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Unit 2 Outline: The Skeletal System 8

Unit 2 Outline: The Skeletal System

Overview of the Skeletal System

♦ The Skeletal System

• Parts of the skeletal system

� (skeleton)

�

�

�

• Divided into two divisions

� skeleton

� skeleton

♦ Functions of Bones

• of the body

• of soft organs

• Storage of and fats

• Blood cell

♦ The Axial Skeleton

• Forms the

part of the body

• Divided into three parts

�

�

�

♦ The Appendicular Skeleton

• (appendages)

• girdle

• girdle

♦ The Skull

• Two sets of bones

�

� bones

• Bones are joined by

• Mandible attached by freely movable joint

♦

• Hollow portions of bones surrounding the nasal

cavity

• Functions

� the skull

� Give resonance and

to voice

Unit 2 Outline: The Skeletal System 9

♦ The Bone

• Only bone that does not

with another bone

• Serves as a moveable base for the

♦ The Vertebral Column

• Vertebrae separated by intervertebral

• The spine has a normal

• Each vertebrae is given a name according to its

location

♦ The Bony Thorax

• Forms a cage to protect major organs

• Made-up of three parts

�

�

� Thoracic

Microscopic Anatomy of Bone

♦ Bones of the Human Body

• The adult skeleton has bones

• Two basic types of bone tissue

� bone

* Homogeneous

� bone

* Small needle-like pieces of bone

* Many open spaces

♦ Bone Markings

• features of bones

• Sites of attachments for ,

tendons, and ligaments

• Passages for and

vessels

• Categories of bone markings

� and processes- grow

out from the bone surface

� or cavities- indentations

♦ Microscopic Anatomy of Bone

Unit 2 Outline: The Skeletal System 10

• (Haversian System)

� A unit of bone

• Central ( ) canal

� Opening in the center of an osteon

� Carries

and

• (Volkman’s) canal

� Canal to the

central canal

� Carries blood vessels and nerves

•

� Cavities containing bone cells (osteocytes)

� Arranged in

rings

•

� Rings around the central canal

� Sites of lacunae

•

� Tiny canals

� Radiate from the canal

to lacunae

� Form a system

♦ Types of Bone Cells

•

� bone cells

•

� Bone- cells

•

� Bone- cells

� Break down bone matrix for

and release of calcium

• Bone remodeling is a process by both osteoblasts

and osteoclasts

Types of Bones and Anatomy of a Long Bone

♦ Classification of Bones

• bones

� Typically longer than wide

� Have a shaft with at both ends

� Contain mostly bone

* Examples: , humerus

• bones

� Generally -shape

� Contain mostly bone

* Examples: , tarsals

• bones

� Thin and flattened

� Usually

� Thin layers of bone around

a layer of spongy bone

* Examples: , ribs, sternum

• bones

� Irregular shape

� Do not fit into other bone classification

categories

* Example: and hip

♦ Gross Anatomy of a Long Bone

•

�

� Composed of bone

•

� of the bone

� Composed mostly of bone

♦ Structures of a Long Bone

Unit 2 Outline: The Skeletal System 11

•

� Outside covering of the diaphysis

� tissue

membrane

• fibers

� periosteum to

underlying bone

•

� Supply bone cells with nutrients

• cartilage

� Covers the external surface of the

� Made of cartilage

� Decreases at joint

surfaces

• cavity

� Cavity of the shaft

� Contains marrow (mostly fat)

in adults

� Contains marrow (for blood

cell formation) in infants

Bone Growth

♦ Changes in the Human Skeleton

• In embryos- skeleton is mostly

cartilage

• Most cartilage is replaced by bone during

development

• Cartilage remains in:

� Bridge of the

� Parts of

�

• Bone salts (minerals)

�

�

♦ Bone Growth

• Epiphyseal plates allow for growth of long bone

during childhood

� New cartilage is continuously formed

� Older cartilage becomes

* Cartilage is

* Bone cartilage

• Bones are remodeled and lengthened until growth

stops

� Bones change somewhat

� Bones grow in

♦ The Fetal Skull

• - fibrous

membranes connecting the cranial bones

� Allow the to grow

� Convert to bone within months after

birth

Unit 2 Outline: The Skeletal System 12

Appendicular Skeleton: The Arm

♦ The Pectoral (Shoulder) Girdle

• Composed of two bones

� - collarbone

� - shoulder blade

• These bones allow the upper limb to have

exceptionally free movement

♦ Bones of the Upper Limb

• The arm is formed by a single bone

�

• The forearm has two bones

�

�

• The hand

� - wrist

� - palm

� - fingers

Appendicular Skeleton: The Leg

♦ Bones of the Pelvic Girdle

• Hip bones

• Composed of three pair of

bones

�

�

� bone

• Bears total weight of the upper body

• Protects several organs

� organs

� Urinary

� Part of the

♦ Differences of the Pelvis

• Female:

� is wider; more circular

� Pelvis is

� Pelvic bones are lighter and thinner

� is shorter and less curved

� Pubic arch is ; more

rounded

Male Female

♦ Bones of the Lower Limbs

• The thigh has one bone

Unit 2 Outline: The Skeletal System 13

� - thigh bone

• The leg has two bones

� - medial

� - lateral

• The foot

� - ankle

� - sole

� - toes

♦ Arches of the Foot

• Bones of the foot are arranged to form three strong

arches

� longitudinal

� transverse

Joints

♦ Joints

• of bones

• Functions

� Hold bones together

� Allow for

• Ways joints are classified

�

�

♦ Functional Classification of Joints

• - immovable joints

• - slightly

moveable joints

• - freely moveable

joints

♦ Structural Classification of Joints

• joints

� Generally

• joints

� Immovable or slightly moveable

• joints

� moveable

♦ Fibrous Joints

• Bones united by tissue

• Examples

�

�

* Allows more movement than sutures

* Ex: distal end of tibia and fibula

♦ Cartilaginous Joints

• Bones connected by

• Examples

Unit 2 Outline: The Skeletal System 14

� Pubic symphysis

� joints

♦ Joints

• Articulating bones are separated by a

joint

♦ Features of Synovial Joints

• cartilage (hyaline cartilage)

covers the ends of bones

• Joint surfaces are enclosed by a fibrous articular

• Joint cavity filled with

fluid

• reinforce the joint

♦ Structures Associated with the Synovial Joint

• - flattened fibrous sacs

� Lined with synovial membranes

� Filled with fluid

� Not actually part of the joint

• Tendon sheath

� Elongated that wraps

around a tendon

Homeostatic Imbalances of the Skeletal System

♦ Bone

• A break in a bone

• Types of bone fractures

� (simple) fracture- does

not penetrate the skin

� Open ( )

fracture- bone penetrates through the skin

• Treated by reduction and

� of the bone

♦ Repair of Bone Fractures

Unit 2 Outline: The Skeletal System 15

• (blood-filled swelling)

is formed

• Break is splinted by

callus

• Bony replaces fibrocartilage callus

• Bone to form a

permanent patch

♦ Inflammatory Conditions Associated with Joints

• - inflammation

of a bursa usually caused by a blow or friction

• - inflammation

of tendon sheaths

• - inflammatory or

degenerative diseases of joints

� Over different types

� The most widespread crippling disease in the

United States

♦ Clinical Forms of Arthritis

•

� Most common arthritis

� Probably related to

processes

• arthritis

� An disease- the

immune system attacks the joints

� Symptoms begin with

inflammation of certain joints

� Often leads to

• Arthritis

� Inflammation of is

caused by a deposition of urate crystals from the

blood

� Can usually be controlled with