Ch. 5 EXAM 2 Flashcards
What does efferent mean
motor
what does afferent mean
sensory
name the pyramidal tracts
and function
lateral corticospinal (primary)
anterior corticospinal (secondary)
main motor pathway
name the extrapyramidal tracts
and function
Rubrospinal
Reticulospinal
Olivospinal
Vestibulospinal
accessory motor
what is gray matter function?
decision making
cell bodies or motor neurons
and synapses
define tract
bundle of axons in the CNS
define nerve
bundle axons outside the CNS
What pathway is bigger? sensory or motor
sensory/afferent
name the DCML pathway
and function
Dorsal Column Medial Lemniscus
- gracile fasciculus
- cuneate fascicles fasciculus
pressure sensors/touch
lamina 1
lamina marginalis
fast pain
A delta fibers
laminae 2,3
substantia gelatinosa
slow pain C fibers- and lamina 5
laminae 1-6
pathway?
mechanoreceptors (pressure)
2 pathways
- DCML to brain
- synapse in dorsal horn of cord
motor cell body neurons in anterior gray horn
lamina VII
- intermediolateral nucleus
- lateral gray horn
lamina VIII
- lots of large motor neurons
lamina 10
- crosstalk
name spinocerebellar tracts
anterior spinocerebellar
posterior spinocerebellar
anterolateral system
spinothalamic tract
- lateral
- anterior
pain
how many rexed laminae
9
sensory and motor gray matter
corticospinal tracts
name all 3 pathways
aka pyramidal tracts
80% motor function- Lateral
motor cortex, internal capsule, pyramids of medulla (crossover), lateral corticospinal tract
17% motor function- Anterier
- crossover in the cord
third pathway 3% motor function
- no crossover
DCML pathway
touch sensors enter dorsal rootlets
grey matter of cord
- dorsal columns
OR
- stays at that level (lateral inhibition)
representation image of parietal lobe sensory locations
homunculus
what is crossover in the medulla called
pyramidal decussation
brainstem in order
- midbrain
- pons
- medulla
neurotransmitter causes of chronic emotional pain
increase of glutamate receptors
decrease of enkephalin receptors
where does emotional pain get sent to
middle of brain near brainstem connects to diencephalon
second order pain neuron
myelinated or not?
always myelinated for fast pain
may or may not be myelinated for slow pain
rubrospinal
extrapyramidal tract
voluntary movements
Reticulospinal
extrapyramidal
muscle tone maintenance
olivospinal
extrapyramidal
cerebellar output to coordinate movement
vestibulospinal
extrapyramidal
eye fixation, muscle orientation during acceleration
balance and eye focus during movement
where is cell body of nocireceptor located
Doral root ganglia?
causes of pain (8)
physical damage
acidosis
potassium
histamine
serotonin - in periphery..but in cord its inhibitory
ACh - in periphery
prostaglandins
bradykinin
descending pain suppression pathway and neurotransmitters
- Enkephalin neuron (excitatory)
- periaqueductal gray
- periventricular nuclei (infront of third ventricle) - Serotonergic neuron
- raphe Magnus nucleus: middle of pons
- releases serotonin (5-HT) excitatory - Enkephalin neuron
- Doral horn
- inhibitory
another name for a morphine receptor
enkephalin receptor
opiate/ Mu receptor
glutamate
top neurotransmitter for pain
excitatory
2nd receiving neuron has glutamate receptors to receive messages from nocireceptor
tricyclic antidepressants
serotonin reuptake inhibition
pain management
old drug 500-60 years
bad side effect (sleepy)
SSRI
serotonin reuptake inhibitor
pain relief
newer drugs
Paxil, prozac
two inhibitory neurotransmitters in the spinal cord
GABA (CNS plus spinal cord)
glycine (spinal cord)
Cl permeability
4 excitatory neurotransmitters
Ach
histamine
glutamate
norepinephrine
dopamine
pleasure and reward
potent motor inhibitor
Parkinson’s not producing enough dopamine leads to over active motor function
what muscle is innervated by more than one motor neuron
ocular muscles
sarcolemma
what carries an action potential down into a muscle cell
transverse tubule
what type of calcium channels open to action potential down a motor neuron
p type Ca channel
what will every skeletal muscle have?
motor neuron
some fibers controlled by more than one motor neuron depending how big the muscle is
what is a motor unit
what is located near the NMJ of skeletal muscle for energy?
mitochrondria
what increases the surface area of of NMJ surface area in the skeletal muscle
subneuronal clefts
- primary cleft = one infolding
- secondary cleft = two infolding
contains ACh receptors and voltage gated Na channels
what does acheytlcholinesterase use to break down acetate + choline
hydrolysis
how many Ach receptors at the NMJ
how many activated?
