Which of the following is the primary function of the glomerulus in the nephron?
Answer: A
The glomerulus is a network of capillaries where ultrafiltration occurs, filtering small molecules like glucose, ions, and urea from blood into Bowman's capsule.
Q.2Easy
The hormone that increases blood glucose concentration is:
Answer: B
Glucagon, secreted by alpha cells of pancreatic islets, increases blood glucose through glycogenolysis and gluconeogenesis.
Q.3Easy
Which enzyme initiates protein digestion in the stomach?
Answer: B
Pepsin is a protease secreted by gastric glands that begins protein digestion in the acidic environment of the stomach.
Q.4Easy
The cardiac cycle duration in a normal adult is approximately:
Answer: B
A complete cardiac cycle takes approximately 0.8 seconds at a heart rate of 72 beats per minute.
Q.5Easy
Which structure in the brain is responsible for maintaining body equilibrium and balance?
Answer: B
The cerebellum coordinates voluntary movements and maintains body balance through proprioceptive feedback.
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Q.6Easy
During inspiration, the diaphragm contracts and moves:
Answer: B
Diaphragm contraction flattens it and moves downward, increasing thoracic cavity volume and decreasing intra-pulmonary pressure.
Q.7Easy
Which hormone is primarily responsible for increasing blood glucose levels during the fight-or-flight response?
Answer: A
Epinephrine (adrenaline) is released by the adrenal medulla during stress and increases blood glucose by promoting glycogenolysis and inhibiting insulin secretion.
Q.8Easy
The blood-brain barrier is primarily composed of which type of cell?
Answer: A
The blood-brain barrier is formed by tight junctions between endothelial cells of brain capillaries, supported by astrocytes that regulate nutrient transport and maintain the barrier's integrity.
Q.9Easy
Which of the following enzymes is responsible for breaking down acetylcholine at the neuromuscular junction?
Answer: A
Acetylcholinesterase rapidly hydrolyzes acetylcholine in the synaptic cleft, terminating neuromuscular transmission and allowing muscle relaxation.
Q.10Easy
The phenomenon where a nerve impulse can jump from one node of Ranvier to the next is called:
Answer: A
Saltatory conduction occurs in myelinated neurons where action potentials jump between nodes of Ranvier, increasing conduction velocity significantly compared to unmyelinated fibers.
Q.11Easy
Which structure in the kidney is responsible for ultrafiltration?
Answer: A
The glomerulus, a network of capillaries in the renal corpuscle, filters blood under hydrostatic pressure to produce the ultrafiltrate that forms the basis of urine.
Q.12Easy
Which of the following hormones is primarily responsible for increasing blood glucose levels during the fasting state?
Answer: A
Glucagon is secreted by alpha cells of pancreatic islets and increases blood glucose by promoting glycogenolysis and gluconeogenesis during fasting.
Q.13Easy
The sinoatrial (SA) node is considered the pacemaker of the heart because:
Answer: A
The SA node has the highest inherent rate of spontaneous depolarization (60-100 bpm), allowing it to set the rhythm for the entire heart.
Q.14Easy
Which of the following best describes the function of the loop of Henle in the kidney?
Answer: B
The loop of Henle, particularly the descending and ascending limbs, creates a countercurrent multiplier system that establishes an osmotic gradient necessary for concentrated urine formation.
Q.15Easy
Tidal volume in a healthy adult human is approximately:
Answer: A
Tidal volume, the volume of air inspired or expired during normal quiet breathing, is approximately 500 mL in adults.
Q.16Easy
Which neurotransmitter is responsible for the transmission of signals across the neuromuscular junction?
Answer: B
Acetylcholine is the primary neurotransmitter at the neuromuscular junction, binding to nicotinic receptors on muscle fiber membranes to trigger muscle contraction.
Q.17Easy
Which of the following is the primary function of the loop of Henle in the nephron?
Answer: B
The loop of Henle creates a countercurrent multiplier system that establishes an osmotic gradient, enabling selective water reabsorption in the collecting duct.
Q.18Easy
Which organ produces erythropoietin (EPO) in response to low oxygen levels?
Answer: C
The kidneys produce approximately 90% of EPO, which stimulates red blood cell production in bone marrow when oxygen levels are low.
Q.19Easy
Which of the following best describes the role of surfactant in respiratory physiology?
Answer: B
Pulmonary surfactant (lipid + protein) reduces surface tension in alveoli, preventing their collapse during expiration and reducing work of breathing.
Q.20Easy
Which hormone primarily regulates sodium reabsorption in the distal convoluted tubule and collecting duct?
Answer: B
Aldosterone, released by the adrenal cortex, increases sodium reabsorption via mineralocorticoid receptors in the DCT and collecting duct.
