A2 - Nervous system Flashcards

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1
Q

Central Nervous System (CNS)

A

Consists of the brain and spinal cord.

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2
Q

Peripheral Nervous System (PNS)

A

Consists of sensory and motor neurons.

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3
Q

Sensory Neurons

A

Neurons that receive information from receptors and transmit it to the CNS.

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4
Q

Motor Neurons

A

Neurons that carry information from the CNS to effectors, such as muscles.

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5
Q

Neurons

A

Cells that receive and transmit nerve impulses or action potentials.

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6
Q

Soma

A

The large cell body of a neuron.

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7
Q

Dendrites

A

Small projections on a neuron that receive signals from other neurons.

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8
Q

Axon

A

A long projection of a neuron that carries nerve impulses away from the soma.

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9
Q

Axon Terminal

A

The end of the axon that communicates with the dendrite of the next neuron

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10
Q

Synaptic Cleft

A

The small gap between the axon terminal and the dendrite of the next neuron.

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11
Q

Nerve Impulse

A

Electrical signals that carry information along neurons.

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12
Q

Action Potential

A

Brief change in voltage across a neuron’s membrane, resulting in a nerve impulse

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13
Q

Ion Balance

A

The equilibrium of ions (charged particles) within a nerve cell.

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14
Q

Nerves

A

Bundles of neurons that form a network throughout the body.

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15
Q

Neurotransmitters

A

Chemicals released by neurons that transmit signals across the synaptic cleft.

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16
Q

Synaptic Cleft

A

The small gap between neurons where neurotransmitters are released and received.

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17
Q

Receptors

A

Proteins on the post-synaptic membrane that bind to neurotransmitters

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18
Q

Glial Cells

A

Cells that support and nourish neurons, digesting dead neurons and producing neuronal components.

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19
Q

Resting Potential

A

Potential difference across the membrane of a neuron in its resting state, with the interior of the cell negative compared to the exterior.

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20
Q

Concentration Gradient

A

Difference in ion concentration between the inside and outside of a neuron

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21
Q

Voltage-Gated Ion Channels

A

Ion channels that open or close in response to changes in voltage.

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22
Q

Threshold Voltage

A

The minimum voltage required to trigger an action potential (around -55mV).

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23
Q

Depolarization

A

Change in membrane potential where the inside of the membrane becomes less negative.

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24
Q

Polarization

A

State of a neuron’s membrane when at rest, with a positive charge outside and negative charge inside.

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25
Q

Stimulus

A

Chemical, mechanical, thermal, or electrical signal that triggers a response in a neuron.

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26
Q

Repolarization

A

Restoration of the internal negativity of a neuron after depolarization, achieved by K+ channels opening and allowing K+ to rush out of the cell. -70mV.

27
Q

Sodium-Potassium Pump

A

Protein pump that actively transports Na+ out of the cell and K+ into the cell, restoring ionic conditions.

28
Q

Hyperpolarization

A

Membrane potential falls below the resting potential, causing the interior of the membrane to become more negative than -70mV.

29
Q

Refractory Period

A

The time taken for the membrane to return to resting potential after hyperpolarization, during which an action potential cannot be generated.

30
Q

Overshoot

A

Excessive increase in the interior membrane potential during hyperpolarization.

31
Q

K+ Channels

A

Potassium ion channels that are slow to close, resulting in excessive efflux of potassium ions.

32
Q

Interior Membrane Potential

A

Electrical charge inside the neuron’s membrane.

33
Q

K+ Permeability

A

Ability of potassium ions to pass through the membrane.

34
Q

Na+ Channels

A

Sodium ion channels that reset during hyperpolarization.

35
Q

K+ Efflux

A

Outward flow or diffusion of potassium ions.

36
Q

Unidirectional Signal

A

Hyperpolarization prevents the neuron from receiving another stimulus and ensures that the signal proceeds in one direction only.

37
Q

Signal Propagation

A

The transmission of an action potential along an axon.

38
Q

Nerve Impulse Speed

A

The speed at which a nerve impulse travels in humans

39
Q

Unmyelinated Fibers

A

Nerve fibers without a myelin sheath, where nerve impulses travel at a speed of 1-3 m/s.

40
Q

Myelinated Fibers

A

Nerve fibers with a myelin sheath, where nerve impulses travel at a speed of 3-120 m/s.

41
Q

Axon Diameter

A

The size of the axon, with larger axons allowing for faster conduction of nerve impulses.

42
Q

Myelination

A

The presence of myelin around a neuron, which increases the speed of nerve impulse conduction.

43
Q

Number of Synapses

A

The quantity of synapses involved in transmitting a nerve impulse, with fewer synapses resulting in faster communication.

44
Q

Myelin Sheath

A

Fatty insulating layer around the axon, formed by Schwann cells, which enhances the speed of action potential travel.

45
Q

Schwann Cells

A

Specialized cells that wrap around the axon to form the myelin sheath

46
Q

Nodes of Ranvier

A

Exposed areas on the myelinated axon where ion exchange occurs.

47
Q

Saltatory Conduction

A

The process of the nerve signal jumping from one node of Ranvier to the next along a myelinated axon, significantly increasing conduction speed.

48
Q

Synapse

A

The junction where two neurons meet, allowing communication between them

49
Q

Presynaptic Neuron

A

Neuron carrying the nerve impulse towards the synaptic cleft.

50
Q

Postsynaptic Neuron

A

Neuron receiving the nerve impulse from the presynaptic neuron and carrying it away.

51
Q

Neurotransmitters

A

Chemical molecules used by the nervous system to transmit messages between neurons or from neurons to muscles.

52
Q

Dendrites

A

Branch-like projections at the end of a neuron’s axon that receive signals from other neurons.

53
Q

Receptor Molecules

A

Molecules on the membrane of the postsynaptic neuron that bind to neurotransmitters.

54
Q

Acetylcholine

A

A common neurotransmitter responsible for muscle contraction.

55
Q

Action Potential Arrival

A

The action potential reaches the pre-synaptic membrane at the end of the axon.

56
Q

Calcium Ion Entry

A

Calcium ion channels open, allowing calcium ions (Ca+2) to enter the axon.

57
Q

Vesicle Movement

A

Vesicles containing neurotransmitters move towards the pre-synaptic membrane.

58
Q

Vesicle Fusion and Release

A

Vesicles fuse with the pre-synaptic membrane and release neurotransmitters into the synaptic cleft.

59
Q

Neurotransmitter Diffusion

A

Neurotransmitters diffuse across the synaptic cleft from high to low concentration, down a concentration gradient.

60
Q

Receptor Binding

A

Neurotransmitters bind to receptors on the post-synaptic cell membrane.

61
Q

Sodium Ion Entry

A

Sodium ion channels open in the post-synaptic membrane, allowing sodium ions to enter and depolarize the membrane.

62
Q

Neurotransmitter Recycling

A

Neurotransmitters are recycled through enzyme degradation or re-uptake into the pre-synaptic neuron.

63
Q

Neurotransmitter Removal

A

Neurotransmitters are removed from the synaptic cleft to prevent continuous stimulation, either by re-uptake or enzyme degradation.

64
Q

Threshold Level

A

The minimum level of neurotransmitter required to produce a postsynaptic action potential.