Muscles
Muscles
Interesting Muscle FactsThirty facial muscles create looks like
surprise, happiness, sadness, and frowningEye muscles are the
busiest muscles in the body. Scientists estimate they may move more
than 100,000 times a dayLargest muscle in the body is the gluteus
maximus muscle in the buttocks.It takes 10 muscles to smile, 12
muscles to frown ... and 1 to make a difference!Smallest muscle in
our body is in the inner ear and is called stapes
What makes our bodies move?MUSCLES!!!
Marionettes are puppets on strings. By pulling different
strings, you make these puppets dance, bow or wave their arms. Your
skeleton is similar to the puppets body. It does not move unless
something pulls on its bones. The strings that pull on your bones
are your MUSCLES.
What is Muscle?Muscle is a tissue composed of bundles of
elongated cells capable of contraction and relaxation to produce
movement in an organ or body part.
Parts of the muscleTendon: white cord made up of extremely
strong tissues Connects muscle to the boneBody: thick part of the
muscleAponeurosis: membrane of connective tissue separating the
muscle from the adjacent muscles
Tendon vs. Ligament
7A tendon is a fibrous connective tissue which attaches muscle
to bone. Tendons may also attach muscles to structures such as the
eyeball. A tendon serves to move the bone or structure. A ligament
is a fibrous connective tissue which attaches bone to bone, and
usually serves to hold structures together and keep them
stable.
Tendinitis is inflammation, irritation, and swelling of a
tendon, which is the fibrous structure that joins muscle to bone.
In many cases, tendonosis (tendon degeneration) is also present.
Causes, incidence, and risk factors Return to top Tendinitis can
occur as a result of injury, overuse, or with aging as the tendon
loses elasticity. It can also be seen in systemic diseases such as
rheumatoid arthritis or diabetes. Tendinitis can occur in any
tendon, but some commonly affected sites are the shoulder, the
wrist, the heel (Achilles tendonitis), and the elbow. Functions of
MusclesMovement of limbs and organsPosture maintenanceEven while
you are still your muscles are continuously at work in order to
maintain your postureJoint stabilizationWithout muscles, some of
our joints would not stay in placeHeat ReleaseMuscle contraction
requires chemical energy75% of this chemical energy is transformed
into thermal energy (ie. heat).The thermal energy that is released
helps maintain body temperature at 37CVoluntary vs. Involuntary
MuscleMuscle can be voluntary or involuntaryVoluntary - consciously
controlled by the brainEx: raising your arm to scratch your head
Involuntary - not consciously controlled by the brain.Ex: the
contraction of the diaphragm during inhalation
There are 3 Types of MuscleAll the functions of muscle are
carried out by 3 different muscle tissues:Skeletal
(Striated)SmoothCardiac
Skeletal Muscle (voluntary -striated)Skeletal
MuscleVoluntaryStriated appearanceAttached to the bones of the
skeletonCan generate a lot of force but tire easily: low
endurance
Smooth Muscle (Involuntary - no striations)Smooth
MuscleInvoluntaryNo striationsMake up the walls of the internal
organs such as the bladder, stomach, and uterus.Do not generate as
much force as skeletal muscle but do not tire easily: medium
endurance
Cardiac Muscle (involuntary - striated)Cardiac
MuscleInvoluntaryNo striationsFound only in the heartHas great
strength and endurance
Antagonistic MusclesAll muscles work in pairs. Whether they are
striated muscle, smooth muscle or cardiac muscle makes no
difference, all muscles must work in pairs.
Antagonistic Muscle PairbicepstricepsWhen biceps contracts, the
triceps elongates and relaxes. When the triceps contracts the
biceps elongates and relaxes.Review QuestionsWhat is a
muscle?Describe the 3 parts of a muscle.What is the difference
between a tendon and a ligament?What are the 4 functions of
muscles?What are the 3 different types of muscles and where can
they be found in the body?Give an example of an antagonistic muscle
pair.What happens to the shape of a muscle when it contracts? And
when it relaxes?
