
• Exchange at the Capillaries
• Cardiovascular Disorders

Cardiovascular System: Blood

• Blood: An Overview
• Red Blood Cells and Transport of Oxygen
• White Blood Cells and Defense Against Disease
• Platelets and Blood Clotting
• Homeostasis

Lymphatic System and Immunity

• Microbes, Pathogens, and You
• The Lymphatic System
• Nonspecific Defenses
• Specific Defenses
• Acquired Immunity
• Hypersensitivity Reactions

Cardiovascular System: Heart and Blood Vessels

Overview of the Cardiovascular System

There are two main structures that make up the cardiovascular system: the heart and the blood vessels. The heart pumps the blood through the blood vessels. Circulation provides service to the cells by exchanging substances with tissue fluid which the actual cells are bathed in.

Blood removes waste products, while at the same time bringing oxygen, and nutrients needed for survival. Blood is able to perform this way by stopping at three main organs. One is the lungs, where CO2 leaves, and O2 enters. Two is the kidneys, where wastes are dropped off and water and salts are retained. Three is the liver, where amino acids are dropped off and proteins are picked up by the blood. These proteins will help transport other substances.

The lymphatic system works hand in hand with the cardiovascular system by collecting excess tissue fluid and giving it back to the cardiovascular system. Water that collects in tissues during exchanges is called lymph as soon as it enters the lymphatic vessels.

The Types of Blood Vessels

• Arteries- these travel from the heart. Three layers make up the arterial wall. Innermost is endothelium (thin layer of cells), then a layer of smooth muscle and elastic tissue, and finally the outer layer of connective tissue. Arterioles are small arteries you are able to see with the naked eye. When their muscle fibers contract the vessel becomes constricted, when they relax, dialation occurs. This regulates blood pressure


• Capillaries- These are a place for exchange. Capillaries are branched of from arterioles. They are a very narrow tube and their wall is made up of only endothelium. Capillary beds are found everywhere in the body. In tissues certain capillaries are open at certain times. If a capillary bed is closed, then the precapillary sphinters will contract


• Veins- travel to the heart. Venules are small veins that drain blood from the capillaries then to join to form a vein. The wall of a vein is the same as an artery, but thinner because there is less smooth muscle and also less connective tissue. Valves are a one way sign for blood. They are found in the veins that blood travels against the flow of gravity and make sure the blood only flows towards the heart.

The Heart is a Double Pump

The heart is a muscle that sits between the lungs, behind the sternum. The myocardium is made of cardiac muscle tissue. The coronary artery and the cardiac vein service the myocardium.

• Surrounding the heart is the pericardium -(membranous sac protecting the heart, the inside secretes a lubricating fluid that allows the pericardium to slide over the surface while the heart pumps blood).


• Septum- is a wall that divides the heart into a right and left side (each side has a thin walled atrium on top and a thicker walled ventricle on the bottom).


• Atrioventricular valves- prevent backward movement of the blood. The one on the right side is the tricuspid (three flaps) and the one on the left is the bicuspid (aka mitral, and only has 2 flaps). The other 2 flaps are semi-lunar valves (half moon shape and are located between ventricles and their attatched vessels- pulmonary trunk and aorta

The passage of blood through the heart is as follows: Superior and inferior vena cava(O2 poor) enter the right atrium. Right atrium sends blood through atrioventricular valve to right ventricle. Right ventricle sends blood through pulmonary semilunar valve into pulmonary trunk. The trunk divides into two pulmonary arteries that go to the lungs. Four pulmonary veins (carrying O2 rich blood) enter the left atrium. The left atrium sends the blood through the bicuspid valve to the left ventricle. The left ventricle sends it through the aortic semilunar valve into the aorta.

Each heartbeat is a cardiac cycle. The two atria contract at the same time, then the two ventricles contract at the same time. Then all the four chambers relax. Systole is the working phase (contraction) and diastole is the resting phase (relaxation of chambers). The sinoatrial (SA) node initiates the heartbeat and sends out the excitation impulse causing the atria to contract. The atrioventricular (AV) node receives the impulse for the ventricles to begin contracting and sends it through the atrioventricular bundle and purkinje fibers. The medulla oblongata, can also regulate and change heartbeat through the parasympathetic and sympathetic portions of the nervous system.

We are able to physically see a person's heartbeat by an electrocardiogram (ECG). This records the electrical changes in the myocardium. The ions in body fluids conduct an electrical current that can be detected on the skin surface. A P wave is an electrical charge from the atrial fibers that is triggered by the SA node. This shows the atria preparting to contract. The QRS complex is showing the ventricles about to contract. The T wave is showing ventricular muscle fibers recovering.

Features of the Cardiovascular System

A pulse is equal to heart rate. The pulse you can feel on arteries close to the skin surface is the surge of blood entering them, causing their elastic walls to expand briefly. Normal pulse rate for an adult is 60-80 beats per minute.

Blood pressure is critical to homeostasis by making sure hte blood gets moved all the way from arteries down to capillaries where exchange with tissue fluid occurs. Blood pressure is measured using a sphygmomanometer. Systolic pressure is heard during ejection of blood from the heart and diastolic pressure happens when the ventricles are relaxing. Normal blood pressure for a young adult is 120/80.

Because blood flow slows down in the capillaries (gives enough time for the exchange), but the velocity increases in the veins, there are other factors involved in venous return.

• First is the skelatal muscle pump- upon contraction they compress the weak walls of the vein, allowing the blood to flow past a valve.
  
• Respiratory pump- by inhaling, the pressure is reduced in the thoracic cavity, allowing blood to flow from a higher pressure cavity, to a lower pressure cavity.


