physio exam 4

skeletal and cardiac muscle

what muscles are striated?

thin and thick filaments

what is skeletal muscle composed of?

sarcolemma

what is the barrier of extra and intracellular and is also the plasma membrane of extrafusal skeletal fibers?

sarco

what is related to the skeletal muscle?

depolarization occurs

what happens to a transmitter when there is a sodium influx?

repolarization occurs

what happens when there is a potassium efflux in a transmitter?

calcium pump will open voltage sensitive channels

what happens with calcium pump in the neurotransmitters?

thick filaments

made of myosin with globular heads

thin filaments

contains actin, tropomyosin, troponins TnC, TnI, TnT

myosin (thick) and actin(thin)

what slides between each other in the sliding filament theory?

tropomyosin

gate that sits in actin groove and blocks crossbridge

troponin (Tn)

hinge on gate made of three proteins

TnC

type of troponin that has calcium binding

TnT

type of troponin that interacts with tropomyosin

TnI

type of troponin that causes inibition

* calcium from sarcoplasmic reticulum now in cytoplasm due to the end plate potential binding to TnC changing its shape and TnT and I.
* troponin rolls back tropomyosin
* set myosin crossbridges actin
* myosin head snaps when in contact with actin
* ATP binds to myosin and cross bridges is released
* myosin breaks down ATP to reset head
* if calcium is around, crossbridge is reformed

what happens in regard with the types of troponin with the Sliding Filament theory?

* depolarizes muscle cell as sodium flows in through a nicotinic receptor
* occurs without summation (means this is all or nothing)
* muscle has no say in the plan as it would be a waste of energy
* action potential is generated

what happens with the sodium end plate potential?

it is post syn and is a type IV nicotinic receptor

what is the motor end plate?

alpha motor neurons

what do extrafusal fibers use?

it is broken down by acetylcholine esterase into acetyl and choline in order to replenish Ach release

when Ach is released from the transmitter, what happens in between before it synapses to the end?

it is sent back to be added to new, repackaged Ach

what happens with acetyl after it was split from the Ach?

taken back to the terminus as they are way harder to make than Ach

what happens with choline after it was split from Ach?

* plasma membrane has extrafusal fibers
* it opens voltage sensitive channels with sodium to have depolarization
* will open potassium voltage sensitive channels to repolarize
* this then causes an action potential generation where it will move along the sarcolemma and into the T tubule

what happens with the sarcolemma with channels and such?

* propagated through the length of sarcolemma but also depolarize deep into tissues through finger like projections inward called Transverse (T) tubule

what happens with action potential propagation?

transverse (T) tubule

invaginations in the sarcolemma for ion exchange to depolarize

amount of tension a muscle fiber can produce

what does crossbridging determine?

sarcoplasmic reticulum

* smooth ER in extrafusal fibers
* opens VS calcium channels in response to T tubule depolarization to release calcium

Ach has to be broken down into acetyl and choline

how can we stop action potential generation?

Myasthenia Gravis

* destroys nicotinic receptors (Autoimmunity)
* symptoms: muscle weakness and flaccid muscles
* treatment: inhibition of Ach esterase to have Ach last longer in synapse and triggers more AP generation

parkinson’s disease

* destruction of dopanergic neurons
* symptoms: tremors, stiffners, balance issues
* treatment: give L-dopa to conver to depamine to last longer in the synpase

sarcomere

* striated muscle fibers


* repeated 2 z-lines
* has myofibrils

myofibril

repeating sections of sarcomeres

titin

binds thick filaments plus provides elasticity for muscle tone

* allows no bends also

z-line

boundary of sarcomere that goes through the thin filaments

nebulin

helps keep the thin filaments in all equal lengths; a molecular ruler

m-line

holds the thick filament to grab onto the thin filament and pull it inward

I band

* considered the light band
* has thin filament and z-line within it

A band

* considered the dark filament
* has m line and the thick filament mainly and the midline

H-zone

A band has a sunny spot within the dark spot with the mid-line thick filament

ATP

what is needed to set myosin head

* z-lines move closer together and I-band gets smaller
* A-band remains the same size

what happens during contractions?

globular heads

what does thick filaments contain on the outside?

isozyme

enzymes that do the same thing in different tissue

motor unit

ratio of alpha motor to innervates extrafusal fibers

70%

what is the max energy percentage to use as a land mark?

* aerobic and take glucose to go through cellular respiration

what if we go below the max energy with sarcomeres in relation to oxygen?

anaerobic where we go through glycolysis to increase oxygen where then we go through anaerobic where pyruvate converts to lactate/lactic acid for NADH+

what happens if we go above the max energy with sarcomeres in relation to oxygen?

