Anatomy Ch. 10- Muscle Tissue

What can cause muscle fatigue?

-build up of intracellular P1 -insufficient Ca2+ - Na+/K+ imbalances

Match the name of the muscle cell component with its function. 1- muscle fiber 2- sarcolemma 3- sarcoplasm 4- sarcoplasmic reticulum 5- T-tubule

1- muscle fiber- metabolic activities; contraction 2- sarcolemma- regulates entry and exit of materials 3- sarcoplasm- site of metabolic processes for normal muscle fiber activities 4- sarcoplasmic reticulum- stores calcium ions needed for muscle contraction 5- T-tubule- transports the action potential from the sarcolemma throughout the entire muscle fiber

Place the events that occur at a neuromuscular junction in order.

1st- nerve signal arrives at synaptic knob 2nd- calcium enters and binds synaptic vesicle 3rd- ACh is released via exocytosis into the synaptic cleft 4th- ACh binds receptors on the motor end plate

Each myosin protein molecule in a thick filament consists of ______ strands.

2

Area B of the sarcomere represents the ______ band.

A

When a muscle fiber contracts, which parts of the sarcomere maintain a constant length throughout contraction?

A band

Identify the components of a sarcomere in the picture provided.

A- I band B- A band C- M line D- Z disc

Using the picture of the sarcomere, match the indicated structures in the diagram with their name.

A- connectin B- thin filament C- M line D- thick filament

Identify each structure in the diagram of a muscle fiber.

A- mitochondrion B- nucleus C- sarcoplasmic reticulum D- T-tubule

Using the image of a muscle fiber, match each structure in the diagram with its name.

A- sarcolemma B- myofibril C- sarcomere D- myofilaments

Glycolysis and aerobic respiration are used to generate ______ in muscle fibers.

ATP

Muscle cells are said to have what characteristic because they can respond to stimulation from the nervous system?

Excitability

True or false: A muscle fiber that is partially shortened can produce a contraction stronger than the contraction it can produce when at its resting length.

False

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

H

The act of shivering is an example of skeletal muscle performing what function?

Heat prodution

Deep invaginations of sarcolemma are called ______.

T-tubules

contraction period

Time when tension is increasing Begins as power strokes pull thin filaments

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

True

True or false: In the absence of calcium, troponin attaches to tropomyosin to hold it in place on the surface of the F actin strand.

True

True or false: Most muscles contain a combination of all three muscle types, slow oxidative, fast oxidative, and fast glycolytic.

True

True or false: Skeletal muscle is usually attached to the skeleton, but it is also found at the openings between the digestive tract and the external environment and the urinary tract and the opening to the external environment.

True

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

actin

Slow and intermediate fibers require oxygen to produce ATP, so the metabolic reactions within these fibers are termed ______.

aerobic

In a muscle cell, the short-term energy is supplied by ______ respiration, whereas long-term energy is supplied by ______.

anaerobic; aerobic

M line

appears as a dark protein disc in center of H zone

troponin

bond to tropomyosin; can bind calcium ions

Functionally, troponin provides a binding site for ______ ions.

calcium

A muscle fiber is what level of organization in the body?

cellular

thin filament

composed of actin, troponin, tropomyosin; bind to thin filaments and cause contraction

thick filament

composed of myosin; bind to thin filaments and cause contraction

Myofibrils

cylindrical organelles specialized for contraction; contain myofilaments that are responsible for muscle contraction

Sarcoplasm is another term for skeletal muscle ______.

cytoplasm

sarcoplasm

cytoplasm of a muscle fiber

A band

dark band containing. both actin and mysoin

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

debt

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

debt

The epimysium of a muscle is composed of ______ connective tissue.

dense irregular

In an isometric contraction, the muscle ______ body movement.

does not produce

actin

double- stranded contractile protein; binding site for myosin to shorten a sarcomere

tropomyosin

double-stranded contractile protein; covers the active sites on actin when muscle cell is at rest

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

elasticity

The connective tissue layer that surrounds an entire muscle is called ______.

