Muscular & Skeletal
Systems
Muscular System
Muscles are the motors that move body
parts.
Bones and joints
have no power to
move on their own.
More than 600
muscles in the body
– 35–40% of body mass
is muscle
Muscular System
Muscle—organ that contracts and
becomes shorter or expands and
becomes longer
– Result = Body parts move, energy is
used, and work is done.
Muscular System
Two Groups of Muscles
1. Voluntary—You can control
these.
Arms, legs, hands, face
2. Involuntary—You can’t control
these; you don’t have to decide to
make these muscles work.
Muscles around the heart
Muscular System
Three Types of Muscle Tissue
1. Skeletal Muscle
Most numerous in body
Looks striped (striated)
Attached to the bones by
tendons
– Tendons—thick bands that pull on
the bone as the muscle contracts
Voluntary
Contract quickly, tire easily
Muscular System
Three Types of Muscle Tissue (cont.)
2. Smooth Muscle
Involuntary
Found in: walls of stomach,
intestine, uterus, etc.
Contracts and relaxes slowly
No striations
Muscular System
Three Types of Muscle Tissue (cont.)
3. Cardiac Muscle
Only found in heart
Involuntary
Has striations
Contracts 70 times per minute (heartbeat)
Muscles at Work
Skeletal muscle movements are
results of pairs of muscles
working together.
– One muscle contracts while
the other muscle relaxes.
– Muscles always pull;
they never push.
Muscles at Work
Results of Muscle Action
– Muscles contract
This produces thermal energy, and it uses
chemical energy.
Thermal energy produces heat that helps
keep body temperature constant.
Chemical energy is from glucose. (When
glucose is used up, muscles are tired and
need to rest.)
Muscles at Work
Results of Muscle action (cont.)
– Over time, muscles become larger or
smaller, depending on how much work
they do.
Skeletal System
Made up of all of the
bones in your body,
it is the framework
of the body.
– Each bone in your body
is a living organ, made
of different tissues.
Cells in bones take in
food and use energy.
Skeletal System
Made up of all of the bones in your
body, it is the framework of the body.
- Five Functions of Skeletal System
1. Framework gives shape &
support to the body.
Skeletal System
Made up of all of the bones in your
body, it is the framework of the body.
– Five Functions of Skeletal System
1. Framework gives shape
and support to the body.
2. Bones protect the
internal organs.
Skeletal System
Made up of all of the bones in your
body, it is the framework of the body.
– Five Functions of Skeletal System
1. Framework gives shape & support to the body.
2. Bones protect the internal organs.
3. Major muscles of the body
are attached to the
bones.
Skeletal System
Made up of all of the bones in your
body, it is the framework of the body.
– Five Functions of Skeletal System
1. Framework gives shape & support to the body.
2. Bones protect the internal organs.
3. Major muscles of the body are
attached to the bones.
4. Blood cells are formed
in red marrow of some
bones.
Skeletal System
Made up of all of the bones in your
body, it is the framework of the body.
– Five Functions of Skeletal System
1. Framework gives shape & support to the body.
2. Bones protect the internal organs.
3. Major muscles of the body are
attached to the bones.
4. Blood cells are formed in red
marrow of some bones.
5. Skeleton is a place where
major quantities of calcium
and phosphorus compounds
are stored.
Bones
The adult skeleton has 206 bones
(baby has 270).
Joints
Any place where two or more bones
meet
Ligaments: tough
bands of tissue that
hold bones together
at the joints