Question

Mixture of Respiratory / Digestive System

a) How is oxygen transported in the blood?

b) What is the chloride shift? (explain please)

c) In ventilation-perfusion coupling how does the body respond to O2 flow and CO2 accumulation

d) Where is bile produced, where is it stored, what is it composed of:

e) What organ does the pancreas deliver enzymes to?

f) The function of hydrochloric acid in the digestive system is

Answer 1

Answer a. Oxygen is inhaled by the nostrils, from trachea it reaches bronchi, then bronchioles and finally reaches alveoli. Alveoli has fine membrane, with high partial pressure of O2 while inhalation. It is single membranous, high surface area that allows easy diffusion of oxygen into the blood. As a result, blood becomes oxygenated, reaches the left atrium, then to left ventricle. From left ventricle enters the aorta, distributed to the whole body, meanwhile causing tissue respiration and as a result nutrients are received by the tissues. Tissues pass their carbon dioxide into the Capillaries by diffusion, blood becomes deoxygenated and returned to the right atrium.

Answer d. Bile juice is produced by the liver. But stored and concentrated in the gall bladder. It is composed of lipase that help in the digestion of the fats plus it also contains the yellow pigments namely, bilirubin and biliverdin.

Answer e. Pancreas is actually a heterocrine organ because it has both exocrine and the endocrine part. Exocrine part is related to the production of enzymes and endocrine to the hormones. Pancreas supplies enzymes to the duodenum part of the small intestine with the help of pancreatic duct. This enzymic secretion contains pancreatic Amylase, pancreatic lipase and proteases to digest carbohydrates, Fats and proteins respectively.

Answer f. HCl of the stomach helps in:

• Sterilising the food by killing the bacteria because of the acidic pH.
• Helps in providing the acidic pH to the enzymes.
• Helps in converting the inactive pepsinogen to the pepsin that helps in the protein digestion.