• Valves- prevent backward flow of blood from occuring, thus always working to move blood towards the heart

Two Cardiovascular Pathways

The first circuit is the pulmonary circuit, where blood circulates through the lungs. Blood from all regions collects in the right atrium where it then moves to the right ventricle and onward to the pulmonary trunk. From here the trunk is divided into right adnd left pulmonary arteries that begin to branch upon approaching the lungs. Arterioles deliver blood to pulmonary capillaries (CO2 given, O2 taken). The blood then travels through the pulmonary venules to four pulmonary veins going to the left atrium (O2 rich )

The second circuit is the systematic circuit where the needs of body tissues are served. The aorta receives blood from the heart and teh superior and inferior vena cavaes return blood to the heart. In the systematic circuit blood travels like this :

Left ventricle -> aorta -> common illiac artery -> femoral artery -> lower leg capillaries -> femoral vein-> common illiac vein -> inferior vena cava -> right atrium

Exchange at the Capillaries

Blood pressure along with osmotic pressure ( created by salts and plasma proteins) are the main forces that control fluid movement through the capillary wall. Blood pressure moves water from the capillaries to tissue fluid, and osmotic pressure moves water from tissue fluid into the capillaries. Water leaves the capillaries(due to blood pressure) at the arterial end. In the middle of the capillaries blood pressure is equal to osmotic pressure and therefore, no net movement of water. This is where oxygen, glucose, and amino acids diffuse out and carbon dioxide and wastes diffuse in. At the venule end osmotic pressure allows water into the capillary.

Cardiovascular Disorders

Hypertension is high blood pressure defined as a systolic number greater than 140 and/or the diastolic number greater than 90. Atherosclerosis (accumulation fatty material in the inner lining of arteries) is a leading cause of hypertension. A low cholesterol and low saturated fat diet can help prevent this. Plaque can cause clots (thrombus if stationary, embolus if dislodged)

A cerebrovascular accident (CVA, stroke) occurs from a small cranial artery bursting or also from embolus' . This blockage prevents oxygen from getting to the brain which can result in death of the brain cells.

A myocardial infarction (MI, heart attack) occurs from parts of the heart muscle dying due to lack of oxygen. A partial blockage of the coronary artery results in angina pectoris which can be temporarily relieved by dialating blood vessels. Coronary bypass operation is when a vein ( most commonly from the leg) is attatched to the aorta and the coronary artery past the obstruction. A different procedure is gene therapy where genes that code for vascular endothelial growth factor are injected into the area of the heart that needs it. This causes new blood vessels to form that will transport around the clogged arteries. People with heart failure can be helped by ICD's, LVAD, heart transplants, bone marrow stem cells, or even total artificial hearts.

Cardiovascular System: Blood

Blood: An overview

Your body contains approximately five liters of blood that is pumped by the heart with every beat. Blood is a liquid tissue composed of formed elements (cells and cell fragment) that is suspended in plasma.

The formed elements ( red and white blood cells, platelets) are produced in red bone marrow that contains stem cells that divide and create many different blood cells.

Plasma (91% water, 9% salts and organic molecules) carries the substances in the blood and distributes heat. Plasma proteins(albumins, globulins, fibrinogen) are produced in the liver and maintain homeostasis by taking and releasing hydrogen ions. Albumins help transport organic molecules. Globulins (alpha, beta, gamma) transport hormones, cholesterol and iron. Gamma help fight disease. Fibrinogen plays a large part in forming blood clots.

There are three main functions blood

• Transport- delivers oxygen and nutrients to the tissues. Takes carbon dioxide and wastes from the tissues to exchange in lungs and kidneys. Hormones that act as signals to influence cellular metabolism are also trasported through the blood.


• Defense- defends against invasion by pathogens. Blood is able to do this by phagocytizing the pathogens and secreting antibodies. Blood is able to clot preventing us from bleeding to death.


• Regulation- can regulate body temperature by transporting heat from active muscles out of the body from blood vessels in the skin. Contains buffers which regulate the body's pH

Red Blood Cells and Transport of Oxygen

Red blood cells (erythrocytes) are specialized for oxygen transport. Copies of hemoglobin replace a nucleus.Each hemoglobin (approx 280 million in one red blood cell) can transport 4 O2 molecules. The hemoglobin is the pigment that gives blood and the cells their red color. Heme is a group in the center of each polypeptide that contains iron. This is able to accept and release oxygen. When the heme is carrying oxygen the shape is oxyhemoglobin, after it is released the shape is deoxyhemoglobin. The oxygen has been diffused into tissue fluid and then cells. Globin is a protein with four "highly folded polypeptide chains"

Red blood cells also transport carbon dioxide. When it is picked up from the tissues it is dispersed as follows: 7% dissolved in plasma, 25% directly transported by hemoglobin(on amino group of globin), 68% transported as bicarbonte ion in plasma (HCO3) See following reaction

Red blood cell only have a life expectancy of around 120 days. When aged they are destroyed in the liver and spleen by macrophages. Upon destruction hemoglobin is released. The globin breaks into amino acids which teh body recycles and the iron is returned to the bone marrow for reuse. The kidneys are able to release erythropoietin to stimulate stem cells to produce more red blood cells when there is not enough oxygen being delivered to the cells.

Anemia (lack of red blood cells and/or hemoglobin), Hemolysis (rupturing of red blood cells) and Sickle-cell disease are all disorders of the red blood cells. Sickle cell is hereditary and occurs when 2 of the amino acid chains in hemoglobin is abnormal. The cells tend to rupture as they travel through the capillaries. Usually sickle-cell is a bad thing, but in some countries where malaria is present, sickle-cell can actually act as a defense against it. When carriers of sickle-cell are infected with malaria, their blood cells sickle. When these cells circulate through the spleen they are filtered out due to their shape, effectively eliminating the parasite with them.

White Blood Cells and Defense Against Disease

White blood cells have a nucleus (no hemoglobin) and are known as leukocytes. They are produced from stem cell in red bone marrow. Colony-stimulating factor (CSF) is a protein that regulates the production of the different types of white blood cells. These white blood cells are not only found in blood, but also in tissue fluid and lymph due to their ability to squeeze through the capillary wall pores.

