Self Evaluation: Unit 2

I am glad this unit is over. I had a hard time getting through it ( my own fault) and I was grateful that we had an extra week.

I am most proud of the the major lab and I am also proud of the compendium reviews. Thirdly I am glad that I finished... it is currently 11:50 pm on Friday, October 24th. Obviously I could pace myself better so I am not trying to finish everything at the last minute. I am a rotten speller and rely upon spellcheck more then I should. I was having trouble with the spellcheck on my blog so it I was using Word and pasting onto the blog which was time consuming.

I tried to follow the guidelines to do A work but it may seem somewhat rushed. Also this evaluation may not be posted before the clock strikes 12.*sigh*

I felt most engaged in the course while doing the major lab assignment. It was interesting to me and I really got into it. I felt most distanced while my husband was getting his third round of chemotherapy, he was very sick and I could not think of anything else.

I am really enjoying the class and the content. I think the course is very well put together and the website is easy to navigate. Nothing that anyone did confused me but I will say that glycolysis and the Krebs cycle makes my head explode. We don't have to look at that again do we?

The ethical issues topic and the idea of nutritionisn were very interesting to me. I was surprised at how interesting I found the subject to be.

Compendium Review: Nutrition

Photo of fresh fruits and veggies taken from http://www.firodiyaheartfoundation.org/Health%20Tips.html

I. Introduction

II. Digestive System

• Digestion
• Parts of the Digestive System
• Problems

III. Glycolysis and the Krebs cycle

IV. Nutrition

• Classes of nutrients
• Minerals
• Vitamins

V. What is "healthy" food anyway?

VI. Conclusion

Introduction

We have all heard the phrase "you are what you eat," and I guess to some extent this statement is true. Obviously what we eat goes through the digestive system and the useful components, vitamins, minerals, proteins, fats and Carbohydrates are broken down and used by the body. Everything else is sent out of the body as waste. So how does the digestive system work? How are nutrients taken from our food and used? What foods are good for us and what should we stay away from?

Digestive System

Digestion

Many of us eat for pleasure, I know I do, but we also need to eat in order to survive. The food that we take in is composed primarily of carbohydrates, fats, and proteins, which are the macromolecules necessary for life. The purpose of digestion is to break down the food that we eat into single unit molecules like sugars, and amino acids. Ingestion is what we take in, in other words what we eat. Digestion is both mechanical and chemical. Mechanical digestion is the process of making food small enough to be acted upon by the digestive enzymes. Most of this process happens in the mouth and stomach. Digestive enzymes are a large part of chemical digestion, these enzymes hydrolyze food into molecular units. The partly digested food with a semi fluid consistency that is passed from the stomach to the small intestine is known as chime. The contents of the GI tract moves from one organ to the next and those components that could not be digested are eliminated. Unit molecules are absorbed into the cells lining the tract and nutrients enter the bloodstream.

A graphic showing the digestive tract, taken from http://www.stjohn.org/images/Content/digestive_tract.gif

Parts of the Digestive System

The mouth is the beginning of the digestive tract, mechanical digestion begins here when we chew up our food. Saliva, containing bicarbonate and enzyme begins the process of chemical digestion. After the mouth, food enters a cavity called the pharynx and then enters the esophagus. the esophagus is a long narrow tube that leads to the stomach.

It is in the stomach and the small intestine that digestion is completed. The stomach is an organ that is located on the left side of the body just below the diaphragm.The stomach is responsible for initiating the digestion of protein, storing food, and moving chyme to the small intestine. It takes approximately 2-6 hours for food (chyme) to leave the stomach.

As I said before, digestion is completed in the small intestine. The small intestine is about 18 inches long, and contains enzymes to digest all types of food.The enzymes enter the small intestine after being secreted by the pancreas via the duodenum. A duct brings in bile from the liver and gallbladder to emulsify fat.

There are three accessory organs of the digestive system that I will discuss briefly here.

Pancreas: The pancreas is an endocrine gland with the purpose of secreting insulin into the blood. Insulin is a hormone that is produced when the blood glucose level rises. Insulin brings the glucose level under control. Pancreatic juice is sent into the duodenum containing sodium bicarbonate and digestive enzymes.

Liver: The liver is a large storage organ. The liver removes iron and vitamins A,D,E, K, and B12 from the blood and stores them. Glucose and glycogen are also stored in the liver in the presence of insulin. The liver also forms urea which is a waste product.

Gallbladder: A pear-shaped organ just below the liver that stores bile.

The cecum, colon, rectum, and anal canal are all part of the large intestine. The large intestine has the function of absorbing water preventing dehydration. There are no digestive enzymes in the large intestine and it does not absorb nutrients. Feces are formed in the large intestine, enter the rectum and defecated through the anus.

Problems

There are several disorders and problems linked to the digestive system and its various organs I will discuss a few of them here.

Lactose Intolerance: When a person does not have the enzyme lactase, they cannot digest lactose which is the primary sugar in milk. People with lactose intolerance may experience diarrhea, bloating, gas, and abdominal cramps.

Diabetes Mellitus: This condition is caused by a deficiency of insulin production and a failure of cells to take up glucose. People who have diabetes will have a high blood glucose level and will "spill" glucose in the urine. There is diabetes type 1 and type 2.

Hepatitis: Inflammation of the liver. There are several forms of viral hepatitis. Hep A is fecal-oral and is acquired through sewage contaminated drinking water. Hep B is sexually transmitted or spread through contaminated blood. Hep C is also spread through contaminated blood.

Disorders of the colon and rectum: There are several disorders of the colon and rectum including diarrhea, constipation, and hemorrhoids. These problems are usually minor and temporary however they can also be symptoms of other problems like cancer or irritable bowel syndrome.

