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. What is the primary function of red blood cells?

A. Clotting blood
B. Transporting oxygen
C. Fighting infection
D. Carrying hormones

Correct answer: B

Rationale: The primary function of red blood cells, also known as erythrocytes, is to transport oxygen from the lungs to the body's tissues and organs. This is essential for cellular respiration and overall body functions. Red blood cells do not play a role in clotting blood, fighting infection, or carrying hormones. Choice A is incorrect because clotting blood is primarily done by platelets and other components of blood. Choice C is incorrect as fighting infection is a function mainly carried out by white blood cells. Choice D is incorrect because carrying hormones is primarily attributed to proteins like albumin and specific hormone-carrying proteins.

3. What is the average normal body temperature in degrees Celsius?

A. 30°C
B. 32°C
C. 35°C
D. 37°C

Correct answer: D

Rationale: The average normal body temperature in degrees Celsius is 37°C. This temperature is considered the standard measurement for the human body under normal conditions. It is essential to know this baseline temperature for monitoring health and detecting abnormalities such as fever. Choice A, 30°C, is too low for the average normal body temperature. Choice B, 32°C, is also below the standard normal body temperature. Choice C, 35°C, is closer but still lower than the average normal body temperature of 37°C.

4. Which organelle in the cell contains the genetic material?

A. Ribosome
B. Nucleus
C. Mitochondria
D. Endoplasmic reticulum

Correct answer: B

Rationale: The correct answer is B, Nucleus. The nucleus is the organelle in the cell that contains the genetic material (DNA). DNA within the nucleus determines the cell's functions and characteristics, making it essential for cell function and replication. Choice A, Ribosome, is responsible for protein synthesis, not genetic material storage. Choice C, Mitochondria, produces energy but does not contain the genetic material. Choice D, Endoplasmic reticulum, is involved in protein synthesis and lipid metabolism but does not house the genetic material.

5. Which of the heart's four chambers is the largest and the strongest?

A. Right atrium
B. Left ventricle
C. Right ventricle
D. Left atrium

Correct answer: B

Rationale: The left ventricle is the largest and strongest chamber of the heart. It pumps oxygenated blood to the body, making it vital for systemic circulation. The right atrium receives deoxygenated blood from the body, the right ventricle pumps this blood to the lungs, and the left atrium receives oxygenated blood from the lungs.