Nokea
Which of the following is not part of the central nervous system?
- A. Retina
- B. Spinal cord
- C. Brain
- D. Heart
Correct Answer: B
Rationale: The central nervous system consists of the brain and spinal cord, which are responsible for processing and coordinating information. The retina is part of the eye, while the heart is part of the circulatory system. Therefore, the correct answer is 'Spinal cord' as it is not part of the central nervous system.
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A person who has damage to their ulnar nerve will have decreased sensation in which part of the body?
- A. Hand
- B. Arm
- C. Leg
- D. Foot
Correct Answer: A
Rationale: Corrected Rationale: Damage to the ulnar nerve typically results in decreased sensation in the hand, particularly affecting the little finger and half of the ring finger. The ulnar nerve innervates the hand and is responsible for providing sensation to these areas. This nerve does not extend to the leg or foot, so choices C and D are incorrect. While the ulnar nerve travels through the arm, its primary sensory impact is felt in the hand, making choice B less specific and therefore not the best answer.
Which structure in the ear is responsible for hearing?
- A. Cochlea
- B. Semicircular canals
- C. Ossicles
- D. Eustachian tube
Correct Answer: A
Rationale: The cochlea, located in the inner ear, is responsible for detecting sound waves and converting them into neural signals that are sent to the brain for processing. It plays a crucial role in the process of hearing by translating mechanical vibrations into electrical signals that the brain can interpret as sound. The semicircular canals (Choice B) are responsible for balance and detecting head movements, not hearing. The ossicles (Choice C) are three tiny bones in the middle ear that transmit sound vibrations from the eardrum to the cochlea. The Eustachian tube (Choice D) helps equalize pressure between the middle ear and the atmosphere, but it is not directly involved in the process of hearing.
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 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.
What is the primary function of platelets?
- A. To fight infections
- B. To clot blood
- C. To carry oxygen
- D. To transport nutrients
Correct Answer: B
Rationale: The primary function of platelets, or thrombocytes, is to clot blood. Platelets play a crucial role in hemostasis by forming clots to prevent excessive bleeding when injuries occur. They are not directly involved in fighting infections, carrying oxygen, or transporting nutrients. Therefore, the correct answer is B.