* phosphocreatine where it gives up a phosphate to make ATP to form creatine and then creatine kinase puts a phosphate to go back to how it started

what is used for short bursts of energy?

twitches

* Ach generated M-potential release calcium
* isometric
* isotonic
* period of contraction and relaxation of a muscle after a stimulation

isometric

same length

isotonic

same tension

* slow twitch muscle fibers
* contract at a lower intensity
* allows longer periods of endurance without fatigue
* oxygen flowing through body and into muscles
* production of more blood vessels to increase blood vessel size
* increases ATP and myoglobin production

what happens when we are aerobic?

* increases size and quantity of fast twitch fibers
* improves strength of muscle and increase muscle size
* short-lived activity without the use of oxygen
* produce lactic acid
* lactic acid buildup causes fatigue
* lactic acid is converted into ATP in heart and liver
* increases phosphate creatine production
* easily converted into ATP

what happens when we are anaerobic?

hypertrophy

increase and growth of muscle cells

in the latent period

in isometric graph, when is Ach entered/released from the terminus and binds to the nicotinic receptor?

there is an increase in muscle tension

in the isometric graph, when calcium leaves, what happens?

there is a decrease in muscle tension

in the isometric graph, when calcium goes in, what happens?

* same length, change in muscle tension
* holding an object up
* muscles generate enough force to prevent object from being dropped

what is isometric contraction?

* same amount of tension, change in length
* muscle max force of contractions exceed total muscle lead
* ex: bicep curls has the muscle contract and elongate

what is isotonic contraction?

* muscle shortens while generating force
* bringing bent arm closer to shoulder

what is concentric contraction?

* muscle elongates while under tension of opposing force
* lowering bent elbow to thigh

what is the eccentric contraction?

stimulating muscle contraction before precious muscle twitch releases which then sums up the amount of muscle tension

what is the summation of twitch?

* sustained muscle contraction
* max tension, no relaxation

what happens in tetany?

* increase in protons and phosphorus

* what happens in short duration of fatigue?

decrease in glycogen

what happens in long duration of fatigue?

* stretches too far so no overlap

in optimal length, what if we stretch til 175%?

* so contracted, can’t go anywhere

in optimal length, what if we contract til 60%?

* can innervate 100% of extrafusal fibers
* alpha motor neuron, but innervate extrafusal fibers as were talking about moving
* dozens at a time to control

what is the motor unit?

* slow oxidative
* fast oxidative
* fast glycolytic

types of fiber

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* aerobic in relation to kreb’s cycle
* has ATP slopes
* has an increase in myoglobin so an increase in affinity
* velocity
* small diameter membrane
* 1st to recruit
* last to fatigue

what is slow oxidative?

* higher affinity
* hold onto oxygen better
* dark meat is oxidative fibers

what does an increase in myoglobin mean?

* krebs cycle
* aerobic
* velocity at which muscle moving
* intermediate diameter
* increase in myoglobin so high affinity
* second to recruit
* seconds to fatigue

what is fast oxidative?

* glycolysis
* anaerobic
* power filter
* decrease in myoglobin
* large diameter
* third to recruit
* first to fatigue

what is fast glycolytic?

* skeletal calcium from ER
* striated like skeletal muscle
* T tubules that are large to hold 25 x more volume
* sarcoplasmic reticulum=intracellular

what is cardiac muscle?

* not striated
* ex: GI tract linings
* has thick and thin filaments
* no fusal with cells
* fusiform (round center shape with tapered ends)

what is smooth muscle?

caveoli

what is the invagination for muscle signaling?

* extracellular source of calcium
* voltage-sensitive channels are outside the cells
* binds to calmodulin inside cell

what happens when calcium goes through the caveoli?

mediates calcium regulation

what is calmodulin?

* when myosin head is phosphorylated so that the contraction is sustained aka tonic contraction
* ex: cervix during pregnancy is latched/contracted

what is the latch mechanism?

pacemaker cells where they leak in sodium until the threshold is released

what are cajal cells

one innervated cell will power all connected cells to allow contraction

what is unitary?

muscle contraction

myosin kinase

muscle relaxation

myosin phosphotase

branches and are intercalated discs( there is a gap junction)

what are the muscles for the cardiac like?

spiraled where we can milk the blood rather than squeezing

how is our muscle like?

very tip of the heart to help pump blood from the ventricles to the rest of the body

what is the apex of the heart

right side

which side of the heart receives blood from the rest of the body?

left side

which side of the heart receives blood from the lungs?

holds valves in place and is an electric barrier

what does connective tissue do in the heart?

connect the right and left atrium

what do interatrial bands do?

tricuspid valve

valve between the right atrium and ventricle?

pulmonary semilunar valv

valve between the right ventricle and pulmonary artery?

bicuspid valve

valve between the left atrium and ventricle

aortic semilunar valve

valve between left ventricle and aorta

1. endocardium
2. myocardium
3. pericardial cavity
4. pericardium


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layers of the hear from inside to out