which structure in the ear is responsible for hearing

HESI A2

Anatomy and Physiology Hesi A2 Practice Test

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

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

Correct answer: A

Rationale: The cochlea, located in the inner ear, is responsible for detecting sound waves and converting them into neural signals that are sent to the brain for processing. It plays a crucial role in the process of hearing by translating mechanical vibrations into electrical signals that the brain can interpret as sound. The semicircular canals (Choice B) are responsible for balance and detecting head movements, not hearing. The ossicles (Choice C) are three tiny bones in the middle ear that transmit sound vibrations from the eardrum to the cochlea. The Eustachian tube (Choice D) helps equalize pressure between the middle ear and the atmosphere, but it is not directly involved in the process of hearing.

2. What is the meaning of exocytosis?

A. The cell engulfs and brings in substances.
B. The cell releases content outside by fusing with the plasma membrane.
C. The cell engulfs liquid material.
D. The cell brings in solid particles.

Correct answer: B

Rationale: Exocytosis is the process by which a cell releases substances to the outside by fusing with the plasma membrane. During exocytosis, vesicles containing molecules fuse with the cell membrane, allowing the release of the contents outside the cell. This process is crucial for the secretion of various substances such as hormones, enzymes, and neurotransmitters. Choices A, C, and D are incorrect as they describe processes different from exocytosis. Choice A describes endocytosis, where the cell engulfs substances to bring them into the cell. Choice C is more aligned with pinocytosis, the process of engulfing liquid material. Choice D refers to phagocytosis, which is the uptake of solid particles by the cell.

3. Which organ in the digestive system absorbs nutrients?

A. Stomach
B. Small intestine
C. Large intestine
D. Esophagus

Correct answer: B

Rationale: The small intestine is the primary site for nutrient absorption in the digestive system. It plays a crucial role in absorbing digested food into the bloodstream, where the nutrients are then circulated to the body's cells for energy and other functions. The stomach primarily breaks down food through the action of acids and enzymes, while the large intestine absorbs water and salts, not nutrients. The esophagus is a muscular tube that connects the mouth to the stomach and does not participate in nutrient absorption.

4. What is the role of the large intestine in the digestive system?

A. Absorbing nutrients
B. Absorbing water and forming solid waste
C. Breaking down fats
D. Secreting digestive enzymes

Correct answer: B

Rationale: The correct answer is B: Absorbing water and forming solid waste. The large intestine plays a crucial role in absorbing water from the remaining indigestible food matter and forming solid waste (feces) to be excreted from the body. This process helps in maintaining the body's fluid balance and eliminating waste efficiently. Choices A, C, and D are incorrect because the large intestine is not primarily responsible for absorbing nutrients, breaking down fats, or secreting digestive enzymes. These functions are mainly carried out in the small intestine.

5. Which organ system is primarily responsible for maintaining temperature control?

A. The skeletal system
B. The digestive system
C. The nervous system
D. The integumentary system

Correct answer: D

Rationale: The integumentary system, which includes the skin, hair, and nails, is primarily responsible for maintaining temperature control in the body. The skin helps regulate body temperature through processes like sweating to cool down and shivering to generate heat. Additionally, blood vessels in the skin can dilate or constrict to control the amount of heat lost or retained by the body. This system plays a crucial role in maintaining homeostasis and keeping the body at a stable temperature. The skeletal system (Choice A) provides structural support and protection to the body but is not directly involved in temperature regulation. The digestive system (Choice B) is responsible for breaking down food and absorbing nutrients, not for regulating body temperature. The nervous system (Choice C) controls body functions through electrical impulses but is not the primary system responsible for temperature control.