Cells + communication in the nervous system

Question 1

What are the key functions of the nervous system?

Answer 1

Sensation
Integration
Activation

Question 2

How can dysfunctions of the nervous system manifest?

Answer 2

Loss (of sensation or function)
Gain (appearance of new features e.g. twitch/ tremor)
Change (in behaviour/ personality)

Question 3

Which glial cells produce myelin?

Answer 3

Oligodendroglia (CNS)
Schwann Cells (PNS)

Question 4

What are the different types of neurons?

Answer 4

Principal cells

Interneurons

Question 5

What are the key features of neurons?

Answer 5

Dendrites (receptive field)
Soma (metabolic and integrating centre)
Axon (one way communication)
Synaptic terminals (release of transmitters, communication with other cells)

Question 6

What is the role of astrocytes?

Answer 6

Form bridge between neuron and blood vessels

Question 7

What is the role of ependymal cells?

Answer 7

Simple, ciliated, cuboidal cells that form the lining of the ventricular system

Question 8

What are microglia cells?

Answer 8

Small glial cells activated by trauma as part of an immune response

Question 9

What is the clinical relevance of glia cells?

Answer 9

Tumours in the CNS more commonly originate in glia cells rather than neurons.

Question 10

What are the 3 main groups of neurons?

Answer 10

Multipolar
Bipolar
(Pseudo) unipolar

[Refers to amount of input into cell body]

Question 11

What are the functions of myelination?

Answer 11

Insulation 
Saltatory conduction (faster transmission)

Question 12

What are the 2 key myelination disorders?

Answer 12

Multiple Sclerosis (CNS) 
Guillain Barre (PNS)

Question 13

What are chemical synapses?

Answer 13

Most common synapses
Fast transmission
Vesicles released from presynaptic terminal and act on receptors on postsynaptic terminal

Question 14

What are electrical synapses?

Answer 14

Slower transmission
Gap junctions
Two channels join to form single junction to allow small molecules and current to pass through
‘Low-pass filter’

Question 15

Which type of synapse is the current major drug target?

Answer 15

Chemical synapses

Question 16

What is Myaesthenia Gravis?

Answer 16

An autoimmune disease affecting the neuromuscular junction where Ach receptors are not responsive to Ach
Causes slowing of muscle activity and reducing tone

Question 17

How would neuromuscular communication effectiveness be tested?

Answer 17

Nerve conduction tests

Electromyography

Question 18

What are the 2 main chemical transmitters in the CNS?

Answer 18

Glutamate (excitatory)

GABA (inhibitory)

Question 19

What is the importance of inhibitory transmitters in the CNS?

Answer 19

Responsible for coding of activity (stops firing of neurotransmitters)
Direct and lateral inhibition
Disinhibition
Synchrony (coordinates activity)
Plasticity (changes strength of activity)

Question 20

What is the difference between direct and lateral inhibition?

Answer 20

Direct inhibition acts on target cell to reduce activity

Lateral inhibition acts on neighbouring cells to reduce activity

Question 21

What is disinhibition?

Answer 21

Activation of inhibitory circuit to cause excitation of cells (by inhibiting an inhibitory cell to prevent it from inhibiting excitatory cell)
Plays a key role in Basal Ganglia circuitry to shape motor function

Question 22

What are the 2 types of transmitters found in the CNS?

Answer 22

Neurotransmitters (rapid cell communication)

Neuromodulators (indirect activity)

Question 23

What are the key excitatory neurotransmitters in the CNS?

Answer 23

Glutamate

Aspartate

Question 24

What are the key neuromodulators in the CNS?

Answer 24

Neuropeptide Y 
Substance P
Vasopressin 
Somatostatin 
Anandamide

Question 25

What are some common interactions betwen neuronal pathways?

Answer 25

NA levels can directly alter 5-HT activity 5HT levels can directly alter DA activity DA levels can directly alter ACh activity ACh levels can directly alter GABA activity

Question 26

Where does communication between neurons and muscles take place?

Answer 26

Neuromuscular junction

Question 27

How does communication at the neuromuscular junction take place?

Answer 27

1) action potentials trigger exocytosis of ACh from synaptic terminal 2) ACh crosses cleft 3) Acts on Cholinergic receptors in motor end plate 4) Muscle contraction initiated 5) Impulse carried through muscle via T-tubules and sarcoplasmic reticulum

Question 28

What are the key inhibitory neurotransmitters in the CNS?

Answer 28

GABA | Glycine

Question 29

What neurotransmitter acts at the neuromuscular junction?

Answer 29

Acetylcholine

Question 30

What neurotransmitters are involved in stress/ arousal?

Answer 30

Adrenaline Noradrenaline Histamine (arousal)

Question 31

What neurotransmitter plays a key role in motivation and motor function?

Answer 31

Dopamine

Question 32

What neurotransmitter plays a key role in homeostasis?

Answer 32

Serotonin (5-HT)

Question 33

What are ionotropic receptors?

Answer 33

Receptors linked to ion channels

Question 34

What are the 4 main types of cutaneous receptors?

Answer 34

Mechanoceptors Thermoceptors Nociceptors Proprioceptors

Question 35

What do mechanoceptors detect?

Answer 35

Tactile sensation (touch, pressure)

Question 36

What do thermoceptors detect?

Answer 36

Temperature changes

Question 37

What do nociceptors detect?

Answer 37

Painful stimuli

Question 38

What do proprioceptors detect?

Answer 38

Changes in head and body position

Question 39

What mechanisms are involved in pathogenesis of neuronal and psychological disorders?

Answer 39

``` Altered neuronal activity Altered synchrony Cellular changes Subcellular change Genetic/epigenetic changes ```