Glycolysis and the Krebs Cycle

A graphic of Glycolysis and the Krebs cycle taken fro Professor Frolich's presentation.

Glycolysis and the Krebs cycle are the main way the cells make ATP. As we learned in the last unit, ATP provides energy and this process occurs in the mitochondria of the cell. Glucose is the reactant for this process. Glucose is diffused through the cell membrane. Insulin, produced by the pancreas, stimulates cells to pick up glucose to be used in cellular metabolism. Sometimes glucose is stored as glycogen in the liver or muscle.

I will tell you, I watched the videos on the web links on this subject and it is a bit over my head!

Table taken from Professor Frolich's power point illustrating what happens to food after it is digested and how it is used by the body.

Nutrition

Classes of Nutrients

A nutrient is a component of food and is used to perform a physiological function of the body. The purpose of nutrients is to give us energy, promote growth and development, and regulate cellular metabolism. Carbohydrates, proteins, and lipids, "the molecules of life' are where we get most of our nutrients. Basically people need a balanced diet with a variety of different foods for good health

I get frustrated with foo guides because they are always changing and vary depending on culture. I appreciated the web link showing the pyramids for different cultures.. The one above is from the textbook, Human Biology page 164, Sylvia S. Mader

Carbohydrates: The preferred energy source of the body is carbohydrates. Plants are a good source of Carbohydrates. Carbohydrates can be simple or complex. Products made from refined grains like white bread and cakes should be minimized in the diet because processing causes these products to lose much of their nutritional value.

I am mostly including this picture because I like the way it looks, it is appetizing to me. The foods above are rich in fiber and carbohydrates, Human Biology, page 158. Sylvia S. Mader.

Proteins: Proteins become amino acids which cells use to synthesize cellular proteins. There are 20 different amino acids and 8 of them are essential and must be a part of the diet. Food taken from animals like eggs, milk, and meat contain all the amino acids needed. Protein can also be found in legumes, seeds, and nuts however alone each is an incomplete protein source. If one essential amino acid is missing, it will prevent the use of the other 19 amino acids.

Lipids: Cholesterol, fats, and oils are all lipids. Those lipids that are solid at room temperature are called saturated fats, for example butter. Oils have unsaturated fatty acids. Remember lipids are used in forming plasma membranes.

Minerals

Certain minerals are required in the diet. There are major minerals and trace minerals. Major minerals are structural components of tissues. and trace minerals are parts of larger molecules. Iron is an example of a mineral that our bodies need, so is calcium. Lack of these minerals can lead to deficiencies like anemia. or osteoporosis. Below is a mineral table from the textbook.

Mineral chart showing different minerals, the sources, and conditions caused by too much or too little. Human Biology, page 161. Sylvia S. Mader

Vitamins

Unlike minerals, vitamins are organic compounds that are used by the body for metabolic purposes. The body is unable to adequately produce these compounds on its own. There are fat soluble vitamins that are stored in the liver, and water soluble vitamins. Deficiencies due to lack of certain vitamins can lead to illnesses like scurvy or rickets.

The above to tables give a listing of vitamins, fat soluble and water soluble. Sources and conditions associated with different vitamins are also listed. Human Biology page 163, Sylvia S. Mader

What is healthy food anyway?

Briefly I wanted to acknowledge Professor Frolich's short portion in the presentation regarding the nutritionism approach. I am not going to talk a lot about this as I covered much of it in the ethical issues essay. What I will say that it had never occurred to me that we need to look at food as food and not nutrients. As I mentioned in my essay, I do not have any health problems or weight issues so I did not always to look at labels. However I did worry that my children might not get all the nutrients they needed and would buy food items with packages proclaiming "vitamin fortified" or "extra C" for that very reason. In some ways I now see that I did them a disservice as my son especially is adverse to eating most fresh fruits and vegetables. I wonder if this is caused by his comfort level being conditioned toward the packaged foods. Remember in Supersize Me where the filmographer talked about an addictive component to McDonald's food? I wonder if that is true of packaged food as well.

I will also say that I have never thought of food as a spiritual experience. I do have have cravings, mostly for fresh vegetables which I thoroughly enjoy. I do know that I am not satisfied with just eating quick meals all the time and I feel happiest when I have cooked something from scratch using whole foods. An example of this is the traditional Thanksgiving meal. About two years ago my daughter and I were watching a morning news program about cooking yams and making your own cranberry sauce. Well we decided to try it ourselves and guess what, our yams and cranberries tasted way better than what comes out of the can, and we felt like we accomplished something.

I found this cute kid's website and thought I would include these cartoons from it. The website deals with making good food choices and it even talks about buying food locally and staying away from processed foods. http://tiki.oneworld.net/food/home.html

Conclusion

There are so many differing opinions out there about food and nutrition that trying to eat healthy can be a confusing experience. The best advice I have heard is just simply to eat a variety of foods from all food groups. Unfortunately Americans often think of food as almost a form of entertainment rather than looking at it as a basic human need. We want our food to be attractive and we are easily influenced by advertising. We are also in a hurry all the time. They say it takes three years to break a habit and I know I have a fast/processed food habit. I have just begun to work on making changes...two years, nine months to go.

Works Cited

Human Biology, Sylvia S. mader

Nutrition presentation, Professor Frolich

tiki.oneworld.net/food/home.html

www.firodiyaheartfoundation.org/Health%20Tips...

http://www.stjohn.org/

Ethical Issues Essay: What is Food?

I have a confession to make…I have never dieted, never counted a calorie, and never looked in the mirror worrying about my weight. This is a difficult subject for me to discuss as my weight is often a conversation piece. “How do you stay so skinny?” or “Don’t you eat?” are common questions I am asked. This presents somewhat of a dilemma. If I say, “That’s just the way I am” it sounds vain. If I admit that I love food and eat quite heartily I am bragging and appear insensitive. Shrugging has become my token response.

