MCAT Biology Practice Test 10: Homeostasis

1. Which of the following would most likely be filtered through the glomerulus into Bowman's space?

• A. Erythrocytes
• B. Monosaccharides
• C. Platelets
• D. Proteins

2. In which of the following segments of the nephron is sodium NOT actively transported out of the nephron?

• A. Proximal convoluted tubule
• B. Thin portion of the ascending limb of the loop of Henle
• C. Distal convoluted tubule
• D. Thick portion of the ascending limb of the loop of Henle

3. Which region of the kidney has the lowest solute concentration under normal physiological circumstances?

• A. Cortex
• B. Outer medulla
• C. Inner medulla
• D. Renal pelvis

4. Which of the following sequences correctly shows the passage of blood through the vessels of the kidney?

• A. Renal artery → afferent arterioles → glomerulus → efferent arterioles → vasa recta → renal vein
• B. Afferent arterioles → renal artery → glomerulus → vasa recta → renal vein → efferent arterioles
• C. Glomerulus → renal artery → afferent arterioles → efferent arterioles → renal vein → vasa recta
• D. Renal vein → efferent arterioles → glomerulus → afferent arterioles → vasa recta → renal artery

5. Which of the following statements is FALSE?

• A. ADH increases water reabsorption in the kidney.
• B. Aldosterone indirectly increases water reabsorption in the kidney.
• C. ADH acts directly on the proximal convoluted tubule.
• D. Aldosterone stimulates reabsorption of sodium from the collecting duct.

6. In the nephron, amino acids enter the vasa recta via the process of:

• A. filtration.
• B. secretion.
• C. excretion.
• D. reabsorption.

7. On a very cold day, a man waits for over an hour at the bus stop. Which of the following structures helps his body set and maintain a normal temperature?

• A. Hypothalamus
• B. Kidneys
• C. Posterior pituitary
• D. Brain stem

8. Glucose reabsorption in the nephron occurs in the:

• A. loop of Henle.
• B. distal convoluted tubule.
• C. proximal convoluted tubule.
• D. collecting duct.

9. Under normal physiological circumstances, the primary function of the nephron is to create urine that is:

• A. hypertonic to the blood.
• B. hypotonic to the blood.
• C. isotonic to the filtrate.
• D. hypotonic to the vasa recta.

10. Diabetic nephropathy is commonly detected by finding protein in the urine of a patient. In such a disease, where is the likely defect in the nephron?

• A. Glomerulus
• B. Proximal convoluted tubule
• C. Loop of Henle
• D. Collecting duct

11. A laceration cuts down into a layer of loose connective tissue in the skin. Which layer of the skin is this?

• A. Stratum corneum
• B. Stratum lucidum
• C. Papillary layer
• D. Reticular layer

12. When the pH of the blood is high, which substance is likely to be excreted in larger quantities in the urine?

• A. Urea
• B. Ammonia
• C. Hydrogen ions
• D. Bicarbonate ions

13. In which layer of the skin can the stem cells of keratinocytes be found?

• A. Stratum lucidum
• B. Stratum granulosum
• C. Stratum basale
• D. Stratum corneum

14. A drug is used that prevents the conversion of angiotensin I to angiotensin II. What is a likely effect of this drug?

• A. Increased sodium reabsorption
• B. Increased potassium reabsorption
• C. Increased blood pressure
• D. Increased blood pH

15. Sarin is a potent organophosphate that can be used in chemical warfare. As an inhibitor of acetylcholinesterase, sarin causes excessive buildup of acetylcholine in all synapses where it is the neurotransmitter. Which of the following symptoms would be most likely to be seen in an individual with sarin poisoning?

• A. Increased urination and increased sweating
• B. Increased urination and decreased sweating
• C. Decreased urination and increased sweating
• D. Decreased urination and decreased sweating