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Flashcards in Somatic Nervous System Deck (22)
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1
Q

Two divisions of the nervous system + definitions

A

Central nervous system- consists of the brain and spinal cord
peripheral nervous system- consists of nerves that pass to and from the CNS

2
Q

Further peripheral nerve division

A

Spinal nerves- carrying information to and from the spine

cranial nerves- carrying information to and from the brain

3
Q

Different types of peripheral nerve cells

A

afferent nerves- sensory nerves

efferent nerves - motor nerves

4
Q

Further division of efferent nerves

A

somatic- voluntary movements, impulses travel to muscles

autonomic- involuntary movements, impulses travel to cardiac muscle, skeletal muscle and glands

5
Q

How many spinal nerves in total?

A

31

6
Q

How many from each group of spinal vertebrae?

A
8 cervical C1-C8
12 thoracic T1-T12
5 lumbar- L1-L5
5 sacral S1-S5
1 coccygeal
7
Q

How many cranial nerves ?

A

12 pairs

8
Q

Dermatome definition

A

a particular region of the body that each spinal nerve innervates

9
Q

Is there overlap between dermatomes?

A

Yes, a lot of overlap between the nerves supplying adjacent segments.

10
Q

Structure of somatic efferent motor fibres

A
  • cell body is located in the motor cortex, brainstorm or spinal cord
  • axon fibre projects to the spinal cord or outside to directly innervate effector organs
  • synapse at neuromuscular junction at end plates on muscle fibres
  • single neuron monosynaptic
11
Q

What is motor neuron disease + symptoms?

A

Group of progressive neurological disorders that destroy motor neurones causing a disruption in the signals between the lower motor neurones and limb muscles

limb muscle stiffness (spasticity) movements become slower, eventual paralysis§

12
Q

Two different types of somatic motor neurone

A

Upper motor neurones- originate from brain

lower motor neurones- originate from spinal cord

13
Q

Sensory nerve fibre structures

A

Have a specialised receptor on the end of the axon

Central cell body in dorsal root ganglia

dendrites- to synapse to relay neurone in CNS

14
Q

Sensory neurone function

A

Convey information to from receptors, such as temperature, touch, pain in skin, position sense and pain in joints and reflex control of movement in muscles, to the CNS

15
Q

Structure of dorsal root ganglion

A

left and right paired spinal nerves are formed from afferent sensory dorsal axons- the dorsal root and the motor ventral efferent axons- the ventral root.

Dorsal Root Ganglion is a group of cell bodies responsible for the transmission of sensory messages to the CNS.

The dorsal root enters the grey matter and the ventral root leaves the grey matter

16
Q

How is pain felt?

A

Nociceptive nerve fibres are activated by mechanical forces or by a variety of chemical mediators in the environment, that are released by tissue damage

17
Q

What happens if sensory neurones are damaged?

A

loss of sensation

18
Q

What is a visceral afferent fibre? where are cell bodies found?

A

Neurone that conducts sensory impulses, usually pain or reflex sensations, from the internal organs, glands and blood vessels to the CNS.

Dorsal root ganglia

19
Q

What nervous system are visceral afferent fibres a part of?

A

Autonomic, but neither sympathetic nor parasympathetic

20
Q

What are mixed nerves?

A

Nerves that contain both afferent and efferent axons and thus conduct both incoming sensory information and outgoing muscle commands in the same bundle.

21
Q

Are somatic nerve fibres myelinated or unmyelinated?

A

Most are myelinated and have a fast to medium velocity

22
Q

What fibres are unmyelinated?

A

C-type pain fibres