Which of the following structures has the lowest blood pressure?
- A. arteries
- B. arterioles
- C. venules
- D. veins
Correct Answer: D
Rationale: Veins have the lowest blood pressure among the listed structures. This is because veins carry blood back to the heart at a slower rate compared to arteries, arterioles, and venules. The lower blood pressure in veins allows for the efficient return of blood to the heart despite the decreased pressure. Arteries have high blood pressure as they transport blood away from the heart at a rapid rate. Arterioles are smaller branches of arteries and contribute to resistance in the circulatory system, leading to a pressure drop. Venules are small blood vessels that collect blood from capillaries and gradually converge into veins, having slightly higher pressure than veins.
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What is the function of amylase?
- A. Breaking down starch
- B. Digesting fat
- C. Breaking down protein
- D. Absorbing water
Correct Answer: A
Rationale: The correct answer is A: Breaking down starch. Amylase is an enzyme that specifically functions to break down starch into smaller sugar molecules such as maltose and glucose. This process is essential for the digestion and absorption of carbohydrates in the body. Choices B, C, and D are incorrect because amylase does not digest fat, break down protein, or absorb water; its primary function lies in starch digestion.
Where do nearly all of the gaseous exchanges between air and blood take place in the lungs?
- A. Pleura
- B. Trachea
- C. Bronchioles
- D. Alveoli
Correct Answer: D
Rationale: Nearly all gaseous exchanges between air and blood take place in the alveoli of the lungs. The walls of the alveoli are thin and surrounded by an extensive network of tiny blood vessels called capillaries. Oxygen from the air diffuses through the alveoli walls and into the bloodstream, while carbon dioxide, a waste product, diffuses from the blood into the alveoli to be exhaled out of the body. This process is essential for respiration and providing oxygen to the body's cells. Choices A, B, and C are incorrect. Pleura is the membrane surrounding the lungs, trachea is the windpipe that carries air to the lungs, and bronchioles are the smaller air passages in the lungs. However, the primary site for gaseous exchange is the alveoli due to their structure and function.
The arteries are part of which system?
- A. Nervous system
- B. Endocrine system
- C. Lymphatic system
- D. Cardiovascular system
Correct Answer: D
Rationale: The correct answer is D, Cardiovascular system. Arteries are blood vessels that carry oxygen-rich blood away from the heart to various parts of the body. They are a key component of the cardiovascular system, which is responsible for transporting blood, nutrients, and oxygen throughout the body. The other options (A, B, and C) are incorrect because arteries are not part of the nervous system, endocrine system, or lymphatic system.
What is true about caloric intake for the average person?
- A. It should increase with age.
- B. It should decline and then increase with age.
- C. It should decline with age.
- D. It should remain constant over a lifetime.
Correct Answer: C
Rationale: Caloric intake for the average person typically declines with age due to factors such as changes in metabolism, muscle mass, and physical activity levels. As people age, their metabolism tends to slow down, and they may also experience a decrease in muscle mass and physical activity, leading to a reduced need for calories. Option A is incorrect because caloric intake generally decreases rather than increases with age. Option B is incorrect as it suggests a fluctuation in caloric intake that is not typically seen. Option D is incorrect as caloric needs usually change over a person's lifetime due to various factors.
Which neurotransmitter controls sleep, mood, and appetite?
- A. Serotonin
- B. Oxytocin
- C. Cortisol
- D. Aldosterone
Correct Answer: A
Rationale: Serotonin is the correct answer. It is a neurotransmitter that plays a crucial role in regulating mood, sleep, and appetite. Serotonin functions to stabilize and control these physiological processes in the brain and body. Imbalances in serotonin levels are commonly linked to conditions like depression, anxiety, and eating disorders. Oxytocin (Choice B) is more associated with social bonding and childbirth. Cortisol (Choice C) is a stress hormone, and while it can influence mood and appetite in response to stress, it is not primarily responsible for regulating these functions. Aldosterone (Choice D) is a hormone that regulates electrolyte balance and blood pressure, not mood, sleep, and appetite.