So what does this have to do with the topic? Well a lot actually. We know that people can have health issues no matter what their weight right? For example as a tall, thin woman with a family history of osteoporosis I have a higher chance of suffering from this condition. I also have to watch my blood pressure as I have an affinity for salty foods. Another issue is my teeth, what I eat will have a direct impact on my teeth, which I want to keep healthy. Lastly, and maybe of greatest concern is my family, as the resident cook, I have an important responsibility in providing healthy well-balanced meals.

So I am going to use this essay as an opportunity to share on a topic that I am usually mum about, my experience with food. I will preface this by saying that the topic is an issue that is most timely considering my husband was just recently diagnosed with hypertension and cancer, two conditions that some say are at the very least impacted (positively or negatively) by diet.

First off, my mother is a relatively good cook. She cooked primarily from scratch and we ate a variety of foods, including fruits and vegetables. Meat was probably the center of our diet and we did eat a lot of ground beef. We seldom ate at the table together but we almost always had a complete meal. I do not remember eating a morning meal on a regular basis and by the time I was in high school I had given up on breakfast altogether. Candy was rationed and so was soda, for my siblings and me anyway.

One thing that really sticks in my mind is soda. My mother was never without her Diet Pepsi, she bought upwards of eight 2 liter bottles of the stuff a week. She also smoked a pack of cigarettes (More Menthols) a day. When I left for school in the morning she would be sitting on the end of the couch smoking and drinking Pepsi, when I got home she was usually in the same exact spot.

So how has my childhood experience with food affected my adult food habits? First off, I do not smoke and I rarely drink soda. I do however have a weakness for candy, particularly the sour kind. I thoroughly enjoy fruits and vegetables and eat fresh greens almost everyday. I still skip breakfast about a third of the time, but most days I have at the minimum a yogurt or banana. I am very physically active and at the age of 39 have no chronic conditions. Sounds good right? Wrong… there is a rotten apple in this picture, it is called time.

Evening meals in our family are frenzied affairs. My husband is out most evenings with church activities and my two children are often busy with their own schedules. So, in order to make all of our appointments our family often resorts to quick meals. I mean Spaghettios, Top Ramen, Mac and Cheese, and from time to time, Taco Bell or McDonalds. Don’t get me wrong I do cook a traditional meal about 2-3 times a week but even on those days the meal may include canned green beans or a package of fast cooking chicken-flavored rice. Now mind you this diet was never a concern for me before. I mean, we always have fresh fruits available and they seem to disappear after only a few days. My kids do not willingly eat salads but they do get some kind of vegetable everyday. What could be the harm?

Well here it comes; two things niggle at the back of my mind. First, what is actually in the foods we are consuming? I know that most of our food travels a great distance to get on our supermarket shelves. What is in that food that keeps it from spoiling? I once read an article talking about how far food travels to get to the local supermarket and I wondered what harm additives and preservatives in that food might do to the body. How do we know they are not harmful? My daughter is 10 years old and is already hitting puberty, I hit puberty at 15. I can’t help but wonder if it has to do with hormones in the milk or meat she consumes.

An example of a particularly convenient "food" is the fruit snack, Years ago I discovered these squishy, sweet tasting, pellets that come in boxes of 6 – 12 pouches. What I liked about them is that they supposedly contain a full day’s vitamin C. As an added bonus you can even get fruit snacks in the shape of Sponge Bob or Scooby Doo. SCORE! They are nutritious and my children liked them. Now fruit snacks are not actually food in the literal sense are they? Also, what else is in them? If you bury a fruit snack in the ground I wonder how long it would take for it to dissolve. Needless to say, I have stopped buying fruit snacks.

The second thing that worries me is the rise in cancer cases. Now I do not have figures on this but I will tell you that when my husband was diagnosed with cancer I could not help but wonder. He does not smoke, he does not drink, he does not work around chemicals, and he eats a (somewhat) well balanced diet, so why does he have cancer. No one knows. What I do know is that he eats a lot of processed foods, products high in salt and preservatives.

I guess my point in all this rambling is that we sacrifice a lot for the sake of convenience. It used to be you knew the people growing your food or you grew it yourself. Now we are lucky if our food comes from the same continent as the one we live on.

Since my husband’s diagnosis I have been making gradual changes. I actually look at labels now. I am working towards reducing the amount of canned and processed food we consume as a family. We grew our own tomatoes and peaches this year and are planning to expand our garden next year. I am also making fresh vegetables more accessible to my children as snacks. I have also discovered that the Crockpot is a wonderful invention.

Habits do not change overnight and the American diet was not formed in a day. I think as people become more informed they will make gradual changes. Who knows, current events may even force us to reconsider how and where we purchase our food.

Unit II- Compendium Review: Oxygen, Microbes, Immunity

For movement( like in running), our muscles need oxygen. How do they get it? This question will be answered in this compendium review. Photo from: www.sheknows.com/articles/803849.htm

I. Introduction to Cardiovascular System

II. Heart and Blood Vessels

• Types of Blood Vessels
• Heart
• Two Pathways
• Capillary Exchange
• Disorders

III. Blood

• Function and Composition
• Red blood Cells
• Platelets
• White Blood Cells

IV. Lymphatic System: Immunity

• Microbes and Pathogens
• Lymphatic system and Organs
• Nonspecific Defenses
• Specific Defenses
• Acquired Immunity
• Problems and Disorders

V. AIDS

• What is it?
• Where did it come from and where is it now?
• Phases
• Structure and life Cycle

VI. Conclusion

The cardiovascular system. Human Biology Page 86, Sylvia S. Mader

I. Introduction

The cardiovascular system transports blood throughout the body and consists of the heart and blood vessels. The heart pumps the blood and blood vessels are the passage ways through which the blood flows. Blood transports oxygen, nutrients and waste products in and out of the body. The lymphatic system aids the cardiovascular system by collecting excess tissue fluid in the lymphatic vessels and returning it to the cardiovascular system. Fluid in lymphatic vessels is called lymph. To maintain homeostasis it is essential that these systems work together. Certain disorders like Sickle Cell Anemia or viruses like HIV can disrupt normal operations of these systems and therefore interfere with homeostasis. In the following paragraphs I will discuss the functions, organs, tissues, and disorders related to these systems.

