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: C

Rationale: The correct answer is C: Thyroid gland. The thyroid gland secretes hormones that regulate metabolism and calcium levels in the body. It produces thyroxine (T4) and triiodothyronine (T3) which control the body's metabolic rate. This gland also plays a crucial role in maintaining calcium levels in the blood. The other choices, A: Pituitary gland, B: Adrenal gland, and D: Pineal gland, do not primarily regulate metabolism and calcium levels in the body. The pituitary gland controls various other hormones, the adrenal gland is responsible for stress response and hormone regulation, and the pineal gland regulates sleep-wake cycles and melatonin production.

Correct Answer: B

Rationale: During the fight-or-flight response, the body needs to prepare for immediate action. Adrenaline, also known as epinephrine, is the hormone released by the adrenal glands in response to stress or danger. Adrenaline triggers physiological changes such as increased heart rate, blood flow to muscles, and heightened awareness to help the body react quickly. Insulin is involved in regulating blood sugar levels, not the fight-or-flight response. Thyroxine plays a role in metabolism, while cortisol is released in response to stress but is not the primary hormone involved in the fight-or-flight response.

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: C

Rationale: The correct answer is C: Retina. The retina contains specialized cells called cones that are responsible for color vision. Cones are sensitive to different wavelengths of light, allowing us to perceive colors. The cornea (A) focuses light onto the retina, the iris (B) controls the amount of light entering the eye, and the lens (D) helps to focus light onto the retina, but they do not directly contribute to color vision.