A&P Muscles, part 1, Muscles Cells

cadiac muscle tissue

-cells are divided and converge, one nucleus per cell, striated, with intercaled disks.

Sarcromere contraction (3 steps)

1. cross bridge formed (myosin heads bind to actin on active sites on G-actin) 2. power stroke (head moves) 3. Thin filament is pulled (when the power stroke happens) ATP and calcium ions are needed. calcium ions regulate sarcomere contraction

striated fine black lines running perpendicular to the fibers, cells are long, multinucleate parallel; it is voluntary muscle

640 skeletal muscles are

T-tubules

Also called transverse tubules, these are deep invaginations of the plasma membrane found in skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.

muscles system

Function: help in movement of: bones; contraction of heart and other organs.

muscle contraction

Interactions between actin and myosin filaments of the sarcomere are responsible for

fascicles

Muscle fibers form strong, larger, string-like bundles called _______which combine to form the larger rope-like muscle organs, like biceps brachii.

mechanical energy (movement), simply by simply by doing two things: contracting and relaxing

Muscle tissues turn chemical potential into _____

tubular infoldings of the sarcolemma which penetrate through the cell and emerge on the other side

T-tubules

sliding filament model of contraction

The theory explaining how muscle contracts, based on change within a sarcomere, the basic unit of muscle organization, stating that thin (actin) filaments slide across thick (myosin) filaments, shortening the sarcomere; the shortening of all sarcomeres in a myofibril shortens the entire myofibril

ligand-gated sodium channels

Which of the following best describes the RECEPTORS on the muscle cell membrane that bind to neurotransmitter?

graded potential

a membrane potential that varies in magnitude in proportion to the intensity of the stimulus

contracting

a muscle contracting is all about sarcromeres _____brining Z-lines closer together

tropomyosin and troponin

actin is blocked by protein bodyguards--called _____ and _____ which keep getting in the way from myosin, but these blockers can bought off with a little ATP and some calcium.

skeletal muscle

biceps brachii, vastus lateralis, gluteus maximus

1. Epiysium (covers upon muscle tissue) 2. perimysium (covers the fascicles) 3. endomysium (covers the muscle fiber)

every muscle contains a few different kinds of connective sheaths or a protective sheaths :

the SR studded with calcium channels that are linked to voltage-sensitive proteins in the membrane of the muscle cell. if you wanna move your arm, your brain sends an action potential along the motor neuron until it synapses with a muscle cell in your arm. The receptors on that muscle cell are ligand-gated sodium channels, so when the motor neuron releases acetylcholine into the synapse, the channels open up, and create a rush of sodium into the cell as a graded potential, which, if strong enough, causes nearby voltage-gated sodium channels to open.

how muscle contraction works?

sarcromeres

it is the repeating pattern of overlapping filaments in lots of ______ that gives skeletal and cardiac muscle tissue striated, or stripped, appearance

actin strands

made up of mostly two light and twisty strands

actin and myosin

muscle cells have coupling proteins called

sarcoplasmic reticulum

muscle cells have their own version of an endoplasmic reticulum--the cells transport and storage system; Organelle of the muscle fiber that stores calcium; specialized endoplasmic reticulum of muscle cells -in the muscles that store calcium -each pump is loaded with ATP to save up some calcium ions

Myofibrils

muscle fiber is up of tiny threads called

1. myofibrils or muscle cells 2.sarcoplasm 3.sarcoplasmic reticulum or SER 4. mutiple cells with mitochondria 5. cellular membrane called sarcolema

muscle fibers contain

artery and vein

muscles are voracious energy hogs each one is rigged up with its own personal nerve to stimulate contraction and its own ______and _____to get it well feed with blood, oxygen, and nutrients it needs to operate.

Sarcromere

myofibrils are divided in lengthwise into segment called _____which contain two tinier strand of proteins--two different kinds of myofilaments called actin and myosin

sarcolema

plasma membrane of a muscle cell

•Z-lines: define the boundaries of each sarcomere •M-line: located in the middle of the sarcomere •I-band: contains only thin filaments •H-zone: consists of only thick filaments •A-band: contains the thick filaments in their entirety

sarcomere structure

actin and myosin overlap

sliding filament model of contraction

stomach, airways, and blood vessels

smooth muscle tissue is found in the walls of all the hollow visceral organs, like: -short tapered cells, but no striations -involuntary, and usefully pushes fluid and other material arounf by contracting and relaxing over and over

3 types of muscle tissue

smooth, cardiac, and skeletal

calcium and ATP

the contraction of muscles need ____ and ____that causes the binding and unbinding that makes the sarcromeres contract and relax

cardiac muscle

the heart has its own muscle tissue which is ____.

myosin strands

thick filaments

myofibril

thousands of tiny, parallel threads called ______squish together to form muscle fiber, which are your actual muscle cells

don't

when muscle cells are at rest the actin and myosin _____touch

change

when stuff bind to proteins, the proteins shape _____. for instance in the troponin, calcuim binds to it so it ___ shape.

pulls

when the myosin binds to actin, releases its own stored energy. the myosin changes shape. it _____actin strand and contracts the muscle cell.