CHAPTER 7 CONT…Why is it important to learn about bones???

Bones consist of: Bone tissue, cartilage, dense connective tissue, blood,

and nervous tissue

Functions of bone:◦ Points of attachment◦ Protect and support◦ House blood producing cells◦ Store inorganic salts◦ Form passageways for blood vessels and nerves

Bones are classified according to their shapes.

◦ Long bone Long longitudinal axes and expanded ends

Ex. Femur, ulna

◦ Short bone Cube like, lengths and widths roughly equal

Carpals, tarsals

◦ Flat bone Plate-like with broad surfaces

Scapula, skull bones

◦Irregular bone Variety of shapes, usually connected to other

bones Vertebrae

◦Sesamoid (round) bone Small, nodular

patella

Epiphysis: articulates with other bones Spongy bone:numerous branching

plates Articular cartilage: hyaline cartilage Diaphysis: shaft of bone Medullary cavity: hollow chamber

filled with marrow Endosteum: lines medullary cavity Periosteum: tough vascular covering

that encloses bone Compact bone: tightly packed tissue

in diaphysis

A bones shape makes possible its function.◦ Processes: bony projections provide sites for

ligaments and tendons to attach.

◦ Grooves and openings: provide passageways for blood vessels and nerves.

oSinus: cavity in bone of skull filled with air in the bones of the face and skull They lighten the weight of the skull and this is the reason why your

head feels heavy and you feel tired and sleepy during a sinus attack. They give resonance to your voice. They also filter and moisten the air that we breathe. They also remove unwanted air particles.

oFontaneles: areas of incomplete

Intramembranous ossification. (soft spots)

*Know entire chart on page 142!!!!!

Body

Lamina

Vertebral foramen

Spinous process

Cervical-7 Thoracic-12 Lumbar-5

First 2 cervical : Atlas (nod head yes) Axis (pivot head)

BODY PART FEMALE MALE

SKULL Smaller, lighter, rounder

PELVIC GIRDLE Lighter, thinner

PELVIC CAVITYWider but shorter

SACRUM Wider

COCCYX More movable

Bones form by replacing existing connective tissue in either of 2 ways:◦ 1. Intramembranous bones originate between

sheet-like layers of connective tissues.◦ 2. Endochondral bones begin as masses of

cartilage that are later replaced by bone tissue.Osteoblasts:

bone forming cellsOssification: formation of bone

*bone growth animation

Endochondral Bones◦ Epiphyseal plate: layers of young cells

undergoing mitosis and producing new cells. This plate thickens and the bone lengthens.

*If the epiphyseal plate is damaged before it ossifies, elongation of the long bone may cease prematurely, or growth may be uneven. For this reason, injuries to the epiphyses of a young person’s bones are of special concern. An epiphysis is sometimes altered

surgically in order to equalize the growth rate of bones developing at very different rates.

A break in a bone Classified by cause and nature of break Major steps for fracture repair

◦ 1. blood escapes from ruptured blood vessels and forms a hematoma.

◦ 2. Spongy bone forms in regions close to developing blood vessels, and fibrocartilage forms in more distant regions.

◦ 3. A bony callus replaces fibrocartilage.

◦ 4. Osteoclasts remove excess bony tissue, restoring new bone structure much like the original.

Hematopoiesis◦ Before birth-in the yolk sac◦ After birth-liver and spleen◦ Later-bone marrow

Marrow◦ Soft, netlike mass of connective tissue

Red marrow: forms erythrocytes, leukocytes, thrombocytes Hemoglobin (carries O2)gives it its red color

Yellow marrow: stores fat eventually replaces red marrow

Bones and muscles interact as levers.

Joints (articulations)-the body has 230◦Functional junctions between bones◦Classified according to the degree of

movement and type of tissue that binds the bone 1. Fibrous

Lie b/w bones in close contact Ex. Sutures in skull Most immovable

2. Cartilaginous Connected by hyaline or fibrocartilage Ex. Vertebrea, ribs, pubis Limited movement

3. Synovial Most joints are these Allow for free movement Some have menisci (shock absorbing pads),

others have bursae (fluid filled sacs)

Classified by shape and movement (pg.165)

1. Ball and socket2. Condyloid3. Gliding4. Hinge5. Pivot6. saddle

Bone cancer Abnormally active osteoclasts destroy bone

Cleft Palate◦ Fusion of palatine process of the maxilla is incomplete at birth

Spina Bifida Laminae of vertebrae fails to unite, vertebral arch remains

incomplete. Lumbar region is usually affected.

Hip fracture◦ Usually in elderly people, occurs in neck of femur b/w

trochanters

Ruptured/Herniated Disk◦ Intervertebral disks are made of tough, outer layer of

fibrocartilage and an elastic central mass. Over time. The disk degenerates or ruptures and can press on spinal cord causing back pain and numbness.

Osteoporosis◦ loss of bone volume and mineral content; spaces fill with fatty

tissue; can cause spontaneous fractures; occurs mainly in white females past menopause

Arthritis◦ Inflamed swollen and painful joints; causes restricted

movements; articular cartilage is damaged◦ Ex. Rhematoid arthritis (severe)