which feature of the ear is most medial

HESI A2

Anatomy HESI A2

1. Which feature of the ear is most medial?

A. Pinna
B. Tympanic membrane
C. Cochlea
D. Outer canal

Correct answer: B

Rationale: The tympanic membrane, also known as the eardrum, is the most medial feature in the ear. It separates the outer ear from the middle ear and serves as a barrier that vibrates in response to sound waves, transmitting vibrations to the middle ear ossicles. The pinna, cochlea, and outer canal are located more laterally in the ear anatomy. The pinna is the visible part of the ear located on the lateral side of the head, the cochlea is a spiral-shaped structure in the inner ear responsible for hearing, and the outer canal refers to the external auditory canal leading to the eardrum.

2. Which hormone is involved in the fight or flight response?

A. Cortisol
B. Adrenaline
C. Thyroxine
D. Melatonin

Correct answer: B

Rationale: The correct answer is B: Adrenaline. Adrenaline, also known as epinephrine, is the hormone involved in the fight or flight response. It is released by the adrenal glands, preparing the body for action by increasing heart rate, dilating airways, and mobilizing energy stores. Choice A, Cortisol, is a hormone released in response to stress but is not directly involved in the fight or flight response. Choice C, Thyroxine, is a hormone produced by the thyroid gland that regulates metabolism and growth, not specifically associated with the fight or flight response. Choice D, Melatonin, is a hormone that regulates sleep-wake cycles and is not involved in the fight or flight response.

3. How does the nervous system work with the muscular system?

A. The muscles of the body produce chemicals that feed the nerves.
B. The nervous system tells the muscles how to respond to the environment.
C. The nervous system releases chemicals that remove excess waste from the muscles.
D. The muscular system provides input that allows the nerves to make decisions.

Correct answer: B

Rationale: The correct answer is B because the nervous system communicates with the muscular system to control voluntary and involuntary muscle movements. The nervous system sends signals to the muscles, instructing them on how to respond to various stimuli in the environment. This communication allows for coordinated movement and responses to external and internal changes. Choice A is incorrect because muscles do not produce chemicals to feed the nerves. Choice C is incorrect because the nervous system does not release chemicals to remove waste from the muscles. Choice D is incorrect because the muscular system does not provide input for the nerves to make decisions.

4. Which hormone is released in response to low blood glucose levels?

A. Insulin
B. Glucagon
C. Cortisol
D. Adrenaline

Correct answer: B

Rationale: Glucagon is the hormone released in response to low blood glucose levels. When blood glucose levels drop, the pancreas secretes glucagon to stimulate the liver to break down glycogen into glucose, increasing blood sugar levels. This helps to restore the body's glucose balance. Insulin, on the other hand, is released in response to high blood glucose levels to lower blood sugar by promoting glucose uptake by cells. Cortisol is a stress hormone, and adrenaline is released in response to stress or danger, not specifically to regulate blood glucose levels.

5. What does the parathyroid hormone regulate?

A. Magnesium
B. Calcium
C. Calcitonin
D. Glucocorticoids

Correct answer: B

Rationale: The parathyroid hormone primarily regulates calcium levels in the blood. It acts to increase calcium levels by stimulating the release of calcium from bones, enhancing calcium reabsorption in the kidneys, and promoting the conversion of vitamin D to its active form, which aids in calcium absorption from the intestines. Therefore, the correct answer is B. Choices A, C, and D are incorrect because the parathyroid hormone does not play a significant role in the regulation of magnesium (Choice A), calcitonin (Choice C), or glucocorticoids (Choice D).