Muscle Tissue for Final EXAM Flashcards by Enide Clerizier

attach the muscle to the bone

tendons

How well did you know this?

Not at all

Perfectly

plasma membrane of a muscle fiber

Sarcolemma

How well did you know this?

Not at all

Perfectly

cytoplasm of a muscle fiber

Sarcoplasm

How well did you know this?

Not at all

Perfectly

long protein cords occupying most of sarcoplasm

Myofibrils

How well did you know this?

Not at all

Perfectly

packed into spaces between myofibrils

Mitochondria

How well did you know this?

Not at all

Perfectly

smooth ER that forms a network around each myofibril

Sarcoplasmic reticulum (SR)

How well did you know this?

Not at all

Perfectly

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

T tubules

How well did you know this?

Not at all

Perfectly

a T tubule and two terminal cisterns associated with it

Triad

How well did you know this?

Not at all

Perfectly

made of several hundred myosin molecules, each molecule shaped like a golf club. Two chains intertwined to form a shaft-like tail and a double globular head. The heads are directed outward in a helical array around the bundle. The heads on one half of the thick filament angle to the left, while heads on other half angle to the right. The bare zone is the area in the middle with no heads.

Thick filaments

How well did you know this?

Not at all

Perfectly

two intertwined strands made up of string of globular (G) actin subunits each with an active site that can bind to head of myosin molecule.

Thin filaments

How well did you know this?

Not at all

Perfectly

segment from Z disc to Z disc

Sarcomere

How well did you know this?

Not at all

Perfectly

Darkest part is where thick filaments overlap a hexagonal array of thin filaments

A band

How well did you know this?

Not at all

Perfectly

not as dark; middle of A band; thick filaments only

H band

How well did you know this?

Not at all

Perfectly

middle of H band

M line

How well did you know this?

Not at all

Perfectly

means light

I band

How well did you know this?

Not at all

Perfectly

provides anchorage for thin filaments and elastic filaments

Z disc

How well did you know this?

Not at all

Perfectly

A segment of myofibril from one Z disc to the next in the fiber’s striation pattern.

Sarcomere

How well did you know this?

Not at all

Perfectly

Fibrous protein strands that carry out the contraction process.

Myofilaments

How well did you know this?

Not at all

Perfectly

one nerve fiber and all the muscle fibers innervated by it

Motor unit

How well did you know this?

Not at all

Perfectly

have about three to six muscle fibers per neuron which allows for
fine degree of control.

Small motor units

How well did you know this?

Not at all

Perfectly

have hundreds of fibers allowing for more strength than control. Leads to powerful contractions.

Large motor units

How well did you know this?

Not at all

Perfectly

Small motor units examples

Eye and hand muscles

How well did you know this?

Not at all

Perfectly

Large motor units examples

Quadriceps femoris and gastrocnemius

How well did you know this?

Not at all

Perfectly

point where a nerve fiber meets its target cell.

synapse

How well did you know this?

Not at all

Perfectly

gap between axon terminal and sarcolemma

Synaptic cleft

a terminal branch at the end of the part of synpatic neuron

synaptic knob

Four major phases of contraction and relaxation

Excitation Excitation–contraction Contraction Relaxation

a process in which nerve action potentials lead to muscle action potentials

excitation

events that link the action potentials on the sarcolemma to activation of the myofilaments, thereby preparing them to contract

Excitation–contraction coupling

the step in which the muscle fiber develops tension and may shorten

Contraction

when stimulation ends, a muscle fiber relaxes and returns to its resting length

Relaxation

the amount of tension generated by a muscle depends on how stretched or shortened it was before it was stimulated

Length–tension relationship

a quick cycle of contraction and relaxation when stimulus is at threshold or higher.

Twitch

very brief delay between stimulus and contraction

Latent period

time when muscle generates external tension

Contraction phase

time when tension declines to baseline

Relaxation phase

an increase in tension that occurs when each successive stimuli is delivered after the relaxation phase of the preceding twitch.

Treppe

higher frequency stimuli produce what

temporal (wave) summation

Each new twitch rides on the previous one generating higher tension with only partial relaxation between stimuli.

wave summation

Higher frequency stimuli with each new twitch riding on the previous twitch. Only partial relaxation between stimuli till it reaches maximum level of tension.

Incomplete Tetanus

Unnaturally high stimulus frequencies (in lab experiments) cause a steady, contraction and muscle never begins to relax.

Complete (fused) Tetanus

Muscle produces internal tension but external resistance causes it to stay the same length.

Isometric muscle contraction

Muscle changes in length with no change in tension.

Isotonic muscle contraction

muscle shortens as it maintains tension

Concentric contraction

example of concentric contraction

lifting weights

muscle lengthens as it maintains tension

Eccentric contraction

example of eccentric contraction

slowly lowering weight

Two main pathways of ATP synthesis

Anaerobic fermentation Aerobic respiration

enables cells to produce ATP in the absence of oxygen; yields little ATP and lactate, which needs to be disposed of by the liver.

Anaerobic fermentation

produces far more ATP; does not generate lactate; requires a continual supply of oxygen.

Aerobic respiration

supply oxygen to the cells in your muscles

myoglobin

transfers Pi from one ADP to another, converting the latter to ATP

Myokinase

the combination of ATP and CP which provides nearly all energy for short bursts of activity. Enough energy for 6 s of sprinting.

Phosphagen system

uses carbohydrates (glucose) stored in the muscles as Glycogen

Glycogen lactic acid system

what type of breathing is Short-Term Energy

Anaerobic Fermentation

what type of breathing is Long-Term Energy

Aerobic Respiration

Three major types of skeletal muscle fibers

- fast glycolytic - slow oxidative - Intermediate fibers

what type of twitch is well adapted for endurance; resist fatigue by oxidative (aerobic) ATP production

slow oxidative

what kind of muscles has slow-twitches (slow oxidative)

muscles that maintain posture (ex: erector spinae of the back, soleus of calf)

white, or type II fibers

Fast glycolytic

what kind of muscles has fast-twitches (Fast glycolytic)

quick and powerful muscles (ex: eye and hand muscles, gastrocnemius of calf and biceps brachii)

what type of twitch is well adapted for quick responses

Fast-twitch (Fast glycolytic)

Properties of cardiac muscle

- Contracts with regular rhythm - works at anytime - resistant to fatigue - cells contract in unison

can contract without need for nervous stimulation

Cardiac muscle

Uses aerobic respiration almost exclusively, rich in myoglobin and glycogen.

cardiac muscle

named for its lack of striations

smooth muscle

lack nerve supply; others receive input from autonomic fibers with many varicosities containing synaptic vesicles

smooth muscle

what type of twitch does cardiac muscles exhibit

slow

Takes longer to contract but can remain contracted for a long time without fatigue

smooth muscle

how does smooth muscle contract

is always triggered by Ca2+, energized by ATP, and achieved by sliding filaments

how does smooth muscle get excited

- Autonomic activity - Hormones, carbon dioxide, oxygen, and pH - Temperature - Stretch - Audtorhythmicity