What happens when the cardiac muscles contract?

Answer 1

Cardiac muscle contracts and relaxes automatically without you having to think about it. When you take exercise your heart beats faster and with a bigger volume. This increase in cardiac output (how fast the blood is pumped around your body) is produced by a hormone called adrenaline. The vagus nerve can make the heart go slower; this happens when you are sitting or lying down.

Answer 2

Electrical current opens up Calcium Voltage Gates ; ACh attaches to the receptors and the channel opens and equals levels of sodium and potassium; electrical signal gets passed up the cell membrane and other channels open, Action potential, calcium binds to troponin and makes tropomyosin to move the myosine heads attach to the active sites, cross bridge; ATP attach to myosine head which causes a power stroke, meaning the myosine detach

Answer 3

Joints, bones and muscles are used in movement. two bones together form a joint where a movement can be made and muscles with repeated contraction and expansion bring about movement in the body.

Answer 4

When our skeletal muscles in our bodies contract they shorten by a process known as the Sliding Filament Theory proposed by Huxley in the 1960's. What happens on a microscopic level is that short sections inside the muscle cells called sacromeres are arranged in long parallel rows and bundled together as long cords called myofibrils. As an action potential, electrical impulse, travels down the cell membrane of the muscle cell, the sacrolemma, the impulse causes calcium to be released and unlock binding sites on the actin filaments so that the myosin heads can attach and pull the actin filaments closer together. These actin and myosin filament are inside all the sarcomeres. When the energy stored in the ATP (adenosine triphosphate) molecule is released, the result is muscle contraction. On a larger scale the muscle has an origin, a an attachment to a more stable structure, usually to bone. And another end that is attached to a structure that is less satble and can move more easily. This is usually another bone and called the insertion site. When the muscle contracts, the joint between the two attachments acts as a lever and causes motion that moves that part of the body.