A. Short answers: 1. What are the different layers in pericardium? Write any thr
ID: 3509218 • Letter: A
Question
A. Short answers:
1. What are the different layers in pericardium? Write any three functions of pericardium. What will happen if there is a sudden fluid accumulation in the pericardial cavity?
2. How cardiac output is defined? What is the normal cardiac output in a healthy adult? Mention three factors each that regulate cardiac output and heart rate.
3. Briefly describe the volume changes in the ventricles during cardiac cycle. What is the Frank-Starling Law of heart? Can you provide a physiological explanation to the phenomenon described by this law?
4. Name different components of cardiac conduction system. Briefly describe the roles each of these components in generating rhythmic contraction of heart? What change in the resting heart rate will you expect if sinoatrial node suddenly stops functioning in a person?
5. What are the main factors that determine vascular resistance to blood flow? Explain why arterioles are the main site for the regulation of vascular resistance. How systemic vascular resistance is related to the mean arterial pressure? Why an increased amount of adipose tissue in the body is often associated with hypertension?
6. Being tired of her sedentary lifestyle, Sylvia makes a resolution to begin an exercise program. She tells you that she wants to make her heart “beat as fast as it can” during exercise to supply more blood to her working muscles. From your knowledge of cardiac cycle do you agree to her argument? Explain to her why that may not be a good idea.
7. Although blood vessels in the body share a common basic structure, distinct differences in morphology could be observed depending on their location in the circulatory path. Mention one feature in the vessel wall structure for each of the five main types of blood vessels (elastic arteries, muscular arteries, arterioles, capillaries and veins) that distinguish them from others. How these structural characteristics contribute to their specific function?
8. Briefly describe the structural characteristics of three major types of capillaries found in the body. For each type, give one example of tissue/organ where they are found and specific functions they serve.
9. What are the main types of proteins found in the blood plasma? In a severe form of malnutrition known as Kwashiorkor swelling of body tissue from fluid accumulation (edema) is observed. From your physiology knowledge can you explain the mechanism for this edema? Could the same reasoning be applied to the edema observed in the lower limbs of a patient suffering from chronic heart failure?
10. Mrs. Brown is in renal failure. Her recent blood tests indicated a hematocrit of 22 (severe anemia). Why is her hematocrit low? What treatment can she be given to raise her hematocrit? Explain how this treatment is expected to work. By peripheral blood examination, will you be able to tell if there is a recent increase in the rate of erythropoiesis? Under what circumstances would you expect the hematocrit to increase above normal range?
11. Name two major pathways that initiate blood coagulation. Which one of these two processes you expect to be faster? How prothrombin and fibrinogen contribute to the coagulation process? How activated platelets help in stabilization of fibrin clot and clot retraction?
12. Neutrophils contribute to body’s defense by phagocytizing the invading pathogens. What are the mechanisms by which neutrophil attempts to kill/neutralize the pathogens after phagocytosis? Briefly describe the steps by which circulatory neutrophils reach the active site of inflammation.
13. What is innate immunity? Enumerate various mechanisms by which our body elicits innate immunity.
14. Briefly describe the steps (you can use a flowchart) of recognition of a bacterial antigen by helper T cells. Enumerate the various mechanisms cytotoxic T cells employ in order to kill an invading pathogen.
15. Humoral immunity is mediated by antibodies. Name the organs and cells where antibodies are normally produced. Describe the mechanisms by which antibodies confer immunity.
16. Due to the presence of breast cancer, Mrs. Franco had a right radical mastectomy in which her right breast and underlying muscle, right axillary lymph nodes and vessels were removed. Now she is experiencing severe swelling in her right arm. Why did the surgeon remove lymph tissue as well as the breast? Why is Mrs. Franco's right arm swollen? Describe briefly the mechanism of lymph formation and flow.
17. What are the primary and secondary lymphatic organs in the body? Describe briefly how the immature T-cells become immunocompetent in the thymus by “positive selection” and “negative selection” process.
18. Esperanza watched as her mother got her “flu shot.” “Why do you need a shot if you're not sick?” she asked. “So I won't get sick,” answered her mom. Explain how the influenza vaccination prevents illness. Why it is important that you get yourself vaccinated even if you feel that you are extremely immune to flu and would rather take a chance to get caught by flu once in a while rather than getting the flu shot of every year.
Explanation / Answer
1. The different layers of pericardium are :
Epicardium which is tge outermost visceral layer
Myocardium is the muscular middle layer
Endocardium the innermost serous layer
Functions-
Protects heart from infection
Maintain the position of heart in mediastinum
In case of overload, it prevents excessive dilatation of heart
It protects heart against any kind of external shock and lubricats the heart
Accumulation of fluid in heart is known as pericardial effusion. Such cases can cause rapid compression of heart a condition known as cardiac tamponade and fatal low blood pressure.