Which hormone is released by the adrenal medulla?
- A. Cortisol
- B. Adrenaline
- C. Insulin
- D. Somatostatin
Correct Answer: B
Rationale: The correct answer is B, Adrenaline (also known as epinephrine), which is released by the adrenal medulla during the body's fight-or-flight response. Adrenaline helps prepare the body for action by increasing heart rate, dilating air passages, and mobilizing glucose and fats for energy, among other physiological responses.
Choice A, Cortisol, is a steroid hormone released by the adrenal cortex involved in the stress response and regulation of metabolism. Choice C, Insulin, is produced by the pancreas and regulates blood sugar levels. Choice D, Somatostatin, is a hormone that inhibits the release of several other hormones in the body, but it is not released by the adrenal medulla.
You may also like to solve these questions
What is the primary function of the respiratory system?
- A. To transport oxygen and remove carbon dioxide
- B. To regulate body temperature
- C. To fight infections
- D. To produce energy
Correct Answer: A
Rationale: The primary function of the respiratory system is to facilitate the exchange of oxygen and carbon dioxide between the air and the bloodstream. Oxygen is taken in during inhalation and transported to cells, while carbon dioxide is removed during exhalation as a waste product of cellular metabolism. Choices B, C, and D are incorrect as they do not reflect the primary function of the respiratory system. Regulating body temperature is mainly controlled by the thermoregulatory system, fighting infections is a function of the immune system, and producing energy is primarily done by the metabolic system.
Which type of muscle is found in the walls of hollow organs?
- A. Skeletal muscle
- B. Cardiac muscle
- C. Smooth muscle
- D. Striated muscle
Correct Answer: C
Rationale: Smooth muscle tissue is found in the walls of hollow organs, such as the intestines, blood vessels, and bladder. It contracts involuntarily, allowing for movements like peristalsis in the intestines and regulation of blood flow in blood vessels. Skeletal muscle (Choice A) is attached to bones and helps in voluntary movements. Cardiac muscle (Choice B) is found in the heart and contracts involuntarily to pump blood. Striated muscle (Choice D) refers to both skeletal and cardiac muscles, which have a striped appearance due to the organization of their filaments. However, smooth muscle (Choice C) is specifically the type found in hollow organs.
Which hormone is released by the posterior pituitary gland?
- A. Oxytocin
- B. Thyroxine
- C. Insulin
- D. ADH
Correct Answer: A
Rationale: Oxytocin is the correct answer. It is released by the posterior pituitary gland and plays a vital role in childbirth and lactation. Oxytocin promotes uterine contractions during labor and milk ejection during breastfeeding. Choice B, Thyroxine, is incorrect as it is produced by the thyroid gland. Choice C, Insulin, is incorrect as it is produced by the pancreas. Choice D, ADH (Antidiuretic Hormone), is also released by the posterior pituitary gland, but it is not the hormone primarily associated with childbirth and lactation.
Which of the following structures regulates the transport of substances in and out of a cell?
- A. Nucleus
- B. Cell membrane
- C. Cytoplasm
- D. Mitochondria
Correct Answer: B
Rationale: The cell membrane, also known as the plasma membrane, is responsible for regulating the transport of substances in and out of the cell. It acts as a selective barrier, allowing the passage of certain molecules while restricting others. This selective permeability helps maintain homeostasis within the cell by controlling the movement of essential substances like nutrients and waste products. The nucleus (Choice A) is the organelle that houses the cell's genetic material and is not directly involved in regulating substance transport. Cytoplasm (Choice C) is the gel-like substance that fills the cell and does not play a direct role in regulating substance transport. Mitochondria (Choice D) are responsible for energy production in the cell through cellular respiration and are not primarily involved in substance transport.
What is the function of the pancreas in digestion?
- A. Secreting digestive enzymes
- B. Producing bile
- C. Storing glucose
- D. Regulating blood sugar levels
Correct Answer: A
Rationale: The correct answer is A: Secreting digestive enzymes. The pancreas aids in digestion by secreting digestive enzymes that are essential for breaking down carbohydrates, fats, and proteins in the small intestine. These enzymes help in the absorption of nutrients from food, facilitating the digestive process. Choices B, C, and D are incorrect. The pancreas does not produce bile (choice B), store glucose (choice C), or primarily regulate blood sugar levels (choice D) in the context of digestion.