which gland produces hormones that regulate sleep

HESI A2

HESI A2 Practice Test Anatomy and Physiology

1. Which gland produces hormones that regulate sleep?

A. Thyroid gland
B. Pineal gland
C. Adrenal gland
D. Pituitary gland

Correct answer: B

Rationale: The pineal gland secretes melatonin, a hormone that plays a crucial role in regulating the sleep-wake cycle. Melatonin production is influenced by exposure to light, with levels increasing in the evening to promote sleep and decreasing in the morning to signal wakefulness. Choices A, C, and D are incorrect because the thyroid gland primarily regulates metabolism, the adrenal gland produces hormones like adrenaline and cortisol related to stress response, and the pituitary gland controls various functions by releasing different hormones but not specifically related to regulating sleep.

2. What is the primary function of the small intestine in the digestive system?

A. To secrete digestive enzymes
B. To absorb nutrients
C. To break down food
D. To absorb water

Correct answer: B

Rationale: The correct answer is B: To absorb nutrients. The small intestine's main role in the digestive system is to absorb nutrients from digested food. It has specialized structures, such as villi and microvilli, that increase its surface area for efficient absorption of nutrients into the bloodstream. Choice A is incorrect because the small intestine does not primarily secrete digestive enzymes; that role is mainly carried out by the pancreas and other digestive organs. Choice C is incorrect because the small intestine primarily absorbs nutrients rather than breaking down food. Choice D is incorrect because the absorption of water primarily occurs in the large intestine, not the small intestine.

3. Which vitamin is essential for calcium absorption?

A. Vitamin A
B. Vitamin D
C. Vitamin K
D. Vitamin C

Correct answer: B

Rationale: Vitamin D is crucial for the absorption of calcium in the intestines. It aids in maintaining optimal calcium levels in the body, promoting strong bones and teeth. Without sufficient Vitamin D, the absorption of calcium can be compromised, leading to potential issues with bone health. Choices A, C, and D are incorrect. Vitamin A is essential for vision, skin health, and immune function. Vitamin K is necessary for blood clotting and bone metabolism. Vitamin C is important for collagen synthesis, wound healing, and immune function, but it is not directly involved in calcium absorption.

4. Which hormone is released in response to low blood glucose levels?

A. Insulin
B. Glucagon
C. Cortisol
D. Adrenaline

Correct answer: B

Rationale: Glucagon is the hormone released in response to low blood glucose levels. When blood glucose levels drop, the pancreas secretes glucagon to stimulate the liver to break down glycogen into glucose, increasing blood sugar levels. This helps to restore the body's glucose balance. Insulin, on the other hand, is released in response to high blood glucose levels to lower blood sugar by promoting glucose uptake by cells. Cortisol is a stress hormone, and adrenaline is released in response to stress or danger, not specifically to regulate blood glucose levels.

5. Which hormone is not produced by the pituitary gland?

A. FSH
B. TRH
C. LH
D. ADH

Correct answer: B

Rationale: Thyrotropin-releasing hormone (TRH) is not produced by the pituitary gland. TRH is actually produced by the hypothalamus and acts on the pituitary gland to stimulate the release of thyroid-stimulating hormone (TSH). On the other hand, FSH (follicle-stimulating hormone), LH (luteinizing hormone), and ADH (antidiuretic hormone) are all hormones directly produced by the pituitary gland.