Nervous Tissue Flashcards

1
Q

What is the function of neurons?

A

Send and receive information through electrical impulses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are common structural features of a neuron?

A
Nucleus
Soma (cell body)
Dendrite
Axon
Axon terminals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the three main functions of the brain?

A
1. Autonomic Functions 
(heartbeat, breathing, digestion, temp)
2. Cognitive skills 
(planning, thinking, emotions, behaviours)
3. Sensorimotor function
(sensation and movement)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the functional unit of the nervous system?

A

Neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the most common type of neuron in human nervous systems?

A

Multipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three main categories of neuron structure

A

Multipolar
Pseudo-Unipolar
Bipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

A motor neuron is an example of which type of neuron structure?

A

Multipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

A sensory neuron is an example of which type of neuron structure?

A

Pseudo-Unipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A retina neuron is an example of which type of neuron structure?

A

Bipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an anaxomic neuron?

A

A neuron without an axons, therefore, it cannot propagate an action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are glial cells?

A

Cells which provide supporting functions to the nervous system in various ways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List the glial cells which exist in the CNS:

A

Astrocyte
Oligodendrocyte
Microglia
Ependymal cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List the glial cells which exist in the PNS:

A

Satellite cell

Schwann cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of oligodendrocytes?

A

Produce myelin to be wrapped around the axon (for neurons in the CNS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Compare the electrical conduction speed of myelinated axons with that of non-myelinated axons:

A

Myelinated axons have a much faster conduction speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of myelin?

A

Wraps around axon to prevent electrical signals escaping and speed up conduction rates through the axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the function of schwann cells?

A

Produce myelin to be wrapped around the axon (for neurons in the PNS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of an astrocyte?

A

Maintain chemical concentrations in extracellular space
Remove waste products
React to damage
Acts as a blood-brain barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the function of the blood-brain barrier?

A

Selectively control which molecules can pass between the bloodstream and nervous tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What substances can pass through the blood brain barrier?

A

Gases (CO2 and O2)
Lipid soluble molecules
Water and certain ions - with helps from proteins!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why may a malfunctioning blood-brain barrier be dangerous / undesirable?

A

Unwanted proteins may cause disruptive neural activity and can lead to a number of CNS diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Explain how the Astrocytes maintain the blood brain barrier:

A

Astrocytes produce more tight junctions to make sure the permeability of the barrier remains relatively low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the function of ependymal cells?

A

Produce cerebrospinal fluid (CSF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which PNS cell performs a similar role as astrocytes?

