PNS contains

cranial, spinal, ganglia, sensory, motor neurons

Sea sponges

Eu, but have no nervous system,

Nerve nets - hydras and jellies

Contraction/expansion of body, lack nerves, reflexes only.

Sea stars

Centralised nervous system, ring of neurons located in centre, radial nerves to tip, form nets. Eye spot for light

Primitive cephalisation

Symmetric animals have ganglia near head to form complex signals

Ganglia molluscs, worms, arthropods

Head ganglia are fused, specialised receptors

Flatworms

2 nerve chords running down body

Invertebrates

Lack myelin but increase axon diameter

Forebrain - optic and olfactory

Telencephalon, diencephalon - cerebrum, thalamus and hypothalamus

Midbrain - mesencephalon

Sulci

Cerebral hemisphere forming valleys between gyri

Hindbrain - Rhombencephalon

My and mesencephalon - medulla, pons and cerebellum

Gyri

Infolded cerebral cortex ridges

Motor

Primary and pre in frontal lobe

Sensory

Primary somato sensory and association in parietal lobe

White matter properties

myelinated, connects grey, larges bundle is corpus callosum

Subarachnoid space contains

CSF produced by choroid plexus

Afferent cortex input from

Ascending thalamus, stem, fore, Axons between commissural fibres and ipsilateral cortex info

Neocortex output

Is excretory from pyramidal, all cortex to thalamus

Neocortex axons

Motor and sensory to basal ganglia, project to stem, chord, contralateral and ipsilateral

Cerebellum

Proprioceptive, aids cerebral cortex in next move

in - Vestibular, chord

out - vestibular, stem

in - cerebellar cortex, motor in neocortex

out - muscle spindles, (pre)motor cortexes

Afferent fibres leave through

ventral anterior root

Spinal nerves all have

posterior dorsal root, containing drg

Monosynaptic reflexes

Muscle sensory fibre then alpha motor neuron

Polysynaptic reflexes

Produces EPSPs and IPSPs, withdrawal reflex

Parasympathetic

craniosacral, rest

Sympathetic

thoracolumbar, fight

Hillock zone is,

trigger for threshold potential, AIS contains v gated na channels

beta IV spectrin

cytoskeletal proteins found in axons and non neuronal cells

MAP2

Neuron specific cytoskeletal protein found in dendrites

Motor neuron

Ventral horn of chord, pale staining nucleus, prominent nucleolus.

Motor neuron nissl

Prominent bodies, but substance absent in axon as little synthesis

Spinal ganglia - DRG and individual

DRG surrounded by connective tissue capsule - continuous with peripheral nerve, surrounded by satellite cells

Cerebellar cortex molecular

external, basket and satellite cells

Cerebellar cortex purkinje

Single layer of Purkinje cells

cerebella cortex granule

internal, granule and golgi cells

Purkinje cells

Largest cell in cerebellum, pear shaped bodies and dendritic afferent tree

BBB composition

Glial membrane around vessels, endothelial tight junction composition

BBB molecular

500 da Max, lipid and gas soluble, integrity reliant on astrocyte feet

Microglia

Phagocytose debris, dormant, cytokines released to help and hinder recovery

Oligodendrocytes

Late development, one will myelinate many axons, MS and leukodystrophies damage this

Unmye PNS

Schwann envelope unmyelinated axons - these have continuous conduction, pain temp and itch

Unmye CNS

Not associated with glia

Sarcolemma

Muscle cell membrane

Sarco retic

Stores calcium

Ligand ion channels, v gated na

at muscle endplate, propagate action potential

isometric

load equals force

concentric

load is less than force, shortens

Eccentric

load is more, lengthens

Type 1 - Slow oxidative, 2x is opposite

Slow twitch, high globin, non fatigued, weaker

Type 2A - fast oxidative glycolytic

Intermediate

Motor unit

one alpha motor and muscle fibres, one alpha will innervate many fibres

Alpha motor neurons

Innervate muscle, soma in ventral horn of spinal chord, arranged topographically according to muscles

Temporal summation

rapid stimulation summed, for a smooth contraction

Spatial summation

More activation means more force, hand muscles

Gamma motor neurons

Innervate intrafusal fibres to control spindle sensitivity, required when muscle shortend

IA afferents

rate of stretch - bag fibres

IL fibres

measure length - chain fibres

Golgi tendon organ

Force sensitive, IB afferents, protective reflex contribution

Myotatic reflex

muscle stretch, IA to alpha. inhibition of antagonists due to interneurons

Clasp knife reflex

tension activates IB, inhibitory interneurons, relaxation. free nerve endings may contribute

Crossed extender reflex

pain via a-delta fibres in DRG, excitatory and inhibitory interneuron. Leg flexes, other extends

Temporal lobe

audio and association