Digestive System

How is the digestion of fats different from that of proteins

and carbohydrates?

• Fat digestion occurs in the small intestine, and the digestion of

  proteins and carbohydrates occurs in the stomach.

• Fats are absorbed into cells as fatty acids and monoglycerides

  but are then modified for absorption; amino acids and glucose

  are not modified further.

• Fats enter the hepatic portal circulation, but digested proteins

  and carbohydrates enter the lymphatic system.

• Digested fats are absorbed in the large intestine, and

  digested proteins and carbohydrates are absorbed in

  the small intestine.

Although the stomach is normally thought of as the major player in

the digestive process, the bulk of chemical digestion actually occurs

in the ______.

• mouth

• appendix

• duodenum

• large intestine

After being absorbed through the intestinal mucosa, glucose and

amino acids are

• absorbed directly into the systemic circulation.

• used to build glycogen and peptides before being released to

  the body cells.

• transported directly to the liver by the hepatic portal vein.

• further digested by bile before release into the circulation.

Which of these pairings is incorrect?

• Fat transport/lymphatic system

• Glucose transport/lymphatic system

• Amino acid transport/circulatory system

• All of these pairings are correct.

5. Intestinal microorganisms aid digestion and absorption by

• digesting cellulose.

• producing glucose.

• synthesizing vitamin K.

• Both a and c are correct.

The _______ and _______ play important roles in the digestive

process by producing chemicals that are required to digest proteins,

lipids, and carbohydrates.

• liver; pancreas

• liver; gallbladder

• kidneys; appendix

• pancreas; gallbladder

Which of the following represents the action of insulin?

• Increases blood glucose levels by the hydrolysis of glycogen

• Increases blood glucose levels by stimulating glucagon production

• Decreases blood glucose levels by forming glycogen

• Increases blood glucose levels by promoting cellular uptake of

  glucose

The small intestine is specialized for absorption because it

• is the last section of the digestive tract and retains food

  the longest.

• has saclike extensions along its length that collect food.

• has no outlet so food remains within it for longer periods of time.

• has an extremely large surface area that allows extended

  exposure to food.

Inactive forms of some molecules are secreted

• because they take less material and energy.

• because they must combine with water to be activated.

• so their activity can be regulated.

• to prevent them from clogging the gland from which they are

  secreted.

Obese humans probably have high levels of leptin because

• leptin stimulates eating.

• something is wrong with the leptin receptors in their brain,

  leading to increased leptin production to make up for the

  apparent shortage.

• weight gain leads to the production of leptin.

• leptin responds to mechanical stimulation in the

  adrenal cortex.