White blood cells fight infection by various methods (phagocytosis, production of antibodies) and have a life span that can vary from a few days to a few years. There are two groups of white blood cells: granular leukocytes and agranular leukocytes.

• Neutrophils (granular)- most abundant type (50-70 percent of white blood cells). Contain a multilobed nucleus and resist staining. They are usually first on scene to bacterial infections and fight using phagocytosis. Pus is a result of large scale death in neutrophils.


• Eosinophils(granular)- Contain a bilobed nucleus and take up eosin (staining them red). Numbers increase upon parasitic worms and allergic reactions


• Basophils (granular)- contain a lobe nucleus and take up a basic stain (leaving them blue). Found in the connective tissue and release histamine.


• Lymphocytes (nongranular)- (25-35 percent of white blood cells). There are B-cells or T-cells. B-cells produce antibodies. T-cells can directly destroy pathogens.


• Monocytes (nongranular)- largest in size. Live in the tissues and become large macrophages using phagocytosis on pathogens, cellular debris and old cells. Stimulate the other white blood cells to defend the body.

Disoders of white blood cells include: severe combined imunodeficiency disease (SCID), leuemia and infectious mononucleosis. SCID is a lack of enzyme in white blood cells leaving them unable to fight any infections. Gene therapy is on the rise to try and cure this if the new stem cells (injected with the correct gene) settle back into the bone marrow to produce healthy lymphocytes. Leukemia is white blood cell proliferation that is uncontrolled and as a result most are not mature and unable to perform the defense functions needed. Infectious mononucleosis is a virus which symptoms can go away, but it's cells remain dormant in throat and blood cells and can be reactivated by stress.

Platelets and Blood Clotting

When megakaryocytes in the red bone marow fragment, this creates platelets (thrombocytes). If a blood vessel becomes damaged, platelets clump at the site to seal the break. Larger damage might also require a blood clot to seal the break. When a blood vessel is punctured, the damaged tissue and platelets release prothrombin activator. This converts prothrombin to thrombin, which severs 2 short amino acid chain from each fibrinogen molecule. These then join to form fibrin which provides the framework for the clot and trap red blood cells. Then blood vessel repair begins and the fibrin is destroyed to restore the fluid plasma.

Disorders of blood clotting include thrombocytopenia (insufficient amount of platelets), and hemophilia (deficiency in a clotting factor, this is an inherited disorder).

Blood Typing and Transfusions

Blood typing is determining the ABO blood group and Rh negative or positive. This must be done prior to transfusion (transfer of blood from one person to blood of another) to assure that agglutination does not occur. This is very important because the plasma membranes on the red blood cells can have glycoproteins that are antigens to other membranes. There are A and B antigens. A has anti-B antibodies, B has anti-A antibodies and O has both antibodies. Antibodies in the plasma should not combine with the antigens on the red blood cell serface. If they combine, this is agglutination.

Rh negative people to not have antibodies to the Rh factor, but their body will make the antibodies if exposed to the factor. If a baby is Rh positive and mom is negative, the Rh positive can leak from the placenta to mom's blood stream. She would then produce anitbodies, which could cause a problem in a second birth if baby was Rh positive. This is hemolytic disease, and hemolysis does not stop when the baby is born. A Rh immunoglobin injection is given to a Rh negative mom after giving birth (up to 72 hours after) to a Rh positive baby so mom does not produce antibodies.

Homeostasis

Homeostasis is only possible if the cardiovascular system delivers oxygen (lungs) and nutrients (digestive) to the tissue fluid and if it also takes away metabolic wastes. Also the lymphatic system has to return tissue fluid to the bloodstream. The muscular system contributes to moving blood through the cardio system by the cardiac and skelatal muscle contracting which moves blood and lymph through veins. Bones contribute calcium which is essential for blood clotting, and the urinary system even contributes by regulating acid-base and salt-water balance in blood and tissue fluid.

Lymphatic System and Immunity

Microbes, Pathogens, and You

Microbes are microscopic organisms and occur throughout the environment. There are good microbes (ones in yougurt, drugs produced by bacteria, decomposers), and harmful ones that can cause infectious diseases. These are called pathogens. The bodies defense to pathogens are: barriers (skin, membranes), first responders (white blood cells), and specified defenses.

Bacteria are single cell prokaryotes that lack a nucleus. They are bacillus o(round), coccus (sphere), and spirillum (curved) in shape. Some can move with flagella, or stick to surfaces with fimbriae. A pilus allows them to transfer DNA between cells. Bacteria are metabolically competent with DNA in one chromosome in the center of the cell. They might also have additional DNA rings (plasmids). Binary fission is bacteria's method of reproduction.

Viruses are like a bridge between living, and nonliving. Without a host, they are essentially chemical, but they gain life once inside a host. Viruses are acellular and made up of two parts: outer capsid of protein units and an inner core of nucleic acid. A virus gains entry into a specific host cell utilizing a lock and key manner. Viral nucleic acid enters the cell and begins coding for protein units in capsid. They also use host enzymes and ribosomes for their own reproduction

Prions are proteinaceous infectious particles and cause degenerative diseases of the nervous system. (CJD, scrapie, mad cow disease). Apparently transmitted by ingestion of infected brain and nerve tissue. They start out healthy but become diseased when prion proteins change shape (rogue shape). This shape converts other normal prion proteins, and now they don't function due to the changed shape.

The Lymphatic System

This consists of lymphatic vessels and lymphatic organs. Four functions are: lymphatic capillaries absorb any extra tissue fluid and then return it to the bloodstream, lacteals (in the small intestine) absorb lipoproteins and transport these to the bloodstream, produces, maintains and distributes lymphocytes, helps the body defend against pathogens.

The lymphatic vessels form an intricite system of capillaries, vessels and ducts that all work to move lymph to the cardiovascular veins in shoulders. The thoracic duct returns lymph from below the thorax, left arm, side of head and neck. The right lymphatic duct returns lymph from right arm, side of head and neck.

