Muscles
Definition:
Muscles are soft tissues in the body that can contract (shorten) and relax (lengthen) to produce movement, maintain posture, and perform essential functions like pumping blood and moving food in the body.
Interesting points:
Muscles are everywhere: About 40–50% of your body weight comes from muscles!
Muscles can only pull, not push: They work in pairs to move your body.
Fastest muscles: Your eyelid muscles are the fastest—they can blink up to 100 times per minute!
Strongest muscle (relative to size): The masseter (jaw muscle) can crush very hard things!
Heart never stops: Your cardiac muscles pump blood continuously, even while you sleep.
Smooth muscles work automatically: Your stomach, intestines, and blood vessels move without you thinking about it.
Muscles produce heat: Moving muscles keep your body warm.
Muscles grow with exercise: Regular activity makes skeletal muscles stronger and bigger.
Smallest muscles: Found in the ears—help you hear by controlling vibrations.
Muscles heal themselves: Minor injuries can repair with rest and nutrition.
Main points:
Types of muscles:
Skeletal muscles – attached to bones, help us move (like arms and legs).
Smooth muscles – inside organs like the stomach, help move food.
Cardiac muscle – heart muscle, helps pump blood.
How they work:
Muscles get signals from nerves.
They pull on bones or organs to make movement happen.
Fun fact:
Your strongest muscle based on size is the masseter, the jaw muscle.
Your heart never stops working—it’s always contracting!