Question

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8. As food travels through the digestive tract it will pass through a series of valves and sphincters IN ORDER

a. Lower esophageal spinster; pyloric specter; ileocecal valve; internal and external anal sphincters

b. ileocecal valve; pyloric sphincter; lower esophageal sphincter; internal and external anal sphincters

c. pyloric sphincter; lower esophageal sphincter; ileceal valve; internal and external anal sphincters

d. internal and external anal sphincters; pyloric sphincter; lower esophageal sphincter; ileoceal valve

14. the uvula and epiglottis are present in order to

a. propel food toward the esophagus and stomach during swallowing

b. prevent food from entering respiratory passages during swallowing

c. assist with mechanical digestion in the mouth during chewing

d. increase peristalsis in the esophagus during chewing

15. The primary function of the stomach is ___ made possible due to the presence of ___ a. absorption, villi

b. digestion, parietal cell secretiond

c. food storage, rugae

d. propulsion; smooth muscle

18. Lipid digestion requires the following steps IN ORDER

a. absorption, micelle formation; enzyme digestion, emulsification

b. emulsification; enzyme digestion; micelle formation; absorption

c. enzyme digestion, absorption; emulsification, micelle formation

d. micelle formation; enzyme digestion; emulsification; absorption

28. The binding of a hormone to an intracellular receptor ( inside the cell) would most likely

a. alter a g- protein couple receptor

b. alter a phosphorylation enzyme

c. after a second a messanger

d. alter DNA and start transcription

Answer 1

Question 8.

Option A stands CORRECT.

As food travels through the digestive tract, the series of valves and the sphincters in order through which the food passes is as follows:

Lower oesophageal sphincter; Pyloric sphincter; Ileocaecal valve; Internal and External anal sphincter.

Lower oesophageal sphincter guards the lower end of oesophagus, Pyloric sphincter guards the lower end of stomach, Ileocaecal valve allows the passage of undigested food from terminal ileum to caecum, Internal and External anal sphincters guards the anal canal.

Question 14:

Option B stands CORRECT.

The uvula and epiglottis are present in order to prevent food from entering the respiratory passages during swallowing.

The soft palate along with uvula moves together to close the passage of nasopharynx by forming a door with passavant's ridge between nasopharynx and oropharynx. Thus it prevents entry of food from entering into nasal cavity.

Likewise, epiglottis forms a leaf shaped flap on top of larynx and closes the larynx during swallowing of food thus preventing the entry of food into glottis.

Question 15.

Option C stands CORRECT.

The primary function of the stomach is food storage made possible due to presence of rugae.

The main function of stomach is to store food and later propel it to intestine. The stomach also mixes and grinds the food thus increasing its surface area, easy for digestion.

The rugae defines wrinklings inside the stomach which allows the stomach to stretch in order to accomodate large amounts of food and helps to move food during the digestion.

Question 18.

Option B stands CORRECT.

Lipid digestion requires the following in order: Emulsification, enzyme digestion, micelle formation and absorption.

Lipids are primarily emulsified in the intestine by detergent action of bile salts, lecithin and monoglycerides. These emulsified lipids are later acted upon by pancreatic lipase and co-lipase for digestion of lipids into free fatty acids.

Later with help of bile salts, lipids form micelles which are cylindrical aggregates of lipids like fatty acids, monoglycerides and cholesterol with hydrophobic ends at the centre. They provides a medium for their absorption into the intestinal epithelial cells by passive diffusion and carrier mediated transport.

Question 28.

Option D stands CORRECT.

The binding of a hormone to an intracellular receptor would most likely alter the DNA and start transcription.

The binding of a hormone with intracellular receptor causes a confirmational change exposing the DNA binding domain of receptor which facilitates transcription of mRNA's by altering DNA. Later they are translated in ribosomes to form new proteins which alter cell function.