which gland is often referred to as the master gland

HESI A2

HESI A2 Practice Test Anatomy and Physiology

1. Which gland is often referred to as the 'master gland'?

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

Correct answer: B

Rationale: The pituitary gland is often referred to as the 'master gland' because it controls the release of hormones from other endocrine glands in the body. It secretes a variety of hormones that regulate various bodily functions and play a crucial role in maintaining homeostasis. The thyroid gland (Choice A) plays a role in regulating metabolism, the adrenal gland (Choice C) secretes hormones involved in stress response, and the pineal gland (Choice D) produces melatonin to regulate sleep-wake cycles, but they are not known as the 'master gland' due to their functions.

2. Which vitamin is essential for the formation of red blood cells?

A. Vitamin A
B. Vitamin B12
C. Vitamin C
D. Vitamin D

Correct answer: B

Rationale: Vitamin B12 is the correct answer. It is crucial for the formation and maturation of red blood cells, playing a vital role in preventing megaloblastic anemia. Additionally, Vitamin B12 is essential for maintaining nerve function. Vitamin A is important for vision and immune function, Vitamin C is necessary for collagen synthesis and immune health, and Vitamin D is crucial for bone health and immune function. Therefore, options A, C, and D are incorrect as they do not play a direct role in the formation of red blood cells.

3. What is the main function of the large intestine?

A. Absorption of nutrients
B. Absorption of water
C. Secretion of digestive enzymes
D. Breaking down fats

Correct answer: B

Rationale: The main function of the large intestine is the absorption of water and electrolytes from indigestible food residues, helping to form solid waste (feces) for elimination. It mainly reabsorbs water and compacts the remaining material into feces, playing a crucial role in maintaining fluid balance in the body. Choices A, C, and D are incorrect because absorption of nutrients primarily occurs in the small intestine, secretion of digestive enzymes mainly occurs in the stomach and small intestine, and breaking down fats primarily occurs in the small intestine with the help of bile from the liver and enzymes.

4. What is the main function of the immune system?

A. To produce hormones
B. To protect the body from infections
C. To remove waste products
D. To regulate body temperature

Correct answer: B

Rationale: The main function of the immune system is to protect the body from infections by identifying and destroying pathogens like bacteria and viruses. It plays a crucial role in maintaining overall health and preventing illnesses. Choice A is incorrect because hormone production is primarily handled by the endocrine system, not the immune system. Choice C is incorrect as waste removal is mainly performed by the excretory system, not the immune system. Choice D is incorrect as regulating body temperature is primarily the role of the thermoregulatory system, not the immune system.

5. Which hormone is involved in the regulation of water balance in the body?

A. ADH
B. Insulin
C. Cortisol
D. Thyroxine

Correct answer: A

Rationale: The correct answer is ADH (antidiuretic hormone), also known as vasopressin. ADH helps regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys. When there is a need to conserve water, ADH levels increase, leading to more water reabsorption and concentration of urine. Insulin is involved in regulating blood sugar levels, not water balance. Cortisol is a stress hormone that helps regulate metabolism and immune response, not water balance. Thyroxine is a thyroid hormone that regulates metabolism, growth, and development, not water balance.