Nervous System Flashcards

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1
Q

What are the two main divisions of the nervous system?

A

Central Nervous System (CNS)

Peripheral Nervous System (PNS)

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2
Q

What are neurons?

A

Conducting cells
Transmit nerve impulses
Are bundled into tissues called nerves in the PNS and tracts in the CNS

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3
Q

What are glial cells?

A

The glial cells surround neurons and provide support for and insulation between between them

They are the most abundant cell type in the CNS

Schwann cells are a type of glial cell

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4
Q

What are the three types of neurons?

A

Sensory neurons

Interneurons

Motor neurons

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5
Q

What do sensory neurons do?

A

Gather information from the sensory receptors (senses) and transmit these impulses to the CNS

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6
Q

What do interneurons do?

A

Only I’m the CNS, they are the link between the sensory and motor neurons, they process incoming sensory information and relay to motor neurons

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7
Q

What do motor neurons do?

A

Transmit info from the CNS to the muscles, glands, and other organs

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8
Q

What are the parts of a neuron? (7)

A
Dendrites
Cell Body (Soma)
Axon
Myelin Sheath
Schwann Cells
Nodes of Ranvier
Neurilemma
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9
Q

What are dendrites in a neuron?

A

Receive information from receptors or other neurons

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10
Q

What is the cell body (soma) in a neuron?

A

Contains nucleus and other organelles

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11
Q

What is the axon in a neuron?

A

Longest cytoplasmic extension from the cell body

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12
Q

What is the myelin sheath in a neuron?

A

Made up of fatty protein and acts as insulation/protection and speeds up nerve impulse

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13
Q

What are Schwann cells in the neuron?

A

They are part of the myelin sheath and are wrapped around the axons

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14
Q

What is the difference between white matter and gray matter?

A

White matter has Schwann cells that produce myelin sheath

Gray matter is unmyelinated

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15
Q

What are the nodes of ranvier in the neuron?

A

Areas between sections of myelin

Impulse jumps from one node to another, speeding up impulse transmission

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16
Q

What is neurilemma in neurons?

A

Only present on some neurons (PNS mostly)
Allows for regeneration after damage
Not on neurons in gray matter (CNS) therefore damage is permanent

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17
Q

What is an action potential?

A

A temporary shift (from negative to positive) in the neurons membrane

It’s caused by ions suddenly flowing in and out of the neuron

Gated sodium and potassium channels open once an action potential has been triggered

These gates open and closes depending on the voltage difference across the cell

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18
Q

What is resting potential?

A

It is negative inside (-70 mV)

There is lots of sodium ions outside the cell

This is a polarized state

A sodium-potassium pump maintains this by pumping 3 sodium out for every 2 potassium in

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19
Q

What is depolarization?

A

Makes the cell less polar

A stimulus causes the polarity to change, sodium gates open and sodium rushes in

The intercellular fluid goes from -70 mV to +40 mV

Before an impulse is generated the threshold potential must be reached

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20
Q

What is repolarization?

A

The neuron must be returned to its original polarity

The sodium gates snap shut, stopping the inward rush of positive ions. At the same time the potassium gates open, letting potassium into the cell

More potassium in the cell means the cell loses positively charged ions and returns back towards resting state

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21
Q

What is hyperpolarization?

A

Makes the cell more negative than its typical resting membrane potential

The potassium gates take a really long time to shut and continue to let potassium in

This means the cell temporarily hyperpolarizes or gets more negative than its resting state (-95 mV)

As the potassium channels shut, the sodium-potassium pump works to re-establish the resting state

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22
Q

What is the refractory period?

A

During this time it is impossible to send another action potential

The sodium gates snap shut, inhibiting sodium from entering the neuron, which would start an action potential

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23
Q

What is the threshold level?

A

If depolarization reaches the threshold level it triggers the action potential

If it doesn’t reach that point, then the neuron remains at rest

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24
Q

What is an all-or-none response?

A

Action potential are an all or none response

This means that an action potential is either triggered or it isn’t, like flipping a switch

A neuron will always send the same size action potential

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25
Q

What is a synapse?

A

How neurons “talk” to each other

The point of communication between two neurons or between a neuron and a target cell

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26
Q

What are the four actions that occur in a synapse?

A
  1. Action potential arrives
  2. Vesicle fuses with plasma membrane
  3. Neurotransmitter is released into synaptic cleft
  4. Neurotransmitter binds to receptor
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27
Q

Describe the effects of excitatory neurotransmitters.

A

Trigger ion channels

Sodium and calcium can enter the cell

Results in more positive membrane potential

If excitatory signals are strong enough an action potential can occur

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28
Q

Describe the effects of inhibitory neurotransmitters.