Primary lymphatic organs are:

• Red bone marrow- produces all types of RBC's. Produces neutrophils, eosinophils, basophils, lymphocytes and monocytes


• Thymus gland- produces thymic hormones, and immature T lymphocytes mature here.

Secondary lymphatic organs are:

• Spleen- filters bood. macrophages destroy pathogens and debris before blood exits


• Lymph nodes- filter lymph. lymphocytes fight infection, and macrophages clean up pathogens and debris


• Lymphatic nodules- patches of lymphatic tissue arranged around the pharynx


• Peyer's patches-encounter pathogens that enter the body by way of intestinal tract

Nonspecific Defenses

Immunity is the ability to combat diseases and cancer. The first line of defense is barriers.

• Skin and Mucous Membranes


• Chemical Barriers-secretions of oil glands can weaken and destroy some bacteria. Lysozyme in tears and saliva can wash away bacteria and microbes. pH of stomach can also kill many types of bacteria


• Resident Bacteria- they use available nutrients and release their own waste to prevent other pathogens from moving in.

The second line of defense is inflammatory response

Neutrophils and macrophages are main players in this defense. Inflamation is recognized by redness, heat, swelling and pain. Damaged tissue releases histamine causing dialation and greater permeability of the capillaries. This allows greater blood flow which is seen by reddened skin. This increased flow brings in the WBC's and lets fluid and blood clotting factors to move into the tissues. The pain normally felt is from this extra fluid pressing on nerve endings.

Neutorphils arrive first destroying debris, dead cells and bacteria. Usually they are enough to localize an infection. When injury is minor inflammatory is short and nearby cells work efficiently to secrete growth factors contributing to new growth and repair of the damaged area. If it is a larger infection and neutrophils need help, they secrete cytokines, which attract monocytes to the area. These become macrophages, which can get lymphocytes to help with defense.

Complement system has complement proteins which work with certain immune responses such as the inflammatory response. Some examples are interferons, and the membrane attack complex.

Specific Defenses

Specific defenses respond to antigens( molecules that have been recognized as a foreign body). Lymphocytes differentiate B-cells or T-cells to recognize these antigens. Each of these lymphocytes has only one type of receptor to combine with a particular antigen, so great diversity is needed and occurs during the maturation process.

B-cells' receptor (BCR). An antigen selects, and binds to only one type BCR and then the B-cell makes multiple copies of itself. This works the same way in T-cells. The B-cells clones become plasma cells which are then able to secrete antibodies to that specific antigen. Some of the clones become memory cells acheiving long term immunity. This defense by the B-cells is antibody-mediated immunity.

T-cells cannot recognize an antigen without help, so an antigen-presenting cell (maybe a macrophage) breaks the pathogen apart and displays it on the MHC protein. By linking a foreign antigen to the self protein, it is showing the T-cell how to recognize "foreign" from "self".

Cytotoxic T-cells look for a specific enemy. When the enemy is found, the T-cell releases perforins which puncture the invading cell. Then they release granzymes into the punctures and these kill the invading cell. This is called cell-mediated immunity.

Helper T-cells secrete cytokines to organize and enhance the immune cells response. Memory T-cells remain to jump start an immune reaction if the antigen has been present before.

Aquired Immunity

This occurs through infection or artificially by medical intervention. Active Immunity can develope when someone is infected with a pathogen, or can be artificially introduced by using vaccines. Passive Immunity is when someone is given antibodies or immune cells to combat a diesease, this is temporary because the antibodies have not produced by the indidvidual. There are monoclonal antibodies that that are the same type, produced by the plasma cells that were derived from the same B-cell. Cytokines are signaling molecules that regulate white blood cell production and function.

Hypersensitivity Reactions

These reactions occure when the immune system's response actually harms the body

• Allergies- this is a hypersensitive response to allergens (pollen, food, animal hair) caused by the IgE antibodies. Histamine is released along with other substances which cause the common symptoms of allergies (runny nose and eyes, wheezing) Anaphalactic shock is a more serious response to an allergen that has entered into the blood stream (bee stings, penicillin)
• Tissue Rejection- this occurs when the patients immune system sees the transplanted tissue as "foreign" and cytotoxic t-cell procede to attack
• Immune System Disorders- an autoimmune disease is when cytotoxic T-cells or antibodies attack the person's own cells. The cause of this is still unknown. (MS, SLE, and rheumatoid arthritis are some examples)

Works Cited

Mader, Sylvia. Human Biology 10th ed

Frolich Powerpoint

Links for Pictures

1. http://www.nhlbi.nih.gov/health/dci/images/sickle_cell_image_1.jpg 2.http://faculty.etsu.edu/currie/images/clot.jpg
3. http://connection.lww.com/products/stedmansmedict/primal/primal_24.jpg
This is very good picture of lymphatic system that was too big to put in blogger
4. http://universe-review.ca/I10-13-lymphatic.jpg
5. http://images.medicinenet.com/images/illustrations/heart_attack.jpg
6. http://cache.eb.com/eb/image?id=92807&rendTypeId=34
7. http://www.vanth.org/vibes/images/normalECG2.PNG

Self and Unit Evaluation

REGARDING YOUR OWN PERFORMANCE

1. What were the three aspects of the assignments I've submitted that I am most proud of?
I am most proud of the compendium reviews, the microscope lab, and the genetics lab.

2. What two aspects of my submitted assignments do I believe could have used some improvement?
The cell model definitly could have used some improvement as far as breaking down the aspects more and getting better pictures of everything. Also I would have liked to complete some external research on my ethical issue topic to add into the essay. I feel these sections can be improved, however I also feel that I did the best I could with the time I had.

3. What do I believe my overall grade should be for this unit?
I truly believe that I earned at least a solid B on this unit. There is room for improvement, but I also spent alot of time and hard work putting everything together

4. How could I perform better in the next unit?
I am going to get going on the lab project as soon as possible, so I am not trying to put everything together at the last minute and also try to spend more time on my writing skills.

