What is the most visible part of the ear?
- A. Ear canal
- B. Cochlea
- C. Organ of Corti
- D. Pinna
Correct Answer: D
Rationale: The pinna, also known as the auricle, is the most visible part of the ear. Its external shape and location make it easily noticeable on the side of the head. The pinna helps in capturing sound waves and directing them into the ear canal, where the sound transmission process begins. The other structures listed, the Organ of Corti, Cochlea, and Ear canal, are essential parts of the ear involved in hearing and sound processing, but they are not as visibly prominent as the pinna. Therefore, the correct answer is the pinna because of its external visibility and role in capturing sound waves.
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What is the primary role of the small intestine in nutrient absorption?
- A. To break down food
- B. To absorb nutrients
- C. To secrete digestive enzymes
- D. To store glucose
Correct Answer: B
Rationale: The correct answer is B: 'To absorb nutrients.' The small intestine is the primary site for nutrient absorption in the digestive system. It plays a crucial role in absorbing nutrients from digested food into the bloodstream, facilitating the delivery of essential nutrients to the body for various functions and processes. Choices A, C, and D are incorrect because while the small intestine does contribute to the breakdown of food and does secrete digestive enzymes, its primary function is to absorb nutrients, not to store glucose.
Which of the following endocrine system glands releases the thyrotrophic-releasing hormone, growth hormone-releasing hormone, and gonadotropin-releasing hormones?
- A. Thymus
- B. Pituitary gland
- C. Pineal gland
- D. Hypothalamus
Correct Answer: D
Rationale: The correct answer is D, the Hypothalamus. The hypothalamus is responsible for releasing various essential hormones, including thyrotrophic-releasing hormone, growth hormone-releasing hormone, and gonadotropin-releasing hormones. These hormones play crucial roles in regulating the functions of other endocrine glands by stimulating or inhibiting their hormone production. The Thymus (choice A) is primarily involved in the immune system, the Pituitary gland (choice B) secretes various hormones but not the ones specified in the question, and the Pineal gland (choice C) mainly produces melatonin, which regulates sleep-wake cycles, and is not related to the hormones mentioned in the question.
When an individual is under stress, hormones are released. Which of the following is not one of the locations in which hormones are released when under stress?
- A. Posterior pituitary
- B. Hypothalamus
- C. Adrenal cortex
- D. Parathyroid
Correct Answer: D
Rationale: During stress, hormones are released from the adrenal cortex, posterior pituitary, and hypothalamus to help the body respond. The parathyroid gland, however, is not typically involved in the stress response by releasing hormones. The posterior pituitary releases hormones like oxytocin and vasopressin, the hypothalamus secretes corticotropin-releasing hormone (CRH) and vasopressin, while the adrenal cortex releases cortisol and aldosterone in response to stress. Therefore, the correct answer is 'Parathyroid.'
Which cellular structure is responsible for producing energy?
- A. Nucleus
- B. Mitochondria
- C. Ribosome
- D. Golgi apparatus
Correct Answer: B
Rationale: Mitochondria are the organelles responsible for producing energy in the cell through a process called cellular respiration. They are often referred to as the powerhouses of the cell due to their role in generating ATP, the cell's energy currency. The nucleus is not involved in energy production but houses the cell's genetic material. Ribosomes are responsible for protein synthesis, not energy production. The Golgi apparatus is involved in processing and packaging proteins for secretion, not energy production.
Which bone does not articulate with any other bone?
- A. Femur
- B. Hyoid
- C. Radius
- D. Tibia
Correct Answer: B
Rationale: The correct answer is the Hyoid bone. The hyoid bone is distinctive as it does not directly articulate with any other bone in the body. Instead, it is held in place by muscles and ligaments, playing a crucial role in supporting the tongue and providing attachment points for various muscles involved in swallowing and speech. The other choices, Femur, Radius, and Tibia, all articulate with other bones in the body. The femur articulates with the hip bone, the radius articulates with the ulna and other bones in the wrist, and the tibia articulates with the femur and fibula.