A&P Chapter 10: Muscle Tissue

Place the stages of cross bridge cycling in order

1. calcium binds troponin; myosin binding site uncovered 2. cross-bridge formation 3. power stroke 4. release of myosin head by ATP 5. reset of myosin head

The sodium-potassium exchange pump moves _____ sodium ions out of the cell for every _____ potassium ions it brings in

3:2

According to the sliding filament theory, the length of the ____ band remains constant, but the _____ zone disappears

A/H

Energy to dive the myosin movement in the sliding filament process is provided in the form of _____

ATP

After being generated, the muscle impulse continues to spread throughout the muscle fiber as long as ____ keeps the motor end plate receptors open

Acetylcholine

The arrival of a nerve impulse at the synaptic knob of a motor neuron causes synaptic vesicles to release ______ into the synaptic cleft

Acetylcholine

To stop motor end plate stimulation, usually acetylcholine is quickly broken down and removed from the receptor by _____

Acetylcholinesterase

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

Actin

Which of the following proteins are found in a thin filament?

Actin

For longer contractions, muscle cells obtain ATP by which process?

Aerobic respiration

A tendon that forms a thin, flattened sheet is called a/an _____

Aponeurosis

The cyclic events of "attach, pivot, detach, return" continues as long as ____ ions remain bound to troponin

Calcium

The sarcoplasmic reticulum stores _____ ions needed to initiate muscle contraction

Calcium

When an actin potential travels down the t-tubules to the terminal cistern of the SR, what ion is released into the sarcoplasm?

Calcium

The wall of the heart is compose of _____ muscle

Cardiac

The sarcolemma of smooth muscle cells has a small invaginations called _____

Caveolae

The long tails of the myosin molecules in the thick filaments points toward the _____ of the filament

Center

The ACh receptors on the motor end plate are _____ ion channels

Chemically-gated

The enzyme acetylcholinesterase resides in the synaptic

Cleft

When smooth muscle is stretch, it responds by _____

Contracting then relaxing

After exposure of the active sites on acting myosin heads attach to the actin and form ____

Cross bridges

In smooth muscle cells, thin filaments are attached to ____

Dense bodies

Myosin head attachment and pivoting do not require energy, but ATP is needed for the myosin head cross bridge to _____ from actin and re-cock

Detach

Acetylcholine moves across the synaptic cleft by _____

Diffusion

A sarcomere is defined as the distance for on Z _____ to the next

Disc

Muscle tissue demonstrates the property of ____ when it is done contracting and returns to its resting length

Elasticity

In a thin filament, individual G-actin molecules are strung together to form ____

F-actin

The majority of skeletal muscle fibers in the body are _____ fibers

Fast glycolytic

Which of the three skeletal muscle fiber types has the largest diameter and provides both power and speed?

Fast glycolytic

In a concentric isotonic contraction, the tension produced is _____ than the resistance

Greater

In a relaxed muscle fiber there are no thin filaments overlapping the thick filaments in the ____ zone

H

In a sarcomere, the _____ zone (or band) is the light, central region of the A band

H

If a muscle cell is stimulated to contract, allowed to partially relax, then stimulated again, its force of contraction the second time will be _____

Higher

When viewed under a light microscope, the light bands, called _____ contain only _____ filaments

I; thin

The calcium needed to activate smooth muscle contraction originates in the _____ around the cell

Interstitial fluid

Smooth muscle contraction is under ______ control

Involuntary

If you strain to push on a wall that does not move, you muscles are in what type of contraction

Isometric

The two types of muscle contractions are: a.) _____ contraction (when muscle contractions but does not change length) b.) _____ contraction (when muscle contract and does change length)

Isometric; isotonic

Smooth muscle cells have a _____ mechanism that allows them to contract with more power and use less ATP than a skeletal muscle cell

Latch bridge

The _____ mechanism allows muscle to maintain muscle contraction without the use of additional ATP

Latch bridge

In order to predict how much tension a muscle can produce when contracting, it is important to consider the ______ relationship of thick and thin filaments

Length-tension

The _____ line is a thin, transverse, protein meshwork structure in the center of the H zone of a sarcomere

M

Skeletal muscle contraction is controlled by _____ neurons

Motor

Upon release from the synaptic knob, acetylcholine attached to receptors on the _____

Motor end plate

During development, many groups of _____ fuse to form single skeletal muscle fibers

Myoblasts

The sarcoplasm of skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures called _____ that extended the length of the cell

Myofibrils

Termination of the nerve impulse at the NMJ results in the passive sliding of _____ back to their original state

Myofilaments

Thick myofilaments are composed of bundles of what protein?

