which structure in the ear is responsible for balance

HESI A2

Anatomy HESI A2 Practice Test

1. Which structure in the ear is responsible for balance?

A. Cochlea
B. Semicircular canals
C. Ossicles
D. Eustachian tube

Correct answer: B

Rationale: The semicircular canals in the inner ear are responsible for maintaining balance by detecting changes in head position and movement. These structures contain fluid and hair cells that send signals to the brain regarding the body's orientation in space, helping us stay balanced and navigate our surroundings. The cochlea is responsible for hearing, the ossicles are involved in sound transmission, and the Eustachian tube helps equalize pressure in the middle ear, but they are not directly related to balance.

2. 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.

3. What is the term for red blood cell production?

A. Hematopoiesis
B. Erythropoiesis
C. Phagocytosis
D. Thrombopoiesis

Correct answer: B

Rationale: The correct term for red blood cell production is erythropoiesis. This process specifically refers to the production of red blood cells, mainly occurring in the bone marrow. Hematopoiesis is a broader term that encompasses the production of all blood cells, including red blood cells, white blood cells, and platelets. Phagocytosis is the process of engulfing and digesting particles by cells like macrophages, not related to red blood cell production. Thrombopoiesis is the production of platelets, not red blood cells.

4. Which organ system is primarily responsible for integrating voluntary movements?

A. Cardiovascular system
B. Digestive system
C. Respiratory system
D. Nervous system

Correct answer: D

Rationale: The correct answer is D: Nervous system. The nervous system is primarily responsible for integrating voluntary movements. This system includes the brain, spinal cord, and peripheral nerves that communicate signals throughout the body to control movement. The brain interprets sensory information, formulates decisions, and sends signals to the muscles to execute voluntary movements. The cardiovascular system is responsible for circulating blood, the digestive system for breaking down food and absorbing nutrients, and the respiratory system for gas exchange in the body. Choices A, B, and C are incorrect as they do not play a primary role in integrating voluntary movements.

5. What is the function of the gallbladder in the digestive system?

A. To produce bile
B. To store and concentrate bile
C. To detoxify harmful substances
D. To regulate blood sugar

Correct answer: B

Rationale: The gallbladder's main function is to store and concentrate bile produced by the liver. Bile is essential for the digestion and absorption of fats in the small intestine. Therefore, the correct answer is B, as the gallbladder acts as a reservoir for bile rather than producing it. Choices A, C, and D are incorrect because the gallbladder does not produce bile, detoxify harmful substances, or regulate blood sugar in the digestive system.