Nervous System 1- Cells and Transmitters Flashcards Preview

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Flashcards in Nervous System 1- Cells and Transmitters Deck (42):
1

How much of the oxygen in the blood system does the brain use

21%

2

What are the 2 main components of the nervous system

1. CNS 2. Peripheral: Somatic and Visceral

3

What does the somatic part of the peripheral nervous system control

The musculoskeletal system

4

What does the visceral part of the peripheral nervous system control

The body's organs (autonomic nervous system)

5

What is the CNS composed of

The brain and spinal chord

6

What are the key parts of a neurone

Nucleus, dendrites, cell body (soma), axon

7

What is a neurone

A nerve cell

8

What are the two types of axons

  1. Myelinated fibre
  2. Unmyelinated fibre

9

What is the function of dendrites

To make/ recieve contact from otehr neurones

10

What is the end part of a neurone called

Axon terminal

11

What is an axon composed of

Schwann cells

12

Label the bottom diagram

My= myelinated sheath

A = axon

N = Schwann cell

13

What happens if Schwann cells in an axon don't have myelinated sheaths

There is slower conduction of action potential 

14

  1. What is the axon terminal of the first axon called?
  2. What is the axon terminal of the secon axon called?
  3. What is the name of the gap between the two axons

  1. Presynaptic axon
  2. Postsynaptic axon
  3. Synapse (synaptic cleft)

15

What is a synapse

A gap in between two neurones so cells can commincate with one another

16

What are the ways in which neurones can vary

(Colin Dendle Ate Ants Surprisingly Smoothly)

  1. Cell body (soma)- size and shape
  2. Dendrites- number, branching and length
  3. Axon- length, diameter, branching
  4. Axon- myelinated or unmyelinated
  5. Synaptic terminals- number/ structure
  6. Synaptic transmission- chemical or electrical

17

What does the morphology of a neurone reflects

The morphology (size and shape) reflects the function of the neurone

18

A neurotransmitter is a chemical that is:

(Some Rats Bite Reindeer)

  • Synthesised by a presynaptic neurone
  • Released into the synaptic cleft
  • Binds to a receptor on the postsynaptic neurone
  • Either excites or inhibits the postsynaptic neurone

19

What is a neurone required to do?

(5 things)

  1. To be stimulated by a neurotransmitter released by another neurone
  2. To respond to the stimulus, either by being excited or inhibited
  3. To convey a message, via an action potential, to its terminal
  4. To release a neurotransmitter from the terminal which will stimulate another neurone (or muscle cell)
  5. To inactivate the neurotransmitter that it has released

20

What are the two most common inhibitory neurotransmitters?

GABA and Noradrenaline

21

What are the two most common excitatory neurotransmitters?

Acetlycholine and Glutamate

22

How are neurotransmitters synthesised

  1. Rough ER produces precursor peptide released in ribosome
  2. Ribosome fuses with golgi apparatus
  3. Active peptide neurotransmitter is produced
  4. Released from golgi apparatus in a secretory granule
  5. Precursor molecule binds with a specific enzyme which produces a neurotransmitter contained within a transporter protein

23

What does the shape of a neurone depend on

It's cytoskeleton (type of protein filament)

24

What type of neurones do actin filaments produce

Little filaments (5nm)

25

What type of neurones do intermediate filaments produce

Give the axon a long cylindrical shape

26

What type of neurones do tubules produce

They are slightly bigger and have a vital function in axonal transport

27

What are the two types of axonal transport

Orthograde

Retrograde

28

Decribe orthograde transport

Molecules / sub-cellular organelles move from cell body to terminal.

2 speeds: Fast (100-400mm/day) or slow (0.25-0.5mm a day)

29

What motor is used in orthograde transport

Kinesin

30

Describe retrograde transport

From terminal to cell body

50-200mm/day

31

What motor is used in retrograde transport

Dynein

32

Give an example of retrograde transport

Once damage occurs and is sensed by terminal of the cell body molecules go back up the axon to the nucleus to trigger proteins needed for repair

33

What is exocytosis 

Fusion and release of content

34

Describe transmitter release at a synapse

  • Not random
  • Movement of vesicles towards presynaptic axon is controlled by action potentials (influx of Ca2+)
  • Neurotransmitter is released
  • Neurotransmitter is recyled once it has exerted its effect

35

Describe the energy supply of neurones

  • All of the events in neurotransmitter synthesis and release require energy
  • Neurones need to generate ATP constantly
  • Protein synthesis uses the most energy- blood supply vital

36

In 1mm3 of cerebal cortex it is estimated that there are

  • 100,000 cells (neurones, neuroglia, endothelial cells)
  • 4 kilometers of axon
  • 500m of dendrites
  • 1,000,000 synpases

This is why so much energy is needed

37

What is the classification name for other types of cells in the CNS apart from neurones

Neuroglial cells

38

How many more neuroglial cells are there than neurones in the CNS 

10 x

39

What are the 3 types of neuroglial cells

  1. Oligodendrocytes
  2. Astrocytes
  3. Microglia

40

What do oligodendrocytes do

Form myelin sheaths for several axon

41

What do astrocytes do

  • Control K+, glutamate and Ca2+ in the extracellular space (take up substances if too much to prevent damage as concentrations must be kept constant)
  • Important roles in development and synapse formation
  • Important roles in the blood-brain barrier and in local blood flow (dilate blood vessels locally if active/ constrict if not active)

42

What do microglia do

Respond to injury of the CNS:

  1. Resting microglia (protein aggregates, proinflammatory signals)
  2. Microglia migrates
  3. Fully activated microglia