5 million
500,000 activated (10%)
how many Ach molecules need to be release
1 million
but produce 2 million
nicotinic Ach receptor
charge and ions
negative pore charge
Na and some Ca enter
some K leaves (barely)… K leak channels if K wants to leave
nAch-R antagonist binding to receptor needs to bind…
to 1 Ach site
what 2 proteins are on the NMJ surface of neuron to attach vesicles
SNAP-25
SNARE
voltage sensor in the t tubule
DHP
dihydropuridine
what meds block DHP sensors
CCB
whats the calcium release channel on the SR called
ryanodine receptor
how does calcium get put back into the SR
SERCA pump
- sarcoplasmic endoplasmic reticulum calcium APTase
burns ATP to put Ca back in SR
depolarization after an action potential… what kind of K channels
LOTS of leaky K channels
some voltage gated K channels
whats the intracellular fluid in skeletal muscle
sarcoplasm
whats located next to the nACh-R allowing an action potential
fast sodium channels
second type of Ach-R
neuronal Ach receptor (motor neuron)
auto-receptor
3 alpha subunits
2 beta subunits
-3 places for Ach binding
small amount of Ach released at the NMJ will feed back onto these receptors
Na and Ca entry causing VP1 to replace VP2
non-depolarizing NM blockers affect both neuron and skeletal muscle… how?
inhibits all Ach-R
including auto receptors on motor neuron- alpha 3 beta 2
how can sux affect the eyes?
ocular muscles controlled by several motor neurons and several NMJ… more Ca coming in, more contraction, increased IOP, vision loss from compression on optic nerve
what is the high conductance nACh-R called
adult
lots of current for short time
Ach falls off quicker
only at NMJ
what is low conductance nACH-R called
fetal
replace as we mature
slow conductance
open longer when ACh binds
adult nACH-R domains
2 alpha subunits
alpha 1
beta 1
delta
alpha
ebsilon
fetal nACh-R domains
alpha 1
beta 1
delta
alpha
gamma
whats the third type of nACH-R
alpha 7
neuronal in muscle
located in CNS/ANS
all 5 subunits bind ACh
what muscle does the ulnar nerve innervate
what happens when stimulated
adductor pollicis
- thumb comes forward
- pinky twitch
*one or both happen
stimulus that recruits all the motor neurons
supra maximal stimuli
what measures the TOF
2 hertz over 2 seconds
2 impulses over 1 second each
4 twitches
Hertz= per second
whats a repetitive high frequency stimulation
tetanic
where should Ach receptors be located
junctional and maybe perijunctional
nerve stimulation of ophthalmic branch of facial nerve
orbicularis oculi
side of face
nerve stimulation of butt area
peroneal nerve
nerve stimulation of lower extremities
posterior tibial nerve
sux potassium leak… what channels (3)
1 leak
#2 voltage gated in junctional area
#3 potassium loss through ACh-R
duration of action of NDMR and sux
NDMR
- onset couple min 2-3 min
- half life min-hours
Sux
- fast onset within 1 min
- very short acting 3 min
how is sux broken down
plasma cholinesterase from the liver
why unequal return of TOF on NDMR
inhibits both neuron and skeletal muscle… VP1 not able to replace VP2
TOF ration
only used with NDMR
B/A
recovery equals 1
ratio increases as drug wears off
what nerve controls the diaphram
phrenic nerve
C3, 4, 5
stimulator settings
50-80
VOLTAGE: force used to push electrons through the tissue, making cell more negative
mA : milli amphers
CURRENT
electrons moving through tissue between 2 electrodes
head lift with NM blocker
how many nACH-R blocked
70%
4 twitches present
post anethesia recvoery
all twitches disappear at what percentage of nACh-R blocked
90-95%
