Which organ is responsible for the production of hormones during stress?
- A. Parathyroid gland
- B. Adrenal cortex
- C. Posterior pituitary gland
- D. Hypothalamus
Correct Answer: B
Rationale: The adrenal cortex is the organ responsible for producing stress hormones like cortisol and aldosterone, which play a crucial role in the body's stress response. During stress, the adrenal cortex releases cortisol, a hormone that helps the body deal with stress by increasing blood sugar, suppressing the immune system, and aiding in metabolism. Parathyroid gland is responsible for calcium regulation, the posterior pituitary gland secretes hormones like oxytocin and vasopressin which are not directly related to the stress response, and the hypothalamus plays a role in regulating hormonal balance and various bodily functions but is not primarily responsible for producing stress hormones.
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What is the role of platelets in the blood?
- A. To transport oxygen
- B. To fight infections
- C. To clot blood
- D. To carry nutrients
Correct Answer: C
Rationale: Platelets, also known as thrombocytes, play a crucial role in blood clotting. When there is an injury, platelets adhere to the site and release substances that form a clot, preventing excessive bleeding. This function is vital for maintaining hemostasis and preventing blood loss. Choice A is incorrect because red blood cells, not platelets, are responsible for transporting oxygen. Choice B is incorrect as white blood cells are primarily responsible for fighting infections. Choice D is incorrect as nutrients are mainly transported by plasma and red blood cells, not platelets.
Which muscle is responsible for breathing?
- A. Diaphragm
- B. Intercostal muscles
- C. Rectus abdominis
- D. Pectoralis major
Correct Answer: A
Rationale: The diaphragm is the primary muscle responsible for breathing. It is a large, dome-shaped muscle located at the base of the chest cavity. When it contracts, it flattens, increasing the volume of the chest cavity and causing inhalation. When it relaxes, it returns to its dome shape, decreasing the volume of the chest cavity and causing exhalation. The intercostal muscles, located between the ribs, assist the diaphragm in breathing by expanding and contracting the chest cavity. The rectus abdominis and pectoralis major are not directly involved in the process of breathing.
Which part of the brain is responsible for regulating breathing and heart rate?
- A. Cerebrum
- B. Medulla oblongata
- C. Cerebellum
- D. Hypothalamus
Correct Answer: B
Rationale: The correct answer is the Medulla oblongata. This structure, located in the brainstem, plays a crucial role in regulating essential functions such as breathing, heart rate, and blood pressure. It serves as a control center for autonomic functions necessary for maintaining life. The Cerebrum (Choice A) is mainly responsible for higher brain functions such as thinking and voluntary movements, not for regulating basic physiological processes like breathing and heart rate. The Cerebellum (Choice C) is involved in coordination, balance, and muscle control, but not in regulating breathing and heart rate. The Hypothalamus (Choice D) plays a role in regulating body temperature, hunger, and thirst, but it is not primarily responsible for controlling breathing and heart rate.
Which brain part is responsible for regulating heart rate and blood pressure?
- A. Cerebellum
- B. Medulla oblongata
- C. Hypothalamus
- D. Pons
Correct Answer: B
Rationale: The medulla oblongata, situated in the brainstem, plays a crucial role in controlling essential functions like heart rate, blood pressure, and breathing. It contains vital cardiovascular and respiratory centers, making it the correct choice for the regulation of heart rate and blood pressure. The cerebellum is primarily involved in coordinating movement and balance, not in regulating heart rate and blood pressure. The hypothalamus is responsible for maintaining homeostasis, regulating body temperature, hunger, and thirst, but not specifically heart rate and blood pressure. The pons is involved in functions like sleep, respiration, and bladder control, not primarily in regulating heart rate and blood pressure.
What is the primary function of the liver?
- A. Detoxifying harmful substances
- B. Producing bile
- C. Producing insulin
- D. Storing glycogen
Correct Answer: A
Rationale: The primary function of the liver is to detoxify harmful substances in the blood. While the liver also produces bile, which aids in digestion, stores glycogen for energy storage, and participates in metabolism, its main and essential function is detoxification. Producing insulin is mainly attributed to the pancreas, not the liver.