Download The Muscular System KEY FILLED IN The Muscles Every movement

The Muscular System
KEY FILLED IN
The Muscles
Every movement that takes place in your body depends on
muscles. They work by shortening or contracting.
There are 3 kinds of muscles.
1. Involuntary (smooth): CONTRACT SLOWLY AND SMOOTHLY,
YOU CANNOT CONTROL THEM, CAN REMAIN CONTRACTED FOR
LONG PERIODS OF TIME. ESOPHAGUS, INTESTINES, OTHER
INTERNAL ORGANS.
2. Cardiac Muscle: YOU CANNOT CONTROL THEM, WORKS 24/7,
STRONGEST TYPE OF MUSCLE. MUSCLE OF THE HEART
3. Voluntary Muscles (skeletal/striped): YOU CAN CONTROL
THEM, OVER 400 IN YOUR BODY, THEY MOVE YOUR FACE,
BONES AND EYES
Major Muscle Groups
Deltoid- SHOULDER
Bicep- FRONT PART OF HUMERUS
Tricep – BACK PART OF HUMERUS
Abdominals – MIDDLE OF THE STOMACH
Pectoralis – CHEST
Trapezius – LOWER NECK/ UPPER BACK
Latissimus dorsi- MIDDLE/ LOWER BACK
Quadricep – FRONT PART OF THIGH
Hamstring – BACK PART OF THIGH
Gluteus – BEHIND
Calf – LOWER LEG
Achilles – ATTACHES CALF TO HEEL
How Muscles Work
Voluntary muscles produce movement by CONTRACTING and
RELAXING.
Muscles get SHORTER when they contract and LONGER when
they relax again.
All voluntary muscles are attached by tendons to bones. These
points of attachment are called ORIGINS and INSERTIONS. Some
muscles have more than one attachment at one end (this is an
indication of strength of the muscle).
Tendons
Tendons attach MUSCLE to BONE.
Ligaments attach BONE to BONE.
As a muscle contracts, the tendons at each end of the muscle
takes the strain.
Tendons must therefore be strong enough to work under HEAVY
LOADS and resist the intense, sudden muscular contractions
involved in sport, e.g. throwing the JAVELIN.
The tendon of origin resists the pull of the muscle whilst the
tendon of insertion exerts the pull on the bone to which it is
attached. This causes the joint to bend or straighten.
Tendons are a CONNECTIVE TISSUE which have a less efficient
blood supply than skeletal muscle. A thorough WARM UP will
stimulate blood flow to the tendons and this will reduce the
chance of INJURY to the tissue. One tendon that is prone to injury
is the ACHILLES tendon.
Muscles for Endurance and Power
Fast and Slow Twitch Muscle Fibers
There are two types of muscle fibers present in voluntary muscles.
 Fast Twitch Fibers
 Slow Twitch Fibers
Fast Twitch Fibers
 FAST, POWERFUL
CONTRACTIONS
Slow Twitch Fibers
 CONTRACT MORE SLOWLY
AND WITH LESS POWER
THAN FAST TWITCH
FIBERS
Burn up their supply of oxygen
usually within 10 SECONDS.
They then have to use the
body’s store of carbohydrates
as a SHORT TERM energy
source. (ANAEROBIC Exercise).
Are able to REPLACE their
oxygen supply while they are
working.
(AEROBIC Exercise)
Tire QUICKLY
Can function for LONGER
periods of time
Used for short term power and
STRENGTH activities (anaerobic
activities)
Used for longer term
ENDURANCE activities (aerobic
activities).
E.x.
E.x.
 In many sporting events we often use both types of fibers at
different times during the activity. Complete the table below
showing examples of the use of both types of muscle fibers
in different sporting activities.
Activity
Marathon Running
Slow Twitch
Most of the race
Fast Twitch
Sprint finish
Effects of Exercise and Training on Muscles
Skeletal muscle responds to training in two ways.
1. Voluntary muscles become STRONGER and more FLEXIBLE
when they are exercised. This development of the muscle is
known as HYPERTROPHY. When exercise STOPS due to injury or
some other reason, muscles begin to lose the STRENGTH and
MASS that was gradually building up during regular activity. This is
known as ATROPHY (wasting of the muscle).
2. Different activities rely of different muscles and muscular
requirement. With REGULAR training, muscles adapt well to the
exercise that they are required to perform. In activities that
involve HEAVY workloads, e.g. SPRINTING, new muscle fibers are
GENERATED (muscle bulk) until the muscles are STRONG enough
to perform the task.