HESI A2 Anatomy and Physiology 2023

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: 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.

Correct Answer: A

Rationale: The correct answer is A: Pancreas. The pancreas is responsible for producing insulin, a hormone that helps regulate blood sugar levels. It contains clusters of cells called islets of Langerhans, which specifically produce insulin. The liver (B) is involved in storing glucose and producing bile, not insulin. The gallbladder (C) stores bile produced by the liver and aids in digestion, not insulin production. The kidneys (D) filter blood and regulate fluid balance, but do not produce insulin. Therefore, the pancreas is the organ responsible for insulin production in the body.

Correct Answer: B

Rationale: The correct answer is B: Hinge joint. The knee joint is classified as a hinge joint because it primarily allows movement in one plane, similar to a door hinge. This type of joint permits flexion and extension movements, which are the main actions of the knee. The other choices are incorrect because: A: Ball and socket joint allows for multi-directional movement, such as the hip joint. C: Pivot joint allows for rotation around an axis, like the joint between the radius and ulna bones in the forearm. D: Saddle joint allows for movements in two planes, like the joint at the base of the thumb.

Correct Answer: B

Rationale: The correct answer is B: Thyroid gland. The thyroid gland produces hormones such as thyroxine (T4) and triiodothyronine (T3), which regulate metabolism by controlling the body's energy production and utilization. The pituitary gland (A) regulates various other hormones but not specifically metabolism. The adrenal gland (C) produces hormones like cortisol and adrenaline, which are involved in stress response, not metabolism. The pineal gland (D) produces melatonin, which regulates sleep-wake cycles, not metabolism. Therefore, the thyroid gland is the correct answer as it directly controls metabolic functions.