1. Muscular System
Life Science, Ms. Wells

2. 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

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

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

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

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

7. Skeletal Muscle: Bundles of Fibers

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

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

10. Cardiac Muscle: Branched Fibers

11. Muscle Types: Fiber Shapes

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

13. 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

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

15. THE END