BIOLOGY (BIOL 235) Assignment 3 Biology 235 Human Anatomy and PhysiologyRebekah Cook
Assignment 3
Weight: 5%
Minimum Pass Grade: 50%
Each question
... [Show More] is worth 10 marks.
1. Fill in the words or phrases that best complete each sentence. Be as specific as possible.
a. Erythrocytes contain the enzyme carbonic anhydrase, which catalyzes the conversion of metabolically produced CO2 and water into carbonic acid.
b. Most old erythrocytes are removed from circulation and destroyed by cells called machrophages, as they rupture passing through the narrow capillaries of the organ called the spleen, liver and red bone marrow.
c. Undifferentiated cells called stem cells reside in the bone marrow, where they continuously divide and differentiate to give rise to each of the types of blood cells.
d. The process of leukocytes squeezing through the capillary wall to exit the vasculature is known as diapedesis. Once they leave the bloodstream to fight a pathological condition, they never return.
e. The genetically-determined glycoprotein and glycolipid antigens found on the surface of an erythrocyte are called agglutinogens, and a person with agglutinins that react with type A and blood type B has type o blood.
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f. During embryonic development, ninety-nine percent of the cardiac fibers are specialized for the function called contraction, whereas the remainder is specialized for inherent and rhythmical electrical activity (autorhythmic) .
g. The action potential delay at the AV node ensures that atrial excitation and contraction are complete before ventrical excitation and contraction commence.
h. The end systolic volume (ESV) is the volume of blood in the ventricle after ejection has been completed. An increase of this volume occurs when the stroke volume is decreased.
i. The three cations, K+, Ca2+, and Na+ have an important effect of heart function. Increased blood levels of Na+ blocks Ca2+ inflow and results in a decrease in the force of contraction, while an excess of K+ blocks the generation of action potentials.
j. An increase in parasympathetic activity has the following effect on stroke volume: decrease stroke volume. An increase in parasympathetic activity weakens atrial contractility.
2. A patient has the misfortune to have both diabetes insipidus and Addison’s disease. How will those conditions affect the patient’s ability to regulate blood pressure?
ADH (antidiuretic hormone) is released from the posterior pituitary to help decrease urine production and decreases the amount of water lost via sweating. There fore an increase in ADH will have more water return to the blood from the kidneys. A decrease or absence of ADH will increase urine output.
Constriction of arterioles, which increases blood pressure. Hyposecretion (low secretion) of ADH can cause diabetes, which will cause homeostatic imbalance. Diabetes insipidus is caused by dysfunction of the posterior pituitary. There is a defect in ADH
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receptors or inability to secrete ADH. Neurogenic diabetes insipidus when the kidneys don’t respond to ADH related to kidney damage or dysfunction of ADH receptors. Symptoms that can occur are large amounts of urine output causing dehydration, hypotension (low blood pressure) related to blood volume decreasing. With addisions disease (adrenal insufficiency) the hormones cortisol in low. Cortisol helps maintain blood pressure so without it you will have hypotension. Aldosterone is a hormone that helps regulate blood pressure. Produced in the adrenal glands' cortex, it tells the kidney and colon to send more sodium into the blood and to release more K+ in the urine.
Aldosterone will also cause reabsorbtion of water from the urine. When the sodium is put back into the blood stream, the water sort of tags along. Blood volume will be increased and blood pressure will be increased. When the body suffers blood loss, or there is low blood pressure/blood volume, renin causes angiotensin, which causes aldosterone to be released. These three hormones operate through a negative feedback loop that works to maintain blood pressure and homeostasis. This means that Aldosterone helps raise low blood pressure to normal. Addison's disease causes hyposecretion of Aldosterone. Many of the cases are autoimmune disorders in which antibodies cause adrenal cortex destruction or block binding of ACTH to it's receptors.
Pathogens can be a cause. Loss of aldosterone cause elevated K+ in the blood and a loss of sodium. Low blood pressure and dehydration result. Both diseases cause low blood pressure as two of the important hormones that work to increase blood pressure and maintain homeostasis are being hyposecreted. The person in with both diseases will have extremely low blood pressure, low blood volume, low cardiac output, dehydration, and low electrolytes among many other symptoms. The patient will lose the ability to regulate blood pressure.
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3. In the correct sequence, list the names of the blood vessels and heart’s chambers that an RBC would travel through (or flow into other vessels) on its journey from the muscles located anterior to the right tibia to the heart, then to the left shoulder muscles, and then back to the heart. Take in consideration only the vessels listed in the Study Guide.
Starting in the anterior tibia vein, which collects deoxygenated blood from the muscles located anterior to the right tibia, the red blood cell will flow through the right popliteal vein to the right femoral vein to the right external iliac vein to the right common iliac vein to the inferior vena cava to the right atrium. The inferior vena cava receives deoxygenated blood from veins posterior to the diaphragm. The inferior vena cava is the largest vein in the body (3.5 cm) in diameter. The RBC will go from the inferior vena cava into the superior part of the right atrium, into the tricuspid valve into the right ventricle. The right
ventricle pumps blood through into the pulmonic valve, and into the pulmonary artery into the lungs, where the RBC will go into the capillaries. The RBC will flow through the pulmonary vein, then into the left atrium, where it will flow into the mitral valve into the left ventricle where it will enter the aortic valve before entering the systemic circulatory system. All systemic arteries branch from the aorta. Deoxygenated blood will return to the heart through the systemic veins. All veins of systemic circulation drain into the superior vena cava, inferior venacava or coronary sinus which in turn empty into the right atrium (which receives deoxygenated blood). In the case of this RBC, we will be looking at the arch of the aorta. After the RBC, travels through the ascending aorta, eventually the ascending aorta will arch to the left, forming the arch of the aorta, which descends and ends at the level of the intervertebral disk between the fourth and fifth thoracic vertebrae. The arch of the aorta will branch into the left subclavian artery,
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which will supply oxygenated blood to the left upper limb. The left subclavian artery will then branch into the axillary artery, which will supply the left shoulder muscles. It will then go through the left axillary vein, through the left subclavian veins until they join with tubular veins to form the brachiocephalic veins where the RBC will enter the superior vena cava, where the RBC will enter the right atrium, and into the heart.
4. Describe the activation, proliferation and differentiation of T cells and B cells and briefly describe the functions of the differentiated cells.
T cells and B cells both develop in the thymus and red bone marrow from stem cells. B cells develop and mature in the red bone marrow. T cells originate in the red bone marrow as pre T cells and travel to the thymus where they mature. T cells are present before puberty and continue through a person’s life. T cells can develop many immune responses. They have antigen receptors that can identify invaders (Ex:bacteria). The thymus releases two types of T cells; Helper T and cytoxin T cells. The helper T encourage B cells to produce antibodies. Cytoxin T cells are also called killer T cells are a type of white blood cells that kill damaging cells such as cancerous cells. T cells can recognize antibody that enter the body related to proteins CD4 and CD8 on the outer surface of T cells. CD4 cells can develop into helper T cells. CD8 cells can develop into cytoxin T cells when recognizing a foreign antigen. Cytoxin T cells are stimulated by interleukin-2 produced by helper T cells that have already become attached to copies of the same antigen.
To activate B cells the B cells will bind to an antigen. B cells take on the antigen into the plasma membrane. Each B cell has different protein because during their development there is intentional shuffling of the DNA to create different combinations of B cells. This allows the B cells to bind to many different foreign [Show Less]