II.Heart and Blood Vessels

Types of Blood Vessels

There are three types of blood vessels, arteries, capillaries, and veins. The arteries carry oxygen rich blood from the heart. Arteries have three layers that provide support when blood enters under pressure. Arterioles are smaller arteries that branch into capillaries. Capillaries are the smallest blood vessels and are present in all regions of the body. It is in the capillaries that diffusion occurs, that exchange of substances like oxygen, nutrients, and carbon dioxide. After leaving the capillaries, oxygen poor blood enters venules which join with veins leading back to the heart.

The drawing above illustrates a capillary bed. The red tube illustrates an artery and the blue tube is a vein. In between is the capillary bed. There is also a close up on the right. Human Biology, page 87. Sylvia S. Mader

Heart

The heart is a muscular organ located between the lungs. The heart pumps blood and is composed primarily of cardiac muscle. Inside the heart, the septum separates the heart into a right and left side There are for chambers within the heart, the upper chambers are the atria, the lower are the ventricles. There are also valves that keep blood flowing in the correct direction.

It is said that the heart is a double pump. This is because the right ventricle sends blood through the lungs and the left ventricle sends blood through the body.Oxygen poor blood never mixes with oxygen rich blood. Blood must go through the lungs before passing from the right side to the left side of the heart.

A heartbeat is known as a cardiac cycle. During a cycle first the two atria contract and then the two ventricles contract.The working phase known, as the systole, refers to the contraction of the chambers, while diastole refers to the resting phase. The SA node helps keep the heart regular. An electrocardiogram is used to irregularities in heart rhythm.

An illustration of the outside of the heart, taken from www.ynhh.org/cardiac/heart/

Inside of the heart

www.ynhh.org/cardiac/heart/

A person can monitor their own heart rate by taking their pulse. This can be done at the radial or carotid artery. The average adult heart rate is somewhere between 60 and 80 beats per minute. The pressure of blood against a blood vessel is called blood pressure and is measured by a sphygomanometer. Systolic pressure is the highest arterial pressure and the diastolic pressure occurs when the ventricles are in the resting phase. A normal resting adult blood pressure is about 120/80 although these numbers can vary from person to person.

Illustration of locations for measuring pulse. Human Biology, page 92. Sylvia S. Mader

Two Pathways

The pulmonary circuit circulates blood through the lungs, and the systemic circuit caters to the needs of the body tissues. The purpose of the pulmonary circuit , if I am understanding it correctly, is to take blood that is O2 poor through the lungs which then enters the left atrium (now oxygen rich) and then is pumped through the body. The systemic circuit is where exchanges with tissue fluid occur and involves all the arteries and veins shown in the figure below. The aorta, the largest artery, receives blood from the heart, and the superior and inferior venae cavae return blood to the heart.

I appreciated this diagram and it was especially useful in identifying the two cardiovascular pathways. Human Biology, page 94. Sylvia S. Mader

Capillary Exchange

As I mentioned before, exchange occurs in the capillaries. This occurs in the midsection with molecules like oxygen and glucose, following their concentration gradients, end exiting the capillary, while wastes and CO2 diffuse into the capillary. Movement of fluid is controlled by blood pressure and osmotic pressure. Blood pressure is higher at the arterial end of the capillary causing water to exit. At the venous end, osmotic pressure is higher, causing water to diffuse into the capillary. At this end almost the same amount that diffused out on the arterial end diffuses into the capillary.

A diagram illustrating capillary exchange. Human Biology, page 96. Sylvia S. Mader

Disorders

It seems like we hear so much about more sensational diseases but the fact is cardiovascular disorders like hypertension, heart attack, and stroke, are the leading cause of death in the USA.

High blood pressure (AKA hypertension) happens when blood moves through the arteries at a higher than normal pressure. As stated before, a normal adult blood pressure is around 120/80. A person has hypertension if the systolic reading is consistently above 140 and/or the diastolic is consistently above 90. It is not unusual for individuals with atherosclerosis, plaque in the arteries, to suffer from hypertension. Unfortunately people with this condition can be asymptomatic for for a long time before the problem is discovered.

Sometimes when plaque is present a clot called a thrombus can form on the arterial wall. If the the clot becomes a thromboembolism, complications like stroke, heart attack, or aneurysm can occur. All three of these are associated with hypertension and atherosclerosis, and all three can result in death. A stoke occurs in the brain and often happens because a cranial arteriole bursts or is blocked by an embolus. A heart attack (AKA myocardial infarction) occurs when a part of the heart muscle dies because of a lack of oxygen. An aneurysm is caused by a ballooning blood vessel.

Diet and physical activity play a role in cardiovascular disease. A sedentary lifestyle and high fat diet can increase the risk of these conditions. Smoking and obesity are also factors. Sometimes individuals have a hereditary predisposition for these kinds of disorders as well.

There are other disorders of the cardiovascular system like heat failure, heart transplants,and dissolving blood clots that are not detailed here.

