Nervous System Flashcards

1
Q

what does our nervous system do

A

tells us we exist and is our basis of reality
coordination, movement, emotion, responds to stimuli, learning

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2
Q

what makes up our nervous system

A

nerve cells called neurons, which transmit signals and impulses

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3
Q

What are dendrites

A

parts of nerve cells that conduct messages towards the cell body

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4
Q

what are axons

A

the part of nerve cells that conduct messages away from the cell body

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5
Q

what are synapses

A

the point where a message jumps from one neuron to another

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6
Q

what is the synaptic cleft / space

A

the gab in a synapse between two neurons

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7
Q

what are myelin sheaths

A

cells that insulate the nerve fibre electrically

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8
Q

what are the nodes of ranvier

A

gabs between the myelin sheaths that speed up nerve impulses

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9
Q

what is the cell body

A

the part that conducts normal cell functions and reactions

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10
Q

what are motor neurons

A

sends a signal away from the brain and CNS to an effector (muscle, fibre or gland) causing it to react
Cell body is inside the CNS
Short dendrite, Long axon

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11
Q

what are sensory neurons

A

start with a sensory receptor (pressure, heat, light)
sends a message to the CNS
Cell body outside the CNS (in ganglia)
Long dendrite, short axon

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12
Q

what are association (inter) neurons

A

relay neurons that are smaller than both sensory and motor neurons
entirely within CNS
both long and short axons and dendrites
convey messages between system parts in CNS

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13
Q

what are ganglia

A

nerve cell clusters or cluster of cell bodies

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14
Q

what are action potentials

A

nerve impulses that move along the length of an axon as a wave of depolarization

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15
Q

how does depolarization occur

A

when ion channels for K+ and Na+ open and cause a change in membrane potential

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16
Q

what are voltage gated channels

A

ion channels occupying the length of an axon that open in response to a change in potential

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17
Q

what domino affect allows nerve impulses

A

when depolarization occurs at one point on a neuron, it trigger the opening of ion channels in the next segment, this causes the depolarization to spread along the length of the axon as a unidirectional wave

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18
Q

What is the All or None response

A

If a minimum electrical stimulus is generated, then an action potential of the same magnitude will always occur, but if the stimulus is below the minimum no response will occur

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19
Q

what is the threshold potential

A

the minimum electric stimulus needed to open voltage gated channels ( around 55 mV )

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20
Q

What happens if the threshold potential is generated

A

an impulses is generated which travels down the axon towards the synapse

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21
Q

what do myelinated axons have that increase impulse speed

A

nodes of ranvier
in saltary conduction
increase to 200 m/s

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22
Q

what is the resting potential

A

the point where the axon is not conducting an impulse
more ATP is needed for the Na+/K+ pumps

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23
Q

what is the first stage of the action potential

A

depolarization
Na+ gated channels open, Na+ rushes in depolarizing the axon

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24
Q

what is the second stage of the action potential

A

repolarisation
K+ channels open, K+ rushes out re-polarizing the axon

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25
Q

what is the refractory / recovery period

A

axon restores the ion concentration as the Na+/K+ pump take the Na+ out of the cell, and K+ into the cell so its ready for the next impulse

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26
Q

what is the membrane on the neuron 1 side of the synapse called

A

the presynaptic membrane

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27
Q

what is the membrane on the dendrite of neuron 2 called

A

the post synaptic membrane

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28
Q

what is between the presynaptic and post synaptic membrane

A

the synaptic cleft or gap

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29
Q

what is contained within vesicles of neuron 1

A

neurotransmitters are contained within these vesicle and are pulled forward by the microtubules

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30
Q

what is on the post synaptic membrane

A

receptors that neurotransmitters bind to

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31
Q

what happens when an impulse moves into a synaptic ending

A

it stimulates vesicles to move to the pre synaptic membrane of the axon

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32
Q

what ions are necessary in the axon bulb in regards to vesicles

A

Ca 2+, which move into the bulb causing microtubules to contract

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33
Q

what happens when Ca2+ molecules cause microtubules to contract

A

the vesicles fuse to the membrane which then empty their contents (neurotransmitter substances) into the synaptic cleft

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34
Q

what happens to neurotransmitters in the synaptic cleft

A

they diffuse towards the receptor sites on the post synaptic membrane of the dendrite which can do one of three responses

