Practice Test

Question 1

Receptors for ______________ reside in virtually all cells of the body.

Answer 1

Cortisol

Question 2

Tyrosine is used to synthesize?

Answer 2

Thyroxine

Question 3

A substance which is not an intracellular 2nd messenger is

Answer 3

adenylate cyclase.

Question 4

Name 3 intracellular second messengers

Answer 4

C cyclic AMP.
D diacylglycerol (DAG).
C calcium-calmodulin.

Question 5

A cytoplasmic enzyme which limits how long a target cell responds to a hormone is

Answer 5

phosphotase

Question 6

In the follicle lumen of the thyroid gland the enzyme which couples two diiodothyronine molecules to form T4 is

Answer 6

thyroperoxidase

Question 7

Thyroglobulin

Answer 7

contains many tyrosine molecules.

Question 8

Of the hormones listed below which has the shortest half-life, i.e., is inactivated most quickly after it enters the blood?

Answer 8

epinepherine

Question 9

Steroid hormones bind to plasma proteins which are synthesized in and secreted from the

Answer 9

liver hepatocytes

Question 10

Cortisol is permissive for the ability of epinephrine to stimulate release of fatty acids from adipose tissue. A requirement of this response is

Answer 10

an exposure of the tissue for several hours to cortisol.

Question 11

name three hormones secreted by the anterior pituitary

Answer 11

G growth hormone.
T thyroid stimulating hormone.
P prolactin.

Question 12

name three hormones secreted by the hypothalamus

Answer 12

C corticotropin releasing hormone.
O oxytocin.
G gonadotropin releasing hormone

Question 13

In negative feedback in the hypothalamic-pituitary-thyroid axis the hormone thyroxine feeds back to inhibit

Answer 13

both the anterior pituitary and the hypothalamus.

Question 14

The cell bodies of neurons which synthesize and secrete antidiuretic hormone (ADH) have their nerve terminals (which release ADH) in the

Answer 14

posterior pituitary.

Question 15

The total amount of fluid absorbed per day from the GI tract into the blood is about _________________ the amount of fluid ingested daily.

Answer 15

seven times

Question 16

The amount of feces excreted per day is about _________________ the amount of food ingested daily.

Answer 16

one-tenth

Question 17

The daily total amount of all secretions by GI exocrine tissues is about _________________ the total volume absorbed by the GI tract.

Answer 17

equal to

Question 18

Choose the best answer regarding the role of the GI tract in bodily function.

a. The primary function of the GI tract is to provide nutrients and water for the nutrition of all of the cells of the body.
b. The GI tract plays a more important role than the kidneys or lungs in the homeostatic regulation of most blood plasma constituents.
c. The GI tract absorbs only about 50% of the nutrients present in the foods that we ingest.
d. The GI tract is a major route of excretion of toxins and waste products of metabolism.

Answer 18

a. The primary function of the GI tract is to provide nutrients and water for the nutrition of all of the cells of the body.

Question 19

The active secretion of Cl- ions is an important mechanism by which several GI tract tissues move salt and water into the GI tract lumen. This involves

Answer 19

downhill leak of Cl- ions through ion channels in the luminal membrane into the luminal fluid.

Question 20

the energy of ATP is utilized to export protons from a low concentration in the cytoplasm of the parietal cell to a high concentration in the pit lumen during the secretion of what?

Answer 20

During the secretion of hydrochloric acid by the parietal cells

Question 21

The list of agents which stimulate the parietal cell to secrete HCl includes

Answer 21

HAG

H histamine.
A acetylcholine.
G gastrin.

Question 22

controls exocrine secretions and smooth muscle motility in the GI tract.

Answer 22

The enteric nervous system (ENS)

Question 23

Choose the statement which best describes the influence of the vagus nerve in influencing stomach function.

Answer 23

Stimulation of the vagus will cause gastric releasing peptide to be released in the vicinity of G cells in the gastric antrum, which respond by secreting gastrin into the blood.

Question 24

During digestion of a meal gastric acid secretion will decline when

Answer 24

high acidity in the stomach lumen causes release of somatostatin.
high acidity in the lumen of the duodenum causes release of secretin.
the meal is largely digested and gastric filling declines

Question 25

What is enhanced by activation of mechanoreceptors (stretch receptors) which communicate with nearby smooth muscle fibers controlled by the ENS?

Answer 25

Motility of the GI Tract

Question 26

During swallowing of food

Answer 26

the upper esophageal sphincter relaxes as part of the swallowing reflex. the bolus of food moves down the esophagus aided by peristalsis. the lower esophageal sphincter relaxes before the bolus of food reaches it.

Question 27

As food accumulates in the stomach during a meal

Answer 27

peristaltic contractions originate in the body of the stomach.

Question 28

The migrating motility complex

Answer 28

is organized by the enteric nervous system in the lower stomach and small intestine.

Question 29

The membrane of smooth muscle fibers in the gastric antrum

Answer 29

can be depolarized to a threshold value which causes action potentials to be generated.

Question 30

Colonic mass movements

Answer 30

occur simultaneously with the gastroileal reflex. advance the chyme toward the terminal colon. may initiate the defecation reflex.

Question 31

An exocrine secretion of sodium bicarbonate by the pancreas

Answer 31

contains HCO3- ions at a concentration 5 times greater than the plasma HCO3- concentration.

Question 32

The list of enzymes secreted by the pancreas includes

Answer 32

CACE C carboxypeptidase B A amylase CE cholesterol esterase

Question 33

During the postabsorptive phase, when there is no chyme in the small intestine the gallbladder.....

Answer 33

the gallbladder is absorbing salts and water and concentrating bile salts, which remain in the gallbladder lumen.

Question 34

Three functions attributable to cholecystokinin are

Answer 34

inhibition of gastric secretion. relaxation of the sphincter of Oddi. contraction of the gallbladder.

Question 35

act as detergents in the intestinal lumen.

Answer 35

Bile Salt Molecules

Question 36

During absorption of the digestion products of fat hydrolysis in the duodenal lumen

Answer 36

absorbed monoglycerides and fatty acids are synthesized into triglycerides using ATP.

Question 37

The list of enzymes that are intrinsic membrane proteins embedded in the intestinal brush border membrane includes:

Answer 37

MED M maltase E enterokinase D dextrinase

Question 38

Chylomicrons do not contain

Answer 38

water-soluble vitamins.

Question 39

Gastric hypersecretion of acid can cause

Answer 39

erosion of the duodenal mucosa and ulceration. steatorrhea. impaired digestion of dietary protein

Question 40

The colonic absorptive mucosa differs from the small intestinal mucosa in that only the colonic mucosa

Answer 40

prevents absorbed Na+ ions from back-diffusing through the epithelium into the colonic lumen.

Question 41

The colon is also referred to as the large intestine because

Answer 41

it has a wider diameter than the small intestine.

Question 42

the duodenum influences the rate of gastric acid secretion by

Answer 42

1. operating through the ENS to inhibit parietal cell secretion when the walls of the duodenum are distended 2. releasing a hormone in response to luminal acidity which operates back upon the stomach to inhibit parietal cell acid secretion directly 3. releasing a hormone in response to amino acids in the luminal chyme which reduces gastric acid secretion and the strength of gastric peristaltic contractions

Question 43

steatorrhea or excessive fat in the stools may be due to

Answer 43

failure of pancreas to secrete NaHCO3 failure of pancreas to secrete lipase failure of betalipoprotein synthesis by enterocytes