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Chapter 15
Support, Movement, and
Responses
I. The Skin

A.
Skin is the largest organ of your body
Skin Structures
1. Three layers of tissue
a) epidermis – outer, thinnest layer
b) dermis – layer below the epidermis.
It is thicker and contains blood vessels,
nerves, muscles, oil & sweat glands,
and other structures
c) fatty layer – insulates the body,
where fat is deposited when people
gain weight
Link to skin picture
2. Melanin – a pigment that protects the
skin and gives it color
B.
Skin Functions
1. Protection
2. Sensory Response
3. Formation of Vitamin D
a) Vitamin D helps absorb calcium into
your blood from food in your digestive
tract
4. Regulates body temperature.
5. Ridding body of wastes.
C.
Skin Injuries and Repairs
1. Injuries include bruises, scratches,
burns, rips, and exposure to harsh
conditions like cold dry air.
D.
Diseases of the Skin
1. Chickenpox, shingles, acne,
psoriasis, melanoma, hives, ringworm,
BO
E.
Taking Care of your Skin
1. Wear sun screen with a minimum
SPF 15.
2. Bathe every day.
3. Use deodorant/antiperspirant.
4. Use moisturizing lotion to prevent
cracks in skin.
5. Avoid stress.
II.
A.

The Muscular System
Movement of the Human Body
You have more than 600 muscles in
your body.
1. Muscle Control
a) Voluntary Muscles – muscles you
are able to control
 skeletal muscles are voluntary
b) Involuntary Muscles – muscles you
cannot consciously control
 cardiac and smooth muscles are
involuntary muscles
c) Tendons – thick bands of tissue that
attach muscles to bones
B.
Working Muscles
 Pairs of muscles work together to
allow parts of your body to move (ex.
biceps and triceps)
 When 1 muscle contracts (shortens
and becomes tighter) the other
muscle relaxes and turns to original
length.
 Muscles always pull and never push.
1. Changes in Muscles
a) Muscles that are used a lot become
larger because there are more muscle
cells added or muscle cells are larger.
b) Muscles that are not used become
smaller.
C.
D.

How Muscles Move
1. Blood carries energy rich molecules
to you muscle cells.
2. Inside the muscle cells the molecules
are changed from chemical energy to
mechanical and heat energy.
3. During rest periods the blood supplies
your muscles more energy rich
molecules.
Skeletal Muscles
(Look at picture)
III. The Skeletal System
A.
Functions of Your Skeletal System
1. Gives you shape and support.
2. Protects internal organs.
3. Muscles are attached to bones and help
move.
4. Forms red blood cells in bone marrow.
5. Stores calcium and phosphorus.
B.
Bone Structure
1. Bone Tissue
a) Periosteum – tough, tight fitting
membrane that covers a bone’s surface
b) Compact Bone
c) Spongy Bone
d) Marrow in cavities of long bones
2. Cartilage – a smooth, slippery, thick
layer at the ends of bones that acts as a
shock absorber
Link to bone picture
C.
Bone Formation
 Your bones start as cartilage.
 You start with 300 bones at birth but
you now only have 206.
 osteoblasts – bone forming cells
 osteoclasts – cells that break down
bone cells
D.


1.
Joints
Joint – any place where 2 or more
bones come together
Ligaments – tough bands that hold your
bones together
Immovable Joints – skull and pelvis
1. Moveable Joints
a) Pivot – one bone moves around
another bone that doesn’t move (arm)
b) Ball and Socket – a bone with a
rounded end that fits in a cup-like cavity
in another bone (shoulder
c) Hinge – back and forth movement
(elbow)
d) Gliding – one part of a bone slides
over another part (wrist)
3. Joint Problems
a) arthritis – starts with pain, stiffness
and swelling of joints
E.
The Skeletal System
(Look at the picture)
IV. The Nervous System
A.
Nerve Cell
1. Neurons – nerve cells
a) Dendrites – receive messages from
other dendrites and send them to cell
body
b) Axons – carry messages away from
cell body
Link to picture of neuron
3.
2. Types of Nerve Cells
a) sensory neurons – receive
information and send messages to
brain
b) motor neurons – conduct
messages from brain to muscles
c) interneurons – relay messages
from sensory neurons to motor
neurons
Synapse – small space between nerve
cells
B.
The Divisions of the Nervous System
1. Central Nervous System – includes
the brain and spinal cord
2. Peripheral Nervous System – all
nerves outside of the CNS that connect
brain and spinal cord to other body parts.
a) Somatic System – controls
voluntary actions
b) Autonomic System – controls
involuntary actions
(heart rate, breathing, digestion)
C.

Safety and the Nervous System
Every mental process and physical
action of the body involves structures of
the central and peripheral nervous
system. Any injury can be serious.
1. Reflex – an involuntary, automatic
response to a stimulus
D.
The Senses
1. Vision
a) cornea – the transparent section at
the front of the eye
b) lens
c) retina – tissue at the back of eye
sensitive to light energy
-rods and cones – 2 types of cells
in retina
d) optic nerve – transfers messages to
the brain
e) brain
2. Hearing
a) an object vibrates producing sound
waves
b) sound waves travel through air
c) sound waves funnel down ear canal
to middle ear
d) eardrum vibrates
e) hammer, anvil, and stirrup vibrate
f) fluids in cochlea vibrate
g) hair cells in cochlea move
h) electrical impulses travel down
auditory nerve to brain
3. Smell
a) molecules in air enter nose
b) olfactory cells are stimulated
c) impulses are sent to the brain
4. Taste
a) Saliva and food rush over taste
buds on tongue
b) impulses are sent to the brain