Nerves, The Brain And Spinal Cord Flashcards

1
Q

What is myelin?

A

An insulating layer that surrounds the axons of neurons

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2
Q

What is myelin composed of?

A

Primarily composed of lipids

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3
Q

What type of axons conduct action potentials quicker?

A

Myelinated axons

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4
Q

What are the gaps in Myelin called?

A

Nodes of ranvier

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5
Q

What is saltatory conduction?

A

When action potentials jump from node to node

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6
Q

What forms myelin in the peripheral system?

A

Schwann cells

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7
Q

What forms myelin in the central nervous system?

A

Oligodendrocytes

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8
Q

Name the 3 main structures of neurons

A

Bipolar
Pseufonipolar
Multipolar

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9
Q

What are the two subdivisions of motor neurons?

A

Upper motor and lower motor neurons

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10
Q

What are upper motor neurones?

A

Neurons that transmit information from the brain to lower motor neurones in the brain stem and spinal cord
Considered part of the CNS

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11
Q

What are lower motor neurones?

A

Neurons within cell bodies in the spinal cord or brain stem whose axons directly innervated skeletal muscle
Considered part of the PNS

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12
Q

What does white matter contain?

A

The axons of the neurons

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13
Q

What does grey matter contain?

A

The cell body of the neuron

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14
Q

What are the percentages of grey matter and white matter in the brain?

A

40% = grey matter
60% = white matter

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15
Q

What are the 3 functions of the nervous system?

A

Sensory input
Integration/central processing
Motor output

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16
Q

What is the central nervous system?

A

Brain and spinal cord

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17
Q

What is peripheral nervous system composed of?

A

All the nerves that branch off from the brain and spine that allow your central nervous system to communicate with the rest of the body

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18
Q

What are neurones?

A

Nerve cells that respond to stimuli and transmit signals

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19
Q

What are the functions of glial cells?

A

Provide support, nutrition, insulation and help with transmission in the nervous system

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20
Q

What are the most abundant and versatile glial cells?

A

Astrocytes

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21
Q

What do Astrocytes do?

A

Exchange materials between neurons and capillaries

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22
Q

Where are Microglial cells found?

A

In CNS

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23
Q

What do Microglial cells do?

A

Act as main source of immune defence against invading microorganisms in the brain and spinal cord

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24
Q

Where are Ependymal cells found?

A

In cavities in your brain and spinal cord

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25
Q

What do Ependymal cells do?

A

Create, secrete and circulate cerebrospinal fluid

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26
Q

What do oligodendrocytes do?

A

Produce and insulate barrier called myelin sheath

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27
Q

What are the only two types of glial cells in the peripheral nervous system?

A

Satellite cells and Schwann cells

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28
Q

What do satellite cells do?

A

Surround and support neuron’s cell bodies

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29
Q

What do Schwann cells do?

A

produce and insulate a barrier called the myelin sheath

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30
Q

What are sensory neurons most commonly?

A

Unipolar

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31
Q

What are motor neurons most commonly?

A

Multipolar

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32
Q

What do interneurons do?

A

Transmit impulses between sensory neurons and motor neurons

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33
Q

What is voltage?

A

The measure of potential energy generated by separated changes

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34
Q

What do we refer to difference in charges in the body?

A

Membrane potential

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35
Q

What is current?

A

The flow of electricity from one point to another

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36
Q

What is the resting membrane potential?

A

-70mV

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37
Q

What is the overall internal charge of a resting neuron?

A

Overall negative charge

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38
Q

What do mechanically gated channels open in response to?

A

The physical stretching of the membrane

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39
Q

What do voltage gated channels open and close in response to?

A

Changes in membrane potential

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40
Q

What is a synapse?

A

The meeting point between two neurons

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41
Q

What are the two types of synapses?

A

Electrical and chemical synapses

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42
Q

How do electrical synapses work?

