HESI A2
HESI A2 Anatomy and Physiology Practice Test
1. What is the normal pH of human arterial blood?
- A. 6.8
- B. 7.4
- C. 7.9
- D. 8.2
Correct answer: B
Rationale: The normal pH of human arterial blood is approximately 7.4. This slightly alkaline pH is crucial for the proper functioning of enzymes and biochemical processes in the body. Any significant deviation from this pH level can result in serious health issues such as acidosis or alkalosis. Choice A (6.8) is incorrect as it is lower than the normal pH of arterial blood, indicating acidity. Choice C (7.9) and Choice D (8.2) are incorrect as they are higher than the normal pH of arterial blood, indicating alkalinity.
2. Which hormone is produced by the adrenal medulla?
- A. Insulin
- B. Adrenaline
- C. Cortisol
- D. Melatonin
Correct answer: B
Rationale: Adrenaline, also known as epinephrine, is the correct hormone produced by the adrenal medulla. It plays a crucial role in the body's fight-or-flight response, increasing heart rate, dilating airways, and mobilizing energy stores to prepare the body for perceived threats. Insulin (Choice A) is produced by the pancreas and regulates blood sugar levels, not by the adrenal medulla. Cortisol (Choice C) is produced by the adrenal cortex and is involved in regulating metabolism, immune response, and stress. Melatonin (Choice D) is produced by the pineal gland and regulates the sleep-wake cycle.
3. 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.
4. What structure links the nasopharynx to the middle ear?
- A. Larynx
- B. Pharyngeal muscles
- C. Eustachian tube
- D. Bronchus
Correct answer: C
Rationale: The Eustachian tube is the structure that connects the nasopharynx to the middle ear. It functions to equalize pressure between the middle ear and the atmosphere, protecting the eardrum from damage and aiding in the drainage of fluid from the middle ear. This connection is essential for maintaining proper ear function and health. The larynx (Choice A) is not the correct structure that links the nasopharynx to the middle ear. Pharyngeal muscles (Choice B) are involved in swallowing and do not directly link the nasopharynx to the middle ear. The bronchus (Choice D) is part of the respiratory system and is not connected to the middle ear.
5. Which type of muscles are involved in peristalsis?
- A. Smooth muscles
- B. Cardiac muscles
- C. Skeletal muscles
- D. Epaxial muscles
Correct answer: A
Rationale: Peristalsis is a coordinated, wave-like muscular contraction that propels food and other materials through the digestive tract. Smooth muscles are responsible for this movement in the gastrointestinal tract, providing the involuntary contractions needed for peristalsis to occur. Skeletal muscles, cardiac muscles, and epaxial muscles are not directly involved in peristalsis. Cardiac muscles are found in the heart and are responsible for its contraction. Skeletal muscles are attached to bones and control voluntary movements. Epaxial muscles are located along the vertebral column and are involved in the movement and stabilization of the spine.
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