A patient has difficulty in accommodation of the eye. Which lens condition is responsible?
Answer: A
Presbyopia occurs due to loss of lens elasticity with age, reducing accommodation ability for near vision.
Q.2Medium
Which of the following hormones is NOT produced by the anterior pituitary?
Answer: C
ADH (Antidiuretic hormone) is produced by the hypothalamus and stored/released by the posterior pituitary, not the anterior pituitary.
Q.3Medium
The normal pH of blood is maintained primarily by:
Answer: D
Blood pH (7.35-7.45) is maintained by multiple buffer systems including bicarbonate, phosphate, and protein buffers working together.
Q.4Medium
In the small intestine, the majority of nutrient absorption occurs in the:
Answer: B
The jejunum is the primary site for nutrient absorption due to its extensive villi and optimal length for absorption process.
Q.5Medium
Which blood cells are responsible for producing antibodies?
Answer: B
Plasma cells (differentiated B lymphocytes) produce and secrete specific antibodies in response to antigens.
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Q.6Medium
The resting membrane potential of a typical neuron is approximately:
Answer: B
The resting potential is maintained at -70 mV primarily by the Na+/K+ ATPase pump and differential ion permeability.
Q.7Medium
A person experiences vasoconstriction and increased heart rate upon seeing a predator. This response is mediated by:
Answer: B
The fight-or-flight response involves sympathetic activation releasing epinephrine and norepinephrine causing vasoconstriction and tachycardia.
Q.8Medium
Which of the following conditions results from deficiency of intrinsic factor?
Answer: B
Intrinsic factor is required for B12 absorption; its deficiency leads to pernicious anemia due to impaired vitamin B12 absorption.
Q.9Medium
In the renal tubule, selective reabsorption of useful substances like glucose occurs primarily in:
Answer: B
The proximal convoluted tubule epithelial cells have numerous mitochondria and microvilli for active transport of glucose, amino acids, and ions.
Q.10Medium
A deficiency of intrinsic factor leads to which type of anemia?
Answer: A
Intrinsic factor, produced by gastric parietal cells, is essential for vitamin B12 absorption in the terminal ileum. Its deficiency prevents B12 absorption, causing pernicious anemia.
Q.11Medium
During increased physical activity, which compensatory mechanism helps maintain blood pH within normal range?
Answer: A
During exercise, lactate production increases blood acidity. Hyperventilation increases CO2 elimination, shifting the CO2-bicarbonate equilibrium to maintain blood pH (7.35-7.45).
Q.12Medium
Which of the following correctly describes the relationship between the parasympathetic nervous system and heart rate?
Answer: A
Parasympathetic acetylcholine activates M2 muscarinic receptors on pacemaker cells, increasing K+ efflux and decreasing Ca2+ influx, causing hyperpolarization and reduced heart rate.
Q.13Medium
In the digestive system, which hormone stimulates the pancreas to release bicarbonate-rich secretions?
Answer: A
Secretin, released by duodenal S cells in response to chyme acidity, specifically stimulates pancreatic ductal cells to secrete bicarbonate, neutralizing stomach acid.
Q.14Medium
Which protein in red blood cells is responsible for the chloride shift mechanism?
Answer: A
Band 3 protein (anion exchanger 1) facilitates the exchange of Cl- for HCO3- across the RBC membrane, allowing CO2 transport as bicarbonate in blood.
Q.15Medium
A patient experiences persistent hyperglycemia despite normal insulin levels. Which condition is most likely?
Answer: A
In Type 2 diabetes, normal or elevated insulin fails to lower blood glucose due to peripheral tissue insulin resistance, often caused by impaired receptor signaling or GLUT4 translocation defects.
Q.16Medium
Which of the following statements about the lymphatic system is correct?
Answer: A
Lymph drains from tissue spaces into lymphatic capillaries, passes through lymph nodes for filtration and immune response, and returns to the bloodstream via the thoracic duct into the left subclavian vein.
Q.17Medium
In the cardiac cycle, the S3 heart sound is associated with:
Answer: A
S3 occurs during rapid ventricular filling phase (early diastole) when blood rapidly enters the ventricle. It's normal in young individuals but may indicate heart failure in older patients.
Q.18Medium
A patient suffers from thyroid deficiency. Which of the following metabolic changes would NOT be expected?
Answer: B
Thyroid hormone deficiency decreases metabolic rate and oxygen consumption. Increased oxygen consumption would not occur; rather, it would decrease significantly.
Q.19Medium
During inspiration, the external intercostal muscles contract. What is the primary consequence of this action?
Answer: D
Contraction of external intercostal muscles elevates the ribs and sternum, increasing thoracic cavity volume, which decreases intrapulmonary pressure and causes air to flow in.
Q.20Medium
Which of the following statements about myelin sheath is correct?
Answer: B
Myelin sheath, formed by oligodendrocytes in CNS and Schwann cells in PNS, increases conduction velocity by enabling saltatory conduction.
