Muscular SystemMuscular System

Function: MovementFunction: Movement

Work with skeletal system Work with skeletal system to move bodyto move body

contract = shorten/tightencontract = shorten/tighten Muscles PULL bones, never Muscles PULL bones, never

pushpush muscle cells are called muscle cells are called

muscle fibersmuscle fibers Often work in pairs/groups Often work in pairs/groups

for one movementfor one movement

Function: Body TemperatureFunction: Body Temperature

HOMEOSTASIS: Muscle contraction releases HOMEOSTASIS: Muscle contraction releases heat to keep your body the right temperatureheat to keep your body the right temperature

Shivers: fast muscle contractions to raise body Shivers: fast muscle contractions to raise body temperaturetemperature

Function: Maintain PostureFunction: Maintain Posture

Most muscles always Most muscles always hold a little bit of hold a little bit of contraction/tensioncontraction/tension

Tension = “muscle Tension = “muscle tone”tone”

Keep you standing up Keep you standing up straight (posture)straight (posture)

Types of MuscleTypes of Muscle

1.1. Skeletal MuscleSkeletal Muscle

2.2. Smooth MuscleSmooth Muscle

3.3. Cardiac MuscleCardiac Muscle Skeletal = you control it (called Skeletal = you control it (called

VOLUNTARY)VOLUNTARY) Smooth/Cardiac = you don’t control it Smooth/Cardiac = you don’t control it

(called INVOLUNTARY)(called INVOLUNTARY)

Skeletal MuscleSkeletal Muscle

Attached to your Attached to your skeletonskeleton

VoluntaryVoluntary Structure = Structure = bundles of bundles of

fibersfibers Examples: quadriceps, Examples: quadriceps,

biceps, triceps, abs, etc.biceps, triceps, abs, etc.

Skeletal Muscle: Bundles of FibersSkeletal Muscle: Bundles of Fibers

Smooth MuscleSmooth Muscle

Inside organsInside organs Involuntary (automatic movements)Involuntary (automatic movements) Shorter fibers than skeletal muscleShorter fibers than skeletal muscle Example: pushes food through stomach and Example: pushes food through stomach and

intestinesintestines

Cardiac MuscleCardiac Muscle

Fibers have branched Fibers have branched shape (like tree shape (like tree branches) that form branches) that form webs and layerswebs and layers

Make up the heart <3Make up the heart <3

Cardiac Muscle: Branched FibersCardiac Muscle: Branched Fibers

Muscle Types: Fiber ShapesMuscle Types: Fiber Shapes

TendonsTendons

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

Muscles and ExerciseMuscles and Exercise

Soreness DURING exercise: chemicals build-Soreness DURING exercise: chemicals build-up as you use up energy (lactic acid)up as you use up energy (lactic acid)

Soreness AFTER exercise: tears and damage Soreness AFTER exercise: tears and damage to muscle fibersto muscle fibers

Healing and replacement of damaged cells = Healing and replacement of damaged cells = muscle growthmuscle growth

Skeletal Muscle DevelopmentSkeletal Muscle Development

Skeletal muscles Skeletal muscles “mature” and strengthen “mature” and strengthen as you grow upas you grow up Increase coordinationIncrease coordination

Babies can’t lift head Babies can’t lift head (neck muscles still (neck muscles still weak)weak)

Video ReviewVideo Review

http://www.discoveryeducation.com/administrators/curricular-resources/science/index.cfm

Minutes 16:50-21:20Minutes 16:50-21:20

THE ENDTHE END