Answers : Endocrine System MCQs

Answers, explanations, and relevant extra information for the 10 high-yield multiple-choice questions on the endocrine system:

To see high-yield multiple-choice questions on the endocrine system, MCQs for NHPC licensing exam click this link 

1. Which hormone is responsible for regulating blood glucose levels by promoting glucose uptake in cells and inhibiting glucose production in the liver?

   Answer: a) Insulin

   Explanation: Insulin is produced by the beta cells of the pancreas. It plays a vital role in glucose metabolism by promoting glucose uptake in cells, particularly in muscle and adipose tissue, and inhibiting glucose production in the liver. This helps to maintain blood glucose levels within a normal range.

2. The primary target organ for antidiuretic hormone (ADH) is:

   Answer: b) Kidneys

   Explanation: Antidiuretic hormone (ADH), also known as vasopressin, is produced by the hypothalamus and released by the posterior pituitary gland. Its primary target organ is the kidneys, where it acts to increase water reabsorption, leading to decreased urine output and water conservation in the body.

3. Graves' disease is characterized by an overactive thyroid gland, resulting in hyperthyroidism. Which of the following antibodies is commonly found in individuals with Graves' disease?

   Answer: e) Thyroid-stimulating immunoglobulin (TSI)

   Explanation: Graves' disease is an autoimmune disorder in which the body produces antibodies that stimulate the thyroid gland to produce excess thyroid hormones. The most relevant antibody in this context is thyroid-stimulating immunoglobulin (TSI), which mimics the action of thyroid-stimulating hormone (TSH) and leads to an overproduction of thyroid hormones.

4. The adrenal cortex primarily produces which class of hormones?

   Answer: b) Mineralocorticoids

   Explanation: The adrenal cortex, the outer layer of the adrenal glands, primarily produces three classes of hormones: mineralocorticoids (e.g., aldosterone), glucocorticoids (e.g., cortisol), and androgens (e.g., dehydroepiandrosterone). Among these, mineralocorticoids are responsible for regulating the balance of minerals, particularly sodium and potassium, in the body.

5. Parathyroid hormone (PTH) plays a crucial role in maintaining calcium homeostasis. What effect does PTH have on blood calcium levels?

   Answer: a) Increases blood calcium levels

   Explanation: Parathyroid hormone (PTH) is produced by the parathyroid glands and plays a major role in regulating calcium levels in the blood. PTH increases blood calcium levels by promoting the release of calcium from bone tissue, increasing calcium reabsorption in the kidneys, and stimulating the activation of vitamin D, which enhances calcium absorption in the intestines.

6. Which endocrine gland is responsible for the production of melatonin, a hormone that regulates sleep-wake cycles?

   Answer: a) Pineal gland

   Explanation: The pineal gland, located deep within the brain, is responsible for producing the hormone melatonin. Melatonin plays a crucial role in regulating the body's circadian rhythm, influencing sleep-wake cycles and other daily physiological processes.

7. Which hormone is released in response to stress and helps the body prepare for a "fight or flight" response?

   Answer: b) Cortisol

   Explanation: Cortisol, often referred to as the "stress hormone," is released by the adrenal glands in response to stress or low blood glucose levels. It helps the body adapt to stressful situations by increasing blood sugar levels, suppressing the immune system, and aiding in the metabolism of carbohydrates, fats, and proteins.

8. Inadequate production of adrenal hormones, such as cortisol and aldosterone, due to adrenal gland insufficiency is known as:

   Answer: a) Addison's disease

   Explanation: Addison's disease, also called adrenal insufficiency, occurs when the adrenal glands do not produce enough cortisol and often aldosterone. This condition may result from autoimmune destruction, infections, or other factors affecting the adrenal glands.

9. Which hormone is responsible for stimulating uterine contractions during childbirth and promoting milk ejection during breastfeeding?

   Answer: a) Oxytocin

   Explanation: Oxytocin is produced by the hypothalamus and released by the posterior pituitary gland. It is known as the "love hormone" or "bonding hormone" because it plays a crucial role in social bonding and maternal behaviors. During childbirth, oxytocin stimulates uterine contractions, and after childbirth, it helps with milk ejection during breastfeeding.

10. Which of the following is NOT a function of the thyroid hormones thyroxine (T4) and triiodothyronine (T3)?

    Answer: d) Stimulation of erythropoiesis

    Explanation: Thyroxine (T4) and triiodothyronine (T3) are produced by the thyroid gland and play essential roles in regulating metabolism, body temperature, and overall growth and development. While they are involved in many physiological processes, they are not directly responsible for the stimulation of erythropoiesis (red blood cell production), which is primarily regulated by the hormone erythropoietin produced in the kidneys.

Relevant Extra Information on Endocrine System:

• The pancreas contains both endocrine and exocrine functions. The endocrine portion consists of clusters of cells called the Islets of Langerhans, where hormones such as insulin and glucagon are produced.
  
  
• ADH also acts on blood vessels, causing vasoconstriction, which helps regulate blood pressure in times of low blood volume.
  
  
• In Graves' disease, patients may experience symptoms such as hyperthyroidism, goiter (enlargement of the thyroid gland), bulging eyes (exophthalmos), and weight loss.
  
  
• Cushing's syndrome is characterized by excessive cortisol production, leading to symptoms like central obesity, moon face, buffalo hump, and easy bruising.
  
  
• Vasopressin (ADH) is also responsible for controlling water balance by influencing thirst perception.
  
  
• The parathyroid glands are four small glands located on the posterior surface of the thyroid gland.
  
  
• Melatonin production is influenced by the amount of light exposure, with increased production in darkness and reduced production in light.
  
  
• During the "fight or flight" response, cortisol increases glucose availability for immediate energy use, while epinephrine and norepinephrine rapidly prepare the body for action.
  
  
• Addison's disease can lead to symptoms such as fatigue, weakness, low blood pressure, and hyperpigmentation of the skin.
  
  
• Oxytocin's role in social bonding and trust extends beyond childbirth and breastfeeding and plays a role in emotional bonding between individuals.

Remember, understanding these high-yield concepts will help you grasp the complexities of the endocrine system and excel in your medical studies and clinical practice. Good luck!