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 muscle is responsible for the extension of the elbow?

A. Biceps brachii
B. Triceps brachii
C. Deltoid
D. Pectoralis major

Correct answer: B

Rationale: The correct answer is B: Triceps brachii. The triceps brachii muscle is responsible for extending the elbow joint. It is located on the back of the upper arm and acts in opposition to the biceps brachii, which is responsible for elbow flexion. The deltoid muscle is primarily responsible for shoulder abduction, not elbow extension. The pectoralis major muscle is involved in movements of the shoulder joint, not the elbow.

3. Which system does the gall bladder belong to?

A. endocrine system
B. urinary system
C. digestive system
D. nervous system

Correct answer: C

Rationale: The gall bladder is part of the digestive system. Its primary function is to store and concentrate bile produced by the liver and release it into the small intestine to aid in the digestion of fats. This process facilitates the breakdown and absorption of fats from the food we consume. Choices A, B, and D are incorrect as the gall bladder is not associated with the endocrine, urinary, or nervous systems.

4. The vena cavae drain blood from the body into the ___________.

A. right atrium
B. right ventricle
C. left atrium
D. left ventricle

Correct answer: A

Rationale: The vena cavae are large veins responsible for returning deoxygenated blood from the body to the heart. They empty into the right atrium of the heart. From the right atrium, the blood is then pumped into the right ventricle before being sent to the pulmonary circulation for oxygenation, making choice A, 'right atrium,' the correct answer. Choices B, C, and D are incorrect because the vena cavae do not empty into the ventricles of the heart; instead, they deliver blood to the atria.

5. Which vitamin is essential for bone health?

A. Vitamin A
B. Vitamin D
C. Vitamin C
D. Vitamin K

Correct answer: B

Rationale: Vitamin D is the correct answer. It is essential for bone health as it helps in the absorption of calcium, a crucial mineral for maintaining strong and healthy bones. Adequate levels of Vitamin D are necessary to prevent conditions like osteoporosis and ensure optimal bone development and strength. Choice A, Vitamin A, is important for vision and immune function, but it is not directly related to bone health. Choice C, Vitamin C, is essential for collagen synthesis and immune function, but it is not primarily responsible for bone health. Choice D, Vitamin K, plays a role in blood clotting and bone metabolism, but Vitamin D has a more direct impact on bone health through its role in calcium absorption.