Question

37-1/Which of the following functions is regulated by the hormone melatonin?

Select one: _

a. Circadian rhythm _

b. Adaptation to stress

c. Start of labor

d. Skin pigmentation

2/A 67 years old women with a family history of a Graves' disease, an autoimmune disease characterised by the presence of antibodies directed against thyroid stimulating hormone receptors in the thyroid gland. Her condition is due to:

Select one:

a. A shortage of B lymphocytes _

b. an implanted "foreign" thyroid gland from an unrelated donor _

C. the failure of her immune system to generate an innate immune response

d. the failure of her immune system to prevent activation of self-reactive lymphocytes

3/Which of the following conditions prolongs the coagulation time?

Select one: _

a. Purpura

b. Anemia _

c. Polycythemia _

d. Hemophilia

4/Which of the following will increase upon stimulation of the parasympathetic nerves to the bronchi?

Select one: _

a. Lung compliance

b. Surface tension

C. Broncho constriction

d. Anatomic dead space

Answer 1

1)Correct answer is option (a) Circadian rhythm

Circadian rhythm or sleep wake cycle is under the control of hormone melatonin. It is released by pineal gland.

Adaptation to stress is controlled by various stress hormones. They are cortisol, catecholamines and thyroid hormones.

Uterine contractions during labour is maintained by oxytocin.

Skin pigmentation is controlled by Melanocyte-stimulating hormone.

2)Correct answer is option (d) the failure of her immune system to prevent activation of self-reactive lymphocytes

Graves' disease is an autoimmune disease. Body's immune system produces abnormal antibodies which mimics TSH. They cause overproduction of thyroid hormones and results in hyperthyroidism.

Failure of her immune system to generate an innate immune response is immuno deficiency which does not occur in Graves disease.

3)Correct answer is option (d) hemophilia

Clotting time is the time taken by blood to get clot. Normal clotting time is 2-8 minutes.

In hemophilia, there is deficiency of clotting factors which results in impaired blood clotting. So, blood clotting takes a longer time than normal.

Anemia is reduction in RBC count and polycythemia is excess RBC. These disorders do not affect clotting factors or clotting time.

Purpura means a purple discoloration of skin. It can result from immune reaction against platelets. This condition is called ITP( Idiopathic thrombocytopenic purpura). Bleeding time is prolonged in this condition. Clotting time is not affected.

4) Correct answer is option (c)Broncho constriction

Parasympathetic nervous system stimulation causes smooth muscles in brochi to contract and it results in broncho constriction.

Lung compliance, surface tension and anatomic dead space are not altered due to parasympathetic stimulation.