Which gland produces hormones that regulate metabolism?

Correct Answer: B

Rationale: The thyroid gland is responsible for producing hormones, such as thyroxine, that play a crucial role in regulating metabolism, energy production, and overall growth and development in the body. The pituitary gland, while important for hormone regulation, does not primarily regulate metabolism. The adrenal gland is responsible for producing hormones like cortisol and adrenaline, which are more related to stress response than direct metabolism regulation. The pineal gland mainly produces melatonin, which regulates sleep-wake cycles and not metabolism. Therefore, the correct answer is the thyroid gland.

Correct Answer: A

Rationale: The biceps brachii muscle is the primary muscle responsible for flexing the forearm at the elbow joint. When the biceps brachii contracts, it causes the forearm to move towards the upper arm, resulting in flexion at the elbow. In contrast, the triceps brachii is responsible for extending the forearm, the deltoid muscle is primarily involved in shoulder movements, and the brachialis muscle also aids in flexion of the forearm but to a lesser extent compared to the biceps brachii.

Correct Answer: C

Rationale: The pituitary gland, often referred to as the 'master gland,' controls the release of hormones from other endocrine glands in the body. It secretes various hormones that regulate many bodily functions, making it a central and vital component of the endocrine system. The thyroid gland (Choice A) regulates metabolism, the adrenal gland (Choice B) produces hormones like adrenaline, and the pineal gland (Choice D) secretes melatonin, but none of these glands are considered the 'master gland' that controls the functions of other endocrine glands.

Correct Answer: A

Rationale: The correct answer is the left ventricle. The left ventricle is the largest and strongest chamber of the heart. It pumps oxygenated blood to the entire body, making it a vital component of the circulatory system. The left atrium receives oxygen-rich blood from the lungs, the right ventricle pumps deoxygenated blood to the lungs for oxygenation, and the right atrium receives deoxygenated blood from the body.

Correct Answer: A

Rationale: The genetic material, which is composed of DNA, is primarily located in the nucleus of a cell. The nucleus serves as the control center of the cell, housing the genetic information that directs the cell's functions and characteristics. Choice B (Mitochondria), C (Ribosome), and D (Golgi apparatus) are incorrect because while these cellular components play essential roles in the cell, they do not house the genetic material. Mitochondria are known as the powerhouse of the cell, responsible for energy production; ribosomes are involved in protein synthesis, and the Golgi apparatus is responsible for processing and packaging proteins for transport.

Correct Answer: B

Rationale: The correct answer is a hinge joint. The elbow joint is a hinge joint that allows for flexion and extension movements, much like the movement of a door hinge. This type of joint permits movement in one plane, similar to the action of opening and closing a door. The other choices are incorrect: A) Ball and socket joints allow for a wide range of motion in multiple directions, such as the hip and shoulder joints. C) Pivot joints allow rotation around a single axis, like the joint at the top of the neck that allows the head to turn from side to side. D) Saddle joints are found in the thumb and have a biaxial range of motion allowing flexion, extension, adduction, abduction, and circumduction.

Correct Answer: C

Rationale: The correct answer is option C: Retina. The retina contains photoreceptor cells, including cones that are responsible for color vision. Cones are sensitive to different wavelengths of light, allowing us to perceive and differentiate various colors. Choice A, Cornea, is the transparent outer layer of the eye that helps focus light. It does not play a direct role in color vision. Choice B, Iris, is the colored part of the eye that controls the size of the pupil and regulates the amount of light entering the eye. While it is essential for adjusting light levels, it is not directly involved in color vision. Choice D, Lens, is responsible for focusing light onto the retina. It helps to form clear images on the retina but does not play a role in color vision.

Correct Answer: B

Rationale: Vitamin B12 is the correct answer. It is crucial for the formation and maturation of red blood cells, playing a vital role in preventing megaloblastic anemia. Additionally, Vitamin B12 is essential for maintaining nerve function. Vitamin A is important for vision and immune function, Vitamin C is necessary for collagen synthesis and immune health, and Vitamin D is crucial for bone health and immune function. Therefore, options A, C, and D are incorrect as they do not play a direct role in the formation of red blood cells.

Correct Answer: B

Rationale: The correct answer is a hinge joint. The knee is a hinge joint that allows for flexion and extension movements, enabling the leg to bend and straighten. This type of joint is designed for movement along one plane, similar to a door hinge. Choice A, ball and socket joint, is incorrect as this type of joint allows for a wider range of motion in multiple directions, unlike the knee joint. Choice C, pivot joint, and Choice D, saddle joint, are also incorrect as they do not accurately describe the type of joint found in the knee.