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35
Q

what are the three possible responses triggered by neurotransmitters

A

1) increase the action potential of the dendrite
2) decrease the action potential of the dendrite
3) initiate an action potential in the dendrite (open Na+ gates)

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36
Q

why can the impulse only go one way across the synaptic gap

A

because the axon only has vesicles and the dendrite receptors

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37
Q

what does Acetylcholine do

A

controls, blood pressure, peristalsis

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38
Q

what does Noradrenalin do

A

raises Heart rate, Blood pressure, and dialation of pupils and bronchioles

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39
Q

what does serotonin do

A

controls mood, works with melatonin to help control sleep, wake up, and well being

40
Q

what does dopamine do

A

deals with control of pleasure and motivation

41
Q

what do enzymes do in the synaptic cleft

A

they break apart the neurotransmitters. this cleans out the gap so that a new impulse can be rapidly transmitted.

42
Q

what happens to the neurotransmitter parts broken apart in the synaptic cleft

A

the parts diffuse back into the axon to be rebuilt into new neurotransmitter substances

43
Q

what is a reflex arc

A

a reflex action (eye blink, hand jerking away from hot objects) in which a stimulus causes a response, without the brain being involved in making a decision

44
Q

what is the direction of a nerve impulse

A

receptor makes a message
sensory neuron takes to CNS (spine)
interneuron passes message to motor neuron
motor neuron takes away from CNS
Effector receives message and reacts

45
Q

what are examples of internal reflexes

A

breathing rate, heart rate, blood pressure, blinking

46
Q

what secondary path is followed after a reflex arc

A

another neuron goes to the brain, but by the time it has arrived the motor neuron has already activated an effector

47
Q

what are the two parts of the Central Nervous System

A

The brain and Spinal cord

48
Q

what protects the central nervous system

A

bone (skull + vertebrae), meninges (wrapping), Cerebral Spinal Fluid (cushion + protection)

49
Q

what Is the primary function of the Central Nervous System

A

Information Processing

50
Q

What makes up the Peripheral Nervous System

A

the nerves and ganglia that lie outside the central nervous system projecting towards and away from it

51
Q

What does the Peripheral Nervous system do

A

carries impulses to and from the CNS

52
Q

What are the two parts of the peripheral nervous system

A

Cranial Nerves (12 pairs)
Spinal Nerves (31 pairs)

53
Q

What nerves are in the Somatic Nervous System

A

nerves that serve the musculoskeletal system and nerves that serves the exterior sense organs

54
Q

What does the somatic nervous system do

A

gives you information about the external environment and allows you to respond to it

55
Q

What does the Autonomic Nervous System do

A

controls the internal organs automatically and without “awareness”, maintains homeostasis and regulates activity of cardiac + smooth muscle reflexes + glands

56
Q

what is the sympathetic system responsible for

A

Fight or Flight

57
Q

what does the sympathetic system do

A

dilates pupils, accelerates heartbeat and breathing, inhibits digestive tract

58
Q

what are the neurotransmitters for the sympathetic system

A

Noradrenalin, Adrenalin, and Epinephrine

59
Q

What is the structure of the Sympathetic system

A

Postganglionic is longer than preganglionic
Comes from middle of spinal cord (thoracic + a few lumbar)
2 motor nerves 1 ganglia

60
Q

What is the Parasympathetic system responsible for

A

Normal activity, rest and digest
maintains a related body state

61
Q

what is the neurotransmitter for the parasympathetic system

A

Acetylcholine

62
Q

What is the structure of the Parasympathetic system

A

Preganglionic is longer than postganglionic
comes from brain, lower part of spinal cord
2 motor nerves 1 ganglia

63
Q

what are the two parts of the autonomic nervous system

A

Sympathetic and Parasympathetic

64
Q

What are the two parts of the Peripheral Nervous system

A

Somatic and Autonomic nervous system

65
Q

What are the three functions of the spinal cord

A
  1. Communication between brain and body
  2. Centre for reflex action
  3. Role in internal organs (ex aortic and carotid bodies)
66
Q

What are the parts of the spinal cord

A

Cervical (neck)
Thoracic
Lumbar (abdominal)
Sacral (tail bone)

