DOH Anatomy & Physiology — Questions and Answers
Question 1: The sinoatrial (SA) node, the primary pacemaker of the heart, is located in which chamber?
- Left ventricle
- Right atrium (Correct answer)
- Left atrium
- Right ventricle
Correct answer: Right atrium
The SA node is situated in the wall of the right atrium near the opening of the superior vena cava and initiates the electrical impulse for each heartbeat.
Question 2: Which lobe of the lung is supplied solely by the middle lobar bronchus?
- Right upper lobe
- Right middle lobe (Correct answer)
- Left lower lobe
- Left upper lobe
Correct answer: Right middle lobe
The right middle lobe is the only lobe supplied exclusively by the middle lobar (secondary) bronchus, which branches from the right main bronchus.
Question 3: What is the normal resting glomerular filtration rate (GFR) in a healthy adult?
- 30–60 mL/min
- 60–89 mL/min
- 90–120 mL/min (Correct answer)
- 150–180 mL/min
Correct answer: 90–120 mL/min
A normal adult GFR is approximately 90–120 mL/min/1.73m²; values below 60 for 3+ months indicate chronic kidney disease, which is staged accordingly.
Question 4: Which hormone is secreted by the beta cells of the islets of Langerhans and lowers blood glucose?
- Glucagon
- Insulin (Correct answer)
- Somatostatin
- Cortisol
Correct answer: Insulin
Insulin is produced by beta cells in the pancreatic islets of Langerhans and facilitates glucose uptake by cells, thereby lowering blood glucose levels.
Question 5: The brachial plexus originates from which spinal cord levels?
- C1–C4
- C5–T1 (Correct answer)
- T1–T4
- L1–L5
Correct answer: C5–T1
The brachial plexus is formed by the anterior rami of spinal nerve roots C5 through T1 and innervates the entire upper limb.
Question 6: Which part of the nephron is primarily responsible for reabsorption of glucose under normal physiological conditions?
- Loop of Henle
- Proximal convoluted tubule (Correct answer)
- Distal convoluted tubule
- Collecting duct
Correct answer: Proximal convoluted tubule
Under normal conditions, virtually all filtered glucose is reabsorbed in the proximal convoluted tubule via SGLT2 transporters; glucosuria occurs when the renal threshold (~10 mmol/L) is exceeded.
DOH Anatomy & Physiology
The sinoatrial (SA) node, the primary pacemaker of the heart, is located in which chamber?