Home Subjects NEET Zoology Human Physiology

NEET Zoology
Human Physiology

Zoology questions for NEET UG — Animal Kingdom, Human Physiology, Genetics, Evolution.

100 Q 6 Topics Take Test
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Difficulty: All Easy Medium Hard 31–40 of 100
Topics in NEET Zoology
Q.31 Medium Human Physiology
A marathon runner experiences 'hitting the wall' around 20km. This is primarily due to:
A Decreased oxygen availability
B Depletion of muscle glycogen stores
C Excessive lactate accumulation
D Calcium channel dysfunction
Correct Answer:  B. Depletion of muscle glycogen stores
EXPLANATION

Glycogen depletion in muscles and liver reduces glucose availability for ATP production, causing sudden fatigue despite continued oxygen availability.

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Q.32 Medium Human Physiology
In the cardiac cycle, what occurs during the isovolumetric contraction phase?
A AV valves close, semilunar valves open
B Volume remains constant while pressure increases
C Blood is ejected from ventricles
D Ventricles fill with blood from atria
Correct Answer:  B. Volume remains constant while pressure increases
EXPLANATION

During isovolumetric contraction, ventricular volume stays constant while pressure rapidly increases as both AV and semilunar valves are closed.

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Q.33 Medium Human Physiology
Which of the following correctly describes the role of the cerebellum in motor control?
A Initiates voluntary movements
B Coordinates movements and maintains balance through error correction
C Controls involuntary reflexes only
D Produces neurotransmitters for muscle contraction
Correct Answer:  B. Coordinates movements and maintains balance through error correction
EXPLANATION

The cerebellum compares intended movements with actual movements, providing real-time corrections for coordination, balance, and fine motor control.

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A patient with spinal cord injury at T5 level loses pain sensation below the waist. Which spinal tract is likely damaged?
A Dorsal column
B Spinothalamic tract
C Corticospinal tract
D Propriospinal fibers
Correct Answer:  B. Spinothalamic tract
EXPLANATION

The spinothalamic tract carries pain and temperature sensation, crossing at the spinal cord level. Damage results in contralateral loss of pain sensation below the injury.

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During gastric digestion, what is the primary function of pepsin?
A Lipid digestion
B Protein breakdown to smaller polypeptides
C Carbohydrate digestion
D Nucleic acid digestion
Correct Answer:  B. Protein breakdown to smaller polypeptides
EXPLANATION

Pepsin is a protease activated in the acidic stomach environment, cleaving peptide bonds in proteins to form polypeptides and oligopeptides.

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Which hormone primarily regulates sodium reabsorption in the distal convoluted tubule and collecting duct?
A Vasopressin
B Aldosterone
C Glucagon
D Parathyroid hormone
Correct Answer:  B. Aldosterone
EXPLANATION

Aldosterone, released by the adrenal cortex, increases sodium reabsorption via mineralocorticoid receptors in the DCT and collecting duct.

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Q.37 Medium Human Physiology
A 45-year-old patient has abnormally high blood glucose despite insulin administration. Which condition is most likely?
A Type 1 diabetes mellitus
B Insulin resistance (Type 2 diabetes)
C Hypoglycemia
D Gestational diabetes
Correct Answer:  B. Insulin resistance (Type 2 diabetes)
EXPLANATION

Type 2 diabetes involves insulin resistance where cells don't respond properly to insulin, maintaining elevated blood glucose despite insulin presence.

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Which of the following best describes the role of surfactant in respiratory physiology?
A Increases surface tension in alveoli
B Decreases surface tension, preventing alveolar collapse
C Increases oxygen diffusion rate
D Produces mucus for pathogen trapping
Correct Answer:  B. Decreases surface tension, preventing alveolar collapse
EXPLANATION

Pulmonary surfactant (lipid + protein) reduces surface tension in alveoli, preventing their collapse during expiration and reducing work of breathing.

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Q.39 Medium Human Physiology
In the process of blood clotting, what is the primary function of thrombin?
A Activation of platelets
B Conversion of fibrinogen to fibrin
C Removal of clots
D Prevention of platelet aggregation
Correct Answer:  B. Conversion of fibrinogen to fibrin
EXPLANATION

Thrombin is a serine protease that cleaves fibrinogen into fibrin monomers, which polymerize to form the structural basis of blood clots.

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Q.40 Medium Human Physiology
How does the parasympathetic nervous system affect heart rate and cardiac output?
A Increases heart rate and contractility
B Decreases heart rate through vagus nerve stimulation
C Has no effect on cardiovascular function
D Increases only contractility without affecting rate
Correct Answer:  B. Decreases heart rate through vagus nerve stimulation
EXPLANATION

The parasympathetic nervous system (via vagus nerve) releases acetylcholine, which decreases heart rate and force of contraction through M2 receptors.

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