Question

1. Answer the following questions about the pancreas. (a) What is the general role of the pancreas in digestion? (b) When does the hepatopancreatic duct open? (c) What would you guess is the reason that many of the digestive enzymes produced by the pancreas are released as zymogens, rather than as fully functional enzymes?

2. Answer the following questions regarding the large intestine. (a) What is the main substance absorbed from the large intestine? (b) What do you consider the main function of the large intestine? (c) How would you characterize bacteria that live in our large intestines: as parasites? symbionts? pathogens? other? Explain.

3.(a) The liquid that gets modified to have become urine comes from where? (b) What structure in a kidney carries out filtration? (c) What is present in blood that is not present in the filtrate? (d) What is the difference between filtrate and urine? Note: Just state a few major differences here.

Answer 1

1.

1. Pancreas is Very important organ for digestion. The pancreatic secretions are rich in enzymes which are necessary for the Digestion. it releases its secretions into the small intestine. Due to the pancreatic secretions, most of the digestion occurs here.
2. Liver secretes bile and bile is required for the digestion of fats. Hepatopancreatic duct opens when there is high fat meal consumption. Increased fats in the the intestine stimulate the hormone cholecystokinin. cholecystokinin acts on the gallbladder and cause contraction of the gallbladder. This leads to release of bile in the biliary duct. It opens in the second part of deuterium and the sphincter of oddi opens.
3. The pancreatic enzymes are released as a zymogens because if they are released as active enzymes then they will cause autodigestion of the pancreas itself. To avoid auto digestion, zymogens are secreted which are activated by the enzyme enterokinase secreted by small intestine, into active enzymes.

2.

1. Large intestine mainly absorbs the water and electrolytes. Organic substances like glucose, alcohol and some drugs can also be absorbed in large intestine.
2. Large intestine is mainly concerned with absorption of water and electrolytes. It also secretes mucin which helps to lubricate the fecal matter. The bacterial flora of large intestine synthesizes Folic acid, vitamin B12 and Vitamin K. But the most important function of large intestine is to store the fecal matter.
3. The bacteria living in the large intestine can be considered as a symbiotics. There take the nutrition from the fecal matter and in exchange, this synthesise Folic acid, vitamin B12 and Vitamin K. They also inhibit the pathogenic organisms' growth.

3.

1. The urine is made from the blood itself. Blood is made up of many components including blood cells, plasma proteins, water, etc. Blood cells come from the bone marrow. Plasma proteins are synthesized primarily by liver. Water is absorbed from the digestive system itself. Some amount of water is reabsorbed from the kidney also.
2. Glomerulus is a structure which filters the blood. Glomerulus is a tuft of capillaries. It receives blood from the afferent arteriole. It filters the blood into the Bowman's space and the remaining blood is sent back into the venous circulation through efferent arteriole.
3. The blood contains proteins and blood cells which are not filtered by the glomerulus. Hence these two things are not present in the filtrate.
4. Filtrate is formed at the Bowman's space itself whereas the urine is formed at the end of the collecting duct. Filtrate is similar to plasma except proteins and blood cells. Whereas the urine contains little amount of proteins also. There is no creatinine in the filtrate whereas urine contains creatinine.