HESI A2
Quizlet HESI A2 Anatomy and Physiology
1. Which gland produces the hormone melatonin?
- A. Pineal gland
- B. Thyroid gland
- C. Pituitary gland
- D. Adrenal gland
Correct answer: A
Rationale: The correct answer is the Pineal gland. The pineal gland is responsible for producing melatonin, a hormone that helps regulate the sleep-wake cycle. Melatonin secretion is influenced by light exposure. Higher levels are observed at night to promote sleep, while lower levels during the day encourage wakefulness. Choices B, C, and D are incorrect as they are not associated with the production of melatonin. The thyroid gland produces hormones like thyroxine and triiodothyronine, the pituitary gland controls various other glands, and the adrenal gland produces hormones like adrenaline and cortisol.
2. What is the primary role of the liver in the body?
- A. Producing insulin
- B. Detoxifying harmful substances
- C. Digesting food
- D. Storing energy
Correct answer: B
Rationale: The correct answer is B: Detoxifying harmful substances. While the liver does produce bile for digestion and stores nutrients like glycogen, its primary function is to filter and detoxify blood coming from the digestive tract before passing it to the rest of the body. Therefore, choices A, C, and D are incorrect. Producing insulin is mainly done by the pancreas, digesting food is primarily the role of the stomach and intestines, and storing energy is a function of various organs like muscles and fat cells.
3. Which organ system is primarily responsible for maintaining temperature control?
- A. The skeletal system
- B. The digestive system
- C. The nervous system
- D. The integumentary system
Correct answer: D
Rationale: The integumentary system, which includes the skin, hair, and nails, is primarily responsible for maintaining temperature control in the body. The skin helps regulate body temperature through processes like sweating to cool down and shivering to generate heat. Additionally, blood vessels in the skin can dilate or constrict to control the amount of heat lost or retained by the body. This system plays a crucial role in maintaining homeostasis and keeping the body at a stable temperature. The skeletal system (Choice A) provides structural support and protection to the body but is not directly involved in temperature regulation. The digestive system (Choice B) is responsible for breaking down food and absorbing nutrients, not for regulating body temperature. The nervous system (Choice C) controls body functions through electrical impulses but is not the primary system responsible for temperature control.
4. Which of the following is not a principal organ of the nervous system?
- A. Brain
- B. Thymus
- C. Ganglia
- D. Spinal cord
Correct answer: B
Rationale: The correct answer is B. The thymus is not a principal organ of the nervous system; it is part of the immune system. The brain, spinal cord, and ganglia are principal organs of the nervous system. The brain is responsible for processing information, the spinal cord helps transmit signals between the brain and the rest of the body, and ganglia are clusters of nerve cells that support the nervous system's functions. Therefore, the thymus is the correct answer as it is not directly involved in nervous system functions.
5. Which type of muscle tissue is found in the heart?
- A. Smooth muscle
- B. Cardiac muscle
- C. Skeletal muscle
- D. Striated muscle
Correct answer: B
Rationale: Cardiac muscle tissue, represented by choice B, is the correct answer. Cardiac muscle tissue is unique to the heart and responsible for its involuntary contractions that pump blood throughout the body. Smooth muscle (choice A) is found in the walls of hollow organs, skeletal muscle (choice C) is attached to bones for movement, and striated muscle (choice D) is a general term that can refer to both cardiac and skeletal muscle but is not specific to the heart.
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