Table of Contents
1. Cardiovascular System and Blood Vessels: heart,capillaries
2. Cardiovascular System and Blood: RBC/WBC
3. Microbes and Immunity
4. AIDS/HIV
It's typical to live each day, and not even realize the work load each system, cell, vessel, or organ performs to keep our bodies homeostatic and functioning. Above is a broad table of contents that I will do my best to describe and bring out the main points. The heart is a valuable part of our body, with each "lubdub" is a new flow of blood entering our systems. There is an abundant amount of cells flowing throughout our bodies, bringing oxygen and nutrients in and riding of wastes. Thankfully, we have WBCs that help fight off unwanted pathogens, they resemble an eagle when it hunts for food, it quickly swoops down and gathers its prey. We definitely need to appreciate the workload these cells do. The earth is full of organisms, microbes, that we need to be watchful for and appreciate the screening they do to our environment. Studying these chapters brings up the importance to keep our bodies healthy; doing our best to prevent the infectious diseases lingering around us each day.
CARDIOVASCULAR SYSTEM AND BLOOD VESSELS: The Cardiovascular system is like the ocean constantly full of swimmers. The swimmers (blood) move throughout the ocean(body) and the fish(other systems in the body) help keep the ocean functioning properly. A swimmer(blood) takes a break on the shoreline; brushes off seaweed (excess wastes), takes a sip of Gatorade(nutrients and oxygen) and dives back into the ocean. This scenario describes the process of the removal of carbon dioxide and the entrance of oxygen in the body. There are three types of blood vesse
ls the book refers to. The picture to the right is of an artery(red) and vein(blue). 1) Arteries: a blood vessel that carries blood away from the heart toward a capillary. The walls are strong, which gives extra support when blood moves around. 2) Capillaries: a small, microscopic blood vessel with thin walls composed of an endothelium layer, gas and nutrient exchange takes place. 3) Veins: a blood vessel that carries blood from a capillary towards the heart. Veins have a valve(similar to a plug) which helps prevent back flow of blood. The walls are thin compared to arteries, meaning when blood enters at high pressures; it causes expansion. The next main focus is the function of the heart: The heart is found between the lungs, behind the breastbone, about the size of your fist, and has 3 muscular layers surrounding it.
The outer layer is the myocardium (cardiac muscle), pericardium(supports and protects), and the epicardium(outer layer). To describe the heart, look at the picture to the right. You will notice that there are four main chambers: Right atrium, right ventricle, left ventricle and left atrium. Also note the valves located between the chambers: their main function is to prevent blood back flow. Next I will discuss the passage of blood. Beginning the flow, blood enters the superior/inferior vena cava to the right atrium. The right atrium to the tricuspid valve-right ventricle-pulmonary valve-pulmonary trunk-divides into two pulmonary arteries(blood travels to the lungs/deoxygenated or poor blood). Oxygenated(rich blood) enters through the pulm
onary veins-left atrium-bicuspid valve-left ventricle- aortic valve- aorta- different parts of body. The picture to the right is color coded, showing the entrance/exit of blood via the veins and arteries. "The human heart beats more than 3.5 billion times in an average lifetime" (wikipedia). These beats are more than "lub dub." Each of those beats is known as a cardiac cycle. During a beat, the atrias squeeze shut(systole) at the same time, and then the ventricles squeeze shut at the same time. Then it goes through a relaxation phase(diastole). When listening to a rhythmic heart through a stethoscope you will notice a "lub" sound, which is the increase pressure of blood, forcing the tricuspid valve to close. This in turn, causes the pulmonary and aortic valves to bounce open. The "dub" is the closing of these valves. "The SA node is called the pacemaker because it usually keeps the heartbeat regular" (Mader 90). A slow functioning SA node is usually fixed by placing an artificial pacemaker. ECG and EKGs can be used to view the heart rhythm for any possible signs of abnormalities. The pulse and blood pressure will be discussed in the lab portion.Cardiovascular Pathway: The right side of the heart pumps blood to the pulmonary circuit( carbon dioxide is dumped off, and oxygen is the traveling partner). The left side of the heart pumps blood in to the systemic circuit(blood delivers oxygen and nutrients to tissues and discards wastes).
