HBOD Exam 3 Chapter 4

epimysium, perimysim, endomysium

the three CT layers in order outside of a skeletal muscle cell

endomysium is made of CT, sarcolemma is a phospholipid bilayer

what is the difference between the endomysium and the sarcolemma

locomotion, thermoregulation, blood sugar regulation, posture, breathing

what are the functions of sk muscle cells

false

true or false: skeletal muscles cells are capable of mitosis

tendon

what connects skeletal muscle to bone

epimysium

this CT layer surrounds a collection of fassicles

perimysium

this CT layer surrounds a single fassicle

a collection of endomysiums surrounding one skeletal muscle cell

what is inside of a fassicle

one single muscle cell with multiple myofibrils, its surrounding sarcolemma and ECF (+ basale lamina, CT fibers)

what is within one endomysium

autonomous gliding

what does the surrounding of only one skeletal muscle cell via endomysium permit

ap traveling down a somatic motor neuron

what is always responsible for skeletal muscle contraction

motor unit

all of the muscle fibers innervated by one neuron

organelle

myofibrils are a type of ___ (cell, tissue, organelle?)

fusion of myoblasts

how did the body originally grow myofibrils

adding sarcomeres to circumference of myofibrils

what actually happens when you grow muscle

one

how many axon terminals can one skeletal muscle cell have

glucagon

what storage form of glucose is stored within endomysium (skeletal muscle cell)

basal lamina

this spans between the endomysium and the sarcolemma, connects the two

CT, collagen

what type of tissue is basal lamina, what is it made of

phospholipid bilayer, extension of sarcolemma

what is the membrane of a t-tubule made of, what is it continuous with

ECF

what is found within a T-tubule

between two T-tubules covering a myofibril

where is the sarcoplasmic reticulum found

over z-lines

where are T-tubules found

between z-lines within a myocyte

where are sarcomeres found

ECF between endomysium

where are satellite cells found

reticular mitochondria

what is found all over the sarcoplasmic reticulum

all between myofibrils

where is mitochondria found within a skeletal muscle cell

IAH, I is actin only, A is length of myosin, H is only myosin

what are the three zones of a sarcomere and what is within each one

nicotinic acetylcholine recepter

what specific receptor on the motor end plate binds acetylcholine

nueromuscular junction

specialized area where a single axon terminal of a somatic motor neuron innervates a skeletal muscle cell’s motor end plate

one

how many neuromuscular junctions can a skeletal muscle cell have

kranocytes

these cells are an umbrella over endomysium that can help with repair of neuron

schwann cells

what myelinates a somatic motor neuron

motor end plate

the bumpy area on the sarcolemma that faces the axon terminal within the NMJ

wallerian regeneration

the slow addition of new axon and schwann cells, not a guarantee this process works

endomysium

what does a somatic motor neuron “poke through” to innervate a motor end plate

true

true or false: when one single neuron experiences an ap, all the muscle cells it innervates (motor unit) should contract in unison

1:100, lots of power

what roughly defines a large motor unit

1:3, fine control and weak

what roughly defines a small motor unit

ligand gated ion channels that lets Na+ flow in when Ach binds

what type of receptor is NAchR

EPSPs

what type of signal does the opening of NAchR essentially function as

the opening of VG Na+ channels on the sarcolemma triggered by EPSPs created by NAchR

what triggers an action potential to reach a myofibril from a neuromuscular junction

positively charged amino acids are repulsed by the sodium bolus created by the ap creating a channel; the bottom (ICF) amino acids closed after a set time trigger the top to close

what opens and closes a VG Na+ channel in the sarcolemma

L-type

what type of calcium channel is slow to open and slow to close

store calcium

what is the main purpose of the sarcoplasmic reticulum

excitation contraction coupling

the process where an ap is generated and spreads to seemingly simultaneous contractions of all sarcomeres within a cell

to create force in muscle cell as directed by nervous system

what is the purpose of excitation contraction coupling

two terminal cisternae and a T-tubule

what is a triad made of

DHPr, Ncx, RYR

what proteins are found within a triad

VG Ca2+ channels, allosteric change to open RYR and allow Ca+ efflux from SR to myofibrils

what is DHPr and what does it do

Na+/Ca+ exhanger; removes 1 Ca+ from the ICF back into SR via exchange of 3 Na+

sarcomere shortening

what causes muscle contraction on a cellular level

nebulin, troponin (I,T,C), and tropomyosin

what proteins interact with actin

myomesin

what is the M-line made of

titan

what connects myosin to the z-line and m-line

Z-line, M-line

actin cocks towards the ___ and power strokes toward the ___

troponin

what does calcium bind to to allow for muscle contraction

ATP binds releasing actin from myosin, ATP is hydrolyzed allowing myosin to orient towards next binding site, a cross-bridge is formed between myosin and actin, dissociation of Pi triggers power stroke, ADP then dissasociates

what are the steps of cross bridge cycling starting with myosin bound to actin after a power stroke

latent period, contraction period, relaxation periods

what are the periods of a single mscle twitch

ap generated, ap spreads causing a Ca+ spike

what happens during the latent period of a muscle twitch

removal of Ca from sarcoplasm back to SR via SERCA pump, minor amount of Ca goes back to ECF of T-tubules (Ncx)

what happens during the relaxation period of a muscle twitch

Ncx, DHPr

within a triad, what specialized proteins are found on the T-tubule

RYR, SERCA

what specialized proteins are found on the surface of the sarcoplasmic reticulum

hydrolyze ATP

fast twitch cells are able to ___ ___ fast

ATPase

myosin heads are a type of ___