T2: Nervous System Flashcards
Two main divisions of NS
CNS
PNS
Is grey and white matter on inside or of brain and spinal cord
Brain= grey outside SC= grey inside
2 parts of PNS
Sensory + motor
how does the sensory and motor each split into two sub groups
somatic/ visceral
the visceral motor division splits into what
sympathetic /para
what are the 3 universal properties of neutrons
- excitable
conduct
secretion (neurotransmitter)
what force does somatic motor and visceral motor produce each
somatic= somatic reflex + contraction visceral= visceral reflex
how is RMpotential maintained and at what voltage
-70, movement of ions
explain summation of postsynaptic changes to get over threshold
threshold reaching requires sum of all signals (net change)
what forms myelin sheath in CNS and PNS
C= oligodendrocytes P= schwann
what does nodes of ranvioer and +concentrations of NA in gaps do
create areas of low and max resistance
what does nerve signal speed depend on
diameter + myelin
describe 3rd week neuron development
ectoderm thicken= neural plate + folds inward= neural groove
neuro fold fuse
describe 3rd week neuron development
neuro folds completely fuse= neural tube (brain + spinal cord)
what is the neural crest
=surrounds sides of neural tube
3 primary vesicles of neural tube
Forebrain (prosencephalon)
midbrain (mesencephalon)
hindbrain (rhombencephalon)
secondary vesicles of the prosencephalon + brain structures
telencephalon = hemisphers diencephalon= thalamus ect
secondary vesicles of the mesencephalon + brain structures
stays midbrain
secondary vesicles of the rhombencephalon + brain structures
metencephalon= pons, cerebellum myelencephalon= medulla oblongata
midbrain functions
hearing, mission
medulla function
vasomotor centres, cardiac
diff. b/w post and pre central gyrus
post=sensory (anterior)
pre= motor (posterior)
how many cranial and spinal nerves
12 cranial
31 spinal
cranial nerve= name mnemonic
on on on they travelled and found voldemort guarding very ancient horcruxes
cranial nerve names + function
olfactory optic oculomotor trochlear trigeminal - face adbuctent- eye facial vestibulocochlear glossopharyngeal vagus- visceral organs accessory= shoulder hypoglossal= tongue
sensory motor both mnemonic for cranial nerves
some say marry money but my brother says big breasts matter more
3 ways to protect CNS
bones
meninges
ventricular system
3 meninges layers
dura matter, arachnoid matter, pia
what produces CSF
granulations in subarachnoid
functions of CSF
buoyancy
protection
chemical stability
pathway for ventricular system
CSF secreted > lateral ventricle > (intraventricular formina) > 3rd ventricle > (cerebral aqueduct) > 4th ventricle > 2 lat apartures/1 median aperture > subarachnoid space > venous blood jugular vein
when is additional CSF aded to pathway
3 4 vent= choroid plexus
ratio of white and grey matter as move down cord
higher up = more white (more tracts)
sections of white matter in cord
dorsal (sensory)
lateral
ventral (motor)
how many neutrons in descending tract
2= upper
lower
3 levels of control skeletal muscle can be stimulated
spinal level (reflex) brainstem level (automated) cerebral (voluntary)
what is the name for the descending tract
lateral + anterior corticospinal (motor)= limbs
where does decussion occurs for descending tracts
medulla
2 levels of fine control
- basal nucei= onset + cessation of movement
2. cerebellum
what is flexor reflex
ipsilateral reflex arc (input output same side
what is crossed extension reflex
contraletal reflex (input out different sides
wha tis intersegmental reflex
input out put different levels of spine
pathway of simple reflex
extensor > spindle > primary afferent nerve
- alpha motor > extensor (ipsilateral arc)
- inhibitory interneuron > alpha motor > flexor (contralateral arc)
fine and course discrimination
fine= 2 points closer
prefixes and suffix for descending and ascending tracts
ascend = spino- descend= -spinal
origin of stimulus receptors
exteroceptors= external interoceptors= internal proprioceptors= position of body
nitesntity of sensation affected by
stimulus intesnity
number of fibres
sensitivity of fibres
how any neutrons in ascending pathway
3
1st 2nd 3rd order