Fun Phys Final Exam

tendons

Skeletal muscle attaches to bone via

endomysium

a muscle fiber is covered in a CT layer called the

fascicle

a group of muscle fibers is called a...

perimysium

a fascicle is covered by a CT layer called the

epimysium

a group of fascicles is covered by a CT layer called the

enthesis

what is the name for the connection of muscle to bone

water, protein, salts/enzymes

what is the chemical composition of muscle

they have increased amounts of capillaries

how does trained muscle have different blood supply than untrained

sarcolemma

what is the term for the membrane that surrounds each muscle fiber and encloses the contents (muscle cell membrane)

sarcoplasm

the cytoplasm of a muscle cell that contains nuclei, genes, mitochondria, and specialized organelles

sarcoplasmic reticulum

this structure provides structural integrity to muscle fibers by wrapping around them

myofibril

highly organized bundles of contractile and elastic proteins that cause contraction

muscle fiber

many myofibrils make up a...

myosin and actin

tropomyosin and troponin

titin and nebulin

what are the components of a myofibril

contractile protiens

myosin and actin are...

regulatory proteins

tropomyosin and troponin are..

structural/accessory proteins

titin and nebulin are...

myosin is a thick filament, actin is the thin filament and found in higher amounts

what is the relationship between the size of myosin and actin

sarcomeres

many____________ are in a myofibril

T tubules

continuations of the sarcolemma are called...

terminal cisternae

enlarged regions at the end of the sarcoplasmic reticulum is called the...

to concentrate and store calcium

what is the purpose of the sarcoplasmic reticulum and terminal cisterna

1 t-tubule flanked by 2- terminal cisternae

what are the components of the triad

sarcoplasm

if t-tubules are extentions of the cell membrane, it has direct contact with the...

it brings action potentials to deeper muscle fibers

what is the purpose of the t-tubule

calcium

when APs run down a t-tubule, what is released

M line

the line that myosin attaches to

A-band

area of a sarcomere where myosin and actin overlap, the M line lies centrally

H zone

area of the sarcomere where there is only myosin, the M line is the center of this zone

it will shrink as actin covers myosin

what will happen to the H zone with muscle contraction

I band

area of the sarcomere that only actin presides in (2)

it will shrink

what will happen to the I band as the muscle contracts?

it will stay the same length (because the length of myosin doesn't change, the areas overlapping will increase)

what will happen to the A band with muscle contraction

z disc

border of a sarcomere where actin attaches to the actin of an adjacent sarcomere

z disc to z disc

a sarcomere extends from which structures?

6

how many actin filaments surround each myosin?

3

how many myosin surround each actin

myosin

of the contractile proteins, which is the one that can actually create movement

using ATP

how does myosin create movement

heavy and light

what are the two protein chains present in myosin

the motor domain that binds ATP and actin and uses the energy to create movement of the head

what is the role of the heavy chain

structural and regulatory roles

what is the role of light chains

ATP, actin

each myosin head has 2 bindings sites, one for ___________ and one for ____________

2

how many F actin polymers twist together to form the thin filaments of the myofibril

it is a calcium binding protein that controls the positioning of tropomyosin

what is the purpose of troponin

it wraps around actin, covering the myosin binding sites

what is the purpose of tropomyosin

titin is elastic, and nebulin is not

what is the difference in properties between titin and nebulin

from Z disc to M line, it returns stretched muscles to the original length

what two places does titin stretch from and what are its functions

it attaches to the z discs and aligns actin filaments longitudinally to assist in alignmentfdddd

what is the purpose of nebulin

no, the areas that overlap change

do the lengths of actin and myosin change with contraction

the filaments slide over each other

how does muscle shorten if the filaments dont change length

they stay the same, because in isometric contraction the muscle fiber length stays the same

what happens to the spacing of the I band and A band during isometric contraction, why?

