UExcel Anatomy and Physiology 3 — Questions and Answers
Question 1: The bicarbonate buffer system in the blood primarily regulates:
- Blood glucose levels
- Blood pH (Correct answer)
- Oxygen saturation
- Plasma osmolarity
Correct answer: Blood pH
The bicarbonate buffer system (CO2/HCO3−) is the primary blood buffer, maintaining pH near 7.4.
Question 2: Which type of cartilage is found in the intervertebral discs?
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage (Correct answer)
- Articular cartilage
Correct answer: Fibrocartilage
Fibrocartilage, which is tough and compressible, makes up the intervertebral discs and pubic symphysis.
Question 3: During depolarization of a neuron, which ion rapidly moves INTO the cell?
- Potassium (K+)
- Chloride (Cl−)
- Sodium (Na+) (Correct answer)
- Calcium (Ca2+)
Correct answer: Sodium (Na+)
During depolarization, voltage-gated Na+ channels open and sodium ions rush into the cell, making the interior more positive.
Question 4: Which organ produces bile salts used in fat digestion?
- Pancreas
- Gallbladder
- Liver (Correct answer)
- Small intestine
Correct answer: Liver
The liver synthesizes bile salts; the gallbladder only stores and concentrates bile before releasing it into the duodenum.
Question 5: Which hormone, produced by the adrenal cortex, promotes sodium retention and potassium excretion by the kidneys?
- Cortisol
- Aldosterone (Correct answer)
- Epinephrine
- Antidiuretic hormone (ADH)
Correct answer: Aldosterone
Aldosterone, a mineralocorticoid, acts on the distal tubule and collecting duct to increase Na+ reabsorption and K+ secretion.
Question 6: The SA node initiates the heartbeat and is located in the:
- Left ventricle
- Interventricular septum
- Right atrium (Correct answer)
- Left atrium
Correct answer: Right atrium
The sinoatrial (SA) node, the heart's pacemaker, is located in the posterior wall of the right atrium near the opening of the superior vena cava.
Question 7: Which cellular organelle is responsible for packaging and modifying proteins for secretion?
- Rough endoplasmic reticulum
- Mitochondria
- Golgi apparatus (Correct answer)
- Lysosome
Correct answer: Golgi apparatus
The Golgi apparatus modifies, packages, and addresses proteins for secretion or delivery to other organelles.
UExcel Anatomy and Physiology 3
The bicarbonate buffer system in the blood primarily regulates: