Nerves Flashcards
What are the components of the central nervous system?
Brain
Spinal cord
What are the components of the peripheral nervous system?
Cranial nerves
Spinal nerves
Autonomic nerves
What is the purpose of autonomic nerves?
Provide communication between brain and organs
What is a group of nerve cell bodies in the CNS called?
A nucleus
What is a group of nerve cell bodies in the PNS called?
A ganglion
What is the name given to a bundle of axons travelling together in the CNS?
A tract
What is the name given to a bundle of axons travelling together in the PNS?
A peripheral nerve
What is the axon or nerve fibre?
An “electrical cable” conveying the action potentials
When is the term “nerve” used?
When referring to a peripheral nerve
What is the myelin sheath?
An electrical insulator
Does a myelinated or an unmyelinated nerve conduct action potentials faster?
Myelinated
What is a peripheral nerve?
A bundle of axons wrapped in connective tissue travelling together to/from the same region of the body or structure
What is the outermost layer of the cerebral hemispheres called?
Cerebral neocortex (cortex for short)
What is the name given to the fissure which separates the two cerebral hemispheres sagittally?
The longitudinal fissure
Which cranial nerves could a pathology in the jugular foramen injure?
CNS IX, X and XI
Why is the area of the brain deep to the grey matter coloured white?
It contains many axons which are myelinated and the myelin gives the whiter appearance
In the spinal cord, which is deep and which is superficial of the white and grey matter?
White matter is superficial
Grey matter is deep
Which structure does the spinal cord pass through to connect with the brain?
Foramen magnum of the occipital bone
At which level does the spinal cord end?
L1/L2
What is the cauda equina?
Lumbar and sacral spinal roots that descend in the vertebral canal to their respective intervertebral foraminae
Which anterior rami mix to make the brachial plexus?
C5-T1
What are the five named nerves that stem from the brachial plexus?
Musculocutaneous nerve Axillary nerve Median nerve Radial nerve Ulnar nerve
Which cranial nerves contain parasympathetic axons?
3, 7, 9 and 10
What are the structures of the soma (superficial to deep)?
Skin Fascia Skeletal muscle Skeleton Internal lining of body cavities e.g. parietal pleura
What is the name given to the receptors which detect pain?
Nociceptors
Which part of the brain is the primary somatosensory area?
Parietal lobe
Which part of the brain is the primary somatomotor area?
Frontal lobe
How many neurones are in the somatic motor pathway?
2 neurones
What is a reflex?
An extremely rapid, involuntary response to a potentially harmful stimulus
What is paralysis?
A muscle without a functioning lower motorneurone is paralysed
On examination of a paralysed muscle, what could be noted about the muscle tone?
Reduced muscle tone - reduced resistance to stretch?
What is spasticity?
When a muscle has an intact and functioning lower motorneurone but the descending controls of the brain are not working, and so the muscle over-contracts continuously
On examination of a spastic muscle, what could be noted about the muscle tone?
Increased tone
Which part of the spinal cord do sympathetic axons descend in?
White matter
Which segments of the spinal cord have lateral horns and why?
T1-L2
To accommodate sympathetic neurones
Which structures in the body wall does the sympathetic system supply?
Skin sweat glands
Skin arrector muscles
All arterioles