REGARDING THE UNIT (adapted from Stephen Brookfield, University of St. Thomas "Critical Incident Questionnaire")
At what moment during this unit did you feel most engaged with the course?
I actually felt most engaged while putting together my reviews. When I had to summarize key concepts, and actually write them down (not just read) I felt like I was learning the subjects the best.

At what moment unit did you feel most distanced from the course?
I felt most distanced while completing the cell model. I ran out of time so it ended up being hectic at the end.

What action that anyone (teacher or student) took during this unit that find most affirming and helpful?
The most affirming and helpful action was taken by Mr. Frolich for being able to understand my work schedule and work with me on it.

What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?
I didn't really notice any confusing actions taken this first unit, I think I was too busy trying to get everything done.

What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.)
I think the unit itself surprised me the most. Just looking at the requirements I felt comfortable in being able to complete everything. It wasn't until I actually started the unit work that I realized just how much information and detail this unit went into

Start of Unit Two

This is just the break between Unit One and Unit Two

Human Insulin Produced by Recombinant DNA Technology

The transfer of a DNA fragment from one organism to a self-replicating genetic element is known as recombinant DNA technology. This process is also referred to as DNA cloning, molecular cloning and gene cloning. This process has been around since the 1970s, and today is practiced frequently in molecular biology labs.
One use for this technology is to create insulin, which is used by diabetics who cannot produce enough on their own. Insulin is produced and secreted by the beta cells of the pancreas' islets of Langerhans and functions to regulate the use and storage of food. The old method of creating insulin was to extract and purify abattoir by-product. This method had side effects of immune bodies producing antibodies against it, which in turn made the insulin inaffective.
Researchers eventually came upon the idea of synthesizing Humalin, and recombinant technology was just the method to use.
In the first step, a plasmid is removed from and E. Coli cell. A special enzyme then opens up this plasmid. The DNA coding for human insulin is inserted into the opened plasmid, which is then closed by another special enzyme (recombination). The recombined plasmid is introduced back into the E. Coli host cell where it divides into new identical cells. The implanted DNA stimulates the cell to produce insulin. Human insulin is the only animal protein to have been made in bacteria in such a way that its structure is absolutely identical to that of the natural molecule, thus reducing the possibility of complications resulting from antibody production.
Today, the majority of insulin dependent patients are now treated with genetically engineered recombinant human insulin. However, doctors and patients have become concerned about the increase in the number of hypoglycemic episodes experienced. Some patients have stated that their awareness of oncoming hypogylcemia attacks has decreased sinced switching.
Being able to use the recombinant method to produce human derived insulin has widely been an improvement for the majority of insulin users. Although many are happy with the new insulin, the fact that some people are not happy means that more studies and research needs to be conducted to ensure complication-free use by all.

Cell Model

For my cell model, I used arts and crafts projects that I had around the house. This model shows a few of the important organelles that can be found in real cells. There are 3 pictures to the right. The first one is of my supplies before starting the project. The 2 is of my cell partway through construction. The 3 is the final completed cell.

• Yellow Foam ball- represents the nucleus. The nucleus contains chromosomes and controls the function of the cell.
• Ceran wrap- represents the nuclear membrane. This is a double membrane surrounding the nucleaus while also attatching to the rough ER. The membrane contains pores that allow substances to pass between the nucleus and cytoplasm.
• Colored string- represents chromosomes- these are chromatin condensed into a compact structure. Chromatin are a network of fine threads in the nucleus made up of DNA and proteins.
• Purple twist ties- represent the rough endoplasmic reticulum. This is system of membranes and channels studded with ribosomes. Proteins are synthesized here
• Nails- represent the ribosomes on the rought ER. In the cytoplasm, this is where protein synthesis occurs, they are made up of RNA and protein in subunits
• Sponge- represents the smooth endoplasmic reticulum. This is connected to the rough ER, but is without ribosomes. The smooth ER synthesizes phospholipids
• Orange felt- represent mitochondria. Cellular respiration occurs here, producing ATP for energy
• Bright green twist ties- represent lysosomes. These are vesicles that contain hydrolytic enzymes for digesting macromolecules
• Dark Green twist ties- represent the golgi apparatus, made up of vesicles, and saccules that process, package and distribute molecules from the cell
• Tan twist ties- represent vesicles. These are membrane bound sacs that store substances in the cell
• Blue duct tape- represents the cell membrane. This regulates the exit and entrance of molecules into or out of the cell.

This picture show DNA replication on the left, and transcription on the right. The pink twist tie is the strand of mRNA that is getting the template from the original DNA





This shows the process of translation where the mRNA interacts with ribosomes. The tRNA carries the amino acid to the mRNA where the anti-codon and codon form base pairs and a polypeptide chain is formed.

For me this lab was useful in the fact that I began to understand the concepts better by physically having to put them together, however "making" these models was more difficult for me rather then drawing them. I also did not have as much time as I would have liked to set aside for this project, so I made do with what I had around the house . Overall it was a beneficial lab, and I'm glad it is finished.

Online Lab- Genetics

Genetics is the study of inheritance, how characteristics are passed from one generation to the next (eye color, blood type, ect). A person's genes are inherited from their parents, one set of chromosomes from each parent cell. Gametes are haploid with only one of each chromosome and therefore one of each gene. When two gametes fuse at fertilization the zygote now has two of each gene (that is a pair of alleles for each gene). Where the alleles are different, one may be recessive and the other dominant. The dominant allele will determine the characteristic.