AP going down an axon terminal releases ACh into a synapse which elicits an electrical signal in the muscle fiber (EPP)

what events happen at the neuro muscular junction that lead to a muscle contraction

calcium is released, creating calcium signals that activate contraction

what happens when the EPP occurs in the muscle

twitch

once contract-relax cycle is called a...

they bring action potentials deep into the muscle so the depolarization stimulates the release of caclium from the sarcoplasmic reticulum

what is the purpose of the t tubules in relationship to action potentials

to ensure that calcium diffuses to all troponin sites

what is the purpose for the extensive amounts of SR that release calcium

ryanodine receptor

what is the name of the receptor that is activated by the AP along the t tubule surface

it pulls tropomyosin off the binding site on actin and allows myosin and actin to bind

what happens when calcium binds to troponin

powerstroke

when myosin binds to actin what happens?

when it binds ATP

when does the myosin cross-bridge detach from actin

myosin returns to its original position so it can bind to a new active site

when ATP binds to myosin, what happens to its postion

in the light chains

where is the ATPase in myosin

to yield energy for contraction

what is the purpose of splitting ATP

joining of actin and myosin

what activates myosin ATPase to split ATP and generate energy

decreased concentrations of cytosolic calcium

what must happen in order for relaxation to occur

troponin is no longer bound so tropomyosin covers actin binding sites, filaments slide back to the original position with the help of titin

when calcium concentration decreases, what else happens

ceasing of the electrical signal and active pumping of ca2+ into the SR

how are cytosolic calcium concentrations decreased

it includes the time needed to release Ca2+ from the SR, move tropomyosin and form cross bridges

action potentials result in a slightly delayed muscle contraction, what is the reason for this extended period

1. to release the cross bridge

2. to pump calcium back into the SR

3. to power the sodium/potassium pump

in what areas is ATP needed to contract and relax muscles

creatine phosphate

aerobic glycolysis

oxidative phosphorylation

what are the 3 sources for ATP production during muscle contraction

on the sarcolemma

where are ACH receptors that causes an AP in the muscle

depolarization

terminal cisternae

_______________________ of the t-tubules results in caclium release from __________ _________ of the sarcoplasmic reticulum

myosin ATPase (split=energy)

when actin combines with myosin-ATP, what is activated

dissociated

in the presence of ATP, what is the state of actin and myosin

fatigue

a condition where a muscle is no longer able to generate or sustain power

central and peripheral fatigue

what are the types of fatigue

feeling tired and wanting to stop activity (psychological)

how would one describe central fatigue

physiological fatigue

what does central fatigue preeceed

decreased ACh release resulting in a failure of EPP

during peripheral fatigue, what occurs at the neuromuscular juntion

change in muscle membrane potential

during peripheral fatigue, what happens to excitation-contraction coupling

leak of calcium from the SR, decreased Ca2+ release, decreased toponin-ca2+ interaction

during peripheral fatigue, what happens to the calcium signal

PCR, ATP, glycogen are depleted

hydrogen, phosphate, lactate accumulates

during peripheral fatigue, what happens to the concentration of energy sources? what accumulates

a motor neuron and all the fibers it innervates

what makes up a motor unit

it is continuously remodeling

how is bone dynamic

Osteoblasts and osteocytes

osteoclasts

what are cellular components of bone

osteoid

what is the name of the matrix of collagen fibers, GAGs, and glycoproteins within bone

osteoblast

which bone cells lays down the mineralized matrix for bone

osteoblasts

what type of cell produces osteoid

osteocyte

once surrounded by osteoid, what does the osteoblast become

lacunae

what is the name for the pit that osteocytes live in

stress

what causes turn over for bones

osteoclast

what type of cell reabsorbs bone cells

hormone, stress, disease tumor

what types of things can stimulate an osteoclasts

inorganic material

what is the part of the bone matrix that makes bone heavy

cortical bone

this type of bone forms the outer shell and has a Haversian lamella

trabecular

this type of bone has a large mesh structure, spaces are filled with red marrow. there is a non-havesian lamella

osteon

what is the structural unit of cortical bone, haversian system

border, central canal, circular layers

what are the structures within an osteon

the central canal

where does the blood supply and nerves for a singular osteon come from