The Four Tissue Types: Muscle
Ever wondered what makes your heart beat or allows you to flex your biceps? That's muscle tissue at work! Our bodies contain three distinct types of muscle tissue, each with unique characteristics.
Skeletal muscle is what helps you move voluntarily. It appears as long, spindly fibers with striations (stripey, parallel fibers) and multiple nuclei per muscle fiber. These are the muscles you consciously control when lifting weights or walking.
Cardiac muscle is found exclusively in the heart. These rectangular-shaped cells have a single nucleus and special structures called intercalated discs that allow electrical signals to pass quickly between cells. This rapid communication is what keeps your heart beating rhythmically.
Smooth muscle surrounds organs that need to expand and contract, like blood vessels, the uterus, and bladder. These small muscle cells are organized in jumbled sheets that can contract simultaneously, allowing for controlled expansion and contraction of hollow organs.
Fun Fact: Your body contains more than 600 muscles, but you only consciously control the skeletal muscles. Cardiac and smooth muscles work automatically!
Epithelial tissue forms most of our skin and creates borders between different organs. These cells come in various shapes: cuboidal cube−shapedwithroundnuclei, squamous (flat with flat nuclei), and columnar tall,column−shaped.