Muscles Test

You have _____ skeletal muscles. They work by _______ bones in different directions.

640, pulling

Twitches

A twitch is the contractile response of a single muscle fiber to a muscle impulse. fast and slow twitch. Slow-twitch: fatigue- resistant, slow-twitch is used for distance because the slow-twitch fibers resist fatigue during prolonged exercise. Fast-twitch: fatigable, forceful exercise, when muscle exerts more than 75% of its maximum tension utilizes fast-twitch fibers. ex; sprinters

recruitment

An increase in the number of motor units being activated. AS the intensity of stimulation increases, recruitment of motor units continues until, finally, all possible motor units in that muscle are activated and the muscle contracts with maximal tension. You can train your recruitment to make it stronger.

Tendon

Connects muscle to bone, individual muscles are separated by fascia which forms tendons.

When your muscle cells are at rest, your actin and myosin cells ______ touch.

DONT

Myofilament

Filament that constitutes myofibrils. Of two types: actin and myosin.

Myofibril

Made out of any sarcomeres in a row. These are the long protein fibers that make up each muscle cell.

Hierachy

Muscles, Fascicles (bundles), Myofibrils, Myofilaments (actin and myosin)

sliding filament theory

Step 1: A muscle contractions starts in the brain, where signals are sent along the motor neuron. Within the motor neuron are vesicles that contain the neurotransmitter, acetylcholine. Acetylcholine reaches the receptors on the muscle sarcolemma which causes an impulse. Step 2: The impulse travels down the membrane and into the transverse tubules where it causes calcium to be released from the sarcoplasmic reticulum. Step 3: Calcium binds to a structure on the actin that causes it to change shape Step 4: The change in shape allows myosin heads to form cross-bridges between the actin and the myosin Step 5: Energy from the ATP is used to create a "power stroke" between the two filaments. The actin filament then slides inward and shortens, or contracts, the whole muscle.

______ muscles help the prime movers by lending a little extra oomph or by stabilizing joints against dislocation

Synergists

threshold stimulus

a minimum amount of stimulation to cause a contraction or a stimulation level that must be exceeded to elicit a nerve impulse or a muscle contraction. When an isolated muscle fiber is exposed to a series of stimuli of increasing strength, the fiber remains unresponsive until a certain strength of the stimulus.

The myofibrils that form your muscle fibers are divided into sections called sarcomeres that contain two different types of proteins (myofilaments) call _______ and __________.

actin, myosin

The muscles that are mainly responsible for a certain movement are that movement's ________ muscles. Muscles that work in reverse of a particular movement are _____ muscles.

agonist (prime movers), antagonist

Fascicle

bundle of muscle fibers

When stuff binds to proteins, the proteins change shape. When the action potential reaches the sarcomere, it releases __________ calcium which binds to the "body guards", allowing the myosin to bond to _______ and stretch out to connect with the actin. With its energy spent, the myosin releases the _______ and detaches from the actin, only to bind to another ATP and repeat the process. This process is called the sliding filament of muscle contraction.

calcium, ATP, ADP

The amazing thing about your muscle tissues is that they turn chemical potential energy into mechanical energy simply by _______________ and ________________.

contracting, relaxing.

Sarcoplasma

cytoplasm of a muscle cell

Whatever one muscle ____, another muscle can _____

does, undo

Layers of connective tissue

epimysium, perimysium, endomysium

Your brain gets your muscles to increase their force by increasing the __________ with which your motor neurons are firing. The faster they fire, the _______ each twitch gets.

frequency, stronger

When a muscle contracts, the bone that moves is called the muscle's ____ point and the bone that doesn't really move is the muscle's _____ point. While doing pushups, Claire's muscles are _____ their insertions toward their origins.

insertion, origin, pulling

________ movements change the length of the muscles involved. __________ do not change the length of the muscles involved.

isotonic, isometric

When a motor unit responds to a single action potential, it's called a twitch. Every twitch has three phases. The _______ period is when the stimulus has arrived but no fore is being produced. There is a brief period of _______ when the actin and myosin are continuously binding and unbinding and the muscle fibers contract. During the _______ period the calcium gets pumped back into the sarcoplasmic reticulum, the binding cycle stops, and the muscle relaxes.

latent, contraction, relaxation

A _______ is a group of muscle fibers that all get their signals from the same, single motor neuron. Since they all listen to one neuron they all act ________ in a single unit. In a big power generating muscle, like your rectus femoris in your quad, each of the thousand motor neurons may innervate a thousand muscle fibers. Those thousand fibers together form a _______ motor unit.

motor unit, together, large

Sarcolemma

muscle cell membrane

Your muscles are energy hogs. Each one is rigged up with its own personal _____ to stimulate contraction and its own ______ and vein to keep it well fed.

nerve, artery

Epimysium

outermost layer, surrounds entire muscle

Muscles never ______, they always ____.

push, pull

Contractions intensify as your motor neurons stimulate more and more muscle fibers in a process called _______ or multiple motor unit summation. It follows something called the _______________.

recruitment, size principle

Perimysium

seperated and surrounds the fascicles (bundles)

There are two rules when it comes to muscles and they have to with proteins: 1. Protein like to change _______ when stuff binds to them 2. Changing shapes can allow proteins to ____________________ with other stuff.

shape, bind or unbind

endomysium

surrounds each individual muscle fiber

When all the little twitches blend together and feel like one gigantic contraction you get _______.

tetanus

Myosin

thick filament

Actin

thin filaments

A skeletal muscle is constructed like a sturdy piece of _______.

wood