Answer the following questions regarding factors affecting the rate of diffusion

Question

Answer the following questions regarding factors affecting the rate of diffusion:

a. A 65 year old African-American man presented to the emergency room with a hypertensive urgency and had 5 mg of sublingual nifedipine administered to him by the ER nurse to reduce his blood pressure. How does the concentration gradient of this drug affect its rate of diffusion into the blood stream?

b. The small intestinal mucosa is distinctive because of the extensive villi and microvilli it possesses. In patients with HIV-enteropathy, there is a significant villous atrophy (loss of villi) and resultant chronic diarrhea. Explain how surface area affects the rate of intestinal absorption.

c. A 75 year old woman is diagnosed with pneumonia secondary to Hemophilus influenza infection. Her arterial blood gas measurements reveal that she is hypoxic (low partial pressure of oxygen) but not hypercapnic (high partial pressure of carbon dioxide). Explain how the solubilities of O2 and CO2 can affect their rate of diffusion across the alveopulmonary membrane.

d. A 75 year old former asbestos factory worker is currently undergoing chemotherapy for asbestosis following several years of exposure to asbestos fibers. He is chronically hypoxic due to pulmonary fibrosis. Explain how the thickness of the alveolocapillary membrane affects gaseous exchange in his lungs.

e. You are evaluating a patient in the emergency room with severe anaphylaxis (systemic allergic reaction) who was said to have eaten a snack containing peanuts. Your options are between two anti-allergy drugs (A and B) with the same solubility and hydrophobicity but differing molecular weights. A has a higher MW than B. Which of them will you administer to the patient and how did your knowledge of the effects of MW on rate of diffusion influence your decision?

Explanation / Answer

Answers -

A) As Nifedipine is used for emergency in hypertension and angina nifedipine is a calcium channel blocker and cause vasodilation which futher decrease the blood flow. As with decreased blood flow & because of vasodilation rate of diffusion will increase due to high surface area will be comes in contact via blood.

B) Micro Villi or extensive villi are responsible for providing larger surface are for absorption, but in villious atrophy villi get damaged or gets flatten.which leads to the samller surface area for absorption which further leads to dehydration and lack of nutrients in blood.

C) In pneumonia the alveopulmonary gets clogged and inflammation occur due to infection as its leads to low diffusion of oxygen in blood stream but the nomal intake of CO2 is keeps on going.

D) Thickness of alveolocapillary due to pulmonary fibrosis will decrease the rate of gaseous exchange in lung as alveolar sacs and capillary are very thin and permeable in normal condition.

E) As anaphylaxis is an IgE mediate antigen - antibody allergic reaction and for the faster responses, better permeability & fast flowing a lower molecule weigh drug should be used that is drug B.

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