Ch 10 Muscle Tissue and Organization

Since precise control is essential in the muscle that move the eye, motor neurons innervating eye muscle may control only ____ muscle fibers

2 to 3

Definine skeletal muscle tissue

4 types of tissue types attach to one to more bones

what are 6 anatomical changes that occur during a contraction to the sarcomere

A band width remains constant H zone disappears Z discs move closer together Sarcomere narrows in length I bands narrow Length of the thick and thin filaments never changes

The dark bands of skeletal muscle are called ____ bands and while the light bands of skeletal muscles are called ____

A bands are the dark bands of skeletal muscle and I bands are the light bands of skeletal muscle

The abbreviation for acetylcholine

ACh

Energy to drive the myosin movement in the sliding filament process is provided in the form of ____.

ATP

Contraction of a muscle fiber requires that the myosin heads in the thick filament bind to active sites on ___ molecules within the thin filaments

Actin

Skeletal muscle actions are grouped according to their primary actions in three types of ______

Agionists Antagonists Synergists

The triceps brachial in the posterior arm is an ___ that causes forearm extension

Agonist

Sacromere

Basic contracting unit of muscle cell consits of actin and myosin filaments between z-lines in a muscle cell

myosin heads

Bind to specific sites on actin molecules to form cross bridges

The cyclic event of " attach, pivot, detach and return continue as long as ___ ions remain bound to troponin

Calcium

the sarcoplasmic reticulum stores ___ needed to initiate muscle contraction

Calcium ions

excitability

Calcium signal

The enzyme acetylcholinesterase resides in the synaptic ___

Cleft

Skeletal muscles have the following

Contain striations Vary greatly in size and shape May be composed of thousands of fibers

After exposure of the active sites on actin, myosin heads attach to the actin and form?

Cross bridges

A-band

Dark band in the middle of the sarcomere composed entirely of thick filament and at the lateral ends overlapping thin filaments

The epimysium of a muscle is composed of ____ connective tissues

Dense irregular

Connective tissue components of skeletal muscle tissue from deepest to most superficial

Endomysium Perimysium Epimysium

Order the connective tissue components of skeletal muscle tissue from deepest to most superficial

Endomysium Perimysium Epimysium

Connective tissue components

Endomysium: Covers myosin fibrils Perimysium: Covers fascicles Epimysium covers skeletal muscle Deep fascia

elasticity

Go back to original form

In concentric isotonic contraction, the tension produce is ____ than the resistance

Greater

The Z disc is a thin transverse protein structure in the center of the ___ band that serves as an attachment site for ___ filament ends

I Band and Thin filaments Dark proteins called connections in the center of the I band where thin filaments attach NOTE: Z disc shorten and narrow when the muscle contracts

Pushing on a wall is an example of ____ contraction where the muscle fibers ___ change length

Isometric Do not

The two types of muscle contractions

Isometric: when muscles contract but does not change length Isotonic: when a muscle contract and does change length

Most muscles have ___ motor units, which means that several ____ neurons are needed to innervate (supply) an entire muscle

Many Motor

Upon release from the synaptic knob, acetylcholine attaches to receptors on the

Motor end plate

A motor unit is composed of a single ____ and all of the muscle fibers it controls

Motor neuron

Neurons that stimulate muscle contractions are called

Motor neurons

What tissues types are present in each skeletal muscle

Muscle Connective Epithelial Nervous

Match each muscle unit with the connective tissue layer that surrounds it

Muscle = epimysium Fascicle = perimysium Muscle cell = endomysium

Muscle components

Muscle are multiple bundles housing many muscle fibers. Fascicle are a bundle of muscle fibers. Muscle fiber are elongated, multinucleate and cylindrical cells. Myofibril are long cylindrical contractile element within muscle cell Myofilament are short contractile proteins of two types thick and thin

although muscle fibers obey the all-or-none principle, the force of muscle contraction can be varied depending on how many ______ units are used

Muscle fibers Activated

Contractility

Muscle shortens

Muscle cells with its description

Myofibrils are cylindrical bundles of myofilaments that are as long as the muscle fibers. Thick filament are composed of myosin Thin filament are composed of actin, troponin and tropomyosin Actin are double stranded contractile protein Tropomyosin are double stranded regulatory protein

Muscle cell components with its functions

Myofibrils are thick and thin filaments. Sacrolemma regulates entry and exit of materials. Sarcoplasm are sites of metabolic processes for normal muscle fiber activities. Sarcoplasmic reticulum stores calcium ions needed for muscle contraction. T-tubule transport muscle impulses from the sarcolemma throughout the entire muscle fiber.

