TRB PG Assistant - Neurophysiology – CNS, PNS, neuron structure, impulse transmission, neurotransmitters, reflexes Online Test (MCQ Quiz)

1. What is the primary function of the central nervous system (CNS)?

A) To transmit sensory information from the body to the brain B) To process information and coordinate bodily activities C) To control voluntary muscle movements D) To regulate involuntary bodily functions like heart rate

2. Which part of the peripheral nervous system (PNS) controls voluntary movements of skeletal muscles?

A) Autonomic nervous system B) Sympathetic nervous system C) Somatic nervous system D) Parasympathetic nervous system

3. What is the main structural and functional unit of the nervous system called?

A) Axon B) Dendrite C) Neuron D) Synapse

4. Which part of a neuron typically receives signals from other neurons?

A) Axon hillock B) Cell body (soma) C) Myelin sheath D) Dendrites

5. What is the long, slender projection of a neuron that conducts electrical impulses away from the cell body?

A) Dendrite B) Axon C) Synapse D) Nerve impulse

6. The gap between two neurons where information is transmitted is known as the:

A) Axon terminal B) Dendritic spine C) Synapse D) Node of Ranvier

7. What is the electrical signal that travels along a neuron called?

A) Neurotransmitter B) Action potential C) Synaptic potential D) Resting potential

8. The process by which a neuron transmits a signal is called:

A) Synaptic transmission B) Impulse conduction C) Action potential generation D) All of the above

9. What is the resting potential of a neuron?

A) The electrical charge across the membrane when the neuron is inactive B) The electrical charge across the membrane during an action potential C) The influx of sodium ions into the neuron D) The efflux of potassium ions from the neuron

10. During an action potential, which ion primarily rushes into the neuron?

A) Potassium (K+) B) Chloride (Cl-) C) Sodium (Na+) D) Calcium (Ca2+)

11. What causes repolarization of the neuron membrane after an action potential?

A) Influx of sodium ions B) Efflux of potassium ions C) Influx of chloride ions D) Active transport of sodium ions out of the cell

12. What are chemical messengers released by neurons to transmit signals across synapses called?

A) Ions B) Action potentials C) Neurotransmitters D) Receptors

13. Which of the following is a common excitatory neurotransmitter in the CNS?

A) Gamma-aminobutyric acid (GABA) B) Acetylcholine (ACh) C) Glutamate D) Dopamine

14. Which neurotransmitter is primarily associated with muscle contraction at the neuromuscular junction?

A) Serotonin B) Dopamine C) Acetylcholine (ACh) D) Norepinephrine

15. Which neurotransmitter is often associated with mood, sleep, and appetite regulation?

A) Glutamate B) GABA C) Serotonin D) Epinephrine

16. What is the role of inhibitory neurotransmitters?

A) To increase the likelihood of a neuron firing an action potential B) To decrease the likelihood of a neuron firing an action potential C) To speed up the transmission of nerve impulses D) To block the release of excitatory neurotransmitters

17. The process of removing neurotransmitters from the synaptic cleft after signal transmission is crucial for:

A) Maintaining continuous excitation B) Allowing for precise and controlled signaling C) Increasing the strength of the signal D) Preventing reuptake by the presynaptic neuron

18. What is a reflex action?

A) A voluntary response to a stimulus B) An involuntary, rapid response to a stimulus C) A learned behavior involving complex thought processes D) A conscious decision made by the brain

19. The pathway followed by a nerve impulse during a reflex action is called a:

A) Synaptic pathway B) Neural circuit C) Reflex arc D) Action potential chain

20. In a simple reflex arc, what is the first component that detects a stimulus?

A) Motor neuron B) Interneuron C) Sensory receptor D) Effector

21. Which type of neuron carries impulses from the CNS to muscles or glands?

A) Sensory neuron B) Motor neuron C) Interneuron D) Afferent neuron

22. The structure that carries out the response in a reflex action is called the:

A) Receptor B) Sensory neuron C) Motor neuron D) Effector

23. The withdrawal reflex (e.g., pulling your hand away from a hot object) is an example of what type of reflex?

A) Autonomic reflex B) Somatic reflex C) Conditioned reflex D) Complex reflex

24. The brain is primarily composed of which part of the nervous system?

A) Peripheral Nervous System (PNS) B) Central Nervous System (CNS) C) Autonomic Nervous System (ANS) D) Somatic Nervous System (SNS)

25. Which of the following is NOT a component of the CNS?

A) Brain B) Spinal cord C) Cranial nerves D) Cerebellum

26. The spinal cord's primary role in the CNS includes:

A) Processing complex cognitive functions B) Initiating voluntary movements C) Relaying sensory information and coordinating reflexes D) Regulating emotions and memory

