1. SKELETAL SYSTEM
radtech-board.ohd.hr.state.or.us

2. Functions of the Skeletal System
Provide points for attachment for muscles, assistance in movement
Protect and support softer tissues
Blood cell production
Stores minerals such as calcium and phosphorus.
and releases into or absorbs minerals from
bloodstream
Form passageways for blood vessels and nerves

3. Bones classified according to shape
Long bones– long with expanded ends
thigh bones (femur) and forearm
Short bones– cube-like
wrists and ankles
Flat bones– plate-like structures with broad surfaces
Ribs, scapula and some bones of skull
4. Irregular bones– variety of shapes
Vertebrae and many facial bones
5. Sesamoid bones– small and nodular
Kneecap (patella)

4. Parts of a Long Bone
Epiphysis– expanded portion at end of bone which forms joint with other bones
Articular Cartilage– hyaline cartilage coating on epiphysis
Diaphysis– shaft of bone
Periosteum– tough, vascular covering of fibrous tissue enclosing the the bone

5. Parts of a Long Bone
5. Compact bone– found in wall of diaphysis is compact bone (no spaces)
6. Spongy bone– found in epiphysis, has numerous branching bony plates, helps to reduce weight
Both compact and spongy bone are strong and resist bending

6. Compact Bone Makes up 80% of the skeleton
Forms external layer of all bones/bulk of the diaphyses of long bone
Provides protection, support, resists stress
Arranged in units called osteon or Haversian canals

7. Parts of a Long Bone
7. Medullary Cavity– hollow chamber along diaphysis
Endosteum– thin layer of cells line medullary cavity
Marrow– specialized type of connective tissue

8. Endochondral Bones (and bone growth)
Most of the bones in the skeleton
Develop in the fetus from masses of hyaline cartilage shaped like future bony structures
Ossification– formation of bones
Osteoblasts– bone-forming cells
Ossification (bone growth) begins in the center of the diaphysis

9. Bone Growth Starts in diaphysis (primary ossification center)
Epiphyseal plate– band of cartilage that is between the primary ossification center and secondary ossification center and has layers of dividing cells (mitosis)
Bone stops growing when ossification centers meet

10. Growth of Bones

11. Bone Growth
Osteoblasts deposit bony matrix around them in the connective tissue
When they are completely surrounded by the bony matrix, they are osteocytes
Osteocytes are bone cells.
Osteoclasts– secrete an acid and clean up old bone cells so new bone can be produced.

12. Homeostasis of Bone tissue
Osteoclasts clean up old bone cells and osteoblasts produce new bone matrix
3 to 5% of bone tissue is exchanged each year

13. Factors Affecting Bone Development, Growth and Repair
Nutrition
In the absence of vitamin D, calcium is poorly absorbed… bones have less calcium (softening and bone deformation can occur)
2. Hormonal Secretion
a) Growth hormone secreted by pituitary gland stimulates division of the cartilage cells in the epiphyseal plates.

14. Factors Affecting Bone Development, Growth and Repair continued…
B) Sex hormones stimulate ossification of the epiphyseal plates
Physical Exercise
Pulling on muscular attachments to bones stresses the bones, stimulating the bone tissue to thicken and strengthen

15. Bone Fractures Use the info on page 137
Define open fracture (compound fracture)
Complete the chart on Bone Fracture types.

16. Blood Cell Formation
Hematopoiesis– the process of blood cell formation
As a fetus, hematopoeisis occurs in the yolk sac, then later in the liver and spleen, then in the bone marrow.
2 types of marrow:
Red marrow– in an infant, it is found in the cavities of most bones
As you age, yellow marrow replaces it
And red marrow is found in the spongy bones of the skull, ribs, sternum, clavicles, vertebrae and hip

17. Blood Cell Formation continued
Red Marrow:
Site of formation of red blood cells, white blood cells and platelets.
Gets its color from hemoglobin in the red blood cells
2. Yellow Marrow
NOT ACTIVE IN BLOOD CELL PRODUCTION
Stores fat

19. Storage of Inorganic Salts (Homeostasis of Calcium)
Bones store calcium
Mostly in the form of calcium phosphate
If blood is low in calcium, osteoclasts will break down calcium phosphate and release Ca to blood stream
High blood calcium stimulates osteoblasts to form bone tissue and store calcium
Maintaining proper Ca levels is important to muscle contractions, nerve impulses, and blood clotting

20. Osteoporosis low bone density

21. 2 Main Parts of Skeleton
Axial Skeleton– supports the head, neck and trunk
Skull– cranium (brain case) and facial bones
Hyoid– between lower jaw and larynx supports the tongue and attachments
Vertebral Column-- backbone
Thoracic cage– protects organs of the thoracic cavity

22. 2 Main Parts of Skeleton
Appendicular Skeleton—consists of bones of upper and lower limbs and bones that anchor the limbs to the axial skeleton
Pectoral Girdle– connects upper limbs to axial skeleton
Upper limbs
Pelvic Girdle– connects lower limbs to axial skeleton
Lower limbs

23. Infantile Skull
Skull is incompletely developed with fibrous membranes connecting the cranial bones
Fontanels– incomplete intramembranous ossification or “soft spots”
Allows the skull to be compressible and change shapes to pass through birth canal.
Fontanels will close after birth

24. Skeleton Parts Complete skeleton chart
Define words and be able to label bones

25. Function of Joints Joint– functional junctions between bones
They bind parts of the skeletal system
Make possible bone growth
Permit parts of the skeleton to change shape during childbirth
Enable the body to move in response to skeletal muscle contractions

26. Types of Joints
Classified by type of tissue (most commonly used type of classification)
Fibrous joint– lie between bones that closely contact one another
A thin layer of dense connective tissue joins the bones at such joints
No appreciable movement
Called a SUTURE between skull bones

27. Types of Joints Cartilaginous Joints
Hyaline or fibrocartilage connects the bones at these joints
Slight flexibility at the discs allows for limited movement
Examples: intervertebral discs, symphysis pubis and 1st rib with the sternum

28. Types of Joints Synovial Joints Most joints are this type
Allow free movement
Articular ends of bones are covered with hyaline cartilage and a surrounding dense connective tissue holds them together
Has an inner lining of synovial fluid which lubricates the joint

29. Types of Synovial Joints
Gliding (or Planar)
Side to side, back and forth gliding movement
Ex: carpal bones at the wrist
Hinge
Produces opening-closing motion
Ex: knee, elbow
Pivot
Rotation around its own longitudinal axis
Ex. Atlanto-axial joint to allow head to turn from side to side (“no”)
Condyloid
Movement in all planes, no rotation
Ex: movement of index finger
Saddle
Mainly in two planes, surface of one bones fit into complementary surface of another
Ex: joint between the carpal and metacarpal of thumb
Ball and socket
Multi-axial movement
Ex: shoulder and hip joints

30. Condyloid Joint

31. Rheumatism and Arthritis
Rheumatoid arthritis
Cartilage has eroded and fibrous tissues ossifies and fuses the joints so that it becomes immovable

32. Types of Joint Movement
Define the types of joint movement and be able to give examples
Flexion Extension
Plantar flexion Dorsiflexion
Hyperextension
Abduction Adduction
Rotation Circumduction
Pronation Supination
Eversion Inversion
Retraction Protraction

33. Skeletal System Interaction (with other systems)
Complete skeletal system interaction chart.