Capillaries: The layer of a capillary is an endothelial lining, meaning only small particles/molecules are capable of moving through. When blood enters the arteriole end(red section) water and molecules small enough to exit, move out of the lining due to an increase in blood pressure. By the time blood reaches the venule(blue section) water moves in by osmosis. In the middle of the capillary, there is no movement; therefore, oxygen and nutrients exit, carbon dioxide and wastes enter, and RBC/proteins remain inside. Cardiovascular disease continues to be the leading cause of death. HTN, atherosclerosis, stroke, and heart attack are a few examples.CARDIOVASCULAR SYSTEM AND BLOOD: "The human body contains about 5 liters of blood, and the heart pumps this amount of blood with every beat!" (Mader 106). There are 3 main activities of blood: transportation(running oxygen and nutrients and supplying to other cells), defense(fighting foreign objects/preventing clots), and regulation(temperature and fluid/electrolyte). Blood travels everywhere throughout our bodies making sure we are ready to face our next big challenge. Whether the challenge is just getting out of bed in the morning, jogging around the block, replenishing our thirst, fighting a cold, or sleeping after a hard days work. During any of these examples, blood continues to flow to all of the systems within us. Their are two compostio
ns of blood to discuss. The test tube picture to the right, shows the separation of the cell fragments. 1) formed elements: RBC(most abundant: delivers oxygen), WBC(work in the tissues: engulf/ defend against foreign objects), and platelets(stick together to form a plug: during a sudden blood loss). 2. Plasma: 90% of this water. Its main function is to transport nutrients and wastes throughout the system .RBC: This is the most common blood cell that delivers oxygen to the lungs. Inside this cell are numerous copies of hemoglobin, which gives
the cell its distinct, color and contains protein(globin) and iron(heme) chains. The Iron chain Each of these chains bind differently to oxygen. Notice in the picture to the right the RBC has an indented(bio concave) center, this helps move gases in and out of the cell "RBC's produce ATP anaerobically, and they do not consume any of the oxygen they transport" (Mader 108). Erythropoesis refers to the production of RBCs. The life span of a RBC is 120 days. An interesting amount of RBCs are destroyed each second, "2 million" (Mader 109). That shows how hard these little cells work to keep up with the demand of transporting oxygen and nutrients to different cells. A couple common RBC disorders are anemia, sickle-cell, hemolysis.WBC: These cells were briefly touched on above, but are important in the immune system; fighting against infections. The two different types of WBC's are granular and agranular leukocytes. Granular are: Neutrophils( most abundant, quick at responding and remove the foreign particles), Eosinophils(help during allergic reactions), and Basophils(releases the chemical histamine). Agranular are: Lymphocytes(help defend the body, consist of 2 types: Natural killer cells(NK cells), Tcells, and B-cells which produce antibodies to help destroy the particles). Monocytes(important function is phagocytosis(eats away/ingests), and it responds quickly to the endangered site). WBC work at making sure the cell is not attacked by the unwanted particle.
MICROBES. Picture the rocks at the bottom of a fish tank, rocks beneath the soil, and rocks on the bed of a river. Flowing through these waters, are microscopic organisms known as microbes(bacteria, fungi). Not only are they found in water, but scattered everywhere on the earth. These microbes are both helpful and a threat to our lives. They help by acting as "decomposers" and are a threat since most microbes( bacteria) are the main source of the many diseases that kill humans. The picture to the right is bacteria, magnified many times over.
All of us have heard the phrase over and over that the number one thing to help stop the spread of infection is: HANDWASHING. Think about the last thing you touched. Was it shaking someones hand, touching your steering wheel, removing your shoe, or opening a door? Think of all the microscopic particles crawling around on that object!!! Bacteria multiply when the environment is suitable for them to grow.Viruses are most commonly referred to when talking about the flu or cold. They infect cells and replicate when they infect a host cell. An interesting thing about viruses is that they carry genetic information, and protect it with a protein coat! To help stop the spread of a virus, is done be immunization. That is why it is important to be up-to-date on immunization. Scientists have studied this background for many centuries, viewing and trying to culture a viral organism. "In the late 19th century, Charles Chamberland, developed a porcelain filter with pores small enough to filter viruses, yet retain all viable bacteria" (Wikipedia). Research obviously has blossomed since then.