27. The PNS is divided into the somatic nervous system and the:

A) Central nervous system B) Autonomic nervous system C) Brainstem D) Cerebral cortex

28. The autonomic nervous system (ANS) is responsible for:

A) Voluntary control of skeletal muscles B) Conscious thought and decision-making C) Regulating involuntary bodily functions D) Processing sensory input from the environment

29. Which division of the ANS prepares the body for 'fight or flight' responses?

A) Parasympathetic nervous system B) Sympathetic nervous system C) Enteric nervous system D) Somatic nervous system

30. The parasympathetic nervous system is primarily involved in:

A) Stimulating heart rate and digestion B) Conserving energy and promoting 'rest and digest' functions C) Initiating rapid muscle contractions D) Causing pupil dilation

31. What is the insulating layer around many axons that speeds up nerve impulse transmission?

A) Dendrite B) Synapse C) Myelin sheath D) Node of Ranvier

32. Gaps in the myelin sheath where the action potential is regenerated are called:

A) Axon terminals B) Dendritic spines C) Synapses D) Nodes of Ranvier

33. The process of impulse transmission along a myelinated axon is called:

A) Continuous conduction B) Saltatory conduction C) Synaptic transmission D) Graded potential

34. What type of synapse involves direct electrical connection between neurons?

A) Chemical synapse B) Electrical synapse C) Axodendritic synapse D) Axosomatic synapse

35. In a chemical synapse, neurotransmitters are stored in vesicles within the:

A) Postsynaptic neuron B) Presynaptic terminal C) Synaptic cleft D) Dendrite

36. When a neurotransmitter binds to its receptor on the postsynaptic membrane, it can cause:

A) Depolarization (excitatory postsynaptic potential - EPSP) B) Hyperpolarization (inhibitory postsynaptic potential - IPSP) C) Both depolarization and hyperpolarization D) Immediate cessation of signal transmission

37. Which neurotransmitter plays a key role in reward pathways and is implicated in addiction?

A) Serotonin B) GABA C) Dopamine D) Glutamate

38. The 'all-or-none' principle of action potential generation means that:

A) A neuron will fire an action potential only if the stimulus reaches a certain threshold B) The amplitude of an action potential varies with the strength of the stimulus C) A neuron can fire multiple action potentials simultaneously D) The speed of an action potential is constant regardless of axon diameter

39. What is summation in neurophysiology?

A) The process of neurotransmitter synthesis B) The combined effect of multiple synaptic inputs on a neuron's membrane potential C) The insulation of axons by myelin D) The rapid firing of a single action potential

40. Which part of the neuron integrates incoming signals?

A) Axon terminal B) Cell body (soma) and axon hillock C) Myelin sheath D) Dendrites only

41. Which of the following is a key characteristic of the peripheral nervous system (PNS)?

A) It is entirely responsible for higher cognitive functions. B) It includes the brain and spinal cord. C) It connects the CNS to the rest of the body. D) It is solely responsible for involuntary actions.

42. The brain region responsible for coordinating voluntary movements and balance is the:

A) Cerebrum B) Cerebellum C) Brainstem D) Thalamus

43. What is the primary role of sensory receptors in the PNS?

A) To transmit commands from the CNS to effectors B) To detect stimuli from the internal and external environment C) To process complex information and form memories D) To regulate heart rate and breathing

44. Which type of neurotransmitter is Gamma-aminobutyric acid (GABA)?

A) Excitatory B) Inhibitory C) Modulatory D) Excitatory and inhibitory

45. What is the term for the process where neurotransmitters are taken back into the presynaptic neuron?

A) Degradation B) Reuptake C) Diffusion D) Synthesis

46. A polysynaptic reflex arc involves:

A) Only a sensory neuron and a motor neuron B) A sensory neuron, a motor neuron, and at least one interneuron C) Only interneurons D) A direct connection from the brain to the effector

47. Which part of the neuron contains the nucleus and major organelles?

A) Axon B) Dendrite C) Cell body (soma) D) Myelin sheath

48. Damage to the myelin sheath can lead to which of the following conditions?

A) Parkinson's disease B) Alzheimer's disease C) Multiple Sclerosis (MS) D) Epilepsy

49. The phenomenon where a neuron becomes less responsive to repeated stimulation after prolonged exposure to a neurotransmitter is known as:

A) Sensitization B) Habituation C) Potentiation D) Depolarization

50. What is the role of acetylcholine (ACh) in the peripheral nervous system?

A) It is the primary inhibitory neurotransmitter. B) It excites skeletal muscles at the neuromuscular junction. C) It regulates mood and emotions. D) It is involved in the 'fight or flight' response.

Neurophysiology – CNS, PNS, neuron structure, impulse transmission, neurotransmitters, reflexes - Online Test

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