Muscle fiber components with its function

Myofibrils contain myofilaments that are responsible for muscle contraction Thick filament bind to thin filaments and cause contraction Thin filament bind to thick filaments and cause contraction Actin are binding sites for myosin to shorten a sarcomere Tropomyosin covers the active sites on actin when muscle cells is at rest

There are many successive groupings of ___ that run the entire length of a myofibril

Myofilaments

The sarcoplasm of skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures termed

Myofilbrils

After the __ heads bind to thin filaments ___ sliding begins

Myosin and myofilament

the point where a motor neuron meets a skeletal muscle fiber

Neuromuscular Junctions

The perimysium of a muscle contains extensive arrays of blood vessels and nerves that supply muscle fascicles. These arrays are called

Neuromuscular bundles

muscle fiber cell terminology

Plasma membrane are sarcolemma Cytoplasm are sarcoplasm Smooth ER are sarcoplasmic reticulum

The motor end plate is specialized region of the

Sarcolemma

The plasma membrane of a skeletal muscle fiber is called the

Sarcolemma

The functional contractile unit of a skeletal muscle fiber is known as a

Sarcomere

myofilaments within myofibrils are arranged in repeating microscopic cylindrical units called

Sarcomeres

At the end of muscle contraction, calcium ions are moved back into the ____ reticulum by ATP driven ion pumps

Sarcoplasmic

An internal membrane complex that is similar to the smooth endoplasmic reticulum of other cells is called the

Sarcoplasmic Reticulum

at the end of contraction when the stimulation from the nerve impulse ceases, calcium ions are pumped back into the

Sarcoplasmic Reticulum

Once started a muscle impulse will travel a long the sarcolemma and into the muscle fiber VIA the

T-tubules

The lever system, how muscle and bone work together to create movement

Tendon: Flat aponeurosis with a cordlike appearance that is attached to the Skelton Origin: non moving muscle attachment Insertion: Moving muscle attachment Lever: Elongated rigi object that rotates around a fixed point called fulcrum

Parts of the sarcoplasmic reticulum that appear as blind sacs perpendicular to the fiber's length are called ________

Terminal Cisternae

T-tubules are located adjacent to __ which are reservoirs storing the calcium ions required for muscle contraction

Terminal cisternae

Anabolic steroids are synthetic substance that mimic the actions of natural

Testosterone

The endomysium contains___ fibers to help bind together neighboring muscle fibers

The endomysium contains reticular fibers

What would be the effects of a drug that blocks the activity of AChE

The muscles cell would be continually stimulated. ACh would remain in the synaptic cleft longer than normal.

H zone

The region at the center of an A band of a sarcomere that is made up of myosin only. The H zone gets shorter (and may disappear) during muscle contraction.

The striated appearance in skeletal muscle cells is due to size and density differences between

Thick and thin filaments

s cross bridges from the myosin heads pivot toward the center of the sarcomere. This action pulls the ___ filaments toward the sarcomere center causing the ___ to move closer together as the sarcomere shortens

Thin and Z discs

The deep invaginations of the sarcolemma that extend into the sarcoplasm of skeletal muscle fibers as a network of narrow membranous tubules are called

Transverse Tubules

the deep invaginations of the sarcolemma that extend into the sacroplasm of skeletal muscle fibers as a network of narrow membranous tubules are called

Transverse tubules

As the troponin changes shape due to binding calcium, it moves the ___ molecule to which it is attached, thus exposing the active sites on the G-actin molecules.

Tropomyosin

troponin attaches to

Tropomyosin

After release from the terminal cisternae, calcium ions bind to ____ causing tropomyosin to move and expose active sites on actin

Troponin

A single myofibril runs the length of the muscle fiber.... True or False

True

True or False : a single myofibril runs the length of the muscle fiber

True

Each rosin protein molecule in a thick filament consists of

Two strands

what is the relationship between motor units and fine control

With more motor units attached to the muscle fiber we have more fine control

motor unit

a motor neuron and its associated muscle fibers

thin filaments

actin, troponin, tropomyosin

A tendon that forms a thin, flattened sheet is called

aponeurosis

Titin

are strands of protein reach from tips of thick filaments to the Z line stabilize the filaments

synergist muscle

assist the agonist, biceps brachili

thick filaments

composed of myosin

Transverse tubules (T-tubules)

deep invaginations of the sarcolemma that extend into the sarcoplasm

terminal cisternae

dilated end-sacs of SR which cross the muscle fiber from one side to the other

Myofilaments

filaments of myofibrils, constructed from proteins, myosin or actin

slow fibers are found

in the trunk and lower limbs

The superior and inferior attachment of a muscle

is a term used for muscles moving the axial skeleton

what is the relationship between motor units and force

less motor units less force

intermediate fibers are found

lower limbs

antagonistic muscles

opposing sets of muscles that are required to move a leg or arm back and forth

neuromuscular junction

point of contact between a motor neuron and a skeletal muscle cell

Agonist

produces a specific movement when it contract, brachilalis flexion of the elbow joint

Z disc

provides anchorage for thin filaments and elastic filaments

Troponin

regulatory protein that binds to actin, tropomyosin, and calcium

Each ___ shortens as the muscle fiber contracts.

sarcomere

The ___ Filament theory explains how muscle fibers shorten during contraction

sliding

Skeletal muscles are classified as voluntary muscles because they are controlled by the

somatic nervous system and we can voluntarily move our skeletal muscles

The location and nature of the muscular connection to the skeleton influences the ___ and ___ and ___ of movement

speed range force

M line

supporting proteins that hold the thick filaments together in the H zone

Extensibility

the ability to be stretched or extended

The epimysium of a muscle surrounds

the entire skeletal muscle

in a muscle the perimysium surrounds

the fascicles of muscle cells

I band

thin filaments only, light band, connection proteins

Myofibril

tightly packed filament bundles found within skeletal muscle fibers

Fast fibers are found

upper limbs