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. The hypothalamus is part of the ___________.

A. cardiovascular system
B. endocrine system
C. respiratory system
D. lymphatic system

Correct answer: B

Rationale: The hypothalamus is a small region of the brain that plays a crucial role in linking the nervous system to the endocrine system. It helps regulate various bodily functions by releasing hormones that signal the pituitary gland to release other hormones that control metabolism, growth, reproduction, sleep, and other important processes. Therefore, the hypothalamus is a key component of the endocrine system. Choices A, C, and D are incorrect because the hypothalamus is not part of the cardiovascular, respiratory, or lymphatic systems.

3. What is the function of white blood cells?

A. To carry oxygen to the cells
B. To fight infection
C. To transport nutrients
D. To clot blood

Correct answer: B

Rationale: White blood cells are a vital part of the immune system. Their primary function is to fight infections by attacking bacteria, viruses, and other pathogens that enter the body. They play a crucial role in protecting the body against illnesses and maintaining overall health. Choice A is incorrect because the role of carrying oxygen to cells is primarily performed by red blood cells. Choice C is incorrect as the transportation of nutrients is mainly carried out by the bloodstream and specialized cells. Choice D is incorrect as the process of clotting blood is primarily mediated by platelets.

4. Through which organ do muscles push food into the stomach via peristalsis?

A. Mouth
B. Small intestine
C. Epiglottis
D. Esophagus

Correct answer: D

Rationale: The correct answer is D, Esophagus. Muscles push food into the stomach via peristalsis in the esophagus. Peristalsis is a coordinated muscular contraction that helps move food from the mouth to the stomach through the esophagus. The rhythmic contractions of the esophageal muscles create a wave-like motion that propels food downward toward the stomach for digestion. Choices A, B, and C are incorrect because the mouth is where digestion begins but does not push food into the stomach, the small intestine is mainly responsible for absorbing nutrients, and the epiglottis is a flap that prevents food from entering the trachea during swallowing, not involved in pushing food into the stomach.

5. Which of the following structures is located in the respiratory system?

A. Larynx
B. Trachea
C. Pharynx
D. Esophagus

Correct answer: A

Rationale: The larynx, also known as the voice box, is a crucial structure in the respiratory system. It is located in the upper part of the trachea and houses the vocal cords. The larynx plays a key role in producing sound and protecting the trachea by closing during swallowing to prevent food from entering the airway. This makes the larynx the correct answer in this context. The trachea (Choice B) is a respiratory structure that connects the larynx to the lungs, allowing air to pass through. The pharynx (Choice C) is a shared pathway for both air and food, located at the back of the throat. The esophagus (Choice D) is part of the digestive system, responsible for transporting food from the mouth to the stomach. Therefore, Choices B, C, and D are not located in the respiratory system.