Topic 13 Muscles + Nerves Flashcards
Multipolar neurone (2)
Single long axon
Many dendrites
Unipolar neurone
Sensory ganglia
Bipolar neurone
Retina
White matter Structure
Axons Carry information to/fro brain
Grey matter role
cell bodies in sensory / motor nuclei
what stain is used for myelin
Weigert
White matter stains what colour and why
Dark - a lot of myelin
Grey matter stains what colour and why
Light - a lot of cell bodies
Ganglia contains what (2)
Ganglion cells + satellite cells
Sensory ganglia are what type of neurones
Afferent neurones
Autonomic ganglia are what type of neurones
efferent neurones
The epineurium covers what
whole nerve
A perineurium covers what
Fasicle
Endoneurium covers what
Individual nerve axons
A fasicle is what
bundle of nerve fibres
Epdendymal // oligodendrocytes // microglia // astrocytes // schwann cells / satellite cells
are all ranges of what
Neuroglia
function of neuroglia (3)
Regulate neurone metabolism
Regulate BBB
Destroy pathogens
Metabolic exchange between neurons + blood
Support framework
Restricts substance across BB barrier
Promotes Neurone growth
Astrocytes
Immune defence
Phagocytic
Microglia
Lines ventricles + central spinal canal
Produces CSF
Cilia on luminal side
Ependyma
Myelinate axons
Common in white matter
Oligodendrocytes
Two main types of peripheral nervous system (PNS)
Satellite
Schwann
What cell type phagocytes dying nerve cells
Schwann
Myelination is done by what cell in the PNS
Schwann
Myelination is done by what cell in the CNS
Oligodendrocytes
Demyelinating myelinoclastic diseases are caused by what
Toxins // infection // chemicals
Demyelinating leukodystrophic is caused by what
Myelin abnormal
Genetics
Idiopathic
Somatic nervous system role
Innervates + controls voluntary + striated muscles
sympathetic postganglionic transmitter
Noradrenaline
Proprioception nerve class
Alpha (largest / fastest)
Touch/pressure nerve class
Beta
Motor - muscle spindles nerve class
Gamma
Pain / Cold / Touch nerve class
Delta (smallest / slowest)
Deep dermis / tendons / joints / genitalia
Vibration / deep pressure
Fast adapting
Pacinian Corpuscles
Oral mucosa / lips / genitalia / finger trips
Touch / vibration / light pressure
Rapid adapting
Meissners / Krauses Bulbs
Deep dermis / ligaments / joint capsules
Stretch / deep pressure
Very slow adapting
Ruffini Organs
Resting potential
-65mV
Nernst Equation
Determines equilibrium for any ion
Phase 1 AP
Na channel open
Na enter
Phase 2 AP
Threshold reached (-40mV)
voltage gated open
Na+ spike
Phase 3 AP
Na close (30mV)
K+ voltage open
K+ flow out of cell
Phase 4
Na+ channel close (-80mV)
Hyperpolarisation
In the absolute refractory period, what can not be elicted
AP
What type of receptor in the muscle is stimulated when passively stretched
Muscle Spindle
When is the Muscle Spindle switched off
Muscle contraction
what receptor responds to excessive tension
Golgi Tendon Organ
What does the golgi tendon organ do
causes relaxation of muscle
Role of ionotropic receptors
Depolarise post synaptic cells
Glutamate + acetylcholine causes influx of what
What does this lead to in a postsynaptic cell
Influx of Na
EPSP (excitatory post-synaptic potential)
What can a EPSP do
Initiate AP
GABA / Glycine causes an influx of what
What does this lead to
Influx of Cl
Leads to IPSP inhibiting AP
feather like shape muscle group
Pennate
Fusiform muscles are what shaped
Spindle shaped
circular muscle groups surround what
Body opening / orifice
Striated
Multinucleated
Voluntary
Attached to skeleton
Skeletal Muscle
Striated
Single nucleus
Involuntary
Branched
Cardiac Muscle
Non striated
Single nucleus
Involuntary
Smooth Muscle
Myosin contains what structure
2 heavy + 2 light
Ca binds to what region of Troponin
TnC region
what happens when Ca binds to TnC on Troponin
Moves tropomyosin
exposes Binding site on Actin
Myosin head with ADP + PI bind to what
Exposed actin filament
Myosin head bends after being exposed to actin filament leading to what (2)
Pulls actin filament
ADP + Pi released
In the cross bridge theory what initiates the power stroke
Inorganic phosphate
Concentric contractions leads to what in a muscle
Muscle shortening
Eccentric contraction leads to what in muscles
Muscle Lengthening
Motor unit consists of what (2)
Motor neuron
Muscle fibres
what reflects the time for excitation-contraction coupling
Latent Period
When does the contraction phase end
What happens to Cytosolic Ca
Ends when muscle tension peaks
Ca increasing
When tension levels plateau and Ca rise to peak levels what is this called
Tetanus
inherent delay at the NMJ is what
0.5-1ms
what subunits present on Nicotinic receptor (NAcH)
2a (what AcH binds)
1b
1d
1g
1 quantum is how many AcH in 1 vesicle
5000 AcH
MEPP -
What are they
Minature End Plate Potentials
Additive
Co-enzyme A is responsible for making what
Acetyl CoA from Acetate
how does AcH get into vesicles (what gradient)
H+ gradient (H leaves)
Synapsin is found on what
what does it anchor to
Vesicles
Actin filaments
V-snare is found on what