In the dragon lab (as seen on the right) we change the alleles of the bottom dragon, until its phenotype (physical characteristics) matched that of the top dragon. For example, the allele for horns is dominant on chromosome 1a and recessive on chromosome 1b, resulting in horns. These characteristics can be predicted (as far as the probability of one characteristic over another) by using a punnett square. In the square, the allele combination of one parent goes on top, and the other parent goes on the side. This can be seen in the fruitfly lab (on the right), where we discovered the probability of the offspring having long wings versus short wings. When both parents are heterozygous, the offspring have a 75% chance of having the dominant phenotype and a 25% chance of having the recessivie phenotype. Important vocabulary for the section is as follows

• Genotype- refers to the genes of an individual


• Phenotype- characteristic of the individual(long wings, short wings, no legs, horns, scales, ext. Does not necessarily have to be easily observable)


• Allele- alternative forms of a gene having the same position on a pair of chromosomes and affecting the same trait


• Cross-is the inheritance of alleles(When we crossed two heterozygous fruit flys their offspring had the poetential to inherit either Ll(long wing) or ll(short wing) alleles


• Dominant allele- is the allele that exerts it phenotypic effect in heterozygote. It will mask a recessive allele. ( In the case of the dragon, the dominant H masks the recessive h, thus givng the dragon horns)


• Recessive allele-is the allele that exerts it phenotypic effect only in the homozygote.( In the dragon lab the f allele from both chromosomes is recessive, which results in a fire breathing dragon)

Our genetic make-up makes us who we are individually, while giving us a combination of traits handed down from our parents, whose traits were handed down from their parents, ect. The basis of evolution is based off of two facts, that DNA determines the nature of an organism, and also that there are mechanisms that DNA can be modified by. Since DNA makes the organism, and this DNA can be changed, the theory is that if successive changes are passed down to successive offspring, changes in the genetic code could occur over a period of time. In this way, genetics and how they are inherited are very important in todays research.

Works Cited

Genetics and Evolution http://atheism.about.com/library/FAQs/evolution/blfaq_evolution_evidence03.htm

Topic Two Compendium Genetics

Table Of Contents

Human Genetics

• Chromosomes and the Cell Cycle
• Mitosis
• Meiosis
• Comparison of Meiosis and Mitosis
• Chromosome Inheritance

Cancer

• Cancer Cell
• Causes and Prevention of Cancer
• Diagnosis of Cancer
• Treatment of Cancer

Patterns of Genetic Inheritance

• Genotype and Phenotype
• One and Two Trait Inheritance
• Beyond Simple Inheritance Patterns
• Sex-Linked Inheritance

DNA Biology and Technology

• DNA and RNA Structure and Function
• Gene Expression
• Genomics
• DNA Technology

Chapter Eighteen Patterns of Chromomsome Inheritance

Chromosomes and the Cell Cycle

The nucleus contains all the chromatin that condenses to form chromosomes when the cells divide. There are 46 chromosomes (23 pairs). Twenty-two pairs are autosomes and one pair are the sex chromosomes.

A Karyotype can say alot about a body cell. Body cells are diploid, meaning they contain 46 chromosomes. The process of mitosis is responsible for this. In dividing cells, each chromosome is made up of sister chromatids. These chromatids each contain a DNA double helix. A centromere holds the chromatids together until a phase of mitosis where they separate and each chromatid becomes a chromosome. These are now daughter chromosomes that separate giving the new cell a full set of chromosomes.

The cell cylce has two parts

• Interphase- time when organelles carry on usual functions. The cell grows larger, the organelles double, chromatin doubles, and DNA synthesis occurs. Lasts approximately 20hrs. Interphase is divided into three stages G1 (before synthesis), S (includes synthesis), G2 (after synthesis)


• Cell Division- follows interphase, has 2 stages. Mitosis (the sister chromatids separate becoming chromosomes and are distributed to the two daughter nuclei). Cytokinesis (division of the cytoplasm).

The cell cycle happens continuously in certain tissues such as red blood cells, skin cells, and the cells that line the respiratory and digestive tracts. Apoptosis(programmed cell death) does away with any cells that are dividing when they shoudn't be

Mitosis

Is duplication division. The nuclei of the two new cells (daughter cells) have the same number and kind of chromosomes as the cell that divides (parent cell).

The centrosome (microtubule organizing center) is also duplicated. After they are duplicated, they separate and form the poles of the miotic spindle. Here they assemble microtubules to make spindle fibers. The chromosomes are attatched to the spindle fibers at their centromeres.

The centrioles (short cylinders of microtubules present in centrosomes) lie at right angles.

There are four phases of Mitosis

• Prophase- centrosomes have duplicated, spindle fibers appear, nuclear envelope fragments, nucleolus disappears



• Metaphase- nuclear envelope is fragmented, spindle occupies former nucleus region, chromosomes are at the equator.



• Anaphase- separation of the sister chromatids, the 2n number of chromosomes move towards each pole.
  


• Telophase- begins when chromosomes arrive at poles. They become chromatin again, spindle disappears, and nuclear envelope components reassemble in each cell



• Cytokinesis- the division of cytoplasm and organelles started by cleavage furrow.

Meiosis

Is reduction division involving two divisions creating 4 daughter cells. Each daughter cell has one of each kind chromosome (half as many as the parent) This is called haploid, and these daughter cells become gametes. Meiosis ensures chromosome numbers stay constant throughout generations. Also the genetic recombination ensures offspring will be genetically different from each other and from the parents.

At the start, the chromosomes occur in pairs and are called homologous chromosomes. These come together and line up side by side (synapsis). When they separate, the daughter nucleus receives on member of each pair. Interkinesis is this period of time between miosis 1 and 2

In meiosis 2 the centromeres divide and sister chromatids separate. In the end, each of four daughter cells has haploid chromosomes and each chromosome has one chromatid. These daughter cells mature into gametes that will fuse during fertilization. Fertilization will restore the diploid number of chromosomes in the zygote (first cell of the new individual)

There are four stages of Meiosis(they are repeated in meiosis 1 and meiosis 2) These are the same as in Mitosis, with key differences in the first 2 phases

• Prophase 1- synapis occurs, spindle appears, nuclear envelope fragments and nucleolus disappears, the exchange of genetic material occurs between the nonsister chromatids and the homologous pair (crossing over)


• Metaphase 1- homologous pairs align at the equator and the maternal or paternal pair can be oriented at either pole making a possibility of 8 combinations in the resulting gametes.
  

