which organ system is primarily responsible for regulating electrolytes

HESI A2

HESI A2 Anatomy and Physiology Practice Test

1. Which organ system is primarily responsible for regulating electrolytes?

A. The endocrine system
B. The urinary system
C. The lymphatic system
D. The nervous system

Correct answer: B

Rationale: The urinary system, specifically the kidneys, is primarily responsible for regulating electrolytes in the body by filtering and excreting excess electrolytes, such as sodium, potassium, and chloride, through urine. The kidneys play a crucial role in maintaining the body's electrolyte balance, which is essential for various bodily functions and overall health. The endocrine system regulates hormones, the lymphatic system is involved in immunity, and the nervous system controls communication in the body. Therefore, the correct answer is B, the urinary system, as it directly handles electrolyte regulation by adjusting their excretion levels.

2. Which type of joint is found in the hip?

A. Hinge joint
B. Ball and socket joint
C. Pivot joint
D. Saddle joint

Correct answer: B

Rationale: The correct answer is B: Ball and socket joint. The hip joint is classified as a ball and socket joint, allowing for a wide range of movement in multiple directions, including rotation. This joint structure provides stability and mobility, making it ideal for the hip's functions in bearing weight and facilitating various movements. Choice A, Hinge joint, is incorrect as hinge joints allow movement in only one plane, like the elbow or knee. Choice C, Pivot joint, is incorrect as pivot joints allow rotation around a single axis, like the joint between the first and second vertebrae. Choice D, Saddle joint, is incorrect as saddle joints are found in the thumb and allow movement in two planes, but they do not describe the hip joint.

3. 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.

4. What is the name of the bone in the human thigh?

A. Ulna
B. Femur
C. Radius
D. Humerus

Correct answer: B

Rationale: The correct answer is B. Femur. The femur, also known as the thigh bone, is located in the human thigh. It is the longest and strongest bone in the human body, extending from the hip to the knee. The ulna, radius, and humerus, on the other hand, are bones found in the arm. Therefore, choices A, C, and D are incorrect as they are bones of the arm, not the thigh.

5. Which part of the brain is responsible for regulating body temperature?

A. Cerebrum
B. Cerebellum
C. Brainstem
D. Hypothalamus

Correct answer: D

Rationale: The hypothalamus is the part of the brain responsible for regulating body temperature, along with controlling other autonomic functions like hunger, thirst, and sleep. It acts as the body's internal thermostat, helping to maintain a stable internal environment despite external temperature changes. The cerebrum is mainly associated with functions like thinking, perception, and voluntary movements, making it unrelated to regulating body temperature. The cerebellum is involved in coordination and balance, not in regulating body temperature. The brainstem is essential for basic life functions like breathing and heart rate, but it is not primarily responsible for regulating body temperature.