High School Biology : Understanding Hormones and Digestion

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #800 : High School Biology

Which of the following hormones stimulates the secretion of hydrochloric acid by specialized stomach cell?

Possible Answers:

Thyroxine

Aldosterone

Gylcogen

Insulin

Gastrin

Correct answer:

Gastrin

Explanation:

The chemical digestion of food is facilitated by the secretion of the hormone gastrin, which stimulates the secretion of hydrochloric acid. Insulin is secreted by the pancreas in response to high levels of blood glucose. Glucagon is secreted in response to low levels of blood glucose. Aldosterone is secreted by the adrenal cortex and increases reabsorption of salt in the kidney, subsequently increasing water retention and blood volume. Thyroxine is secreted by the thyroid and increases the metabolic rate of most body cells. 

Example Question #1 : Understanding Hormones And Digestion

What is the function of the digestive system?

Possible Answers:

Breakdown and absorb nutrients for use by the body

Deliver oxygen gas to the tissues of the body

Provide a site for gas exchange

Expel wastes and maintain stable internal water balance

Correct answer:

Breakdown and absorb nutrients for use by the body

Explanation:

This is a fundamental question that checks for clear understanding of the purpose of the digestive system. The digestive system includes the mouth, esophagus, stomach, small intestine, and large intestine. The primary functions of these structures are to break down and absorb nutrients from ingested food.

The respiratory system is responsible for providing a site for gas exchange (namely the alveoli). The circulatory system delivers oxygen to tissues, while the excretory system removes nitrogenous wastes and maintains water balance via kidney function.

Example Question #2 : Understanding Hormones And Digestion

Which of the following compounds assist in digestion in the stomach?

Possible Answers:

Pepsin and bile

Bile and HCl

HCl and pepsin

HCO3- and pepsin

Correct answer:

HCl and pepsin

Explanation:

It is important to know sites of production and action of the digestive enzymes. In the stomach, the very low pH environment facilitates gastric enzyme function, so we can already assume that an acidic compound is involved in the stomach.

HCl, or hydrochloric acid, is the acidic compound released by parietal cells and functions to kill microorganisms, digest acid labile substances, and activate pepsinogen to create pepsin.

The second main digestive compound of the stomach is pepsin, a protease, which digests amino acids into smaller peptides. It is released as a zymogen, or inactive form, by chief cells before it is activated to pepsin. The inactive form of pepsin is called pepsinogen.

Bile is a substance produced by the liver, stored by the gall bladder, and secreted into the duodenum of the small intestine for emulsification of fat globules. HCO3-, or bicarbonate ion, is a basic substance released by the pancreas into the duodenum to neutralize the entering chyme, reducing acidity to allow for optimal enzyme activity in the duodenum. Neither bile, nor bicarbonate are active in the stomach.

Example Question #93 : Tissues, Organs, And Organ Systems

At what point in the digestive tract are proteins first digested?

Possible Answers:

The stomach

The mouth

The small intestine

The esophagus

Correct answer:

The stomach

Explanation:

The stomach contains the enzyme pepsin, which helps sever the peptide bonds between amino acids and breaks protein molecules into smaller fragments. As the contents of the stomach enters the small intestine, more digestive enzymes are added to further digest the proteins; however, the first step occurs in the stomach.

It is important to note that the mouth is the first location at which carbohydrates are digested, due to the protein amylase found in saliva.

Example Question #94 : Tissues, Organs, And Organ Systems

Which hormone is responsilbe for simulating the production of gastric acid in the stomach?

Possible Answers:

Gastrin

Amylase

Motilin

CCK (cholecytokinin)

Pepsin

Correct answer:

Gastrin

Explanation:

The presence of food in the stomach stimulates the release of gastrin, which stimulates the secretion of gastric acid (). The acid in the stomach aids in digestion, and also functions as a nonspecific line of defense from infection, destroying most pathogens. Cholecystokinin is a hormone produced by the small intestine, and is responsible for stimulating release of digestive enzymes by other gastrointestinal organs. Amylase is an enzyme that breaks down starch. Motilin is a hormone that aids in digestion via pathways other than stimulating production of gastric acid in the stomach. 

Example Question #3 : Understanding Hormones And Digestion

Which enzyme is responsible for the breakdown of startch?

Possible Answers:

Gastrin

Pepsin

Amylase

Lysozyme

Insulin

Correct answer:

Amylase

Explanation:

Amylase is the enzyme secreted in salvia and into the small intestine by the pancreas that breaks down startch. Insulin is a hormone released from the pancreas that decreases blood glucose levels. Lysozyme is an enzyme present in saliva, tears, and sweat, and functions as a natural antibacterial. Pepsin is an enzyme responsible for the breakdown of proteins. Gastrin is a hormone released by the cells of the gastrointestinal organs which stimulates secretion of  from the stomach, ultimately aiding in digestion. 

Example Question #4 : Understanding Hormones And Digestion

The number one stimulator for acid production in the stomach is __________.

Possible Answers:

not eating for several hours 

distention of the stomach

eating salty food

smelling food

Correct answer:

distention of the stomach

Explanation:

When food is swallowed and reaches the stomach, the distension of the stomach is the number one stimulator for acid production. Smelling food and chewing food does stimulate acid production, however, the rise in acid produced is not as significant as produced by distention of the stomach. 

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