A

Send an ion current flowing directly from the cytoplasm of one nerve cell to another through small windows called gap junctions

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43
Q

Why are electrical synapses super fast?

A

Because the electrical signal is never converted from its pure electrical state to any other kind of signal, the way that it is in a chemical synapse

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44
Q

What is the main advantage of chemical synapses?

A

They convert the signal in steps from electrical to chemical and back to electrical which allows for different ways to control an impulse

45
Q

What do excitatory neurotransmitters do?

A

Depolarise the postsynaptic neuron by making the inside more positive and bringing it closer to its action potential threshold

46
Q

What do inhibitory neurotransmitters do?

A

Hyper-polarise the postsynaptic neurone by making the inside more negative

47
Q

What does the likelihood of postsynaptic developing an action potential depend upon?

A

The sum of all the excitations and inhibitions in that area

48
Q

What does serotonin do?

A

Mainly inhibitory and plays a role in regulating moods appetite, circadian rhythms and sleep

49
Q

What does dopamine do?

A

Influences emotion and attention

50
Q

What does norepinephrine do?

A

Triggers your fight or flight response, increases your heart rate, primes muscles

51
Q

What is summation?

A

The process that determines if an action potential will be generated by the combined effects of excitatory and inhibitory signals

52
Q

What is spatial summation?

A

Multiple simultaneous inputs

53
Q

What is temporal summation?

A

Repeated inputs

54
Q

What are the two systems of the nervous system?

A

Central nervous system and peripheral nervous system

55
Q

Where is the brain?

A

The brain lies in the carnival cavity and its continuous with the spinal cord through the foremen magnum at the base of the skull

56
Q

What are the 4 parts that the brain is divided into?

A

Brain stem
Cerebellum
Diencephalon
Cerebrum

57
Q

What are the 3 parts of the brain stem?

A

Midbrain
Pons
Medulla oblongata

58
Q

What is the midbrain associated with?

A

Vision, hearing, motor controls, sleep and wakefulness, alertness and temperature regulation

59
Q

What is the pons associated with?

A

Breathing and respiratory rhythm

60
Q

What does the pons form a bridge between?

A

The cerebrum and the cerebellum

61
Q

What centres does the medulla oblongata contain?

A

Cardiac, respiratory, vomiting and vasomotor
(Deals with autonomic functions of breathing, heart rate and blood pressure as well as the sleep-wake cycle)

62
Q

Where do descending neurons cross to the opposite side?

A

In the medulla oblongata

63
Q

What is the cerebellum responsible for?

A

Coordination of voluntary movements
Motor-learning
Balance
Emerging evidence in role of learning and attention

64
Q

Where in the brain contains more neurons than the rest of the brain combined?

A

Cerebellum

65
Q

Where is the cerebellum located?

A

At the back of the brain/posteriorly

66
Q

What two things does the diencephalon contain?

A

Thalamus and hypothalamus

67
Q

What does the hypothalamus do?

A

Regulates homeostasis through influence on autonomic system and pituitary gland

68
Q

What is the thalamus’s function?

A

Principle relay station for sensory input

69
Q

What are the two hemispheres of the brain divided by?

A

The longitudinal fissure

70
Q

What are sulci?

A

Folds/wrinkles in the brain that the surface of the brain is covered in

71
Q

What are the two hemispheres of the brain connected by?

A

Corpus Callosum

72
Q

What is the Corpus Callosum?

A

Large bundles in fibres connecting the right and left hemispheres

73
Q

What does the Corpus Callosum allow?

A

It allows information to move between the hemispheres

74
Q

What are the two different parts of the nervous system?

A

Central nervous system and peripheral nervous system

75
Q

What is the purpose of myelin?

A

Myelin acts as insulation on the axons
This allows for quicker conduction of nerve impulses

76
Q

How is myelin made in the PNS?

A

Made by Schwann cells

77
Q

How is myelin made in the CNS?

A

By oligodendrocytes

78
Q

What is the role of the upper motor neurons?

