Color Textbook of Histology 3rd Edition by Leslie P. Gartner – Test Bank

ISBN-10: 1416029451, ISBN-13: 9781416029458

1. The fluidity of the plasmalemma has well-established clinical significance. Which of the following molecules decreases the cell membrane fluidity?

1. glycerol
2. phosphate group
3. cholesterol
4. integral proteins
5. peripheral proteins

Explanation:

The answer is c. Cholesterol decreases membrane fluidity. The polar heads of phospholipids molecules are composed of glycerol, to which a positively charged nitrogenous group is attached by a negatively charged phosphate group. Unsaturated fatty acyl molecules increase membrane fluidity. Integral and peripheral proteins do not have an effect on membrane fluidity.

2. A patient suffering from asthma has difficulty breathing and is treated with albuterol, a drug that relaxes bronchiolar smooth muscles. Albuterol acts as a(n)

1. cholinergic receptor antagonist
2. cholinergic receptor antagonist
3. adrenergic receptor antagonist
4. adrenergic receptor agonist
5. inhibitor of kinase phosphorylases

Explanation:

The answer is d. Albuterol is an agonist that acts on β₂-adrenergic receptors that are located mainly on the cell membranes of bronchial tissues and, therefore, do not have many side effects. If it were an antagonist, then it would cause smooth muscle constriction.

3. A patient suffering from asthma has difficulty breathing and is treated with albuterol and ipratropium, drugs that relax bronchiolar smooth muscles. Ipratropium acts as a(n)

1. cholinergic receptor antagonist
2. cholinergic receptor antagonist
3. adrenergic receptor antagonist
4. adrenergic receptor agonist
5. inhibitor of kinase phosphorylases

Explanation:

The answer is a. Ipratropium is a cholinergic receptor antagonist and interferes with the binding of acetylcholine, a neurotransmitter, to its receptor sites on the cell membrane, thus preventing the contraction of bronchiolar smooth muscle. The two drugs are used in combination agonist-antagonist therapy to have the desired effect of maintaining an open airway.

4. A 9-month-old female Jewish baby, whose parents were born in Poland, is seen by her pediatrician because of neurologic problems, including generalized paralysis and blindness. The pediatrician should suspect that the child is suffering from

1. spina bifida
2. cranial nerve X (vagus nerve) disorder
3. Tay-Sachs disease
4. Fabry’s disease
5. Refsum’s disease

Explanation:

The answer is c. Tay-Sachs disease affects mostly children of Eastern European Jewish ancestry as well as certain families in Lousiana of Cajun ancestry. Children suffering from this lysosomal-storage disease cannot catabolize GM₂ gangliosides that accumulate in their lysosomes, and the enlarged lysosomes interfere with cell function. The interference is most problematic in the neurons of the central nervous system and causes death by the third year of life. Neither spina bifida nor vagus nerve disorders would cause generalized paralysis or blindness. Fabry’s disease, although a lysosomal-storage disorder, is due to an X chromosomal defect and affects only males. Refsum’s disease is due to the accumulation of phytanic acid, a by-product of chlorophyll metabolism, and affects older children who already eat fresh fruits and vegetables