Related topics: genes · protein · mice · cells · stem cells

What can sharks teach us about our hearts?

This time of year, it's hard to escape sharks—on TV at least. But perhaps that heartbeat-like theme from "Jaws"—da-dum, da-dum—has you wondering, "What might I learn about my own heart from a shark?"

Ants perform amputations to save injured nestmates

Saving lives through surgery is no longer exclusive to humans. In a study published July 2 in the journal Current Biology, scientists detail how Florida carpenter ants, a common, brown species native to its namesake, selectively ...

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Muscle (from Latin musculus, diminutive of mus "mouse") is the contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to produce force and cause motion. Muscles can cause either locomotion of the organism itself or movement of internal organs. Cardiac and smooth muscle contraction occurs without conscious thought and is necessary for survival. Examples are the contraction of the heart and peristalsis which pushes food through the digestive system. Voluntary contraction of the skeletal muscles is used to move the body and can be finely controlled. Examples are movements of the eye, or gross movements like the quadriceps muscle of the thigh. There are two broad types of voluntary muscle fibers: slow twitch and fast twitch. Slow twitch fibers contract for long periods of time but with little force while fast twitch fibers contract quickly and powerfully but fatigue very rapidly.

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