Chapter 33: The Nervous System Flashcards

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1
Q

What does the nervous system allow for?

A

A rapid response to stimuli in animals

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2
Q

What is a stimulus?

A

A change in the environment that triggers a response

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3
Q

What are the two nervous systems called?

A

Central nervous system

Peripheral nervous system

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4
Q

What does the cns involve?

A

Brain

Spinal cord

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5
Q

What does the pns involve?

A

Nerves outside the cns

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6
Q

What are the four processes in response to a stimulus?

A

Reception
Transmission
Integration
Response

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7
Q

What is reception?

A

Detecting the stimulus using sense organs and neutrons

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8
Q

What is transmission?

A

Message carries to and from the cns

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9
Q

What is integration?

A

Message sorted, processed and response decided in cns

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10
Q

What is response?

A

Effectors stimulated by neurons

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11
Q

What are effectors?

A

Muscles and glands

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12
Q

What is a neuron?

A

Nerve cell

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13
Q

What do neurons do?

A

Carry information as electrical impulses

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14
Q

What are the three types of neuron?

A
Sensory neuron (afferent) 
Motor neuron (efferent) 
Interneuron
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15
Q

What does a sensory neuron do?

A

Takes messages from receptors to cns

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16
Q

What does motor neuron do?

A

Takes messages from cns to effectors

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17
Q

What does an interneuron do?

A

Takes messages between sensory and motor neuron

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18
Q

What do dendrites do?

A

Fibres that carry impulses towards the cell body

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19
Q

What do axons do?

A

Carry impulse way from cell body

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20
Q

What does a Schwann cell do?

A

Make myelin sheath

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21
Q

What is a myelin sheath?

A

Membrane that insulates the electrical impulses

Speeds up the transmission of neurotransmitter

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22
Q

What is a cell body?

A

Contains nucleus and organelles

Forms dendrites, axons, neurotransmitter chemicals

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23
Q

What does a cell body do?

A

Received impulse

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24
Q

How can you distinguish between the motor neuron and sensory neuron?

A

Motor neuron - cell body is at the top

Sensory neuron - cell body is in the middle

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25
Q

What is a neurotransmitter swelling?

A

Swelling at the end of axon that releases chemicals that carry impulses from one nerve to the next

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26
Q

What is the gap between axons called?

A

Node of ranvier

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27
Q

What is a nerve impulse?

A

Movement of ions from dendrites to axon to neurotransmitter swellings

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28
Q

What is an ion?

A

A charge particle

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29
Q

What is a threshold?

A

Minimum stimulus needed for an impulse to carry

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30
Q

What is the all or nothing law?

A

Threshold reached, an impulse is carried

Threshold not reached an impulse is not carried

31
Q

What is a refractory period?

A

Delay between impulses

32
Q

Where are neurotransmitters stored?

A

Vesicles in the swellings

33
Q

What is a ganglion?

A

Group of cell bodies located outside the cns

34
Q

What is a nerve fiber?

A

Many axons or dendrites combined

35
Q

How does an impulse travel once is gets to the synapse?

A

An impulse cannot cross the synapse so chemicals are released called neurotransmitters.
They diffuse across the synaptic cleft and combine with receptors on dendrites of the following neuron.
Impulse then carried by that neuron

36
Q

What happens when myelin is present around the neuron?

A

The impulse jumps from one node of ranvier to another - travels very fast
If no myelin, impulse must travel along entire length of neuron - slow movement

37
Q

How does an impulse travel?

A

When threshold is met:
Axon changes permeability to ions
Allows transmission of impulse
As one section changes permeability the next follows (domino effect)
Once impulse jumps to next section the previous section returns or original state

38
Q

What is a synapse?

A

Region where two neurons come into close contact

39
Q

What is a synaptic cleft?

A

Tiny gap between the two neurons at synapse

40
Q

What chemical is a neurotransmitter made of?

A

Acetylcholine (ACh)
Dopamine
Noradrenalin

41
Q

How is a neurotransmitter activated?

A

Impulse stimulates neurotransmitter swelling in presynaptic neuron to release chemical

42
Q

Where are neurotransmitter made?

A

Some made in cell body, most made in neurotransmitter swelling

43
Q

How is a neurotransmitter inactivated?

A

Neurotransmitter is activated, then it diffuses across synaptic cleft, then it combines with receptors on post synaptic neuron - broken down by enzymes
Digested neurotransmitters are reabsorbed back into swellings
They are recycled and reused

44
Q

What are the four function of synapse?

A
  1. Transmit impulse
  2. Control direction of impulse - neurotransmitter swellings found on only one side of synaptic cleft, act as a valve
  3. Prevent overstimulation of effectors
  4. Impulse blocked by certain chemicals in drugs
45
Q

What is grey matter made of?

A

Cell bodies

Dendrites

46
Q

What is white matter made of?

A

Nerve fibres

Axons

47
Q

What protects the brain?

A

Bone

Meninges

48
Q

What is the meninges?

A

Three layer membrane around brain with cerebrospinal fluid

49
Q

What is the function of the meninges?

A

Acts as a shock absorber on the brain

50
Q

What is the cerebrum?

A

Makes up 75% of brain

Two halves left side and right

51
Q

What are the functions of the cerebrum?

A
Controls voluntary movements 
Received impulses from sense organs 
Thinkings 
Intelligence 
Emotions 
Personality
52
Q

What does he right hemisphere of the brain control?

A

Left side of body

Responsible for art, music, emotions

53
Q

What does left hemisphere of the brain control?

A

Right side of body

Language, hand use, maths, logic

54
Q

Where are the two matters in the cerebrum?

A

grey matter is outside

White matter is inside

55
Q

What is the cerebellum?

A

Second largest part of brain
Controls muscular coordination and balance
Response are involuntary

56
Q

What does the medulla oblongata do?

A

Connects spinal cord to brain

Controls breathing, blood pressure, coughing, sneezing

57
Q

What does the pituitary gland do?

A

Produces hormones

58
Q

What does the thalamus do?

A

Sorts impulses

59
Q

What does the hypothalamus do?

A

Responsible for the internal environment of the body
Temperature
Appetite
Blood pressure

60
Q

What does the dorsal root do?

A

Carries sensory nerve axons into the spinal cord

61
Q

What does the ventral root do?

A

Carries motor nerve axons away from the spinal cord

62
Q

Where are cell bodies found?

A

Cns

Dorsal root ganglion

63
Q

In the spinal cord where are the two types of matter?

A

White matter is outside

grey matter is inside

64
Q

Name a disease?

A

Parkinson’s disease

65
Q

Name a cause of that disease?

A

Failure to produce neurotransmitters

66
Q

What are the results of that disease?

A

Inability to control muscle contraction

67
Q

What are the symptoms of that disease?

A

Trembling of limbs

Inability to move properly

68
Q

What is the prevention of that disease?

A

None

69
Q

What is the treatment of that disease?

A

Physiotherapy

70
Q

What is a reflex action?

A

An involuntary, automatic response to a stimulus

71
Q

Give an example of a reflex action?

A

Blinking

72
Q

What is the reason for a reflex action?

A

Protects the body

73
Q

What is a reflex arc?

A

Pathway taken by an impulse in a reflex action

74
Q

What are the 5 steps in a withdrawal reflex?

A
  1. Receptors on finger are stimulated by flame
  2. Sensory neurons carry impulse into spinal cord through dorsal root
  3. Impulse splits - one goes to interneuron onto motor neuron - other goes to the brain
  4. Motor neuron takes the impulse straight out of the spine (ventral root) to the effector, causes a reflex
  5. Impulse reaches brain but we don’t notice straight away and then we feel pain