I got this picture from the National Geographic website, it is an image of red blood cells. http://science.nationalgeographic.com/science/health-and-human-body.html

III Blood

Function and Composition

We already learned in the last unit that blood is a connective tissue. Our bodies contain approximately 5 liters of this fluid. There are three basic functions of blood, transport, defense, and regulation.

Transport: Blood has the role of delivering oxygen and nutrients to the tissues. It also serves in the role of garbage collector, picking up CO2 and other wastes.

Defense: The blood contains certain cells that are able to destroy pathogens and other harmful substances. Some of these cells also produce antibodies that are able to incapacitate pathogens for destruction. The blood is also capable of clotting when an injury occurs which prevents blood loss.

Regulation: The blood assists in regulating body temperature. Blood also helps to maintain its own water-salt balance. Therefore, blood plays a role in homeostasis.

The blood is composed of cells and cell fragments (known as formed elements) suspended in a liquid called plasma. The formed elements include red blood cells, white blood cells, and platelets. These elements are produced in red bone marrow. The liquid medium carrying different substances in the blood is known as plasma. Plasma is 91% water with 9% consisting of various salts and other organic molecules. There are three major types of plasma proteins, albumins, globulins, and fibrinogen.

Diagram showing the different types of blood cells produced by stem cells in the bone marrow, page 106. Human Biology, Sylvia S. Mader

Red Blood Cells

Red Blood cells (RBCs) are produced in the bone marrow by stem cells. RBCs are very specially designed to transport oxygen. They do not contain a nucleus, but instead contain hemoglobin, a pigment that is responsible for giving red blood cells and blood a red color. There are about 4-6 million RBCs in every cubed mm of blood! An estimated 2 million red blood cells are destroyed per second in the liver and spleen. Sometimes individuals do not have enough hemoglobin or an insufficient number of red blood cells, this condition is called anemia.

It is the shape of red blood cells that makes them specially suited to carry oxygen. The lack of a nucleus helps create their biconcave shape. In sickle cell disease, red blood cells have an irregular shape and tend to rupture when they pass through narrow capillaries.

This is a photo of sickle cells I found at www.nlm.nih.gov/.../ency/imagepages/1223.htm

Hemoglobin transports about 25% of CO2 and 7% is dissolved in plasma. The remaining 68% is transported as the bicarbonate ion in the plasma. When it reaches the lungs (via blood), CO2 diffuses out of the blood.

Platelets

Everyday our bodies produce 200 billion platelets. Platelets/thrombocytes are responsible for causing blood to coagulate and clot. When a blood vessel is broken, platelets will clump together at the site of the damage and form a seal. Larger punctures or cuts may require a blood clot to prevent further bleeding. My father suffers from a condition called ITP, Idiopathic thrombocytopenic purpura, his platelets are extremely low and it seems to have something to do with his antibodies attacking his platelets. He is at a high risk if he is injured because of his low platelet count. Another blood clotting disorder is Hemophilia, which is genetic.

White Blood Cells

White blood cells (AKA leukocytes) fight infection. Many of them are phagocytic, meaning they can engulf and destroy pathogens. These cells are larger than RBCs, contain a nucleus, lack hemoglobin, and are translucent. There are also fewer white blood cells than RBCs. There are several different types of white blood cells and they are regulated by a protein called a colony stimulating factor. The two classifications for white blood cells are granular leukocytes and agranular leukocytes. This is because some have noticeable granules and some do not.

Granular Leukocytes: Neutophils, eosinophils, and Basophils are all granular leukocytes. 50-70 percent of all white blood cells are neutrophils, making them the most common white blood cells. Neutrophils are phagocytic and usually respond first to a a bacterial infection. Their death after fighting an infection results in pus.

Not much is known about the function of eosinophils, but they do have a role in dealing with an allergic reaction or fighting a parasitic worm infection.

Basophils have a U-shaped nucleus and become a blue color when stained. Basophils work in the connective tissues to release histamine during a allergic reaction. Histimine works to dialate the blood vessels but also constricts the air tubes leading to the lungs.

Agranular Leukocytes: Lymphocytes and monocytes are agranular leukocytes. They do not have granules and their nonlobular nucleus has caused them to be called mononuclear leukocytes.

Monocytes can be found in the tissues where they differentiate into macrophages, and are the largest of the white blood cells.. In the skin they become dendritic cells. Macropgages and dendritic cells phagocytize old cells, cellular debris, and pathogens as well. They can also stimulate other white blood cells to come to the body's defense.

Here is a macrophage engulphing invading microbes, taken from Professor Frolich's power point.

Lymphocytes are the white blood cells responsible for specific immunity to different poisons and pathogens. Lymphocytes can be B-cells or T-cells. The descendants of B-cells (AKA plasma cells) produce antibodies. Antibodies are proteins that combine with certain pathogens, marking them for destruction. Cytotoxic T-cells directly destroy pathogens, and the AIDS virus attacks T-cells affecting an individual's ability to fight infection.

Lymphatic System and Immunity

Microbes and Pathogens

Our bodies need to have defenses against pathogens like bacteria and viruses. Bacteria are prokaryotes and do not have a nucleus. Bacteria are the most abundant lifeform on the planet and most do not actually cause disease. However some can be harmful and even kill us. Strep throat, syphilis, and tuberculosis are bacterial diseases.

Viruses are acellular and cannot live independently of cells. Diseases like colds, flus, measles, and AIDS are caused by viruses. Virus particles are significantly smaller than bacteria. There are two parts to viruses, the outer capsid and an inner core of nucleic acid. Although there are many different viruses, they all have these two subunits. Viruses take over the metabolic machinery of the host cell. Once inside a host cell, the virus relies on that cell's enzymes and ribosomes to reproduce.

