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MUSCULAR
SYSTEM
General Information
Muscles account for 50% of body weight
Protects organs
– What organs?
Gives body shape and posture
Provides movement
– Muscles contract to cause the movement
How many muscles in human body?
– Over 600 muscles
Changes potential energy into kinetic energy
– POTENTIAL ENERGY- is energy that is stored
within an object (in this case our muscles), not
in motion but capable of becoming active
– KINETIC ENERGY - energy in motion
Parts of the muscle
Origin
– The less movable of the two
attachments
Belly
– The fleshy center part of the muscle
Insertion
– The more movable attachment
– Where movement takes place
Picture
TENDONS ATTACH
MUSCLES TO BONES
TYPES OF MUSCLE
VOLUNTARY
– Muscles that you have control over
– Skeletal
INVOLUNTARY
– Can contract without you telling it to
- The brain mainly controls these types of
movements
– Smooth
CARDIAC
– Heart
Smooth Muscle
Help control breathing, blood
pressure, and the movements of the
digestive system
Reacts slowly
Tires slowly
Cardiac Muscle
Also is an involuntary muscle
Hardest working muscle in body
Contraction of cardiac muscle fibers
make the heart beat
Skeletal Muscle
Associated with the bones of the body
Moves the skeleton (bones)
Fast and powerful movements
Tire quickly
Composition of skeletal muscle
– Fiber: individual muscle cell, can be up to 1
foot long.
– Bundle: a group of muscle fibers
– Skeletal muscle is made up of a group of
bundles
Action of Skeletal Muscles
Muscles work by contracting (shortening)
Muscles always work in pairs.
– Ex: Biceps and Triceps
One contracts while other extends
Skeletal muscles contract only when they
receive a message from a nerve to do so.
– Nerves message is carried from brain and
spinal cord to muscle
Action (ALL or NONE)
No such thing as a weak or strong
contraction of a muscle fiber
When a muscle fiber receives a
message to contract it does so
Strength of muscle contraction
depends on how many muscle fibers
receive the message to contract
Major Muscles and What They Move
1.
2.
3.
4.
5.
6.
7.
Sternocleidomastoid
Turns head
Deltoid
Raises upper arm
Pectorals
Moves arms across chest
Biceps
Raises lower arm
Rectus abdonimis
Flexes torso
External obliques
Assists in breathing
Quadriceps
Straightens and raises leg
Major Muscles and What They Move
8. Trapezius
Raises shoulder
9. Latissimus Dorsi
Lowers upper arm
10.Triceps
Lowers Forearm
11.Gluteus Maximus
Extends thigh
12.Hamstrings
Bends leg at knee
13.Gastrocnemius
Extends or lowers foot
How do your muscles get
BIGGER?!?!
Discuss with your partner next to
you the following question:
– How do your muscles get bigger?
BIGGER MUSCLES (continued)
When you work out your muscles
cells (muscle fibers) get bigger
They get bigger by creating small
“tears” in the muscle fiber
Your muscle rebuilds muscle in the
tear filling in the open gap
Rep Range Percent of 1 Goal
Rep Max
Desired
1-5 reps
85% - 100%
Strength and
Power
6-8
75% - 85%
Strength
9-12
70% - 75%
13-20 +
60% - 70%
Some Strength
and some
muscle
endurance
Muscle
Endurance and
Little Muscle
Strength
Group Discussion
If you were to work out and have big
muscles and then one day stop
working out, do your muscles turn
into fat? Explain why they do or why
they do not.
Problems of the Muscular System
Torn Muscle
– Muscle has been torn or pulled away from the
bone or has been damaged within itself
– Results from overworking muscle or a severe
or suddenly pull or strain on a muscle
– May require surgery and takes up to 3-4
months to heal
Muscle Strain
Any type of soreness that develops in a muscle
because of overuse. It is caused by small
tears to the muscle or tendon
Takes anywhere from 1-3 weeks to heal
Problems of the Muscular System
Cramped Muscle
– Muscle will involuntarily remain contracted rather than
relaxed
– Prevention:
Stretching before and after activity
Hydrate (H20 and electrolytes)
Avoid excessive exercise in hot weather
– Remedies:
Stretch, rest, and more H20
Muscular Dystrophy
– group of disorders characterized by progressive muscle
weakness and loss of muscle tissue
– Occurs because bodies inability to produce proteins for
muscle production
– No cure but ways to better lives of people with disorder
– Genetic Disorder
STEROIDS
How Do Anabolic Steroids Work?
– Anabolic steroids are drugs that resemble the
chemical structure of the body's natural sex
hormone testosterone, which is made naturally
by the body.
– Testosterone directs the body to produce or
enhance male characteristics such as increased
muscle mass, facial hair growth, and deepening
of the voice, and is an important part of male
development during puberty.
– When anabolic steroids increase the levels of
testosterone in the blood, they stimulate muscle
tissue in the body to grow larger and stronger.
– However, the effects of too much testosterone
circulating in the body can be harmful over time.
DANGERS OF ANABOLIC
STEROIDS
Physical
Start to develop
traits of the opposite
sex
Oily Skin
Severe Acne
Heart Problems
Problems with:
–
–
–
–
Liver
Kidney
Muscles
Bones
Mental/Emotional
–
–
–
–
Mentally Addicting
Depression
Suicide
Roid Rage
When a person
becomes extremely
violent and
aggressive
– Self Absorbed
Don’t care about
anyone or anything
else
Taking Care of Your Muscles
Nutrition
– Eat a variety of foods
Aerobic Exercise
– Running, swimming, cycling
Strength Training
– Weight Lifting
Stretching
– Before and after exercise
BMI
BMI Calculator
http://3dscience.com/subcategory.asp?cID=18
http://www.jdenuno.com/6~Muscles.
htm
http://www.umanitoba.ca/faculties/s
cience/biological_sciences/lab15/biol
ab15_2.html#Muscular