NEET UG - Neural control and coordination - neuron structure nerve impulse transmission reflex action Online Test (MCQ Quiz)

1. What is the basic functional unit of the nervous system?

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

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

A) Axon hillock B) Myelin sheath C) Dendrites D) Axon terminal

3. The long projection of a neuron that conducts electrical impulses away from the cell body is called the:

A) Dendron B) Synapse C) Axon D) Soma

4. What is the insulating layer around the axon of many neurons?

A) Neurolemma B) Myelin sheath C) Neurilemma D) Schwann cell

5. Gaps in the myelin sheath along an axon are known as:

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

6. The cell body of a neuron is also called the:

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

7. What is the junction between two neurons called?

A) Synapse B) Ganglion C) Plexus D) Neuromuscular junction

8. The transmission of a nerve impulse across a synapse is typically mediated by:

A) Electrical signals only B) Chemical neurotransmitters C) Hormones D) Mechanical pressure

9. Which ion is primarily responsible for the resting membrane potential of a neuron?

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

10. During the generation of an action potential, which ion channels open first, leading to depolarization?

A) Potassium channels B) Chloride channels C) Sodium channels D) Calcium channels

11. The rapid influx of sodium ions into the neuron causes:

A) Repolarization B) Hyperpolarization C) Depolarization D) Resting potential

12. What happens during repolarization of a neuron?

A) Sodium ions rush into the cell B) Potassium ions rush out of the cell C) The membrane potential becomes more positive D) The cell becomes more permeable to sodium

13. The 'all-or-none' principle of nerve impulse transmission means that:

A) A neuron can fire with varying strengths B) A neuron fires to its maximum capacity or not at all C) The impulse strength depends on the stimulus duration D) The impulse travels slower in myelinated axons

14. Saltatory conduction, which speeds up nerve impulse transmission, occurs in:

A) Unmyelinated axons B) Dendrites C) Myelinated axons D) Cell bodies

15. Neurotransmitters are released from the:

A) Presynaptic terminal B) Postsynaptic membrane C) Dendrites D) Cell body

16. Which of the following is a common excitatory neurotransmitter?

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

17. Which of the following is a common inhibitory neurotransmitter?

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

18. The space between the presynaptic terminal and the postsynaptic membrane is called the:

A) Axon hillock B) Synaptic cleft C) Node of Ranvier D) Dendritic spine

19. What is a reflex action?

A) A voluntary movement initiated by the brain B) An involuntary, rapid, and automatic response to a stimulus C) A learned behavior based on past experiences D) A conscious decision-making process

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

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

21. Which component of a reflex arc detects the stimulus?

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

22. The sensory neuron transmits the impulse from the receptor to the:

A) Effector B) Motor neuron C) Central nervous system (spinal cord or brainstem) D) Interneuron

23. An interneuron, also known as a relay neuron, is typically found in the:

A) Peripheral nervous system B) Sensory pathway C) Central nervous system D) Motor pathway

24. The motor neuron transmits the impulse from the CNS to the:

A) Receptor B) Sensory neuron C) Effector (muscle or gland) D) Interneuron

25. The effector in a reflex arc is responsible for:

A) Detecting the stimulus B) Transmitting the signal to the CNS C) Carrying out the response D) Processing the information in the CNS

26. A simple reflex arc typically involves how many neurons?

A) Two (sensory and motor) B) Three (sensory, interneuron, motor) C) Four D) Five

27. The knee-jerk reflex (patellar reflex) is an example of a:

A) Polysynaptic reflex B) Monosynaptic reflex C) Voluntary response D) Complex learned behavior

28. In the knee-jerk reflex, the sensory neuron directly synapses with the:

A) Interneuron B) Motor neuron C) Effector muscle D) Receptor

29. Withdrawal reflexes, like pulling your hand away from a hot object, are examples of:

A) Monosynaptic reflexes B) Polysynaptic reflexes C) Somatic reflexes D) Autonomic reflexes

30. The role of the interneuron in a polysynaptic reflex arc is to:

A) Generate the initial impulse B) Transmit the impulse directly to the effector C) Integrate signals and modulate the motor output D) Detect the stimulus

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

A) Axon B) Dendrite C) Cell body (Soma) D) Axon terminal

32. The process by which neurotransmitters are removed from the synaptic cleft is important for:

A) Continuous stimulation of the postsynaptic neuron B) Allowing the postsynaptic neuron to repolarize C) Increasing the speed of transmission D) Generating a stronger signal

33. Which glial cells form the myelin sheath in the Central Nervous System (CNS)?

A) Schwann cells B) Oligodendrocytes C) Astrocytes D) Microglia

34. Which glial cells form the myelin sheath in the Peripheral Nervous System (PNS)?

A) Oligodendrocytes B) Schwann cells C) Astrocytes D) Ependymal cells

35. The resting membrane potential is approximately:

A) +30 mV B) -70 mV C) 0 mV D) +70 mV

36. The depolarization phase of an action potential reaches a peak of about:

A) -70 mV B) -55 mV C) +30 mV D) 0 mV

37. Hyperpolarization occurs when:

A) Sodium ions enter the cell B) Potassium ions leave the cell excessively C) Sodium-potassium pump is activated D) The membrane potential returns to resting level

38. The sodium-potassium pump is crucial for maintaining the concentration gradients of ions across the neuron membrane, requiring:

A) ATP B) ADP C) Glucose D) Oxygen

39. Which of the following is NOT a primary neurotransmitter involved in human neural function?

A) Serotonin B) Dopamine C) Endorphin D) Melatonin

40. The refractory period ensures that:

A) Action potentials can travel in both directions along the axon B) A neuron can fire multiple times rapidly C) An action potential travels in one direction and prevents summation of impulses D) The resting potential is always maintained

41. What is the primary function of the axon terminal?

A) Receive signals B) Integrate signals C) Release neurotransmitters D) Generate action potentials

42. A drug that blocks the reuptake of a neurotransmitter would likely:

A) Decrease the effect of the neurotransmitter B) Increase the concentration and effect of the neurotransmitter in the synaptic cleft C) Prevent the release of the neurotransmitter D) Block the receptors on the postsynaptic membrane

43. Which type of neuron transmits information from the CNS to effectors?

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

44. The 'trigger zone' for generating an action potential in a neuron is the:

A) Axon terminal B) Dendrite C) Axon hillock D) Synaptic cleft

45. Which statement best describes the role of receptors in a reflex arc?

A) They send signals to motor neurons. B) They convert stimulus energy into electrical signals. C) They transmit signals within the CNS. D) They carry out the response.

46. The process of summation in neurons refers to:

A) The integration of multiple inhibitory postsynaptic potentials B) The summing of excitatory and inhibitory postsynaptic potentials C) The accumulation of neurotransmitters in the synapse D) The rapid firing of action potentials

47. When a postsynaptic neuron receives an inhibitory neurotransmitter, it causes:

A) Depolarization B) Hyperpolarization C) Repolarization D) An action potential

48. Which reflex is primarily involved in maintaining balance and posture?

A) Withdrawal reflex B) Stretch reflex C) Crossed-extensor reflex D) Pupillary light reflex

49. The propagation of an action potential along an axon is a form of:

A) Chemical signaling B) Electrical signaling C) Mechanical signaling D) Hormonal signaling

50. What is the consequence of a stimulus that is subthreshold for a neuron?

A) A full action potential is generated. B) No action potential is generated. C) The neuron fires multiple action potentials. D) The resting potential becomes more negative.

Neural control and coordination - neuron structure nerve impulse transmission reflex action - Online Test

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