1 Organisation of the Nervous System Flashcards Preview

LCRS Neuroscience and Mental Health > 1 Organisation of the Nervous System > Flashcards

Flashcards in 1 Organisation of the Nervous System Deck (21):

Q: How is the nervous system structurally divided?

A: 2 parts
-central nervous system (brain and spinal cord)
-peripheral nervous system (nerves and ganglia outside the brain and spinal cord)


Q: What are ganglions?

A: clusters of neuronal cell body


Q: Draw a diagram summarising the organisation of the nervous system. Identify efferent and afferent flow.

A: brain and spinal cord = 1. CNS
2. PNS
3. sensory division // 4. motor division
5. autonomic motor division // 6. somatic (motor) division (spinal nerves and cranial nerves)

5 goes into
7. sympathetic division (spinal nerves only)
8. parasympathetic division (spinal nerves and cranial nerves)

go into 3
9. somatic sensory
10. autonomic sensory

5->7+8 (efferent)

9+10-> 3->2->1 (afferent)


Q: What is the PNS functionally divided into? (2-1,3)

A: Somatic (motor) PNS
-Controls motor and sensory function of the body wall e.g. skin and skeletal muscles

Autonomic Nervous System
-Has Sympathetic and Parasympathetic arms
-Also called: Visceral NS, Vegetative NS, Involuntary NS
-controls function of viscera (internal organs)


Q: Differentiate between efferent and afferent axons. What are interneurones?

A: efferent= propagate AP from brain and spinal cord to the periphery (motor neurones)

afferent= propogate AP towards brain and spinal cord from PNS (sensory neurones)

interneurones= CNS neurons that synapse with other CNS neurons within the brain and spinal cord (can be either of the top 2)


Q: How do axons enter and leave the CNS?

A: through pairs of spinal nerves and cranial nerves


Q: Name the 3 main parts of the brain.

A: 1. cerebral cortex (cerebrum)
2. cerebellum (hind brain)
3. brain stem


Q: Describe the cerebrum. (2)

A: -made of 2 hemispheres
-each receives sensory information from and controls movement on opposite of body


Q: What does the cerebellum control?

A: coordination of movement


Q: Describe the brain stem. (2) Function? Damage?

A: -most primitive part
-densely packed fibres

-regulates vital functions (eg consciousness and breathing)
-damage here can be fatal


Q: What is the spinal cord? Includes?

A: -string of nerve tissue from below brain to first lumbar vertebrae

-grey matter
-white matter


Q: Where does the CNS end in terms of the spinal cord? What emerges from the spinal cord? what are they part of?

A: margins of spinal cord

dorsal and ventral roots (part of the PNS)


Q: What do spinal nerves contain? (3) How? What is the whole nerve surrounded by? components?

A: -both afferent and efferent axons = bundled into fascicles surrounded by perineurium
-blood vessels

-tough epineurium capsule
-individual axons are also wrapped with myelin and endoneurium (though some are unmyelinated eg pain neurones)


Q: What is a neurone function? How?

A: transmit and receive AP/ stimulate target tissue eg induce contraction of smooth muscle/secretion from a gland

when AP reaches a neuronal chemical synapse -> neurotransmitters released by a presynaptic terminal bind to post-synaptoc receptors of the neuron/muscle/gland it is synapsing with


Q: Apart from neurones, name 4 other cell types essential to nervous system development, microanatomy and function.

A: glial cells


Q: How does regeneration differ between PNS and CNS? (3,4)

A: -axons in peripheral nerves can regenerate after injury
-recovery is often compromised by non-specific target reinnervation and aberrant axon sprouting (eg can lead to neuropathic pain)

-axons in CNS are unable to regenerate over long enough distances to be useful. This is because:
- presence of inhibitory molecules in the CNS but not in the PNS (e.g. differences in myelin)
-Absence of guidance cues that stimulate axon growth during development
-Some loss of intrinsic axon growth capabilities by the neurons


Q: Are neuronal cell bodies in grey or white matter? therefore the other?

A: grey

white comprises ascending and descening axon tracts to and from the brain


Q: Is grey or white matter peripheral?

A: white is peripheral and grey is central


Q: What do sensory inputs activate? where? What occurs?

A: sensory neurones in the spinal cord grey matter

transmit AP upwards to sensory cortex of the brain (ascending tracts)


Q: Where do neurones in the motor cortex extend? What occurs?

A: -opposite direction to sensory inputs
-extend downward to synapse with spinal motor neurones

transmit AP for voluntary movement (descending tracts)


Q: What's required for a reflex motor response? (3) Not?

A: only the somatic sensory inputs to, (interneurones) and motor outputs from spinal cord

NOT communication with the sensorimotor cortex