Functions of the Skeletal System
Movement: Muscles work on the foundation
of the bones to allow for movement.
2. Support: The backbone is the main support
center for the upper body.
3. Protection: The bones of your skull protect
the brain.
4. Storage: Bones store minerals, such as
calcium, for use by the body.
5. Blood Cell Formation: Red and white blood
cells are formed by marrow.
1.
Two Major Parts of Skeletal System
Axial: supports the
central axis of the body;
includes skull, vertebral
column, ribcage.
 Appendicular: consists
of the bones of the
arms, legs, pelvis,
shoulder area
*THERE ARE 206 BONES
IN AN ADULT
SKELETON

Appendicular/Axial Skeleton
Labeling
Appendicular Skeleton Labeling
What are bones?

Bones: solid network of living cells and
protein fibers that are surrounded by
deposits of calcium salts.
Bone Structure
Periosteum: tough layer of connective tissue
surrounding bone
 Compact bone: thick, dense layer of bone
containing Haversian canals – containing
blood vessels
 Spongy bone: strong layer found inside
compact bone
 Bone Marrow: soft tissue located inside bone
cavities

Types of Bone Marrow
•
•
Yellow Marrow – made up primarily of fat
cells
Red Marrow – produces red blood cells,
some white blood cells, and platelets
Development of Bones
The skeleton of an embryo is composed
almost entirely of cartilage
 Cartilage: connective tissues with cells that
are scattered in a network of protein fibers
including collagen and elastin
 Ossification: process of cartilage being
replaced by bone
 During adolescence/early adulthood,
cartilage in growth plates are replaced by
bone – stopping growth!

Joints
Joint: place where one bone attaches to
another
 Depending on its type of movement, a
joint is classified as immovable, slightly
movable, or freely movable

Types of Joints

Immovable: allow for no
movement
 Ex. Skull

Slightly Movable: small
amount of restricted
movement
 Ex. joint between
adjacent vertebrae
Types of Joints
Ball-and-Socket: Round end of one
bone fits snuggly into another
 Ex. Shoulder and Hip

Types of Joints
Hinge Joint: movement at joint occurs in
one direction, like a door
 Ex. Knee and Elbow

Types of Joints
Pivot Joint: bone resting atop another
bone permitting free movement
 Ex. Neck, Wrist, Ankle

Types of Joints
Saddle Joints: permit one bone to slide
in two directions
 Ex. knuckles

Structure of Joints
Ligaments: tough
connective tissue that
connects bone to bone
 Synovial Fluid: a
substance that enables
joints to slide over each
other smoothly

Skeletal System Disorders

Arthritis: Inflamed/stiff
joints

Osteoporosis:
weakening of bones,
especially in women
Muscular System
More than 40% of the mass of a human
is muscle
 Muscular system includes large muscles
displayed by some athletes
 Muscular system also includes many
tiny muscles used to help regulate blood
pressure, move food, and power every
movement of the body

Types of Muscle Tissue: Skeletal
Usually attached to bones
 Responsible for voluntary movements:
dancing, walking, typing
 Referred to as striated muscle
 Controlled by the central nervous
system
 Consists of muscle fibers, connective
tissue, blood vessels, and nerves

Skeletal Muscles Labeling
Types of Muscle Tissue: Smooth
Usually not under voluntary control
 Found in walls of hallow structures:
stomach, blood vessels, intestines
 Can function without nervous system
stimulation

Types of Muscle Tissue: Cardiac
Found in the heart ONLY!
 Cells may have up to two nuclei
 Is not under control of the central
nervous system

Muscle Tissue Makeup

Myofibril: smaller structures that make
up a muscle; composed of two filaments
 Myosin: the name of the protein that
composes the thick filament
 Actin: the name of the protein that
composes the thin filament
Muscle Contraction
A muscle contracts when the thin
filaments in the muscle fiber slide over
the thick filaments
 ATP is used to power muscle
contractions
 Large amounts of ATP are needed!

Muscle and Bone Interactions
Tendon: attaches bone
to muscle
 Origin: attachment of
muscle to immovable
bone
 Insertion: attachment to
bone that moves when
muscle contraction
 Muscles move from
insertion point to origin

Exercise and Health
Muscle tone: result of skeletal muscles
remaining in a state of partial contraction
 Regular exercise is important in
maintaining muscular strength
 Aerobic exercise causes the body
systems to become more efficient

Muscle Pain

Sprain: wrenching,
twisting, stretching
injury to a ligament

Strain: injury to
muscle or tendon –
often caused by
overuse
Muscle Pain
Shin splints
 Shin splints is pain
resulting from damage to
the muscles along the shin.
Pain is felt in different areas,
depending on which muscles
are affected.
Shin splints represent an
"overuse injury" and occur
most commonly in runners.
Integumentary System Functions
Barrier against infection and injury
 Regulates body temperature
 Removes waste products from the body
 Provides protection against ultraviolet
radiation from the sun

Skin
Serves as a gateway through which
sensations such as pressure, heat, cold,
and pain are transmitted to the nervous
system
 Two main layers: epidermis, dermis
 Below the dermis is a layer of fat and
connective tissue to insulate the body

Structure of Skin
Skin: Epidermis
Epidermis has two parts: outside portion
is made of dead cells, inside portion is
made of living cells
 As cells move from the inner layer
towards the outer layer, they create
keratin – a fibrous protein
 Eventually the cells die and form a
waterproof coating – skin
 The outer layer of cells is shed every 4-5
weeks

Skin: Epidermis
Epidermis contains melanocytes – cells
that produce melanin
 Melanin protects skin from the damage
of UV rays
 Differences in skin color are due to the
differences in the amount of melanin
produced

Skin: Dermis
Dermis contains collagen, blood
vessels, nerve endings, glands, smooth
muscle, hair follicles
 The vessels in the dermis help control
body temperature: contracting and
widening as needed

Skin: Dermis

Dermis contains two types of glands:
 Sweat glands: produce perspiration; sweat
contains salts, water, and other compounds;
sweat helps get rid of waste
 Sebaceous glands: produce an oily
secretion called sebum; sebum helps keep
the epidermis flexible and waterproof
Skin Cancer
Skin cancer = abnormal growth of cells
in the skin
 Excessive sun exposure can produce
skin cancer
 SPF 15 should be the minimum!!!

Hair and Nails


Keratin forms the basic
structure
Hair
 Functions: protect surface of the
body from UV; prevent
dirt/particles from entering body
 Hair Follicles: tubelike pockets of
epidermal cells that produce hair

Nails
 Nail root: area of rapidly dividing
cells from which nails grow
 Grow at a rate of 3mm per month