epimysium

A piano player uses her hands for brief quick movements. Which muscle fiber type would you therefore predict to be predominant in these muscles?

fast glycolytic

A skeletal muscle cell is also called a muscle

fiber(s)

sarcomere

functional contractile unit of skeletal muscle

Each myosin strand has a free ______ and an attached tail.

head

What part of a myosin molecule does ATP bind to?

head

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

The diameter of a muscle fiber will predict ______.

how much power it will produce

When a nerve impulse reaches the end of an axon of a neuromuscular junction, calcium flows ______ the synaptic knob.

into

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

isometric

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

I band

light band containing thin filaments only; light band containing thin filaments only

H zone

lighter region in the middle of an A band; contains thick filaments only

Z disc

made of dark proteins that create a zig-zag line

Slow fibers have a relatively large number of ______. This permits slow muscle fibers to produce a greater amount of ______ than fast muscle fibers while contractions are underway.

mitochondria; ATP

Athletes have more defined muscles than non-athletes even while at rest because they have ______ motor units contracting all the time.

more

In a motor unit, a single ____ neuron typically controls numerous muscle fibers in a muscle.

motor

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

motor neuron

muscle fiber

muscle cell

What is the force generated when a skeletal muscle is stimulated to contract called?

muscle tension

The sarcoplasm of a skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures called ____ that extend the length of the cell.

myofibrils

Myofibrils are made of ______.

myofilaments

Myofibrils consist of bundles of short ______.

myofilaments

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

myofilaments

Thick filaments are assembled from bundles of the protein called ____

myosin

Thick myofilaments are composed of bundles of ____ protein molecules.

myosin

T-tubule

narrow, tubular extensions of the sarcolemma into the sarcoplasm

After you stop running, you notice that you keep breathing heavily for some time. This is because your body is in ______.

oxygen debt

sarcolemma

plasma membrane of a muscle fiber

As you hold a barbell and begin to flex your arm in a curl, your biceps brachii slowly lifts the weight by using more and more motor units. This phenomenon, which increases the strength of the contraction, is referred to as ____

recruitment

As you struggle to twist open a jar, more motor units are called into action until you finally generate enough force to open it. This is an example of ______.

recruitment

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

reticulum

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

sacromeres

After stimulation of ACh receptors, a muscle impulse spreads quickly along the ____ and into the muscle fiber along T-tubules.

sarcolemma

The plasma membrane of a skeletal muscle fiber is called the

sarcolemma

Within a myofibril, each ______ shortens as the muscle fiber contracts.

sarcomere

Within a myofibril, Z discs separate the functional contractile units known as ____

sarcomeres

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

sarcoplasmic

During the development of skeletal muscle cells, some myoblasts do not fuse and instead become ______ cells.

satellite

If a skeletal muscle is injured, surrounding ____ cells may be stimulated to differentiate and assist in its repair and regeneration.

satellite or stem

Approximately 40-50% of your body weight is _____ muscle.

skeletal

Attached to the skeleton and surrounding the openings of the urinary and gastrointestinal traces are locations of ______ muscle.

skeletal

Maintenance of posture and production of heat are functions of ______ muscle.

skeletal

The ____ filament theory explains how muscle fibers shorten during contraction.

sliding

sarcoplasmic reticulum

smooth endoplasmic reticulum in a muscle fiber

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 force generated when a skeletal muscle is stimulated to contract is muscle ____

tension

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

terminal cisternae

The epimysium of a muscle surrounds ______.

the entire skeletal muscle

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

latent period

time between application of a stimulus and the beginning of a response in a muscle fiber; there is no tension

As you sit there reading this your muscles, even your relaxed ones are not completely relaxed and soft. This is because they have some background tension called resting muscle ______.

tone

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

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

Upon release from the terminal cisternae, some calcium ions bind to ______ causing it to change shape. Multiple choice question.

troponin

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

twitch

Thick filaments are about ______ the diameter of thin filaments.

two times