IMMUNITY. This defense mechanism helps ward off diseases from entering the body. It builds blockades, and send the WBCs to help engulf the unwanted particles. Antigens are referred to as: "molecules the immune system recognizes as foreign to the body" (Mader 130). The B cells and T cells are like sensors, they recognize antigens and bind to them with their receptors. Antibody-Mediated Immunity is the defense process of a B cell and its receptor making copies, which turn into plasma cells and memory B cells. Cell- Mediated Immunity is when T cells find help from others and then attack the diseased/cancerous cell(note the blue and red T cells below: found each other, and are now forming a plan to attack the green, infected blob to the right). Again, the cells work together to help cure, in this case, an infected cell. Cytotoxic T cells are like sticky glue, settling into a piece of foa
m: they bind to the infected cell, settle onto the membrane, puncture little pores, and suffocate the infectious cell. Helper T cells give out directions to cytokines(chemicals used for communication). A memory T cell stores information of a previous antigen occurring in the body, if it resembles the same antigen again, it will alarm other cells to activate. Fighting against these antigens can be a lot of work, but the cells manage to alarm those needed to help destroy the infectious antigen.
There are two types of acquired immunity to briefly touch on. Active immunity: Vaccines are used to help expose our bodies to a specific antigen. (Earlier I discussed the purpose of memory T cells, this is where they function) Children are recommended to receive immunizations to help prevent diseases (chicken pox, tetanus). Passive Immunity: This is a temporary immunity passed on from individual to individual.
AIDS/HIV. This disease, acquired immunodeficiency syndrome, was first discovered in 1981. Killing more than 25 million since its recognition in 1981(wikipedia). AIDS damages and weakens the immune system, caused by the human immunodeficiency virus (HIV). It is believed that HIV "originated from chimpanzees," in sub-Saharan Africa. The transmission is also thought to come from the blood of the chimpanzee transferring into the wound of a human (Biology). There is not a cure for this deadly disease, but some drugs are used for treatment and learning to be safe and use precaution measures help stop the spread of AIDS/HIV. Transmission of HIV is by direct contact of mucous, blood, and bodily fluids (semen,blood, vaginal fluid, and breast milk), contaminated needles, sexual intercourse, and blood transfusions. HIV destroys the T cells which are manditory to help keep the immune system functioning properly. When there is less than 200 microliters of these cells, it destroys the cell mediated immunity that helps recognize antigens(as mentioned earlier); leading to the well known condition: AIDS. A few symptoms related to AIDS are: fevers, night sweats, swollen glands, weakness, weight loss, and chills (wikipedia). Antiretroviral therapy is being used to help lengthen the life span of an individual infected with AIDS. Education continues to be an important concept to pass on to help stop the spread of this struggling disease.
In conclusion, I will tie what I stated in the beginning; studying these chapters definately makes me think more of what is happening inside my body as I move on each day. The cadiovascular system pumps blood through the heart and systems continuously, through its specific pathway. The blood is helpful in transporting, regulating, and fighting to keep our bodies functioning. Microbes live everywhere around us, and keep a balanced environment, but also causes diseases. Immunity keeps our bodies out of harms way, with the help of WBC and immunizations. AIDS is an unfortunate disease that destroys the T cells in the body, weakining the immune system. Keeping a healthy, productive lifestyle will hopefully keep my body strong and ward off any stray pathogens!
WORKS CITED:
Mader, Sylvia S. Human Biology. Boston: McGrawHill Companies, Inc. 2008.
Quotes
http://en.wikipedia.org/wiki/heart and RBC
pictures of heart, arteries, RBC
www.mhe.com/biosci/es[/2001_saladin/folder_structure/tr/rr3/slo.index.htm
picture of capillary
http://training.seer.cancer.gov/
picture of blood composition(plasma and formed elements)
http://www.biology.arizona.edu/immunology/tutorials/AIDS/impacts.html
pciture infected cell/helper T cell
No comments:
Post a Comment