Nokea
Which vitamin is essential for calcium absorption?
- A. Vitamin A
- B. Vitamin D
- C. Vitamin K
- D. Vitamin C
Correct Answer: B
Rationale: Vitamin D is crucial for the absorption of calcium in the intestines. It aids in maintaining optimal calcium levels in the body, promoting strong bones and teeth. Without sufficient Vitamin D, the absorption of calcium can be compromised, leading to potential issues with bone health. Choices A, C, and D are incorrect. Vitamin A is essential for vision, skin health, and immune function. Vitamin K is necessary for blood clotting and bone metabolism. Vitamin C is important for collagen synthesis, wound healing, and immune function, but it is not directly involved in calcium absorption.
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What is the most visible part of the ear?
- A. Pinna
- B. Organ of Corti
- C. Cochlea
- D. Ear canal
Correct Answer: A
Rationale: The pinna, also known as the auricle, is the external part of the ear that is most visible. It helps in collecting sound waves and directing them into the ear canal for further processing by the ear structures. The pinna's visible location makes it easily identifiable as the prominent external feature of the ear. Choices B, C, and D are incorrect. The Organ of Corti is located within the cochlea and is responsible for converting sound vibrations into electrical signals. The cochlea is a spiral-shaped, fluid-filled structure in the inner ear that plays a crucial role in hearing. The ear canal is a passage that leads to the eardrum and is not the most visible part of the ear.
Which of the following structures regulates the transport of substances in and out of a cell?
- A. Nucleus
- B. Cell membrane
- C. Cytoplasm
- D. Mitochondria
Correct Answer: B
Rationale: The cell membrane, also known as the plasma membrane, is responsible for regulating the transport of substances in and out of the cell. It acts as a selective barrier, allowing the passage of certain molecules while restricting others. This selective permeability helps maintain homeostasis within the cell by controlling the movement of essential substances like nutrients and waste products. The nucleus (Choice A) is the organelle that houses the cell's genetic material and is not directly involved in regulating substance transport. Cytoplasm (Choice C) is the gel-like substance that fills the cell and does not play a direct role in regulating substance transport. Mitochondria (Choice D) are responsible for energy production in the cell through cellular respiration and are not primarily involved in substance transport.
Which hormone is released by the pancreas to lower blood glucose levels?
- A. Insulin
- B. Glucagon
- C. Cortisol
- D. Somatostatin
Correct Answer: A
Rationale: Insulin is the hormone released by the pancreas to lower blood glucose levels. Insulin facilitates the uptake of glucose into cells, helping to decrease blood glucose levels and store excess glucose for energy or future use. Glucagon, on the other hand, raises blood glucose levels by promoting the breakdown of glycogen into glucose. Cortisol and somatostatin do not directly regulate blood glucose levels in the same manner as insulin and glucagon.
Which bone does not articulate with any other bone?
- A. Femur
- B. Hyoid
- C. Radius
- D. Scapula
Correct Answer: B
Rationale: The hyoid bone is the correct answer as it is the only bone in the human body that does not articulate with any other bone. Instead, it is suspended in the neck by ligaments and muscles, providing support for the tongue and serving as an attachment point for various throat and tongue muscles. The femur (Choice A), radius (Choice C), and scapula (Choice D) all articulate with other bones in the body at various joints, making them incorrect answers for this question.
Which gland regulates the body's metabolic rate?
- A. Pituitary gland
- B. Thyroid gland
- C. Adrenal gland
- D. Pineal gland
Correct Answer: B
Rationale: The thyroid gland is responsible for regulating the body's metabolic rate by producing hormones such as thyroxine (T4) and triiodothyronine (T3). These hormones play a crucial role in controlling the body's metabolism, affecting processes like growth, energy production, and temperature regulation. The pituitary gland is known as the 'master gland' but primarily regulates other endocrine glands by releasing hormones that stimulate their function. The adrenal gland is responsible for producing hormones like adrenaline and cortisol, which are involved in the body's response to stress. The pineal gland secretes melatonin, a hormone that regulates sleep-wake cycles and circadian rhythms, but is not directly involved in regulating metabolic rate.