Top Answer
User Avatar
Wiki User
Answered 2009-10-22 16:30:52
Cardiac Muscle and Tetany

In cardiac muscle, the mechanism of contraction is essentially the same as in skeletal, but the excitation-contraction coupling mechanism differs slightly. T-tubules invaginate at the level of the Z-lines. The SR is relatively poorly developed (cisternae are small or absent - in most EM sections 'diads' and not 'triads' are seen), and provides insufficient Ca2+ to fully activate the contractile apparatus. Unlike those in skeletal muscle the ryanodine channels in cardiac muscle are activated by Ca2+ in the cytosol (calcium activated calcium release) and Ca2+ entry through the dihydropyridine channels is an important trigger of Ca2+ release. Significant amounts of Ca2+ enter the fibre from the ECF during the AP, which consequently has a long plateau phase caused by slowly inactivating Ca2+ channels in the sarcolemma, prolonging AP (c. 200 ms). Ca2+ is also released from sub-sarcolemmal binding sites during the AP. Because the AP lasts almost as long as the twitch, heart muscle cannot be tetanized.

User Avatar

Your Answer


Still Have Questions?

Related Questions

Is the cardiac muscle voluntary?

No because the heart is a cardiac muscle and you cant' control the heart

What are repeated contractions of the cardiac muscle?

TENDONS cant you guys realize this

Is the cardiac muscle a voluntary or involuntary?

involuntary.. u cant tell your heart when to beat lol

What are the properties of cardiac muscles?

- rhythmicity : capability of rhythmic self-excitation therefore no need for external control -conductivity: conduction of action potential along specialised muscle cells. -excitability: ability of muscle fibers to get exited . -contractility; ability of cardiac muscle to contract . It also has a long refractory period meaning it cant tetanus

Can cardiacmuscle be tetanize?

No. One of themost interesting feartures of cardiac muscle is that it has a long refractory period and so conduction cant be continuous and so tetanus is impossible.

What kind of muscle can you cant control?

involuntary muscle

How do you shape your muscle?

You cant!

how can you contract your smooth muscle?

you cant

Can Valium help muscle pain?

No it cant

What muscle that move and work without your control?

your heart is the muscle that you cant move yourself

Can you pull or push your muscles?

You can pull a muscle which means it really aches but you cant push a muscle

How do you tell a dragon from a butterfly?

you cant. They are completely identical.

Why cant the heart muscle take a little rest?

The heart muscle cannot take a little rest.they cant take a rest even in a few minutes because if they will rest we will die.

Is half your weight muscle?

muscle weighs more than fat. you cant go by that rule all the time.

Where can smooth muscle be found?

blood vessel walls-LZthe stomach. it is an involuntary muscle and you cant control your stomach.

There are some cells that can not go through Mitosis In other words an organism can not make any new ones when the cells die Human nerve and muscle cells are examples?

cardiac muscle cells are one example of cells that cant undergo mitosis because they can't stop they're current action (for obvious reasons) so they can never start replication

Explain voluntary and involuntary muscles Give an example of at least one voluntary muscle and at least one involuntary muscle Explain why it is important that these muscles are voluntary or involun?

voluntary is muscles you choose to move, whereas involuntary are muscles that move without your will. an involuntary muscle wouuld be your heart and that it pumps blood, which is a cardiac muscle, a voluntary muscle is like you moving your hand up and down, and that is a skeletal muscle. its important because if you had to think to make your heart pump blood, you would probably die in your sleep. Also, its important for a skeletal muscle to be voluntary, because if it wasnt you cant ever control it, and it moves by itself.

Do protein help you gain muscle?

Protein is the raw ingredient from which muscle is made by the body, if your body doesnt have enough protein it cant maintain muscle it already has, and secondly build new muscle tissue.

Why can't you live with out the skeletal muscle?

You cant live without the skeletal muscle because the skeletal muscle helps with your joints not to move in an uncomfortable position and the skeletal muscle it was keep the bones from breaking to easily.

Do molecules ever completely stop moving?

No they cant stop moving completely, but may be some change is happened in there speed.But they can't stop completely.

How do you swim breaststroke faster?

move your arms faster, if you cant do that, get more muscle

What are aphiarthrotic joints?

when your muscle dont work as well and you cant move as fast

Can a person live without muscle?

no. A person cannot live without muscle because you would not be able to survive, plus, your heart is a muscle, and we all know you cant live without that

How do you build muscles by doing nothing?

you cant building muscle takes energy and time

Can you stand without the gastrocnemius muscle?

u cant stand without the gastrocnemius muscle.FAKE