Muscular System Notes 13-3. Muscular System has many functions: Movement Movement Body temperature Body temperature Posture Posture Food source Food source.

Muscular SystemMuscular SystemNotes 13-3Notes 13-3

Muscular System has many Muscular System has many functions:functions:

MovementMovement Body temperatureBody temperature PosturePosture Food sourceFood source

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)

Function: Food SourceFunction: Food Source

Meat that you eat is Meat that you eat is muscle!muscle!

Types of Muscle TissueTypes of Muscle Tissue

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 skeleton Attached to your skeleton by tendons (CT)by tendons (CT)

VoluntaryVoluntary Structure = Structure = bundles of bundles of

fibersfibers striatedstriated Examples: quadriceps, Examples: quadriceps,

biceps, triceps, abs, etc.biceps, triceps, abs, etc. React quickly, tire quicklyReact quickly, tire quickly

Skeletal Muscle: Bundles of FibersSkeletal Muscle: Bundles of Fibers

Skeletal muscles cross jointsSkeletal muscles cross joints

And work in pairs by contracting and relaxing.

Muscles at WorkMuscles at Work

Because muscle cells can only contract, not Because muscle cells can only contract, not extend, skeletal muscles must work in pairs. extend, skeletal muscles must work in pairs. While one muscle contracts, the other muscle While one muscle contracts, the other muscle in the pair relaxes to its original length.in the pair relaxes to its original length.

FUN Facts!FUN Facts! There are more than 630 muscles in the body.

On average, the body weight is 40% muscle.

Out of the 630 muscles, 30 of them are facial muscles, which help to create all those different faces of happiness, surprise, joy, sorrow, sadness, fright, etc.

The biggest muscle in the bodyThe biggest muscle in the bodyis the gluteus maximus (buttock)is the gluteus maximus (buttock)

Smooth MuscleSmooth Muscle

Inside organsInside organs Involuntary (automatic Involuntary (automatic

movements)movements) Shorter fibers than skeletal muscleShorter fibers than skeletal muscle React slowly, tire slowlyReact slowly, tire slowly Example: pushes food through Example: pushes food through

stomach and intestinesstomach and intestines

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 StriatedStriated InvoluntaryInvoluntary Never tireNever tire

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

The muscle gets thicker and therefore strongerThe muscle gets thicker and therefore stronger

Can Muscles get hurt?Can Muscles get hurt?

It is possible to hurt a muscle because they can become pulled, hence "pulled muscle."

Can actually tear a muscle the same way that a ligament or tendon gets torn or a bone gets broke.

And they can heal themselves with rest and time.

Muscles can also cramp, which is when a muscle stays contracted

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)

Muscular System VideoMuscular System Video

http://youtu.be/RsWNyqnHQ2I