67
Q

What parts of the spinal cord have peripheral nerves

A

The thoracic, lumbar, and sacral

68
Q

what happens when the spinal cord is severed

A

loss of sensation and voluntary movement

paraplegia if in thoracic region
Quadriplegia if in Cervical

69
Q

What is adrenalin

A

a hormone produced by the medulla (inner layer) of the adrenal glands (one on top of each kidney)

70
Q

What is adrenalin responsible for

A

the flight or fight response

71
Q

What are the 6 things adrenaline does

A

1) Dilates pupils to raise visual alertness
2) Increases heart rate to supply more blood to body faster
3) Decreases blood flow and peristalsis of digestive tract
4) Increases blood flow to the CNS and skeletal muscles (contraction for action)
5) Widens air passage way
6) Contraction of diaphragm (gasp)

72
Q

What effects does adrenaline continue

A

sympathetic nerve impulses as a neurotransmitter

73
Q

what are the four lobes of the cerebrum

A

the Frontal
the parietal (back)
the occipital (dorsal + behind parietal)
the temporal (below frontal and parietal)

74
Q

what does the medulla oblongata do

A

controls the unconscious aspects of the body like heartbeat, breathing, vomiting, coughing, sneezing, hiccoughing, swallowing, and controlling internal organs

75
Q

Where is the Medulla Oblongata

A

Closest part to the spinal cord

76
Q

What is the Cerebrum responsible for

A

consciousness (info processing, responding, Q’s, memory)

77
Q

What are sulcus

A

groves that divide each hemisphere into the 4 lobes

78
Q

what are parts of the cerebrum

A

outer layer: Cortex
Left + Right Hemisphere
4 lobes

79
Q

What does the Thalamus do

A

it is the central real station for sensory impulses, where it sorted out messages, before sending them to the cerebrum or appropriate regions of the brain
“gatekeeper of the cerebrum

80
Q

Where is the thalamus

A

below the corpus callous
last stop before the cerebrum

81
Q

what does the cerebellum do

A

receives sensory info and motor output
lets the body have smooth and graceful motions (muscle coordination)
maintains body position in space (proprioception)
in charge of balance by receiving sensory info from the inner ear

82
Q

describe the appearance of the cerebellum

A

2nd largest part of the brain
resembles a butterfly

83
Q

what is the hypothalamus in charge of

A

homeostasis, hunger, sleep, thirst, body temp, blood pressure
links the nervous and endocrine system (controls the pituitary gland)
controls the internal organs

84
Q

where is the hypothalamus

A

below the thalamus

85
Q

what is the corpus callosum

A

the portion of the brain that connects the two cerebral hemispheres to share info
horizontal tract, first nerve connection between hemispheres

86
Q

what do each cerebral hemispheres have

A

their own memory and style of thinking

87
Q

what does the pituitary gland do

A

links the nervous and endocrine system
the master gland

88
Q

what are the three parts of the brain stem

A

the mid brain
pons
medulla oblongata

89
Q

what does the midbrain do

A

relay station for tracts between cerebrum and spinal cord/cerebellum

90
Q

what does the Pons do

A

contains bundles of axons between body and rest of CNS, functions with medulla oblongata

91
Q

what is the pituitary gland

A

a small gland (two parts, anterior and posterior lobes) that produces a large number of hormones, many of which control the release of hormones from other glands in the body. The “Master Gland”

92
Q

what does the posterior pituitary gland do

A

releases hormones that are made in the hypothalamus and stored in the post pit gland
these hormones are transferred and stores in special hollow nerve ribres that run from the hypothalamus to the post pit gland
ex ADH and Oxytocin

93
Q

what does the anterior pituitary gland do

A

makes and releases its own hormones. stimulated to release its hormones by releasing hormones from the hypothalamus. blood connection between the hypothalamus and the ant. pit

94
Q

what hormones are made in the Ant. Pit gland

A

growth hormones
prolactin
FSH and LH
Thyroid stimulating hormones (TSH)
Adrenal Cortex Stimulating Hormone (ACTH)
Melatonin

95
Q

what monitors the levels of pituitary hormones in the blood and how are they controlled

A

the hypothalamus monitors the levels and they are controlled by a negative feedback system (except oxytocin) so the levels remain relatively constant. Sex hormones FSH and LH vary in the female