A

Upper motor neurons transmit information from the brain to the lower motor neurons and interneurons in the brain stem and spinal cord

79
Q

What is the role of the lower motor neurons?

A

Lower motor neurons are neurons with cell bodies in the spinal cord or brain stem whose axons directly innervate skeletal muscle

80
Q

What is the difference between grey and white matter?

A

White matter contains the axons
Grey matters contains the cell bodies

81
Q

What is an action potential?

A

Brief depolarisation of the axon caused by a change in currents
Causes a biological change reaching transferring signal down the axon

82
Q

What are the 2 lobes of the cerebrum called?

A

Left and right hemisphere

83
Q

What structure connects the 2 halves of the cerebrum together?

A

Corpus Callosum

84
Q

What makes up the diencephalon?

A

Thalamus and hypothalamus

85
Q

What is the role of the thalamus?

A

Thalamus is the sensory relay station
All sensory information synapses here and it helps to control sensory stimulus

86
Q

What is the role of the hypothalamus?

A

Hypothalamus is responsible for homeostasis, helps to control hormones, temperature, etc

87
Q

Where are the basal ganglia located?

A

Deep within the brain

88
Q

What are the 5 nuclei of the basal ganglia?

A

Caudate nucleus
Globes Pallidus
Putamen
Substantia Nigra
Subthalamic nucleus

89
Q

What is inferior to the cerebrum?

A

Brain stem and cerebellum

90
Q

What are the 3 different components of the brainstem?

A

Midbrain
Pons
Medulla

91
Q

What vital structures are located in the brainstem?

A

Control centres for respiration and heart

92
Q

What is the role of the cerebellum?

A

Coordination of voluntary movements, motor-learning, balance, emerging evidence in role in learning and attention

93
Q

What is the name of the skeletal structure that protects the spinal cord?

A

Vertebral column

94
Q

Describe the gross structure of the complete spinal cord

A

Spinal cord is covered in meninges and between meninges and spinal cord is cerebral spinal fluid. The cord does not extend all the way down the vertebral column, it stops at approximately T12/L1 it then becomes the peripheral nerves

95
Q

Describe the key functions of the spinal cord

A

Connects the peripheral nerves with the CNS
Transmits sensory information towards the brain and transmits motor information towards the muscles

96
Q

What is the purpose of the tracts in the spinal cord?

A

Transmit different information in the spinal cord

97
Q

What are the main elements of the peripheral nervous system?

A

Motor and sensory peripheral nerves and the autonomic nervous system

98
Q

Describe the function of the autonomic nervous system

A

Control and modulation of particular autonomic and involuntary body systems

99
Q

What are the three targets that the ANS works on?

A

Smooth muscle
Cardiac muscle
Glands

100
Q

Name three mechanisms of peripheral nerve injuries

A

Crush
Compression
Severed nerve

101
Q

Name the ascending afferent sensory spinal tracts

A

Dorsal column
Spinocerebellular tract
Spinothalamic tract

102
Q

Name the efferent descending motor spinal tracts

A

Corticospinal tract
Rubrospinal tract
Reticulo spinal tract
Tecctospinal tract
Vestibulo spinal tract

103
Q

What is the dorsal column responsible for?

A

Fine touch
2 point discrimination
Vibration
Conscious proprioception

104
Q

What is the spinothalamic tract responsible for?

A

Pain
Course touch/pressure
Temperature

105
Q

What is the spinocerebellar tract responsible for?

A

Unconscious proprioception
Coordination

106
Q

What is the tectospinal tract for?

A

Auditory and visual

107
Q

Name some causes of a spinal cord injury

A

Road traffic accidents
Sports related injuries
Spinal stroke
Spinal canal stenosis
Tumour
Inflammation of spinal cord
Viral infection of spinal cord
Development/congenital abnormalities

108
Q

What symptoms do you get from a complete spinal cord injury?

A

Complete loss of function below point of injury (motor, sensory, autonomic dysfunction)