Skeletal System
Functions:
1)
2)
3)
4)
5)
Supports body
Protects internal organs
Provides for movement
Stores mineral reserves
Provides a site for blood cell formation
Skeletal System
► Has
206 bones
► Divided
into two sections:
1) Axial: skull, vertebral column, ribs, and
sternum
2) Appendicular: all other bones
Structure of Bones
► Bones
are living tissue!!
► Periosteum – tough layer of connective
tissue surrounding bone
► Compact bone – beneath the periosteum
(dense but not solid)
► Haversian canals– tubes that run through
compact bone and contain blood vessels
and nerves
Structure of Bones
►
Spongy bone – inside outer layer of
compact bone
► Osteocytes
– digest away old bone
► Osteoclasts – maintain healthy bone
► Osteoblasts – make new bone
3-D Section of Bone Tissue
Bone Homeostasis
► 1.Most
of our skeleton is constantly being
broken down, and built back up
► 2.Amount
of bone built up = amount of
bone broken down
► 3.This
balance of breakdown and buildup is
called bone homeostasis
► Bone
marrow – soft tissue center of bone
 Maintains the balance of minerals
 Serves as a storage for minerals (Ca, P)
 Two Types:
1) Yellow – made mostly of fats, aids in Red
Blood Cell (RBC) production
2) Red – produces RBCs, white BC, and cells to
help clotting
Skeletal Development
► The
skeleton of the embryo is made of
cartilage
► Bone
begins to replace cartilage by 9th week
of development (known as ossification)
Joints
►
►
►
Joints – where two or more bones meet
Most allow movement
Some are fixed (no movement): skull
Pelvis, Sexual Dimorphism
Types of Joints
►
Five types:
1) Ball and socket: allows rotational movements
(shoulder, hip)
Ball and Socket Movement
Types of Joints, Cont’d
2) Pivot: bones twist against each other (atlas
and axis of your vertebrae)
Pivot Joint in Arm
Types of Joints Cont’d
3) Hinge: back and forth movements much like a door
(elbow, knee)
Types of Joints
4) Gliding: bones slide
against each other
(wrist)
5) Saddle: Freely
moveable joint found
only in the thumb
Joint support
► Ligaments: bands of tissue that connect bone to bone
 Surrounds joints with wide range of motion and little
skeletal support
► Cartilage: covers bone ends and allows for smooth
movement. Can also be found in joint to provide
cushion (meniscus)
► Bursa: sacs of fluid that act as shock absorbers
► Tendons: bands of tissue that connect muscle to bone
(patella tendon, Achilles)
Problems with Skeletal System Breaks
► Complete/Incomplete
(Greenstick)
► Displaced
► Simple/Compound
(breaks skin)
► Impacted or Comminuted
► Spiral
► Hairline
Breaks - Complete & Displaced
Breaks - Incomplete/Greenstick
Breaks - Spiral
Breaks - Compound
Breaks - Comminuted
Breaks - Hairline
Osteoporosis
Problems with Skeletal System Rheumatoid arthritis
► Inflammation
in joints
► Redness, warmth, swelling, pain, fatigue
► Occurs on both sides of body
► Genetic, environmental, hormonal factors;
immune system attacks the joints and other
organs
Rheumatoid arthritis
Problems with Skeletal System Dislocation
Normal
Dislocated
Dislocation
Normal
Dislocated