A

Satellite cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the function of microglia?
Similar to that of a macrophage, migrate and engulf pathogens found in the CNS
26
What is the function of a satellite cell?
Maintain chemical concentrations in extracellular space Remove waste products React to damage Acts as a blood-brain barrier
27
Ionic concentrations at rest create an extracellular environment with what charge?
Net +ve charge
28
Ionic concentrations at rest create an intracellular environment with what charge?
Net -ve charge
29
What is the resting membrane potential?
(-70 mV) | It is generated by the unequal distribution of Sodium, Potassium and Chloride ions
30
What is the result of the Sodium Potassium pump?
3 Sodium ions are pumped out of the cell and 2 Potassium ions are pumped into the cell
31
What is an action potential?
A significant but transient rise in the membrane potential
32
Explain how a stimulus triggers depolarisation:
Stimulus causes an influx of +ve ions Change in the voltage from -ve to +ve This is depolarisation
33
What is repolarisation?
The stage directly following depolarisation where there is a sustained efflux of Potassium ions from the membrane
34
What is hyperpolarisation?
Directly following polarisation, the membrane potential is more negative than it typically is and another action potential cannot be created until resting membrane potential is restored
35
Where in a neuron is the action potential generated?
The axon hillock, (where the axon is connected to cell body)
36
How does an action potential propagate (move) through an axon?
A wave of depolarisation as voltage-gated Sodium channels produce a regenerative current to retain the amplitude of the action potential
37
Where are voltage-gated Sodium channels found?
At gaps in the myelin sheath known as the Nodes of Ranvier
38
What factors may affect the speed of an action potential moving down an axon?
Myelination Axon diameter Temperature
39
``` Place the following 'stages' in order: Repolarisation Depolarisation Stimulus Hyperpolarisation ```
1. Stimulus 2. Depolarisation 3. Repolarisation 4. Hyperpolarisation
40
Explain the process of synaptic transmission:
Action potential reaches axon terminal Calcium channels open Calcium causes vesicles to release a neurotransmitter Neurotrasmitter diffuses across synaptic cleft and bind to post synaptic receptor Receptors activated and Sodium channels open in post synaptic cell
41
What is a neurotransmitter?
A chemical messenger which transmits signals across a synapse between neurons
42
What is spatial summation?
Excitatory potentials from many neurons triggering a stimulus threshold
43
What is temporal summation?
Successive stimuli from one neuron triggering a stimulus threshold
44
What is the main difference between spatial and temporal summation?
``` Spatial = less signals from many neurons Temporal = many signals from one neuron ```
45
What structures make up the CNS?
Brain and Spinal Cord
46
What structures make up the PNS?
All nerves in the body excluding those in the CNS (Brain and Spinal Cord)
47
What is the function of the autonomic nervous system?
Regulate the internal environment
48
What are the two divisions of the autonomic nervous system?
Sympathetic | Parasympathetic
49
What is the function of the somatic nervous system?
Enables us to interact with the external environment
50
What are the two divisions of the PNS?
Autonomic nervous system | Somatic nervous system
51
What is the spinal spinal cord?
A long, delicate cord of the nervous system which is responsible for transmitting nerve signals to and from the brain
52
Where is the spinal cord located?
In the vertebral canal, protected by the vertebral column
53
Explain how spinal nerves leave the vertebral column:
A pair of spinal nerves pass through the intervertebral foramen, (one on each side)
54
How many pairs of spinal nerves are there?
``` 31 pairs: 8 Cervical 12 Thoracic 5 Lumbar 5 Sacral 1 coccygeal ```
55
What is the dorsal root?
The supply of afferent (sensory) fibres which provide information to the spinal cord
56
What is the ventral root?
The supply of efferent (motor) fibres providing information from the spine to muscles
57
What is the 'mixed' spinal nerve and why is it important
It is a bundle of afferent and efferent nerves passing in different directions, it exists so both nerves can squeeze through the intervertebral gap
58
What is the dorsal ramus?
A branch from the mixed spinal nerve carrying fibres through to the skin and deep muscles of the back
59
What is the ventral ramus?
A branch from the mixed spinal nerve carrying fibres through to the anterolateral parts of the trunk and limbs
60
What are grey and white rami?
A branch making connections with the ANS via the sympathetic ganglion
61
What is the dorsal root ganglion?
A cluster of sensory neurons
62
What is a dermatome?
An area of skin supplied by the afferent (sensory) fibres of a single spinal nerve
63
T / F: | Dermatomes are individual and specific to each person
False, there may be some tiny differences but can be generally mapped on an anatomical model
64
What is a myotome?
A group of muscles which are innervated by the efferent (motor) fibres of a single spinal nerve
65
Why can myotomes be clinically relevant in assessing spinal damage?
A change (loss) in muscle strength within a particular myotome may indicate damage to a particular spinal nerve root
66
What is a spinal plexus?
A bundle of ventral rami which come together and branch out to form named peripheral nerves.
67
Name the 4 spinal plexuses and give their root values:
``` Cervical plexus (C1-C4) Brachial plexus (C5 - T1) Lumbar plexus (L1 - L4) Sacral plexus (L4 - S4) ```
68
What is the nerve formed at the cervical plexus and which muscles does the plexus innervate?
Phrenic Nerve: | Innervate the back of the head, neck, shoulders and diaphragm
69
What is the nerve formed at the brachial plexus and which muscles does the plexus innervate?
Median Nerve, Radial Nerve, Ulnar Nerve: | Innervate the upper limbs
70
Why can dermatomes be clinically relevant in assessing spinal damage?
Impaired sensation of a specific dermatomal region may indicate damage to a particular spinal nerve root
71
What is the nerve formed at the lumbar plexus and which muscles does the plexus innervate?
Femoral Nerve: | Innervate the anterior and lateral aspects of the thigh
72
What is the nerve formed at the sacral plexus and which muscles does the plexus innervate?
Sciatic Nerve: | Innervate the posterior of thigh and below the knee
73
What structures are present in a peripheral nerve?
``` Perineurium Endoneurium Epineurium Fascicle Axons ```
74
What is a fascicle?
A bundle of individual neurons with a shared purpose
75
What is the perineurium?
A cell layer surrounding the fascicle
76
What is the endoneurium?
The connective tissue in-between axons
77
What is epineurium?
The outer layer of a peripheral nerve, it is dense, irregular connective tissue