A

Trigger potassium channels to open

Potassium flows out of cell

Results in a more negative transmembrane potential (hyperpolarization)

Because the cell is in hyperpolarization it cannot have an action potential (refractory period)

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29
Q

What is temporal summation?

A

Occurs when multiple signals from one neuron occur close enough in time to combine and trigger an action potential

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30
Q

What is spatial summation?

A

The effect of triggering an action potential in a neuron from one or more presynaptic neurons

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31
Q

What does the neurotransmitter acetylcholine do?

A

It’s an excitatory neurotransmitter at neuromuscular junction

Can be either excitatory or inhibitory in other places

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32
Q

What does the neurotransmitter cholinesterase do?

A

An enzyme that breaks down acetylcholine

Removes acetylcholine from receptors to allow the membrane to repolarize

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33
Q

What does the neurotransmitter norepinephrine do?

A

Can be either inhibitory or excitatory

Found in both the CNS and PNS

Causes wakefulness

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34
Q

What does the neurotransmitter GABA (gamma-aminobutyric acid) do?

A

It causes an inhibitory response

Found in the CNS

Associated with motor behaviour

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35
Q

What is the function of the meninges in the brain?

A

Membranes that protect the brain

Surround the brain and spinal cord

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36
Q

What is the function of the cerebrospinal fluid in the brain?

A

Is the “shock absorber”

Circulated between the innermost and middle membranes of the brain and spinal cord

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37
Q

What is the function of the cerebrum in the brain?

A

Muscular control and balance

The largest and most highly developed part of the human brain

Stores sensory information and imitators voluntary motor activities

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38
Q

What is the function of the cerebral cortex in the brain?

A

The outer layer of the cerebral hemispheres

divided into four lobes

A thin layer of gray matter that makes humans so smart

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39
Q

What is the function of the frontal lobe in the brain?

A

Control movement of voluntary muscles (walking, speech)

Linked with intelligence, personality, memory, and conscious thought

40
Q

What is the function of the parietal lobe in the brain?

A

Associated with touch, temperature, awareness, and body position

linked to emotions and interpreting speech

41
Q

What is the function of the temporal lobe in the brain?

A

Associated with auditory reception (hearing)

Linked to memory, and interpretation of sensory information

42
Q

What is the function of the occipital lobe in the brain?

A

Associated with vision and interpreting visual information

43
Q

What is the function of the corpus callousm in the brain?

A

Links right and left hemispheres

A nerve tract that allows communication between the two cerebral hemispheres

44
Q

What is the function of the thalamus in the brain?

A

Receives sensory information from other areas of the nervous system and sends this information to the cerebral cortex

45
Q

What is the function of the hypothalamus in the brain?

A

Controls hormones

46
Q

What is the function of the cerebellum in the brain?

A

Region of the brain that coordinates muscle movement and balance

47
Q

What is the function of the pons in the brain?

A

Relay centres

Acts as a relay system by sending nerve messages between the cerebellum and the hindbrain

48
Q

What is the function of the medulla oblongata in the brain?

A

The hindbrain region that joins the spinal cord to the cerebellum

The site of autonomic nerve control

49
Q

What is the function of the olfactory bulbs in the brain?

A

Main function is smell

50
Q

What is the central nervous system?

A

Brain and spinal cord

Controls most functions of the body and mind

51
Q

What is peripheral nervous system?

A

Consists of the nerves and ganglia outside of the brain and spinal cord

The main function is to connect the CNS to the limbs and organs

52
Q

What are somatic nerves?

A

Part of the peripheral nervous system associated with the voluntary control of body movements

Consists of afferent nerves (sensory nerves) and efferent nerves (motor nerves)

53
Q

What are autonomic nerves?

A

Part of the PNS that control muscles of internal organs and glands

Involuntary nervous system

54
Q

What is the sympathetic nervous system?

A

Prepares the body for the “flight of fight” response during any potential danger

55
Q

What is the parasympathetic nervous system?

A

Inhibits the body from overworking and restores the body to a calm and composed state

“Rest and digest”

56
Q

What are the five components of a reflex arc?

A
  1. Sensory receptor (affector)
  2. Sensory neuron (affector)
  3. Interneuron (spinal cord)
  4. Motor neuron (efferent)
  5. Effector (muscle)
57
Q

What happens during the sensory receptor step in the reflex arc?

A

Receptor in skin detects a stimulus

Affector neuron

58
Q

What happens during the sensory neuron step in the reflex arc?

A

Sends electrical impulses to a relay neuron in the spinal cord

Affector neuron

59
Q

What happens during the interneuron step in the reflex arc?

A

Connects sensory neurons to motor neurons

Located in spinal cord

60
Q

What happens during the motor neuron step in the reflex arc?