Examples of viruses, adenoviruses cause colds and influenza viruses cause the flu. Notice that although different, both contain the two subunits, page 123. Human Biology, Sylvia S. Mader

Lymphatic System and Organs

The lymphatic system includes the lymphatic vessels and the lymphatic organs. The vessels form a system consisting of capillaries, vessels, and ducts that carry lymph to cardiovascular veins in the shoulders. The lymphatic capillaries take up excess tissue fluid. The fluid inside lymphatic vessels is colorless and called lymph. There are two ducts in the lymphatic system, the thoracic duct and the right lymphatic duct.

There are primary lymphatic organs like red bone marrow and the thymus gland, and secondary organs which are the lymph nodes and spleen. The red bone marrow is where white blood cells mature while the spleen and lymph nodes are staging areas. The spleen is the largest lymphatic organ and filters the blood. Lymph nodes filter lymph. Lymph nodes can be found at various sites throughout the body including armpits and at the groin area. Lymph nodes around the neck will sometimes swell up when an infection is present.

Nonspecific Defenses

Nonspecific defenses include barriers to entry and the inflammatory response.

The skin is a very effective barrier to pathogens. Of course a cut or abrasion causes a tear in that barrier and can provide access to pathogens. Mucous membranes found in the respiratory, digestive, urinary, and reproductive tracts also serve as barriers to infection.

Chemical barriers also provide nonspecific defense. Chemical barriers are found in secretions from the oil glands in our skin. The secretions from these sebaceous glands contain chemicals that can weaken or even kill bacteria. Lysozyme is found in saliva, tears, and perspiration and it also kills bacteria. Stomach acid kills or stops the growth of many types of bacteria.

There are certain kinds of bacteria that normally live in the mouth, intestine, and other parts of the body. These bacteria consume nutrients and cause waste that prevent harmful bacteria from living there. This actually makes these bacteria a nonspecific defense.

Specific Defenses

Specific defenses are important when nonspecific defenses are unable to prevent an infection. Once an antigen has gained entrance to the body, specific defenses go to work to destroy it. Specific defenses also work to protect us from cancer. Lymphocytes, B and T cells, are the main players in specific defense. These cells recognize invading antigens by using their specific antigen receptors. The shape of these receptors allows B and T cells to combine with the antigen. Each Lymphocyte has only one type of receptor, therefore we need lots of different B and T cells to protect us from all the different antigens that exist in this world. It is amazing to me that our bodies have this ability! In 1987 (the year I graduated from high school), Susumu Tonegawa won the nobel prize for his findings regarding antibody diversity.

B and T cells differentiate into other types of cells to play different roles in fighting disease. For example, B cells become Plasma cells and memory B cells. B cells with a receptor for a particular antigen are stimulated to clone themselve, most of those cloned B cells become plasma cells and some become memory B cells. Plasma cells produce antibodies and memory cells help create long term immunity. B cell defense is known as antibody mediated immunity.

Antibodies are Y-shaped protein molecules with antigen binding sites at the tips of the Y. Each arm of the antibody includes a "heavy" polypeptide chain and a "light" polypeptide chain. There are constant regions for these chains located in the trunk of the Y where the amino acid sequence is set.

A picture of an antibody taken from www.jdaross.cwc.net/humoral_immunity.htm

There are five classes of circulating antibodies. IgG antibodies are the main type in circulation, they even cross the placenta from the mother to the fetus. IgM antibodies are pentamers (clusters of five Y-shaped molecules linked together) and are the largest in circulation. They are the first antibody formed by newborns and the first formed with a new infection. IgA antibodies have two Y-shaped structures and are found in body secretions like saliva and milk. IgD antibodies are found on the surface of immature B cells. IgE antibodies are antigen receptors on basophils and are responsible for fighting off parasitic worm infections and have a role in allergic reactions.

T cells directly attack diseased cells and cancer cells, this is known as cell-mediated immunity. T cells have a unique T cell receptor, similar to B cells. However T cells could not recognize antigens without the help of an antigen-presenting cell (APC) like a macrophage. After an APC has phagocytized a pathogen, it travels to a lymph node or the spleen where there are T cells. By displaying the foreign protein on its surface, the APC is able to "activate" the T cell (and its offspring) to recognize the pathogen. Cytotoxic T cell are the ones that go out and actually destroy the pathogens, they are also responsible for cell-mediated immunity. Helper T cells regulate immunity by secreting cytokines, which are chemicals that enhance the response to immune cells. Helper T cells do not fight infections directly. Memory T cells (like memory B cells) remember the antigen and can start an immune reaction to an antigen that was previously present in the body.

Diagrams of the different kinds of B and T cells. Figure on the left shows B cells and the one on the right shows T cells, pages 131 and134. Human Biology, Sylvia S. Mader

Aquired Immunity

There are two types of aquired immunity, active and passive. Active immunity occurs when a person developes antibodies against a particular pathogen. This can happen naturally when an individual gets infected and after they are well, produces antibodies against that particular infection. Sometimes active immunity is induced through the use of vaccines like DPT or polio. In Passive immunity, a person is actually give specific antibodies through an injection. Passive immunity is temporary because the antibodies were not actually produced by the individual's plasma cells.

Disorders

Autoimmune diseases like MS or Lupus occur when a person's cytotoxic T calls or antibodies attack the body's own cells. We do not know what causes autoimmune diseases. Sometimes a person has an immune deficiency where the body is no longer able to protect itself from disease. This is the case with AIDS. I will cover AIDS in the next section.

V. AIDS

What is it?

The human imminodeficiency virus (HIV) causes aquired immunodeficiancy syndrome (AIDS). The virus weakens the immune system by infecting cells, especially helper T cells and macrophages. Because their immune system has been compromised, people who have HIV are more susceptible to opportunistic infections that take advantage of the weakened immune system. Like many viruses, there is more than one strain of HIV, but there are two main types, HIV-1 and HIV-2, with HIV-1 being the more powerful and common strain. The advanced stage of HIV is known as AIDS. When an infected individual progresses to AIDS they begin to develop more and more opportunistic infections.