Myosin

An internal membrane complex in skeletal muscle cells that is similar to the smooth. endoplasmic reticulum of other cells is called the sarcoplasmic _____

Reticulum

Within a myofibril, each _____ shortens as the muscle fiber contracts

Sarcomere

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

Sarcoplasmic reticulum

During development of skeletal muscle cells, some myoblastes do not fuse and instead become _____ cells

Satellite

The length-tension relationship of _____ muscle cells is limited by the Z-discs which are lacking in _____ muscle cells

Skeletal; smooth

Smooth muscle contraction is _____, resistant to _____, and usually sustained for an extended period of time

Slow; fatigue

Although smooth muscle cells have both thick and thin filaments, they're not precisely aligned, so no visible ____ are present

Striations

A "step-wise" increase in the force of contraction of a single muscle fiber motor unit due to repeated stimulation is called _____

Summation

A narrow space separating the synaptic knob and the motor end plate

Synaptic cleft

A nerve impulse travels through a axon to its _____

Synaptic knob

The motor end plate has folds indentations to increase the membrane surface area adjacent to the _____

Synaptic knob

_____ distribute the muscle impulse throughout the inside of the muscle fiber

T-tubules

An action potential travels down the sarcolemma, throughout the t-tubules, to the _____

Terminal cisternae

As a result of ACh stimulation, calcium ions are released from the _____ of the sarcoplasmic reticulum

Terminal cisternae

When calcium ions bind to troponin, which of the following then occurs?

The myosin binding sites on actin are exposed

The striated appearance in skeletal muscle cells is due to size and density difference between _____ and _____ filaments

Thick; thin

In a sarcomere, Z discs serve as anchors for _____

Thin filaments

Single unit muscle cells contract ____

Together

Spread of muscle impulses along the sarcolemma, then down the _____, causes calcium ions to leak out of the SR into the sarcoplasm of the muscle fiber

Transverse tubules

The two regulatory proteins associated with thin myofilaments are:

Tropomyosin and troponin

Calcium ions bind to what protein in a thin myofilament?

Troponin

Upon release from the terminal cisternae, some ions bind to _____ causing it to change shape

Troponin

Smooth muscle cells retains its mitotic ability

True

T/F: In the absence of calcium, troponin attaches to tropomyosin to hold it in place on the surface of the F actin strand

True

A single contraction and relaxation of a muscle fiber is referred to as a muscle

Twitch

Each myosin protein molecule in a thick filament consists of _____ strands

Two

Thick filaments are about _____ the diameter of thin filaments

Two times

Autonomic motor neurons that control smooth muscle contraction have bulbous swellings called _____ that contain synaptic vesicles

Varicosities

In which activities are muscles in an isometric contraction?

-Sitting up very straight -Holding a yoga pose -Pushing on a locked door

The skeletal muscles arrange in layers along the walls of the abdominal cavity and the floor of the pelvic cavity perform what function?

-Support -Protection -Contraction

A neuromuscular junction contains a(n) _____

-Synaptic knob -Motor end plate -Synaptic cleft

Which of the following proteins are found within a sarcomere?

-Actin -Connectin

Which are characteristics of oxidative fibers?

-Good for endurance -Use of aerobic respiration -Red -High concentration of myoglobin

Smooth muscle is found in which of the following locations

-In the wall of the uterus -Around blood vessels -In the wall of the small intestine

Smooth muscle shows a different length-tension relationship than skeletal muscle because _____

-It lacks Z discs but has dense bodies -The arrangement of the thick and thin filaments allows for contraction even when stretched

Which are characteristics of glycolytic fibers?

-Low concentration of myoglobin -White