HESI A2 Anatomy and Physiology 2023

Correct Answer: B

Rationale: The correct answer is B: Ball and socket joint. This type of joint allows for movement in multiple directions due to its structure where a rounded end of one bone fits into a cup-like socket of another bone. This design enables flexion, extension, abduction, adduction, and rotation. Other choices are incorrect because: A: Hinge joint allows movement in one plane only. C: Pivot joint allows rotational movement around a single axis. D: Saddle joint allows for movement in two planes but not as freely as a ball and socket joint.

Correct Answer: A

Rationale: The correct answer is A: Nucleus. The genetic material, DNA, is located within the nucleus of a cell. This is where the DNA is stored and protected. The nucleus also houses the nucleolus, which is responsible for producing ribosomes. Mitochondria (B) is responsible for energy production, not genetic material storage. Ribosomes (C) are involved in protein synthesis, not DNA storage. Golgi apparatus (D) is responsible for packaging and processing proteins, not housing genetic material.

Correct Answer: C

Rationale: The correct answer is C: Pituitary gland. The pituitary gland is known as the 'master gland' because it controls the functions of other endocrine glands in the body by secreting various hormones that regulate growth, metabolism, reproduction, and stress response. It is located at the base of the brain and is divided into anterior and posterior lobes, each with distinct functions. The other choices are incorrect because the thyroid gland regulates metabolism (A), the adrenal gland produces hormones involved in stress response (B), and the pineal gland regulates sleep-wake cycles and melatonin production (D), but none of them have the overarching control over other glands like the pituitary gland does.

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for controlling balance and coordination. It receives information from the sensory systems, such as the inner ear and visual system, and integrates this information to coordinate smooth movements. The cerebrum (B) is mainly involved in higher brain functions like thinking and problem-solving. The medulla oblongata (C) controls vital functions such as breathing and heart rate. The brainstem (D) is responsible for basic life functions like breathing and consciousness. Thus, the cerebellum is the specific region of the brain that directly controls balance and coordination.

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for balance and coordination as it receives sensory information from the inner ear and muscles to control movement. It coordinates muscle actions and maintains posture. The cerebrum (B) is responsible for higher brain functions, the medulla oblongata (C) controls basic life functions like breathing and heart rate, and the hypothalamus (D) regulates body temperature, hunger, and thirst. Thus, the cerebellum is the most appropriate choice for balance and coordination.