Muscular System Life Science, Ms. Wells

Function: Movement Work with skeletal system to move body contract = shorten/tighten Muscles PULL bones, never push muscle cells are called muscle fibers Often work in pairs/groups for one movement

Function: Body Temperature HOMEOSTASIS: Muscle contraction releases heat to keep your body the right temperature Shivers: fast muscle contractions to raise body temperature

Function: Maintain Posture Most muscles always hold a little bit of contraction/tension Tension = “muscle tone” Keep you standing up straight (posture)

Types of Muscle Skeletal Muscle Smooth Muscle Cardiac Muscle Skeletal = you control it (called VOLUNTARY) Smooth/Cardiac = you don’t control it (called INVOLUNTARY)

Skeletal Muscle Attached to your skeleton Voluntary Structure = bundles of fibers Examples: quadriceps, biceps, triceps, abs, etc.

Skeletal Muscle: Bundles of Fibers

Smooth Muscle Inside organs Involuntary (automatic movements) Shorter fibers than skeletal muscle Example: pushes food through stomach and intestines

Cardiac Muscle Fibers have branched shape (like tree branches) that form webs and layers Make up the heart <3

Cardiac Muscle: Branched Fibers

Muscle Types: Fiber Shapes

Tendons Attach muscles to bones White skinny part of muscle “Gristle”

Muscles and Exercise Soreness DURING exercise: chemicals build-up as you use up energy (lactic acid) Soreness AFTER exercise: tears and damage to muscle fibers Healing and replacement of damaged cells = muscle growth

Skeletal Muscle Development Skeletal muscles “mature” and strengthen as you grow up Increase coordination Babies can’t lift head (neck muscles still weak)

THE END