Introduction to the Nervous System

These flashcards cover key terms and concepts related to the Nervous System, including its structure, function, and components.

1. Nervous System

A complex network responsible for receiving stimuli, processing information, and generating responses.

2. Sensory Receptors

Cells or organs that detect changes in the environment (stimuli).

3. Integration

The process of interpreting sensory input and making decisions.

4. Motor Output

The response generated by activating effectors (muscles, glands, organs).

5. Central Nervous System (CNS)

Comprises the brain and spinal cord, and serves as the command center for processing information.

6. Peripheral Nervous System (PNS)

Includes all neural structures outside the CNS, enabling communication between the CNS and the rest of the body.

7. Afferent Division

Part of the PNS that carries sensory information to the CNS.

8. Efferent Division

Part of the PNS that transmits motor commands from the CNS to the effectors.

9. Somatic Nervous System

Controls voluntary movements by activating skeletal muscles.

10. Autonomic Nervous System

Regulates involuntary functions, controlling smooth muscle, cardiac muscle, and glands.

11. Parasympathetic Division

Part of the autonomic nervous system that promotes rest and digestion.

12. Sympathetic Division

Part of the autonomic nervous system that triggers the fight or flight response.

13. Neurons

Specialized cells that conduct electrical impulses throughout the nervous system.

14. Action Potentials

Electrical impulses created by the rapid influx of sodium ions in neurons.

15. Dendrites

Branch-like structures of neurons that receive signals from other neurons.

16. Soma (Cell Body)

The central part of a neuron that contains the nucleus.

17. Axon

Long projection of a neuron that transmits impulses away from the cell body.

18. Axon Hillock

Region of the axon that generates action potentials.

19. Myelin Sheath

Fatty layer around axons which speeds up electrical conduction.

20. Nodes of Ranvier

Gaps in the myelin sheath that facilitate rapid signal transmission.

21. Neurotransmitters

Chemicals released by neurons to communicate with target cells.

22. Synapse

The junction between two neurons where neurotransmitters are released.

23. Presynaptic Neuron

Neuron that releases neurotransmitter into the synapse.

24. Postsynaptic Neuron

Neuron that receives neurotransmitter and responds to it.

25. Ligand-Gated Channels

Ion channels that open in response to neurotransmitter binding.

26. Voltage-Gated Channels

Ion channels that open or close in response to changes in membrane potential.

27. Resting Membrane Potential

The electrical potential difference across the neuronal membrane at rest, typically around -70mV.

28. Depolarization

A decrease in membrane potential, making the inside of the cell more positive.

29. Hyperpolarization

An increase in membrane potential, making the inside of the cell more negative.

30. Repolarization

Return of the membrane potential back to resting after depolarization.

31. Excitatory Postsynaptic Potential (EPSP)

A postsynaptic potential that makes the neuron more likely to fire an action potential.

32. Inhibitory Postsynaptic Potential (IPSP)

A postsynaptic potential that makes the neuron less likely to fire an action potential.

33. Sodium-Potassium Pump

A membrane protein that helps maintain resting potential by moving Na+ out and K+ into the cell.

34. Oligodendrocytes

Glial cells in the CNS that produce myelin sheaths.

35. Schwann Cells

Glial cells in the PNS that form myelin sheaths around peripheral axons.

36. Astrocytes

Glial cells that support and protect neurons and regulate the external environment.

37. Microglia

Immune cells of the CNS that remove debris and dead cells.

38. Ependymal Cells

Glial cells that line the ventricles of the brain and produce cerebrospinal fluid.

39. Multiple Sclerosis

A disease characterized by the loss of myelin in the CNS.

40. Reflex Arc

The neural pathway that controls reflex actions.

41. Interneurons

Neurons that connect sensory and motor neurons within the CNS.

42. Mixed Nerves

Nerves containing both sensory and motor fibers.

43. Pseudounipolar Neurons

Sensory neurons with a single process that divides into two branches.

44. Bipolar Neurons

Neurons with two processes; one axon and one dendrite.

45. Multipolar Neurons

Neurons with multiple dendrites and one axon; most common type.

46. Synaptic Vesicles

Small sacs that store neurotransmitters at the axon terminal.

47. Exocytosis

The process of releasing neurotransmitters into the synapse.

48. Summation

The process by which multiple postsynaptic potentials combine to determine if an action potential occurs.

49. Action Potential Threshold

The level of depolarization (-55mV) that must be reached to trigger an action potential.

50. Conduction Velocity

The speed at which an action potential travels along an axon.

51. Myelination

The process of forming a myelin sheath around an axon.

52. Type A Axons

Large diameter, myelinated axons that conduct impulses quickly.

53. Type B Axons

Medium diameter, lightly myelinated axons that conduct impulses at moderate speeds.

54. Type C Axons

Small diameter, unmyelinated axons that conduct impulses slowly.

55. Neuroglia

Supporting cells in the nervous system that outnumber neurons.

56. Blood-Brain Barrier

A protective barrier that restricts access of substances to the brain.

57. Membrane Potential Change

Changes in the electrical state of a neuron following stimulation.

58. Calcium Ions (Ca++)

Important ions that play a role in neurotransmitter release at synapses.

59. Potassium Ions (K+)

Ions that are important for repolarization and establishing resting membrane potential.

60. Sodium Ions (Na+)

Ions that are crucial for depolarization during action potentials.