Where did it come from and where is it now?

Most scientists believe that HIV originated in Africa. It is also thought that modern day HIV may have evolved from an immunodeficiency virus sometime in the 1950s. The virus has been further traced to similar viruses found in primates, and researchers have speculated that the virus may have mutated after people ate meat from primates.

British scientists have proven that AIDS came to their county sometime around 1959, and American scientists believe that HIV entered the US around the 1950s as well. The first documented American case of the virus was in a 15 year old boy who died in 1969. The boy died with skin lesions caused by a cancer now widely associated with AIDS. AIDS was not identified as the cause of death in many cases because the disease is not extremely infectious and patients die of oppurtunistic infections rather than the disease itself. It was in 1982 that the term AIDS was coined and HIV was found to be the cause of AIDS in 1983-84.

AIDs is prevalent in the human population all over the world, making it a pandemic. An estimated 38.6 million people today are living with HIV infections, 2.3 million of which are children. Almost 25 million people have died of AIDs since the epidemic began and today almost 1% of the world's adult population have HIV.

Sub-Saharan Africa are among the hardest hit regions. There are approximately 24 million people in Sub-Saharan Africa and 8.3 million in Asia living with HIV infections. North America, western and Central Europe have about 2million HIV infections. In the US African Americans and Hispanics made up about 70% percent of all newly diagnosed HIV/AIDS infections. Although AIDS is still a problem in the USA, obviously the real epedemic is in Sub-Saharan Africa and Asia.

Public health professionals like myself have dealt with HIV/AIDS in the context of TB infections. There was a lot of useful information on HIV and its relationship to TB at http://healthinitiative.org/html/index.htm.

Map of Africa showing where AIDs has become an epidemic. I took this picture from professor Frolich's PowerPoint.







To the right is a picture of HIV taken from www.healthinitiative.org/.../hivbig.htm









Phases and categories

There are different subtypes of HIV infection, some are more common in other parts of the world. For the purpose of this categoriztion I will be referencing HIV1B. There are basically three categories of infection, the acute phase, chronic phase, and AIDS.

Acute phase: During the acute phase the infected person is usually asymptomatic, in fact they most likely do not know they are infected and feel fine. Sometimes however there are flu-like symptoms during the first few weeks of infection. It is important to remember that the infected individual is still able to transmit the virus even if they feel fine. At this stage the CD4 T cell count will still be high and will never have fallen below 500, so in other words, the immune system still functions like normal. The viral load, the number of HIV particles in the blood is also still lower than the CD4 T cell count.

Chronic phase: Once a person's CD4 T cell count has dropped between 499 and 200 they may begin to display symptoms. There are many different symptoms that may show up at this stage, some of the more common ones are yeast infections, fatigue, shingles, unexplained fevers, sores on the mouth or tongue, and swollen lymph nodes. Also the viral load will begin to rise during this stage of infection.

AIDS: Remember that HIV is the virus that causes AIDS, the breakdown of the immune system. During the AIDS phase the infected individual will have a CD4 Tcell count below the 200 mark and/or will have one of the opportunistic infections common with AIDS. There are over 25 of these AIDS-defining illnesses. To name a few: Mycobacterium Tuberculosis, which is a bacterial infection that gets into the lymph nodes or lungs, Pheumocystis jiroveci pneumonia is a fungal infection of the lungs, and kaposi's sarcoma is a rare cancer of the blood vessels. Once a person is diagnosed with AIDS they usually die within two to four years, however new drugs have been developed to fight these infections and patients are living longer. It is important to remember that it is not AIDS that actually kills the person but the opportunistic infection brought about by the compromised immune system.

Structure and Life Cycle

As I mentioned earlier, viruses cannot live outside of cells and HIV is no exception. HIV is a retrovirus and is a single strand of RNA surrounded by proteins. Once the virus gets into a cell it inserts itself into the DNA and using a protein called reverse transcriptase it bigins to copy itself. Then it wraps itself up in proteins and "buds" out of the cells, pretty insidious if you ask me!

I found this micrograph of HIV buddng from a white blood cell at http://science.nationalgeographic.com/science/photos/aids/aids-virus.html. the website offers an interesting slide show about HIV and AIDS.

HIV infects helper T cells. Helper Tcells are the ones that stimulate cytoxic T cells and B cells. In other words the helper T cells are the ones responsible for the immune response, they do not actually kill antigens themselves. So once a helper T cell is infected with HIV it recognizes that it is now itself an antigen and it calls in the troops. This is how the helper T cells are killed off by the other cells. Once the helper T cells are at dangerously low levels the body is no longer equipped to fight off opportunistic infections.

From the powerpoint presentation, this picture shows how HIV gets into the cell and replicates itself.

I got this graphic at http://www.biology.arizona.edu/immunology/tutorials/AIDS/HIVimmune.html from the web links, It shows the progress of the disease. I appreciated this particular website, I thought it was very informative

To wrap up this portion on HIV/AIDS I should mention how it is transmitted. HIV is transmitted by blood and other bodily fluids, it is not airborn. It also does not last long outside the blood. It can be transmitted through sexual intercourse, infected blood, by sharing needles, and in some cases through a mother's milk.

