BDS 1st Year Physiology Important MCQs With Answers

Physiology is an important subject in BDS 1st Year. It covers concepts related to homeostasis, body fluid compartments, nerve physiology, and other basic functions of the human body. Revising these concepts through MCQs can help you recall important points and identify areas that need further revision.

The following questions cover important Physiology concepts, including homeostatic mechanisms, body water, electrical neutrality, action potentials, nerve fibres, axonal transport and saltatory conduction.

BDS 1st Year Physiology Important MCQs With Answers

The following MCQs can be used for quick revision. Attempt each question before checking the answer.

Q1. Which of the following statements is false regarding the physiological concept and core principles of homeostasis?

A. The term was coined by an American physiologist, Sir Walter Cannon
B. The equilibrium maintained is dynamic, with normal ranges fluctuating based on physiological conditions
C. Homeostasis prioritizes maintaining blood pressure and sodium values over blood pH
D. It is maintained by an interplay of body control mechanisms regulated by the nervous and endocrine systems

Answer: C. Homeostasis prioritizes maintaining blood pressure and sodium values over blood pH

Q2. Which of the following correctly differentiates positive feedback from negative feedback mechanism?

A. Negative feedback amplifies the deviation while positive feedback resists it
B. Positive feedback restores the variable back to its normal set point
C. Negative feedback is life-threatening while positive feedback is always protective
D. Positive feedback amplifies the response away from set point while negative feedback restores it back to normal

Answer: D. Positive feedback amplifies the response away from set point while negative feedback restores it back to normal

Q3. What is the total body water content in a normal healthy adult male weighing 70 kg?

A. 42 litres
B. 36 litres
C. 50 litres
D. 28 litres

Answer: A. 42 litres

Q4. Why is the fluid in each body compartment electrically neutral?

A. Ions constitute approximately 95% of the solutes in the body fluids
B. Na⁺ and Cl⁻ are largely extracellular, whereas K⁺ and PO₄³⁻ are predominantly intracellular
C. Essentially all of the body K⁺ and Na⁺ is in the exchangeable pool
D. Sum of concentration of cations equals the sum of concentration of anions in each respective compartment

Answer: D. Sum of concentration of cations equals the sum of concentration of anions in each respective compartment

Q5. Match the ionic change with the stage of the action potential.

Stages:

1. Resting membrane potential

2. Depolarization

3. Repolarization

4. Hyperpolarization

Ionic Events:
a. Slow closure of voltage-gated K⁺ channels
b. Voltage-gated K⁺ channels open
c. Voltage-gated Na⁺ channels open
d. Action of Na⁺/K⁺ pump

A. 1-a, 2-b, 3-c, 4-d
B. 1-d, 2-c, 3-a, 4-b
C. 1-d, 2-c, 3-b, 4-a
D. 1-d, 2-b, 3-c, 4-a

Answer: C. 1-d, 2-c, 3-b, 4-a

Q6. What is the cause of after-hyperpolarization during a nerve action potential?

A. Fast closure of Na⁺ channels
B. Slow closure of Na⁺ channels
C. Fast closure of K⁺ channels
D. Slow closure of K⁺ channels

Answer: D. Slow closure of K⁺ channels

Q7. Choose the false statement regarding the myelin sheath.

A. Made up of both proteins and lipids
B. Increases conduction velocity of nerve
C. Formed by Schwann cells in the peripheral nervous system
D. At nodes of Ranvier, there is a 1 nm area of unmyelinated axon

Answer: D. At nodes of Ranvier, there is a 1 nm area of unmyelinated axon

Q8. An obese man develops weakness in his left arm after sleeping in an awkward position following alcohol intake. Which type of nerve fibers are most susceptible to this type of injury?

A. A fibers
B. B fibers
C. C fibers
D. All are equally susceptible

Answer: A. A fibers

Q9. How is the resting membrane potential affected in Hyperkalemic Periodic Paralysis?

A. Increased (less negative)
B. Decreased (more negative)
C. Remains the same
D. May increase or decrease

Answer: A. Increased (less negative)

Q10. A 10-year-old boy is bitten by a rabid dog. After a few days he develops hydrophobia and delirium. The rabies virus reaches the central nervous system via which axonal transport pathway and which motor protein?

A. Anterograde, Kinesin
B. Retrograde, Kinesin
C. Anterograde, Dynein
D. Retrograde, Dynein

Answer: D. Retrograde, Dynein

Q11. A surgeon accidentally cuts the radial nerve during surgery. What is the rate of axonal regeneration following nerve injury?

A. 1–3 cm/day
B. 1–3 mm/hour
C. 1–3 cm/hour
D. 1–3 mm/day

Answer: D. 1–3 mm/day

Q12. Match the following with the type of neurons.

a. Retina
b. Dorsal root ganglion
c. Neurons of invertebrates
d. Purkinje cells of cerebellum

A. a-i, b-ii, c-iii, d-iv
B. a-i, b-iii, c-ii, d-iv
C. a-ii, b-iii, c-i, d-iv
D. a-iii, b-ii, c-iv, d-i

Answer: B. a-i, b-iii, c-ii, d-iv

Q13. On the Strength–Duration curve, X and Y represent:

A. Rheobase, Chronaxie
B. Utilization time, Chronaxie
C. Chronaxie, Rheobase
D. Chronaxie, Utilization time

Answer: A. Rheobase, Chronaxie

Q14. Saltatory conduction in myelinated nerve fibers provides which advantage over conduction in unmyelinated fibers?

A. Bidirectional conduction of impulses
B. Increased speed of conduction and conservation of ionic energy
C. Elimination of the absolute refractory period
D. Generation of action potentials at any point along the axon

Answer: B. Increased speed of conduction and conservation of ionic energy

Key Topics Covered in BDS 1st Year Physiology Important MCQs

These questions cover several important areas of Physiology:

• Homeostasis: Concept of homeostasis and the difference between positive and negative feedback.

• Body fluid compartments: Total body water, intracellular fluid and extracellular fluid.

• Electrical neutrality: Balance between cations and anions in body fluid compartments.

• Nerve physiology: Action potential, resting membrane potential, depolarisation, repolarisation and hyperpolarisation.

• Myelin and nerve fibres: Functions of myelin, nodes of Ranvier and susceptibility of different nerve fibres.

• Axonal transport: Retrograde transport and the role of dynein.

• Nerve regeneration: Rate of axonal regeneration following peripheral nerve injury.

• Neuron types: Classification of neurons found in the retina, dorsal root ganglion, invertebrates and cerebellum.

• Strength–duration curve: Rheobase and chronaxie.

• Saltatory conduction: Increased conduction speed and conservation of ionic energy.

For more MCQ questions and medical exam preparation, you can practise on the PW MedEd App.

Practising BDS 1st Year Physiology Important MCQs can help you revise core concepts through question practice. Questions on homeostasis, body fluids, nerve physiology and action potentials can be used for quick revision before examinations.