anatomy muscle tissue quiz

Skeletal Muscle

Striated, attached to bones to manipulate the skeleton, multi nucleated

Cardiac Muscle

Striated, surrounding heart and aorta

Smooth Muscle

Non striated, made of thick and thin filaments.

What is a muscle made of?

Fasicles

What is the Fascicle made of?

Muscle fibers

What are muscle fibers made of?

Myofibril

What is at the end of myofibril filaments?

Sarcomere

Two chemicals in the sarcomere

Myosin and Actin. They are myofilaments

What is the fascicle?

A discrete bundle of muscle cells segregated by a connective tissue sheath.

What is a muscle fiber?

An elongated multinucleate cell, has striated appearance most of time.

What is myofibril?

Rod like contractile elements that occupy most of the muscle cells segregated and volume. Comprised of sarcomeres and they appear banded.

what is the Perimysium?

Muscle membrane that surrounds and protects the fascicle.

What is Myosin?

2 heavy and 4 light polypeptide chains, rod like tail attached to a flexible hinge with 2 globular heads.

What is the Epimysium?

Overcoat of dense irregular connective tissue that surrounds the whole muscle. Protects.

what is actin?

Kidney shaped polypeptide subunits with 2 active sites for binding.

What is the endomysium?

A wispy sheath of connective tissue that surrounds and protects each muscle fiber. Fine areolar connective tissue.

What is a motor neuron?

A nerve that is responsible for contracting the muscle

What is the Axon Terminal?

The bulbous distal endings of the terminal branches of an axon

What is calcium?

A mineral nutrient necessary for muscle function and neural transmission.

What is a calcium channel?

Portals that let acetylcholine in

What is Na+?

It chemically binds to a gage and makes it open.

What is K+?

K+ chemically binds to a gate and makes it open

What is the synaptic cleft?

The fluid filled space (gap) between neurons

What is the sarcolemma?

Plasma membrane of the muscle.

What is a voltage gate?

A gate that opens in response to action potential

What is a chemical gate?

A gate that opens when a particular molecule binds to it.

What does acetylcholine do?

It acts as a neurotransmitter that helps to get the signal across the synaptic cleft (gap)

Where are actin and myosin attached?

At the Z line. (The zig zag looking line at the end that touches both)

Where is the M line?

In the middle of the sarcomere.

What happens when muscle fiber is pulled towards the M line?

It shortens.

What do myosin heads do?

Attach to the twisted actin filament and pull them.

What is it called when the sarcomere gets shorter?

Sliding Filament Theory

what is the energy source for myosin in sliding filament theory?

ATP

What is step one of sliding filament theory?

Contraction cycle begins, ATP energizes the myosin head and is converted into ADP + P

What is step two of the sliding filament theory?

The actin active sites is exposed, calcium ions bond to the tropin, removing the tropomyosin that was stopping myosin from bonding, and allowing it to bind to the active site an create a cross bridge formation

What is step three of sliding filament theory?

The myosin head attached pivots and completes a power stroke. Energy stored in the head is used to pull actin filaments to the M line and ADP + P is released from the myosin head.

What is stage four of sliding filament theory?

detachment. New ATP attaches to the myosin head and the cross bridge detaches as a result. The new ATP stops myosin from being binded.

What is stage five of sliding filament theory?

Myosin resets. The free myosin head splits ATP into ADP + P and released energy re-cocks the myosin head to prepare for the cycle to start over for a new power stroke.

How long will sliding filament theory cycle continue?

Until the muscle is fully contracted.