Nervous System Flashcards

1
Q

What is the CNS made up of

A

Spinal chord and brain

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2
Q

What is the peripheral system made up of

A

All the other neurones

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3
Q

What does the peripheral system split into

A

Systematic nervous system and the autonomic nervous system

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4
Q

Systematic nervous system

A

Conscious control

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5
Q

Autonomic nervous system

A

Unconscious body activating

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6
Q

What is the autonomic nervous system made up of

A

Parasympathetic- slows things down - acytlcholine ….

Sympathetic-speeds things up- noradrenaline

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7
Q

Receptor

A

Specific, will only detect one type of stimulus. Can be cell or protein, transforms stimuli into electrical impulse ( chemical change)

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8
Q

Sensory neurone

A

Single long dendron, single short axon

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9
Q

Relay neurone

A

Within the CNS, many short dendrites, many short axons

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10
Q

Motor neurone

A

Many short dendrites, single long axon, ends with a neuromuscular junction

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11
Q

Effector

A

Muscle or gland, brings about a response

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12
Q

Potential difference

A

More positive ions on outside than on the inside so we say this is the resting potential

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13
Q

Resting potential

A

When,

(1) SODUIM POTASSIUM PUMP: active transport 3Na+ out, 2K+ in
(2) VOLTAGE GATED SODIUM ION CHANNEL: closed, membrane is not permeable to Na+
(3) POTASSIUM ION CHANNEL: open, some k+ diffuses out down electrochemical gradient, doesn’t reach equilibrium due to positive charge on outside

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14
Q

What makes up an action potential ( in order)

A
  1. Resting potential
  2. Generator potential
  3. Threshold
  4. Depolarisation
  5. Depolarisation
  6. Re polarisation
  7. Hyper polarisation
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15
Q

What is the refractory period

A

Another action potential cannot be started, makes action potentials- discrete ( don’t overlap)- unidirectional (one way)

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16
Q

AP:resting potential

A

Sodium potassium pump
Active transport
Na out
k in

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17
Q

AP Generator potential

A
Weak stimulus 
Some Na channels open
Some Na diffuses in
Does in reach threshold
Nak pump stores resting potential
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18
Q

AP Threshold

A

Greater potential reaches threshold
Many voltage gated Na channels open
Na diffuses into axon
Positive feedback

19
Q

AP depolarisation

A

Na channels are open

Na diffuses in

20
Q

AP Repolarisation

A

K channels open ( voltage gated)
K diffuses out
Voltage gated Na close

21
Q

AP Hyperpolarosation

A

When membrane potential is more negative than resting potential , k channels close

22
Q

The all or nothing law

A

If a generator potential reaches threshold it will trigger an action potential

23
Q

What’s the myelin sheath

A

Schwann cells make the myelin, it’s an electrical insulator - prevents depolarisation, prevents movement of ions in/out of the neurone

24
Q

Saltatory conduction

A

When an action potential jumps between the nodes of ranvier

25
Q

Points to remember about saltatory conduction

A

Speeds up transmission of nerve impulse, cytoplasm conducts enough charge to depolarise the next node

26
Q

Nodes of ranvier

A

The gaps in the myelin sheath, lots of Na and K channels

27
Q

What can only happen at the nodes of ranvier

A

Depolarisation

28
Q

Diameter of the axon

A

Less resistance, more surface area for ion movement, greater diameter the faster the speed of action potential

29
Q

Synapse

A

A junction between two neurones

30
Q

Describe the steps of a cholinergic synapse

A
  1. AP arrives at presynaptic knob 2. Ca channels open and diffuse in 3. Causes vesicles to fuse with membrane 4. Ach diffuses across cleft 5. Ach binds to receptors on postsy 6. Some Na channels open and diffuses in 7. Voltage gated Na channels open 8. AP triggered at postsy 9. Acetylcholinerase breaks down Ach 10. Products reabsorbed into presy
31
Q

Evidence that synapse are unidirectional

A

Only receptors on the post synaptic membrane, neurotransmitters released from presy, diffuse from high to low concen across synaptic cleft

32
Q

Synaptic divergence

A

When one neurone joins many neurones, spreads the AP to other parts of the body

33
Q

Synaptic convergence

A

When many neurones join a single neurone, amplifies signal

34
Q

Spatial summation

A

When neurotransmitters from multiple neurones combine to trigger an action potential in a post synaptic neurone

35
Q

Temporal summation

A

A strong stimulus will cause more frequent AP’s, release more neurotransmitters which add up to trigger an AP in the postsy

36
Q

Neuromuscular junction

A

A synapse between a motor neurone and a muscle fibre

37
Q

Differ eat compared to a cholinergic synapse

A

More receptors on postsy, so an AP is always generated in postsy, acetlycholinerase found in pits in postsy, receptors called nichotinic chollinergic receptor

38
Q

Exteroceptors

A

Respond to a stimuli from the external environment

39
Q

Enteroceptors

A

Respond to stimuli from the internal environment

40
Q

Proprioceptors

A

Respond to tension with tendons and muscles

41
Q

Why is there lots of mitochondria in the synaptic bulb

A

ATP for active transport, making neurotransmitters, synaptic vesicles-Golgi, removal of calcium after AP

42
Q

Cholinergic synapse

A

Neurones that release acytlcholine

43
Q

Adrenergic synapse

A

Neurones that relates noradrenaline