what does it bind to on the membrane
Vesicle
T snare
Tubocurarine is what
Non Depolarising competitive nAChR antagonist
how does Tubocurarine work
competes with AcH for nicotinic receptor
what does the effect of Tubocurarine lead to
Muscle paralysis
Succinylcholine is what
Depolarising nAChR agonist
Succinylcholine leads to what
Flaccid Paralysis
if Succinylcholine is administered with halothane what does this lead to
Malignant hyperthermia
Neostigmine // edrophonium are what
Cholinesterases inhibitors
Neostigmine is used for
Treating myasthenia gravis
Edrophonium is used for what
diagnosing myasthenia gravis
what is given as an antidote to nerve gas agents
Atropine
puffer fish / newts / toads have what toxin
Tetrodotoxin
Tubocurarine is a toxin found in what
what does it bind to
Arrow poison
binds to nAcH receptor
Inhibition of Ca channels + autoimmune condition present in 60yr older is what syndrome
what synaptic disorder is it
Lambert Eaton Syndrome
Presynaptic disorder
Lambert Eaton Syndrome is associated with what
Small cell lung cancer
o Fatigue o Weakness in limb muscle groups o Abnormal reflexes o Dry mouth Xerostomia Insufficient saliva production o Doesn’t usually affect respiratory /facial / eye muscles o Hyperhidrosis o Areflexia
Lambert eaton syndrome
Electromyography + chest xray can be used for what diagnosis
Lambert Eaton Syndrome
How does amifampridine work
what is it used in
blocks K+ channel
AP increased
More AcH released
Lambert Eaton Syndrome
Myasthenia Gravis is an autoimmune condition against what
what sort of synaptic disorder is it
nAcH
Post synaptic disorder
women at early age w/hyperplasia
men at older age w/cancer of thymus
what do these lead to
Myasthenia Gravis
Neostigmine binds to cholinesterase how
covalent bond
Is cardiac muscle smaller than skeletal
yes
100um x 15um
how many nuceli does each cardiac cell contain
1-2 nuclei
how much of a cardiac cell is mitochondria
30%
how much of a skeletal cell is mitochondria
2%
mechanical coupling in an intercalated disk is done by what
Desmosomes (macula adherens)
Electrical coupling in an intercalated disk is done by what
gap junction
Fascia adherens role
anchor site for actin
Contractile cell dont do what
initiate their own AP
what potential is found in auto-rhythmic cells
no resting membrane potential
Wolff-Parkinsons-White Syndrome is a disorder of what?
What electrical pathway does it go down instead
Disorder of conduction system of heart
bundle of kent
what does Wolff-Parkinsons-White lead to
Supraventricular Tachycardia
Phase 0 of a ventricular AP
Na Channel Open
Phase 1 of ventricular AP
Na Channel close
Phase 2 of ventricular AP (2)
Ca channel open
Fast K+ close
Phase 3 of ventricular AP (2)
Ca Channel close
Slow K+ open
Phase 4 of ventricular AP
resting potential
SA + AV node AP upstroke is dependent on what
Ca
Ventricular upstroke is dependent on what
Na
Class 1 antiarrhymic agents
Sodium channel blockers
what do Class 1 antiarrhymic agents treat
Ventricular ectopies
Class 2 antiarrhymic agents
Beta blockers
Class 2 antiarrhymic agents do what
decrease sympathetic nervous system
Class 3 antiarrhymic agents
Potassium channel blocker
Class 3 antiarrhymic agents do what
prolong repolarization
Class 4 antiarrhymic agents
calcium channel blockers
Class 4 antiarrhymic agents do what
Reduce contractility of heart
in Cardiac Excitation-Contraction Coupling, where does a AP arrive at?
What does this open
Arrives at T tubules
Opens L-type Ca channels
digoxin inhibits what
what does this increase concentration of
inhibits Na/K ATPase
increases intracellular Ca
AcH in the parasympathetic stimulates what nerve
Vagus nerve
Frank starling law
resting length of cardiac muscle set below optimum
in dilated cardiomyopathy, what happens to the heart
enlarges
in dilated cardiomyopathy, what happens to the lungs + heart failure
Fluid build up in lungs
Left heart failure
if theres a build up of fluid in tissues / organs / swelling of ankles what could this be caused by
Right heart failure
Myocardial disarray can be caused by what
hypertrophic cardiomyopathy
causes of hypertrophic cardiomyopathy
Genetic mutation
2 layers of SM
circular layer
Longitudinal layer
What muscle has more actin than myosin
Smooth muscle
What is not found in SM (3)
no sarcomeres
No striations
No T tubules
Instead of T tubules in SM, what is found instead
Caveolae
what does Ca bind to in SM
Calmodulin
What does Calmodulin interact with
what does this phosphorylate
Myosin kinase
Myosin
when Ca decreases in SM what happens
calmodulin complex dissociates and inactivates myosin kinase
what is the most common unit in SM
when does it contract
Single unit
in response to stretch
what unit of SM allows fine control but is slow and allows sustained contraction
what does it lack
multi-unit
lacks gap junctions
benign growth in female reproductive tract
Leiomyoma (fibroids)
Leiomyoma is common in what race
which women are also prone to this
afro-caribbean
women approaching menopause
Symptoms of Leiomyoma
heavy uterine bleeding
