HESI A2
Quizlet HESI A2 Anatomy and Physiology
1. Which gland produces melatonin?
- A. Pineal gland
- B. Thyroid gland
- C. Adrenal gland
- D. Pituitary gland
Correct answer: A
Rationale: The correct answer is the Pineal gland. This gland is responsible for producing melatonin, a hormone that helps regulate the sleep-wake cycle. Melatonin production is influenced by exposure to light, with levels typically rising in the evening to promote sleep and falling in the morning to aid wakefulness. The Thyroid gland (choice B) produces hormones that regulate metabolism, the Adrenal gland (choice C) produces hormones like adrenaline and cortisol, and the Pituitary gland (choice D) controls several other glands in the endocrine system.
2. What is the main function of the nervous system?
- A. Transporting blood
- B. Protecting the body from infection
- C. Regulating body temperature
- D. Digesting food
Correct answer: C
Rationale: The main function of the nervous system is to control and coordinate body activities by transmitting signals between different parts of the body and responding to internal and external stimuli. This allows for the regulation of body temperature, movement, sensory perception, and various other functions necessary for homeostasis. Choices A, B, and D are incorrect as they do not align with the primary role of the nervous system. Transporting blood is mainly carried out by the circulatory system, protecting the body from infection is a function of the immune system, and digesting food is the role of the digestive system.
3. What is the primary function of platelets in the blood?
- A. To carry oxygen
- B. To fight infections
- C. To clot blood
- D. To transport nutrients
Correct answer: C
Rationale: The correct answer is C: To clot blood. Platelets, also known as thrombocytes, have a primary function in blood clotting. They help in the process of coagulation, forming clots to prevent excessive bleeding when injuries occur. Platelets play a crucial role in maintaining the integrity of the circulatory system by sealing off damaged blood vessels and promoting wound healing. Choices A, B, and D are incorrect because platelets do not carry oxygen, fight infections, or transport nutrients in the blood.
4. Where is a herniated lumbar disc most likely to cause pain?
- A. Along the radial nerve
- B. Within the spinal cord
- C. Along the sciatic nerve
- D. Along the tibial nerve
Correct answer: C
Rationale: A herniated lumbar disc is most likely to cause pain along the sciatic nerve. The sciatic nerve is a long nerve that extends from the lower back down the back of each leg. Compression of the sciatic nerve by a herniated disc can lead to symptoms such as pain, numbness, tingling, or weakness that radiates down the leg. This condition is commonly referred to as sciatica. Choices A, B, and D are incorrect because a herniated lumbar disc typically affects the sciatic nerve, not the radial nerve, spinal cord, or tibial nerve.
5. Which part of the brain controls involuntary actions such as breathing and heart rate?
- A. Cerebrum
- B. Cerebellum
- C. Medulla oblongata
- D. Hypothalamus
Correct answer: C
Rationale: The medulla oblongata, located at the base of the brainstem, controls essential involuntary actions such as breathing, heart rate, and blood pressure. It plays a crucial role in maintaining vital functions necessary for survival. The cerebrum is responsible for voluntary actions, conscious thought, and sensory processing, making it an incorrect choice. The cerebellum primarily coordinates movement, balance, and posture, not involuntary actions like breathing and heart rate. The hypothalamus regulates body temperature, thirst, hunger, and controls the endocrine system, but it is not directly responsible for controlling breathing and heart rate.
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