Flashcards MSState ExPhys Ch.1 Muscles

involuntary; found in hollow organs

smooth

this muscle lines the intestines, uterus, and trachea

smooth

involuntary and self-regulated; striated and interconnected

cardiac

this type of muscle is influenced by the nervous and endocrine system

cardiac

voluntary, striated, and multinucleated; involved in movement

skeletal

this type of muscle makes up over 600 muscles in the body and 40-50% of body weight

skeletal

attach muscle to bone

tendons

outer layer, surrounds entire muscle

epimysium

bundle of muscle fibers

fasciculus

middle, surrounds fasciculus; conduit for blood vessels and nerves

perimysium

inner layer, surrounds each muscle fiber

endomysium

below endomysium; thin layer of protective tissue

basal lamina (basement membrane)

muscle cell membrane

sarcolemma

muscle cytoplasm

sarcoplasm

between sarcolemma and basal lamina; stem cells; role in growth and repair

satellite cells

rod-like structures run lengths of fibers; contain contractile proteins

myofibrils

line up end to end along myofibril; basic functional unit of fiber

sarcomere

invaginations (folds) of sarcolemma running deep into fiber; transmit EPP (end-plate potential) deep

transverse tubules (t-tubules)

network of membranous channels surrounding myofibril; storage site for calcium

sarcoplasm reticulum (SR)

enlarged portions of SR abutting (right next to or touching) t-tubules

terminal cisternae

3 layers of connective tissue

epimysium, perimysium, endomysium

one function of the 3 CT layers is to transfer force from ________ to _______

muscle; bone

The 3 layers of the muscle fuse to form _________

tendons

2 more functions of the 3 CT layers is

protection and elasticity

the ____________ layer of CT is a conduit for nerves and blood vessels

perimysium

the ____________ layer of CT electrically isolates individual fibers, which controls who contracts and who doesn't

endomysium

where a muscle and nerve meet

neuromuscular junction

type of neuron that innervates skeletal muscle fibers (always releases acetylcholine)

alpha motor neuron

alpha motor neuron and all the fibers it innervates

motor unit

when a motor unit sends an outgoing action potential all its fibers will contract

all-or-none principle

area of sarcolemma involved in NMJ, invaginated

motor end plate

the _____ of the motor end plate increases surface area

folds

chemically-induced change of the electrical potential of the motor end plate

EPP

the max contraction of a sarcomere is the length of the ________

a-band

2 filaments that make up the sarcomere

actin and myosin

which filament doesn't change length during contraction

myosin

the _________ is the area of only myosin

h-zone

the ________ is the area of only actin

I-band

the ________ is wherever myosin is (it doesn't matter if actin is there or not)

A-band

what are the outside borders of the sarcomere called?

z-line

actin is attached to what part of the sarcomere

z-line

myosin is attached to what part of the sarcomere

m-line

is the a-band light or dark?

dark

is the h-zone light or dark?

light

when we contract, our ___________ slide over one another

filaments

How many actin filaments are associated with one myosin filament

6

from a cross-sectional view, what type of structure are actin and myosin arranged in

hexagonal

what is the ratio between actin and myosin

2:1

every actin is associated with how many myosin?

3

How many degrees are between every actin?

60

What are the 3 parts of a myosin molecule

globular head, hinged pivot point, fibrous tail

consists of 2 myosin molecules, with 2 heads; interacts with actin

crossbridge

develops force to pull actin over myosin

crossbridge

stabilizes myosin longitudinally and adds elasticity

titin

one of the largest proteins ever discovered

titin

what 3 proteins make up actin filaments

actin, troponin, tropomyosin

stabilizes actin longitudinally

nebulin

what does g in g actin stand for?

globular

what does the f in f actin stand for?

filamentous

on every g actin, there's an actin active site for ______ to attach

myosin

regulatory protein

troponin

lays on actin and tropomyosin at every 7th g-actin

troponin

what is TNT

troponin tropomyosin

what is TnI

troponin inhibition

what is TnC

troponin calcium

binds to calcium and starts contraction

TnC

single-stranded polymer; at rest covers actin active sites and keeps myosin from binding

tropomyosin

triggered by voltage

ryanodine receptors

interact with ryanodine receptors and triggers calcium channels to open on SR

DHP (dihydropyridine) receptors

helps cause the SR to release calcium

t-tubules

another term for tropomyosin shift

steric blocking model

____ binding to ______ triggers troponin to tug tropomyosin and uncover actin active sites

Ca; TnC

causes tropomyosin to slide over to reveal actin active sites and begin contraction

troponin

what does ECC stand for

excitation contraction coupling

Excitation Contraction Coupling is everything before ____________

contraction

causes axon terminal of alpha-motor neuron to release ACh (acetylcholine)

action potential

binds receptors on motor end plate, sending end-plate potential down sarcolemma and t-tubules

acetylcholine

carries end-plate potential (EPP) deep into the fiber

t-tubules

what does DHP stand for

dihydropyridine

activates DHP receptors

EPP

What does Ca bind with to cause the tropomyosin shift?

TnC

What happens during ECC?

active active sites are exposed

theory; basic steps by which myosin and actin interact to cause muscle contraction

Huxley's Sliding Filament Theory of Crossbridge Cycling

Step 1: ATP binds to ______ head while in more favored (____ _______) position

myosin; low energy

what is the favored position of the myosin head?

low energy

Step 2: ATP _______; myosin head is "loaded" into less favored (_____ _______) position

hydrolysis; high energy

the enzyme that hydrolyzes ATP

ATPase

Step 3: _____ occurs turning ATP to ADP; actin and myosin bind with a ______ (noncovalent) bond

ECC; weak

Step 4: the inorganic ___________ (Pi) leaves, making bond _______ (covalent)

phosphate; strong

Step 5: "___________;" actin is pulled along with myosin; ADP is released

powerstroke

Step 6: _____ binds

ATP

Step 7: binding of ATP triggers actin-myosin ______________; breaks crossbridge

dissociation; crossbridge

As long as ____ is present, actin active sites remain open and process repeats

Ca

keeps tropomyosin away

Ca

requires energy to get calcium back into the SR

muscle relaxation

_______ of crossbridge cycles in 1 muscle contraction

billions

___________ ________ is asynchronis

crossbridge cycling

What is Type I

slow twitch (ST)

another term for slow twitch

slow oxidative (SO)

another term for oxidative

aerobic