NCBTMB Anatomy and Physiology 3 — Questions and Answers
Question 1: The thoracic duct, the largest lymphatic vessel, drains lymph from all areas EXCEPT which region?
- Lower limbs
- Left upper extremity
- Right side of the head (Correct answer)
- Abdominal viscera
Correct answer: Right side of the head
The right side of the head, right upper extremity, and right thorax drain into the right lymphatic duct, not the thoracic duct.
Question 2: Which carpal bone is most commonly fractured and has a high risk of avascular necrosis due to its blood supply?
- Lunate
- Scaphoid (Correct answer)
- Trapezium
- Hamate
Correct answer: Scaphoid
The scaphoid is the most frequently fractured carpal bone, and its retrograde blood supply makes it susceptible to avascular necrosis.
Question 3: What is the primary function of the nephron loop (loop of Henle) in the kidney?
- Filters blood plasma into the nephron
- Secretes hydrogen ions to regulate pH
- Creates an osmotic gradient to concentrate urine (Correct answer)
- Reabsorbs glucose from the filtrate
Correct answer: Creates an osmotic gradient to concentrate urine
The loop of Henle establishes a concentration gradient in the renal medulla by reabsorbing sodium and chloride, enabling the production of concentrated urine.
Question 4: Which neurotransmitter is released at the neuromuscular junction to initiate skeletal muscle contraction?
- Dopamine
- Norepinephrine
- Acetylcholine (Correct answer)
- Serotonin
Correct answer: Acetylcholine
Acetylcholine (ACh) is released by motor neurons at the neuromuscular junction and binds to nicotinic receptors on muscle fibers to trigger contraction.
Question 5: In anatomical position, which term describes a structure closer to the point of attachment of a limb?
- Distal
- Lateral
- Proximal (Correct answer)
- Inferior
Correct answer: Proximal
Proximal means closer to the point of origin or attachment, such as the shoulder being proximal to the elbow.
Question 6: The erector spinae muscle group runs parallel to the vertebral column and primarily performs which action?
- Flexion of the trunk
- Extension and lateral flexion of the spine (Correct answer)
- Rotation of the cervical spine only
- Compression of the intervertebral discs
Correct answer: Extension and lateral flexion of the spine
The erector spinae group (iliocostalis, longissimus, spinalis) extends the spine and assists with lateral flexion when contracting unilaterally.
Question 7: Which part of the brain regulates body temperature, hunger, thirst, and circadian rhythms?
- Thalamus
- Hypothalamus (Correct answer)
- Cerebellum
- Medulla oblongata
Correct answer: Hypothalamus
The hypothalamus regulates homeostatic functions including body temperature, hunger, thirst, sleep cycles, and hormone release from the pituitary gland.
