Question

1. Describe the role of the lipoproteins in transport of triglycerides and cholesterol.

2. Describe the flow of bile from its site of production to where it enters the GI tract.

3. Describe the movement of Oxygen and CO2 in gas exchange between the lungs, blood and peripheral cells. You do not have to give exact numbers for the pressures. Indicate the direction of the movement of the gases.

4. If a person had end diastolic volume of 150 mL and end systolic volume of 70 mL with a heart rate of 100 bpm, what is their stroke volume and cardiac output?

5. The blood hydrostatic pressure (HPb) at the arterial end of the capillary is 35 mm Hg. The HPb at the venous end is 15 mm Hg. The colloid osmotic pressure of the blood is 25 mm Hg. Calculate net filtration pressures and say where filtration and reabsorption occur.

6. Describe hormonal changes during the different stages of the menstrual cycle.

Answer 1

In the intestine, the fats are digested into triglycerides and cholesterol. These molecules cannot enter the blood stream as such. Triglycerides and cholesterol are coated with protein, cholesterol and phospholipids to form chylomicrons. Chylomicrons enters the lymph and finally enters systemic circulation.

Thus lipoprotein help in absorption of lipids by forming chylomicrons.

2nd question-

Bile is secreted by hepatocytes. It Contains bile acids,bile pigments, cholesterol, lecithin and fatty acids. From hepatocytes,bile is released into canaliculi . From here, it passes through small ducts and hepatic duct and reaches the common hepatic duct. From common hepatic duct, bile is diverted either directly into the intestine or into the gallbladder.

3rd question-

Exchange of gases between blood and alveoli takes place through respiratory membrane. It is formed by epithelium of respiratory unit and endothelium of pulmonary capillary.

At the lungs level, the partial pressure of oxygen is low and that of carbon dioxide is high in capillary as compared to that in alveoli. Because of this pressure difference, the oxygen moves from alveoli to blood and carbon dioxide move from blood to alveoli.

At the tissue level, opposite to above happens and oxygen Moves from capillaries into the cells and carbondioxide moves from cell into the capillaries due to pressure difference.

4th question-.

Stroke volume is given by-

End diastolic volume - end systolic volume

= 150- 70

= 80 ml

Now,

Cardiac output(CO) can be calculated by formula-

CO= stroke volume × heart rate

= 80ml × 100 bpm

= 8000ml/minute

Or 8 litre per minute.