Nokea
Which of the following describes a reflex arc?
- A. The storage and recall of memory
- B. The maintenance of visual and auditory acuity
- C. The autoregulation of heart rate and blood pressure
- D. A stimulus and response controlled by the spinal cord
Correct Answer: D
Rationale: Choice D correctly describes a reflex arc. A reflex arc is a neural pathway that controls a reflex action. It involves a specific sequence of events that occur in response to a stimulus, which is rapidly and involuntarily processed by the spinal cord. The spinal cord coordinates the quick processing of sensory input and the generation of a motor response without involving the brain, allowing for rapid protective responses. Choices A, B, and C are incorrect because they do not accurately describe a reflex arc. A reflex arc is specifically related to the rapid and involuntary response to a stimulus through neural pathways involving the spinal cord, not memory storage, visual and auditory acuity maintenance, or heart rate and blood pressure autoregulation.
You may also like to solve these questions
Which blood vessels transport blood from the capillaries back to the heart?
- A. Arterioles
- B. Veins
- C. Venules
- D. Capillaries
Correct Answer: B
Rationale: Veins are the correct answer as they are the blood vessels that carry blood from the capillaries back to the heart. Veins have thinner walls compared to arteries and contain valves to prevent blood from flowing backward. This transport of blood from the capillaries to the heart is essential for the circulatory system to maintain proper blood flow and oxygenation levels. Arterioles are small branches of arteries that lead to capillaries, not vessels that transport blood back to the heart. Venules are small vessels that collect blood from capillaries and lead to veins. Capillaries are the smallest blood vessels where the exchange of gases and nutrients occurs between blood and tissues, not vessels that transport blood back to the heart.
Which of the following is unique to covalent bonds?
- A. Most covalent bonds are formed between the elements H, F, N, and O.
- B. Covalent bonds are dependent on forming dipoles.
- C. Bonding electrons are shared between two or more atoms.
- D. Molecules with covalent bonds tend to have a crystalline solid structure.
Correct Answer: C
Rationale: The correct answer is C: 'Bonding electrons are shared between two or more atoms.' This statement is unique to covalent bonds. In covalent bonds, atoms share electrons to achieve a stable electron configuration, which leads to the formation of a bond. This sharing of electrons is a fundamental characteristic of covalent bonds and distinguishes them from other types of chemical bonds, such as ionic bonds, where electrons are transferred rather than shared. Choices A, B, and D do not represent unique characteristics of covalent bonds. Choice A describes some common elements involved in covalent bonds, choice B refers to the concept of dipoles, which can also exist in other types of bonds, and choice D describes a property of molecules (crystalline solid structure) that is not exclusive to covalent bonds.
What is the normal (complete) flow of blood through the heart?
- A. Right atrium → lungs → left atrium → body
- B. Left atrium → left ventricle → body → right atrium
- C. Right atrium → right ventricle → lungs → left atrium → left ventricle → aorta → body
- D. Right ventricle → left ventricle → body
Correct Answer: C
Rationale: The correct flow of blood through the heart starts with the right atrium receiving deoxygenated blood from the body, followed by the right ventricle pumping blood to the lungs for oxygenation. Oxygenated blood then returns to the heart through the left atrium, then passes to the left ventricle which pumps it out to the body through the aorta. This flow ensures that blood is properly oxygenated before circulating through the body. Choice A is incorrect as the blood does not go directly from the left atrium to the body, skipping the left ventricle. Choice B is incorrect as it does not follow the correct flow sequence in the heart. Choice D is incorrect as it does not include the full pathway of blood through the heart.
Which locations in the digestive system are sites of chemical digestion? I. Mouth II. Stomach III. Small Intestine
- A. II only
- B. III only
- C. II and III only
- D. I, II, and III
Correct Answer: D
Rationale: Chemical digestion occurs in all three locations in the digestive system - the mouth, stomach, and small intestine. Enzymes in the saliva break down carbohydrates in the mouth, gastric juices in the stomach help break down proteins, and enzymes in the small intestine further break down macronutrients like carbohydrates, proteins, and fats. The mouth initiates the digestion of carbohydrates, the stomach digests proteins, and the small intestine continues the breakdown of carbohydrates, proteins, and fats. Choice A is incorrect because chemical digestion does occur in the mouth. Choice B is incorrect as both the stomach and small intestine are sites of chemical digestion. Choice C is incorrect as the mouth is also a location of chemical digestion, not just the stomach and small intestine.
What are the three types of capillaries?
- A. Continuous, fenestrated, sinusoidal
- B. Continuous, discontinuous, fenestrated
- C. Sinusoidal, alveolar, continuous
- D. Continuous, fenestrated, vascular
Correct Answer: A
Rationale: The correct answer is A: Continuous, fenestrated, sinusoidal. Capillaries are classified into three types based on their permeability: continuous (least permeable), fenestrated (moderately permeable), and sinusoidal (most permeable). Choices B, C, and D are incorrect because they do not represent the three main types of capillaries. Choice B includes 'discontinuous' which is not a recognized type. Choice C includes 'alveolar' which is not a type of capillary, and Choice D includes 'vascular' which is too broad and not specific to capillary classification.