A

Sends electrical impulses to an effector

Efferent neuron

61
Q

What happens during the effector step in the reflex arc?

A

Produces a response

In the muscles

62
Q

What are the three layers of the eye?

A

Sclera

Choroid

Retina

63
Q

What is the path of light through the eye?

A
  1. Cornea
  2. Lens
  3. Retina
  4. Optic nerve
  5. Occipital lobe
64
Q

What is the function of rods in the eye?

A

Provide vision at low light levels

65
Q

What is the function of cones in the eye?

A

Provide vision at a higher light level

Colour vision

66
Q

What is the function of sclera in the eye?

A

The white of the eyes

Provides protection and structure

67
Q

What is the function of the choroid in the eye?

A

Between the retina and sclera

Has blood vessels for nourishment

68
Q

What is the function of the retina in the eye?

A

Photoreceptors

69
Q

What is the function of the iris in the eye?

A

Opaque disk of tissue that surrounds the pupil and regulates the amount of light entering the eye

70
Q

What is the function of the lens in the eye?

A

Focus the image on the retina

71
Q

What is the function of the pupil in the eye?

A

The opening for light to enter the inner eye

72
Q

What is the function of the fovea cebtralis in the eye?

A

Contains a high density of cones and provides acute vision

73
Q

What is the function of the optic nerve in the eye?

A

Takes messages to the brain

The blind spot of where the optic nerve attaches to the retina

74
Q

What is the function of the cornea in the eye?

A

Protects the eye and reflects light toward the pupil

75
Q

What are the two main functions of the ear?

A

Hearing

Balance

76
Q

How does hearing work in the ear?

A

Sound waves are collected by the outer ear, amplified by the middle ear, and converted to signals in the organ of corti in the inner ear

77
Q

How does the ear maintain balance?

A

Controlled by the semicircular canals of the inner ear

78
Q

What structures are in the outer ear?

A

Pinna

Auditory Canal

Tympanic Membrane (ear drum)

79
Q

What structures are in the middle ear?

A

Ossicle bones

Eustachian tube

80
Q

What structures are in the inner ear?

A

Cochlea

Basilar Membrane

Organ of Corti

Semi circular canal

Auditory nerve

81
Q

What is the function of the pinna in the ear?

A

To collect sound

82
Q

What is the function of the tympanic membrane in the ear?

A

Thin layer of connective tissues that separates the outer and middle ear (ear drum)

83
Q

What is the function of the auditory canal in the ear?

A

Transmits sound from the pinna to the ear drum

84
Q

What is the function of the ossicle bones in the ear?

A

Job is to amplify the sound waves so they travel through the thicker, fluid filled structures within the inner ear

85
Q

What is the function of the cochlea in the ear?

A

Fluid-filled substance containing the basilar membrane and organ of corti

The sites of sound waves converting into electrical impulses that brain can understand

86
Q

What is the function of the organ of corti in the ear?

A

Sits above the basilar membrane

Contains hair cells which move and open ion channels

87
Q

What is the function of the auditory nerve in the ear?

A

A sensory nerve that transfers auditory information from the cochlea to the brain

88
Q

What is the function of the semi circular canal in the ear?

A

Three tiny fluid-filled tubes in the inner ear that helps maintain balance

89
Q

What is the function of the Eustachian tube in the ear?

A

Extends from the middle ear to the mouth and nose

Equalizes air pressure

90
Q

What is the path of a sound wave through the ear?

A
  1. Sound waves enter the outer ear and travel through the ear canal to the ear drum
  2. The eardrum vibrates from the incoming sound waves and sends these vibrations to the ossicle bones
  3. The ossicle bones amplify the sound vibrations and send them to the cochlea
  4. Once the vibrations reach the fluid inside the cochlea, a travelling waved forms along the basilar membrane
  5. Bending causes pore like channels to open up and causes chemicals to rush into the cell, which sends an electrical charge
  6. The auditory nerve carries this electric signal to the brain which turns it into a sound that we recognize and understand
91
Q

What are the five types of receptors?

A

Mechanoreceptors

Photoreceptors

Chemoreceptors

Thermoreceptors

Proprioceptors

92
Q

What are mechanoreceptors?

A

Stimulated by pressure (sound or touch)

93
Q

What are photoreceptors?

A

Detection of light (photons) we perceive as vision

Two types are rods and cones

94
Q

What are Chemoreceptors?

A

Are stimulated by certain chemicals

Two types are olfactory receptors and taste receptors

Olfactory receptors: detect chemical stimuli we perceive as smell

Taste receptors: detect chemical stimuli we perceive as taste

95
Q

What are thermoreceptors?

A

In skin, sense hot of cold

96
Q

What are proprioceptors?

A

Received stimuli from within the body

Responds to body position and movement