To achieve optimum effectiveness in promoting exchange or movement of fluids or molecules from one body compartment or system to another, such as from the ... [Show More] lumen of the gastro-intestinal tract to the extra-cellular fluid surrounding the baso-lateral membrane of enterocytes, evolution has favored development of a gastro-intestinal tract with _____.
A. more branching or folds, and finger-like projections on apical cell membranes
B. increased thickness and more rigid extra-cellular matrix
C. larger enterocyte cells with increased vesicle capacity for storage
D. decreased blood supply
A
Compared with a smaller cell, a larger cell of the same shape has _____.
A. less surface area
B. less surface area per unit of volume
C. a smaller average distance between its mitochondria and the external source of oxygen D. a smaller cytoplasm-to-nucleus ratio
B
Extra-cellular fluid is _____.
A. the internal environment inside animal cells
B. identical to the composition of blood
C. a common site of exchange between blood and body cells
D. found only in the lumen of the small intestine
C
Most types of communication between cells utilize _____.
A. the exchange of cytosol between the cells
B. the movement of the cells
C. chemical or electrical signals
D. the exchange of DNA between the cells
C
An elephant and a mouse are running in full sunlight, and both overheat by the same amount above their normal body temperatures. When they move into the shade and rest, which animal will cool down faster?
A. The elephant will because it has the higher surface-area-to-volume ratio.
B. The elephant will because it has the lower surface-area-to-volume ratio.
C. The mouse will because it has the higher surface-area-to-volume ratio.
D. They will cool at the same rate because they overheated by the same amount.
C
Once labor begins in childbirth, contractions increase in intensity and frequency, causing more contractions to occur until delivery. The increasing labor contractions of childbirth are an example of which type of regulation?
A. positive feedback
B. negative feedback
C. feedback inhibition
D. enzymatic catalysis
A
When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of _____.
A. negative feedback
B. positive feedback
C. opposing systems
D. protein-protein interactions
C
An example of a properly functioning homeostatic control system is seen when _____.
A. the core body temperature of a runner rises gradually from 37°C to 45°C
B. the kidneys excrete salt into the urine when dietary salt levels rise
C. a blood cell shrinks when placed in a solution of salt and water
D. the blood pressure increases in response to an increase in blood volume
B
Positive feedback differs from negative feedback in that _____.
A. positive feedback benefits the organism, whereas negative feedback is detrimental
B. positive feedback is required to achieve a goal or complete a process, while negative feedback maintains optimum conditions
C. the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter
D. positive feedback systems have only effectors, whereas negative feedback systems have only receptors
B
Which of the following is an example of negative feedback?
A. During birthing contractions, oxytocin (a hormone) is released and acts to stimulate further contractions.
B. When a baby is nursing, suckling leads to the production of more milk and a subsequent increase in the secretion of prolactin (a hormone that stimulates lactation).
C. After a blood vessel is damaged, signals are released by the damaged tissues that activate platelets in the blood. These activated platelets release chemicals that activate more platelets.
D. Low acidic pH in the stomach 1-2 hours after a meal diminishes the release of gastric juice containing hydrochloric acid into the stomach lumen
D
Which pair incorrectly associates a physiological process with the appropriate hormone?
A. release of stomach gastric juice — gastrin
B. release of bicarbonate solution from the pancreas into the duodenum via the bile duct — secretin
C. release of amylase from the pancreas into the duodenum via the bile duct — prolactin
D. release of bile from the gall bladder into the duodenum via the bile duct — cholecystokinin (CCK)
C
Because the foods eaten by humans are often composed largely of macromolecules, we need to have mechanisms for _____.
A. dehydration synthesis
B. acid and enzymatic hydrolysis
C. regurgitation
D. demineralization
B
In the stomach, protein digestion is enabled by:
A. gastrin stimulation of ECL, parietal and chief cells,
B. acetylcholine stimulation of G cells,
C. gastrin-releasing hormone stimulation of goblet cells,
D. pepsinogen stimulation of ECL cells
A
Parietal cells in gastric pits release _______?
A. hydrogen and chloride ions that combine into an acid that unfolds large proteins making them vulnerable to enzymatic attack by pepsin, a proteolytic enzyme that functions optimally in acidic environment,
B. pepsinogen, an inactive form of a proteolytic enzyme, that once unfolded in an acidic environment, cleaves itself into pepsin, the active enzyme,
C. histamine that stimulates ECL cells to release pepsinogen,
D. gastrin into the stomach lumen, enabling gastrin to unfold large proteins making them vulnerable to pepsin-mediated digestion.
A
Examine the digestive system structures in the figure above. The parasympathetic nervous system releases acetylcholine (Ach) to stimulate histamine, gastric juice and pepsinogen release in location _____.
A. 1
B. 3
C. 8
D. 9
B
Examine the digestive system structures in the figure above. Most of the digestion of fats occurs in structure(s) _____.
A. 3 only
B. 4 only
C. 1 and 4
D. 3 and 4
B
Secretin, a hormone released from S cells in the duodenal wall by acidic solutions, stimulates _____.
A. the release of dissacharidases from the pancreas
B. the release of CCK from I cells in the duodenal wall
C. the release of bicarbonate solution from the pancreas
D. options B and C, combined
D
On completion of stomach digestion of a meal, acid chyme released from the stomach into the duodenum stimulates the S cells and I cells in the duodenal wall to release hormones into the blood that stimulate the pancreas to_____.
A. neutralize the acidic mixture in the duodenum
B. initiate the emulsification of lipids in the duodenum
C. initiate the digestion of carbohydrates and proteins in the duodenum
D. options A, B and C, combined
D
The pancreas is involved in the digestion of _____.
I. protein
II. fat
III. carbohydrates
A. I and III
B. I, II, and III
C. II and III,
D. III only
B
Two sophomore undergraduate students studying for their animal physiology quiz decide to take a break for a lunchtime burger. Before reaching the cafeteria, nervous impulses from the parasympathetic nervous system, via the dorsal vagal complex, will initiate gastric secretion by triggering release of which molecule?
A. norepinephrine
B. vasoactive intestinal polypeptide (VIP)
C. gastrin-releasing peptide (GRP)
D. nitric oxide
C
Ingested dietary substances must cross cell membranes to be used by the body. For glucose, absorption is enabled by _____ in the apical membrane of enterocytes.
A. Na+/amino acid co-transporters
B. Na+/glucose co-transporters
C. Aquaporin-3
D. Na+/K+ ATP-ase pumps
B [Show Less]