IV. Conclusion

Basically I think the main thing I got out of this major topic was an understanding of how the body systems work together to maintain homeostasis. How the respiratory system is linked to the cardiovascular system, how our blood is so closely linked with the immune system. I also appreciated the section on AIDS. I had a very special friend and mentor who died of AIDs in the late 1980s. We met when I was recovering from an illness at UCLA medical center, he was a volunteer there. He never discussed his condition with me, maybe because I was so young (I was only 15 at the time I knew him) and AIDS was a big news item at the time. I remember him telling me about having Karposi's Sarcoma and showing me his hands which were covered in lesions. My family moved and I lost touch with him before he died. It was not until I was an adult and learned of his death that I began to put it all together and asked my father about him. My father admitted that my friend died of AIDS. I have always felt cheated that I did not get the opportunity to show my friend that I did not care that he had AIDS, of course I loved him no matter what. I just hope he was trying to protect me rather than keeping it from me out of fear of rejection. I hope that eventually we find a way to erradicate this terrible disease.

Works cited

Human Biology, Sylvia S. Mader

Blood, Oxygen, and Immunity,power point- Larry M. frolich

www.ynhh.org/cardiac/heart/

www.sheknows.com/articles/803849.htm

http://www.biology.arizona.edu/immunology/tutorials/AIDS/HIVimmune.html

http://science.nationalgeographic.com/science/photos/aids/aids-virus.html

www.nslc.wustl.edu/sicklecell/sicklecell.html

www.healthintiative.org

Unit II Lab Project: Exercise Physiology

My goal for this lab was to measure my pulse, respiration, and blood pressure after doing three different activities. In order to get a clear idea of how these activities might alter each rate, I first took the measurements after resting at least ten minutes at various times. The fifth reading was taken early in the morning before I did anything.

For my three activities I chose drinking coffee, one hour of general housework, and twenty minutes of moderate-high impact aerobics. I was most interested in testing myself after drinking coffee in the morning. I usually have 2-3 cups before I really get going for the day. Twice I have had a doctor's appointment in the morning shortly after my coffee fix and on both occasions my blood pressure was elevated, which is unusual for me. My suspicion was that because caffeine is a stimulant, it affected my blood pressure briefly.

Below is the table containing my hypothesis for this assignment. I knew that physical activity and working my muscles would create the need for more oxygen, causing my heart to work faster. I also know that certain stimulants can cause changes in heart rate and blood pressure. So I based my hypothesis on what I knew.

I expected my heart rate and blood pressure to increase slightly after drinking at least two cups of coffee. I expected my respiration to remain basically the same. After doing one hour of basic housework (vacuuming, sweeping, mopping, dusting, picking up, etc.) I predicted that my pulse and respiration would increase somewhat while my blood pressure increased only slightly, if at all. Lastly I predicted that my heart rate and respiration would increase significantly during aerobic exercise and my blood pressure would increase only slightly.

Hypothesis table

To gather my data I used a sphygmomanometer. We have one that my husband uses to check his blood pressure. I also used a stop watch for testing my pulse and respiration (30 seconds). I took my pulse at the radial artery. I also carefully watched the clock during my activities like housework and aerobics in order to get an accurate reading. I took my blood pressure about ten minutes after drinking two cups of coffee.

Taking my pulse.


Measuring blood pressure, I always used my left arm.



Drinking my coffee, the mug says "Goodbye God, we're going to Bodie."

I do a lot of housework and I wanted to know if I was reaching a training level with my heart rate.

Sweeping the front porch wearing my favorite Ramones T-shirt.

Aerobics with my daughter. I did a 20 minute workout that included a warm up, cool down and one and a half minute anaerobic drill.

Above you will find the actual results.

I was the most accurate in predicting respiration, there were no real surprises there. I was also fairly close on the pulse measurements although I anticipated a higher pulse after aerobic exercise than the actual results. My blood pressure was higher than the baseline after drinking coffee, but not as high as my prediction.

I was the most off the mark in regards to my blood pressure after aerobic exercise. I predicted that it would rise slightly when in actuality it decreased significantly. I know that if a proper cool down is not done after exercise blood pressure can drop and cause fainting (vagal response). I did do a five to eight minute cool down but wondered if I did not do it right, however I did not feel faint or sick. I did a google search on this and I found this statement:

Dynamic activities depend mainly on energy derived from consuming oxygen (aerobic). Thus they increase the body’s need for oxygen. Because blood delivers oxygen to the body, aerobic activity challenges the heart and circulatory system to meet this increased need. In dynamic exercise, oxygen consumption and heart rate increase in relation to the intensity of the activity. Systolic blood pressure rises progressively, while diastolic blood pressure stays the same or decreases slightly. Pulse rate rises, and blood flow to the muscles increases. Thus, aerobic exercise exerts primarily a volume load on the heart.

-http://www.americanheart.org/presenter.jhtml?identifier=3034814

Anyway, I am physically active but not necessarily physically fit (I do low impact aerobics three times a week for sixty minutes and walk a total of 150 minutes per week). So maybe I should try an easier routine next time.

Below are the charts for each measure:

Pulse rates for each activity. Of course the highest result is after aerobic exercise.




Respiration rates. Notice no change between baseline and coffee, probably because I was just sitting there watching the news (sometimes when John McCain or Sarah Palin are on my respiration and BP go up).

Looking at this graph it would appear that coffee does increase my blood pressure slightly. I have read that it is a temporary increase. The highest increase is after exercise, I predicted the highest rate to be after I drank coffee.

Here you can see the significant change in my diastolic rate after aerobic exercise. I do not think it is a dangerous level, but it is significant nonetheless. The highest rate was after drinking coffee which is as I thought it would be.



Conclusion

Obviously what we do or don't do affects our metabolic rate. Physical activity works the muscles, which causes the heart to work faster causing changes in pulse, respiration, and blood pressure. Having a general idea of your normal rates is useful because they seem to vary somewhat from person to person. Knowing your resting heart rate for example is helpful when doing exercise as you can use it to measure exertion and training levels.

This was an interesting assignment and I enjoyed doing it.