1a Cells of the Nervous System

Question 1

What are the four lobes of the brain called?

Answer 1

Frontal, temporal, parietal and occipital

Question 2

What is the function of the cerebellum?

Answer 2

Fine movement, balance and fine coordination

Question 3

What is a soma?

Answer 3

A cell body

Question 4

What is a unipolar neurone?

Answer 4

A neurone with one axonal projection

Question 5

What is a bipolar neurone?

Answer 5

Where the cell body is in the middle of the axon

Question 6

What is a pseudo-unipolar neurone?

Answer 6

single axonal projection splits into two, cell body is not embedded into the axon

Question 7

What are the three shapes of the multipolar cells?

Answer 7

Pyramidal, Purkinje and golgi cells

Question 8

What are dendrites?

Answer 8

Projections off the axon which receive signals from other neurones

Question 9

What is an astrocyte? And what is its function?

Answer 9

A highly abundant cell which is important in maintaining blood brain barrier and keep the neurones in place

They function as structural cells and are known to play an important role in cell repair, synapse formation, neuronal maturation and plasticity.

Question 10

What is the function of the oligodendrocytes>

Answer 10

They produce myelin in the CNS

Question 11

How many cells do oligodendrocytes produce myelin for?

Answer 11

Myelinates many axons

Question 12

What is the function of a Schwann Cell?

Answer 12

Functions to produce myeline for the peripheral nervous system

Question 13

how many axons does one schwaan cell myelinate?

Answer 13

One

Question 14

what are microglial cells?

Answer 14

They are the immune cells of the Central Nervous System - similar to macrophages

Question 15

What are ependymal cells?

Answer 15

Epithelial cells lining the ventricles that regulate the production of CSF

Question 16

How is resting membrane potential generated?

Answer 16

3 Sodium ions pumped out for every 2 potassium ions that are pumped in
This results in a high concentration of Na+ outside the neurone, sets up a high concentration gradient so that sodium ions can flow in to generate an action potential

Question 17

Is the inside of the neurone more positive or negative than the outside?

Answer 17

The inside is more negative - more positive charge is leaving then entering, therefore inside will be more negative

Question 18

What helps to move the NA+ and K+ ions to generate resting membrane potential?

Answer 18

The Na+/K+ ion pump - Active transport so ATP dependant

Question 19

Which ions are in high concentration outside the neurone?

Answer 19

Na+ and Cl-

Question 20

Which ions are in high concentration inside the neurone?

Answer 20

K+

Question 21

What is the resting membrane potential?

Answer 21

-70mV

Question 22

When the inside of the neurone becomes more negative, what is this known as ?

Answer 22

Hyperpolarisation

Question 23

When the inside of the neurone becomes more positive, what is this known as?

Answer 23

Depolarised

Question 24

What is the neuromuscular junction?

Answer 24

The junction between the motor neurone and muscle

Question 25

Describe what happens at the neuromuscular junction?

Answer 25

1. Action potential arrives at the pre-synaptic bouton 2. Ca2+ ion channels open 3. Ca2+ binds to NT vesicles containing ACh 4. They diffuse and ACh released into synaptic cleft through exocytosis 5. ACh binds to nicotinic ACh receptors on sarcolemma of skeletal muscle 6. Action potential then travels down the T Tubules which runs close to the sarcoplasmic reticulum 7. The depolarisation of the sarcolemma causes the sarcoplasmic reticulum to release ca2+ which leads to muscle contraction

Question 26

What is botulism?

Answer 26

When botulinum toxin disrupts the ACh release from the pre-synaptic terminal - leads to muscle weakness

Question 27

What is the name of the condition where you produce autoantibodies against the nAChr's on the skeletal muscle

Answer 27

Myasthenia gravis

Question 28

What is Lambert-Eaton Myastenic Syndrome?

Answer 28

An autoimmune disorder where you produce antibodies directed against voltage gated calcium channels

Question 29

What is the difference between Myasthenia Gravis and Lambert-Eaton Myastenic Syndrome?

Answer 29

MG = antibodies against nAChrs Lambert- Eaton = antibodies against voltage gated calcium channels

Question 30

What are golgi cells?

Answer 30

GABA neurones found in the cerebellum

Question 31

What are purkinje cells?

Answer 31

GABA neurones found in the cerebellum

Question 32

What are pyramidal cells?

Answer 32

Cells with Pyramid shaped cell bodies

Question 33

What are the three common features of neurones?

Answer 33

Soma, Axon and dendrites

Question 34

What is the difference between dendrites and axons?

Answer 34

Dendrites are highly branched and are not covered in myelin

Question 35

What can axons brnach off into?

Answer 35

Collaterals

Question 36

What are microglia?

Answer 36

Neuronal macrophages

Question 37

At resting membrane potential, what has happened to the Voltage-gated Na+ channels (VGSCs) & voltage-gated K+ channels (VGKCs) ?

Answer 37

They are closed

Question 38

What happens to the voltage gated sodium channels when the membrane undergoes depolarisation?

Answer 38

Sodium influx

Question 39

What causes membrane repolarisation?

Answer 39

VGKCs opens at a slower rate and causes  efflux of K+ from cell

Question 40

What pump restores the ion gradients across the membrane of a neurone?

Answer 40

Na+ / K+ ATPase pump restores the ion gradient

Question 41

How does the myelin prevent the AP from spreading?

Answer 41

because it has - high resistance & low capacitance

Question 42

What are the nodes of ranvier?

Answer 42

Small gaps of myelin intermittently along axon

Question 43

What is saltatory conduction?

Answer 43

The jumping of the AP between the nodes of ranvier

Question 44

What is a axodendritic cell?

Answer 44

connection between presynaptic terminal and a neuronal dendrite

Question 45

what is a axosomatic synapse?

Answer 45

Connection between presynaptic terminal and neuronal soma

Question 46

What is a Axoaxonic synapse?

Answer 46

: connection between presynaptic terminal and neuronal axon

Question 47

What type of communication occurs between nerve and effector cells?

Answer 47

Paracrine communication - due to neurotransmitter release

Question 48

What is the pathophysiolgy of Botulism?

Answer 48

Botulinum toxin (BTx): irreversible disrupts stimulation-induced ACh release from presynaptic nerve terminal