Comparison of Meiosis and Mitosis

Meiosis occurs only in the reproductive organs to produce the gametes. Mitosis occurs in all tissues during growth and repair.

• DNA replication take place only once prior to both. Meiosis needs 2 nuclear divisions instead of one


• Meiosis produces 4 daughter nuclei, and after cytokinesis there are 4 daughter cells, while in mitosis there are only 2


• The 4 daughter cells in meiosis are only haploid while the 2 in mitosis are diploid


• Daughter cells from meiosis are not genetically identical to each other or parent cells, while in mitosis the daughter cell are genetically identical to each other and parents.

Chromosome Inheritance

An individual carries 22 pairs of autosomes and two sex chromosomes. Each pair of autosomes carries alleles for particular traits. When a person ends up with too many or few autosomes or sex chromosomes this is called nondisjunction. Nondisjunction happens during meiosis 1 when both members of a homologous pair go into the same daughter cell, or it can also happen in meiosis 2 when the sister chromatids fail to separate and both daughter chomosomes end up in the same gamete.

• Trisomy- An egg with 24 chromosomes is fertilized by a normal sperm. Only trisomy 21 (Down Syndrome) has a chance of survival after birth. Trisomy in the sex chromosomes has a greater chance of survival. Cells of females function with only one X chromosome( the other is a mass of chromatin called a Barr body). Poly X females and XXY(Klinefelter syndrome) males are seen frequently XYY (Jacobs syndrome) is due to nondisjunction during meiosis2 of spermatogenisis.


• Monosomy-An egg with 22 chromosomes is fertilized by a normal sperm. A zygote with one X chromosome is called Turner syndrome

Changes in chromosome structure is another type of chromosomal mutation

• Deletion- an end of a chromosome breaks off, or two simultaneous breaks lead to the loss of an internal segment
  
• Duplication-presence of a chromosomal segment more than once in same chromosome


• Inversion- segment of chromosome is turned 180
  
• translocation- movement of a chromosome segment to another nonhomologous chromosome
  
  

Chapter 19 Cancer

Cancer Cells

Cancer is really over 100 different diseases, but cancer cells have common characteristics

• Cells lack differentiation- they are non specialized and don't contribute to the functioning of a body part


• Cells have abnormal nuclei- enlarged and may contain an abnormal number of chromosomes. These cells fail to undergo apoptosis


• Cells have unlimited replicative potential- immortal and keep dividing unlimitedly. Telomeres protect the ends of chromosomes and get shorter each time, in cancer telomerase rebuilds telomere sequences, keeping the telomeres at a constant length so the cell can keep dividing.


• Cells form tumors- they do not stop dividing when they come into contact with neighbors


• Cells have no need for growth factors- cancer cells continually divide even when stimulatory growth factors are absent and inspite of inhibitory growth factors.


• Cells gradually become abnormal- the cell has a mutation that causes it to start dividing (initiation). A tumor developes, cells continue to divide and undergo mutations (Promotion). One cell has a selective advantage over the others and is eventually able to invade surrounding tissue ( Progression).


• Cells undergo angiogenesis and metastisis- formation of new blood vessles and the spread of cancer throughout the body from the place of origin

The cell cycle is able occur repeatedly due to mutations in two types of genes, Photo-oncogens (prevent apoptosis and accelerate the cell cycle), and Tumor-suppressor genes (inhibit the cell cycle and promote apoptosis)

The photo-oncogens become oncogens (this is a gain of function mutation and over expression is the result). Also the tumor-suppressor genes become inactive (this is a loss of function mutation)

Types of Cancer

• Carcinomas- epitheal tissues


• Sarcomas- muscle and connective tissue


• Leukemias- blood


• Lymphomas- lymphatic tissue

Causes and Prevention of Cancer

Cancer can be caused by different facters including

• hereditary,


• environmental carcinogens (such as ultraviolet light from sunlight and tanning lamps, radon gas, and nuclear emissions). Also under the environmental category is organic chemicals such as tobacco products which are responsible for 80% of all cancers. Pollutants and viruses (hepatitis B and C, Epstein-Barr and HPV)


• Dietary choices- high fat diets

Diagnosis of Cancer

Tests for cancer include: pap test, mammogram, tumor marker test, tests for gentic mutations, biopsy and imaging.

C hange in bowel of bladder habits

A sore that does not heal

U nusual bleeding or discharge

T hickening or lump in breast or elsewhere

I ndigestion or difficulty in swallowing

O bvious change in wart or mole

N agging cough or hoarsness

Treatment of Cancer

Standard therapies are surgery (effective for CIS), radiation (localized, causes chromosomal breakage and cell cycle disruption), and chemotherapy ( treats the entire body, and whenever possible, chemotherapy is specifically designed for a particular cancer)

Newer therapies are immunotherapy (immune cells are genetically engineered to bear the tumors antigens), p53 therapy(this gene triggers cell death in only cancer cells)

Chapter 2o Patterns of Genetic Inheritance

Genotype and Phenotype

Genotype refers to the genes of the individual. Alleles are alternative forms of a gene having the same position on a pair of chromosomes and affecting the same trait. These are designated by a letter, a capital for dominant allele and lowercase for recessive. Alleles occur in pairs, normally 2 for each trait. (homozygous dominant AA, homozygous recesive(aa), heterozygous (Aa) )

Phenotype is the physical appearance of the individual, for example freckles. The phenotype is not necesarily easily observable, for example color blindness.

One and Two Trait Inheritance

When the chromosomes are reduced in gametogenesis, so are the alleles meaning that the gametes carry only one allele for each trait-no 2 letters in a gamete can be the same letter of the alphabet.

One trait crosses are easily shown through punnett squares. These allow you to figure the chances or probability of an offspring having a certain genotype/phenotype.

