Ch. 10 Muscle Tissue

Place the following events in the correct order of occurrence once Ach diffuses across the synaptic cleft of a NMJ:

1. Ach binds to receptors on the motor end plate 2. The resulting action potential moves down the sacrolemma 3. the action potential moves down the t-tubles 4. the action potential reaches the terminal cristernae of the SR 5. Calcium ions are released into sacroplasm

Place the events at a neuromuscular junction in order:

1. arrival of nerve signal at synaptic knob 2. calcium entry into synaptic knob 3. exocytosis of Ach into synaptic cleft 4. Binding of Ach to motor end plate

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

Receptors in the motor end plate bind with the neurotransmitter _________ released from the synaptic knob

ACh

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

M

The ______ discs that anchor the sacromere on either end in skeletal muscle are absent from smooth muscle cells

Z

ACh is an acronym for _______

acetylocholine

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

In a muscle cell, the short term energy is supplied by _____ respiration, while long term energy is supplied by ______

anaerobic/aerobic

Smooth muscle contraction is under ______ control of the nervous system

autonomic

The sacroplasmic reticulum stores______ ions needed to initiate muscle contraction

calcium

The sacrolemma of smooth muscle cells has small invaginations called ______

caveolae

the enzyme acetylcholinesterase resides in the synaptic _______

cleft

The amount of additional oxygen that must be inhaled in order to restore pre-exercise levels is called oxygen _______

debt

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 sacromere is defined as the distance from one Z ______ to the next

disc

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

fast glycolytic

Match each stage of a muscle twitch with the amount of tension generated

latent period: there is no tension contraction period: tension increases relaxation period: tension decreases

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

motor

Neurons that stimulates muscle contraction are called ______ neurons

motor

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

motor end plate

Skeletal muscle fibers are ________

multinuclear

match the muscle component with its description

muscle: multiple bundles housing many muscle fibers fascide: a bundle of muscle fibers muscle fiber: elongated, multinucleated, cylindrical cell myofibril: long, cylindrical contractile element within muscle cell myofilament: short contractile proteins of two types: thick and thin

myofibrils are made of ______

myofilaments

thick filaments are composed of bundles of what protein molecule?

myosin

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

myosin binding sites on actin are exposed

The point where a motor neuron meets a skeletal muscle fiber is called the _______ junction

neuromuscular

Smooth muscle cells have a single, centrally located ______

nucleus

The immediate supply of ATP for use in muscle contraction is generated by the _____ system

phosphagen

The plasma membrane of a skeletal muscle-fiber is called the ______

sacrolemma

Within a myofibril, each ____ shortness as the muscle fibers contracts

sacromere

A contracting skeletal muscle fiber typically shortens as all of its ______ shorten in length

sacromeres

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

sacroplasmic reticulum

Thick and thin filaments maintain their ________, whether the muscle is relaxed or contracted

same length

Match the muscle tissue with its appearance or shape

skeletal: long, cylindrical fiber cardiac: short, branched cell smooth: fusiform-shaped cell

Type I muscle fibers contract more _______ than type 11a and 11b muscle fibers

slowly

What type of muscle forms the majority of the walls of the digestive tract?

smooth

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

summation

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

support, contraction, and protection

A neuromuscular junction contains a(n) _________

synaptic cleft, synaptic knob, motor end plate

The motor end plate has folds and indention to increase the membrane surface area adjacent to the ______

synaptic knob

A cord-like structure that attaches muscle to bone is a ______

tendon

Slow-twitch and fast-twitch muscle fibers differ primarily in ______

their ATPase which splits ATP

The H-band (or H-zone) is more lightly shaded because only _______ filaments are present

thick

Under the light microscope, the dark (A) bands observed in skeletal muscle contain ________ filaments

thick & thin

Thin filaments in smooth muscle cells contain which proteins?

tropomyosin and actin

Which are characteristics of oxidative fibers?

use aerobic respiration, good for endurance, high concentration of myoglobin, and red

Smooth muscle is found in which of the following locations?

*in the wall of the small intestine *around blood vessels *in wall of the uterus