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Basic muscle summation -an increase in the frequency with which a muscle is stimulated increases the strength of contraction. With increased stimuli to the heart if summation occurred the contractions would keep increasing.
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The repair of cardiac muscle and nervous tissue occurs only by?
fibrosis
The band that occurs where two cardiac muscle cells join together?
The intercalated disc is the band that forms by the joining of two cardiac muscles. These muscles work together to form a syncytium.
What is ischemic heart tissue?
Ischemia occurs when there is not enough oxygenated blood reaching the cardiac muscle cells.
Uncontrolled muscle contractions the same as skeletal muscle contractions?
Uhh, no uncontrolled muscle contraction occurs in smooth and cardiac muscles... there are many differences between these two types of muscles; controlled and uncontrolled muscle contraction.....
A muscle is stimulated and exhibits a contraction twitch Before this twitch is over it is stimulated again and a second twitch occurs piggyback on the first one and causes a higher contraction?
summation
How is wave summation achieved in vivo?
simply: Wave summation occurs when a second stimulus is applied before relaxation occurs completely. In depth: In order for a muscle to contract electrical shock or nerve impulse must cause voltage-sensitive tubule proteins (T-tubules) of sarcoplasmic reticulum to change shape and allow Ca2+ into cytosol. Ca2+ binds to troponin (changing its shape) allowing myosin (makes thick filaments) to attach to actin ( makes thin filaments). Myosin pulls itself along actin via ATP hydrolysis, this is called a cross bridge cycle, basically shortening of muscle. Before the contraction stops, another stimulus is sent to the muscle allowing more Ca2+ into the cytosol which keeps allowing cross bridge cycle. wave summation means the contractions are added together. thus increasing the force of the second stimuli. force will increase until the muscle reaches its threshold.
What is meant by summation at a synapse and how can the two ways it is accomplished be described?
Summation is the method in which signal transmission between neurons occurs. Summation occurs through excitatory neurotramitters and inhibitory neurotransmitters. Excitatory produces depolarization of the postsynaptic cell. Inhibitory mitigates the effects of an excutatory neurotransmitter. For more information visit the Related Link.
What is the difference between wave summation and tetanus?
in wave summation muscular fibers recieve second stimulus after a refractory period and before fiber relaxes while in tetanus the fiber receives 20-30 stimuli per second and it relax partialy.
Where is the cardiac stomach?
The cardiac portion of the stomach is in the lower section of the stomach. It is also called the "cardia". It is the place where most carbohydrate digestion occurs. It also stores ingested food.
What is muscle tissue?
Muscle tissue accounts for nearly one-half of the total body weight and consists of three distinct subtypes: • striated (skeletal) muscle • smooth (visceral) muscle, and • cardiac muscle Each type of muscle cell is designed to perform one basic function. Striated muscle is attached to bones that move the skeleton. Smooth muscle is located in the walls of hollow internal structures, such as the intestines and blood vessels, allowing such organs to expand and contract. Cardiac muscle occurs only in the heart, where it forms the walls and enables the heart to pump blood. When viewed under the light microscope, striated muscle cells appear long and thread-like with alternating light and dark cross strips called striations. In contrast, smooth muscle has no striations, Cardiac muscle cells, each of which has a nucleus, are slightly striated. Each cardiac muscle cell tends to divide into a "y" or "x" shape, so that it has more than two ends and joins more than two other cells, i.e., it intercalates. The ends of one cardiac muscle cell are separated from adjoining cells by a band called an intercalated disk. Unlike skeletal muscle, smooth muscle and cardiac muscle are controlled involuntarily, i.e., an individual cannot stop or start the muscle action. highly cellular and well vascularized
What happens to the muscle when experiencing a cramp?
When a muscle cramp occurs, the muscle contracts forcibly and involuntarily and doesn't relax for the time the cramp lasts. The cramp can last from few seconds up to few minutes.
When a second EPSP arrives at a single synapse before the effect of the first have disappeared what occurs?
temporary summation