In two trait crosses a gamete will receive one short and one long chromosome of either trait. All possible combinations of chromosomes and alleles are in the gametes. The alleles for two genes are on these homologues. A gamete will never have two of the same letter. A dihybrid genotype occurs when an individual is heterozygous in two regards (WsSs)

With genetic diseases there are two types: Autosomal Dominant (alleles AA or Aa) and Autosomal Recessive (aa). Some examples of dominant diseases are: marfan syndrome and huntington disease. Examples of recessive diseases are: tay-sachs disease, cystic fibrosis, phenylketonuria, and sickle cell.

Beyond Simple Inheritance Patterns

Polygenic traits (skin color and height) are governed by more than one set of alleles. Each dominant allele codes for a product , consequently these dominant alleles have a quantitative effect on the phenotype and the effects are additive. This results in continuous variation of phenotypes, with distribution resembling a bellshaped curve.

Incomplete dominance is when the heterozygote is intermediate between two homozygotes (wavy hair). Codominance is when alleles are equally expressed in a heterozygote (blood type AB)

Sex linked Inheritance

An allele on the x chromosome is x-linked and one on the y chromosome is y-linked. Most sex linked alleles are only on the x chromosome. Usually a sex linked disorder is recessive so females must receive a recessive allele from each parent. With x-linked traits, a male only needs to receive the trait from one allele from the mother. Examples are: color blindness, muscular dystrophy, and hemophilia.

DNA Biology and Technology

DNA and RNA Structure and Function

Genetic material must be able to replicate, store information, and undergo mutations to provide genetic variability. DNA is composed of two strands that spiral about each other. Each of these strands is a polynucleotide. These strands run in opposite directions and are attatched by the four bases. DNA replication lets each strand serve as a template for a new strand, thus cutting down on the errors.

RNA is made up of nucleotides containing the sugar ribose (adenine, uracil, cytosine,,and guanine). RNA is single stranded and helps DNA with protein synthesis.

• Ribosomal RNA (rRNA)is produced in the nucleolus and joins with proteins in the cytoplasm to form subunits of ribosomes.
• Messenger RNA (mRNA) is produced in the nucleus can carries genetic information from DNA to the ribosomes
• Transfer RNA (tRNA) is produced in the nucleus and transfers amino acids in proteins.

Gene Expression

The first step is transcription. A strand of mRNA forms complementary to a portion of DNA. The second step is translation. A sequence of nucleotides is translated into amino acids. The genetic code is a triplet code in order to be able to code for at least 20 amino acids.

• Transcription- begins with RNA polymerase which opens the DNA helix in front. RNA polymerase joins the RNA nucleotide to make a mRNA molecule.
• Translation- tRNA brings amino acids to the ribosomes where polypeptide synthesis occurs. Each ribosome has a binding site for mRNA and two sites for 2 tRNA molecules. At the other end of the tRNA is a specific anticoden (group of 3 bases that are complementary to the mRNA codon). Poly peptide synthesis starts with initiation where mRNA binds to smaller ribosomal unit after which the larger unit associates with the smaller. Elongation means the polypeptide lengthens and incoming tRNA complex arrives at the A site and receives the peptide from outgoing tRNA. Termination occurs at a codon, that does not code for an amino acid, and teh ribosome dissociates into the two sub units and falls off the mRNA molecule.

There are a variety of factors that mechanisms regulate gene expression. These are sectioned in 4 levels of control. Two for the nucleus and two for the cytoplasm

• Transcriptional Control- in the nucleus, regulates what genes and how fast transcription occus
• Posttranscriptional Control- in the nucleus, affects how the mRNA is processed before exiting the nucleus and how fast the mature mRNA leaves
• Translational control- in the cytoplasm, before there is a protein product, this controls the life expectancy of mRNA
• Postranslational control- in the cytoplasm, after protein synthesis, the polypeptide product may have to undergo more changes before it become biologically functional.

Genomics

This is the study of genomes. Due to the Human Genome Project they were able to find the order of A, T, C, and G in our genome. Genome size is not proportionate to the number of genes and does not correlate to the complexity of the organism.

Functional genomics works to find out how the 25000 genes function in cells, and how they work to create a human being. Proteomics is the study of the structure, function, and interaction of cellular proteins. Bioinformatics is the application of computer technologies to the study of genome.

Gene therepy can be used to modify a person's genome by inserting genetic material into human cells to treat a disorder. This is done either by Ex vivo gene therapy is outside the body and in vivo gene therapy is inside the body. Gene therapy is growing more popular as a part of cancer therapy to make healthy cells more tolerant and tumor more vulnerable.

DNA technology

Genes can be isolate and cloned using recombiant DNA. To create this the technician needs a vector (a way the gene of interest is introduced to a host cell). A restriction enzyme cleaves, human DNA and plasmid DNA. Then the enzyme DNA ligase is used to seal foreign DNA into the opening created in the plasmid. Bacterial cells take up the plasmid alowing gene cloning to occur as the plasmid replicates. The bacterium is transformed and can now make a product (such as insulin) that it was unable to make before.

Specific DNA sequences can be cloned. The polymerase chain reaction can create copies of a segment of DNA. PCR requires the use of DNA polymerase and a supply of nucleotides for the new DNA stands. Advances in DNA technology is rapidly moving towards coming up with solutions for curing diseases and new ways of fighting cancer.

Works Cited

Mader, Sylvia Human Biology 10th edition

Frolich Power Points

Links for Pictures

1. http://www.accessexcellence.org/RC/VL/GG/images/protein_synthesis.gif
2. http://www.allthingsbeautiful.com/all_things_beautiful/images/metastasizing_cancer.jpg
3. http://www.tobacco-facts.info/images/chest_x-ray_lung-cancer.jpg
4. http://upload.wikimedia.org/wikipedia/commons/archive/5/56/20061004031648!%20Macs_killing_cancer_cell.jpg
5. http://www.allthingsbeautiful.com/all_things_beautiful/images/metastasizing_cancer.jpg