What is the skeleton of adults composed of?

Where does cartilage remain in adults?

Hyaline  cartilage is replaced by bone.

Cartilage remains in external ear, bridge of the nose, larynx, trachea, joints, and parts of the rib cage.

1-Support + protect the body as an internal framework

2-Provide a system of levers to allow muscle mvmt

3-Lipid + mineral storage in bones

4-Hematopoiesis in red marrow bone cavities

Axial: bones that lie around the body's center of gravity

Appendicular: bones of the limbs, or appendages

Skull (29) = cranium (8) + facial bones (14)

Thoracic cage (27) = ribs (24) + floating ribs (2) + sternum (1)

Vertebral column (26) = cervical (7) + lumbar (5) + sacral (14)

Upper limb = humerus + radius + ulna

Hands/wrists = carpals + phalanges + metacarpals

Pectoral girdle = clavicle + scapula

Pelvic girdle= ilium + ischium + pubis

Lower limb = femur + patella + tibia + fibula

Feet/ankles = tarsals + metatarsals + phalanges + talus + calcaneus

1-Articular cartilages: cover bones at movable joints

2-Costal cartilages: found connecting the ribs to the sternum

3-Laryngeal cartilages: construct the larynx (voice box)

4-Tracheal: reinforce passageways of the respiratory system

5-Bronchial: reinforce passageways of the respiratory system

6-Nasal: support the external nose

7-Intervertebral discs: separate and cushion vertebrae

8-External ear hyaline cartilage

What is perichodrium?

What type of tissue is it?

What is its function?

Dense connective tissue that surrounds skeletal cartilages.

Function: resists distortion of cartilage when subjected to pressure; plays role in cartilage growth and repair

Function of hyaline cartilage

where would you find it in the skeletal system

provide sturdy support with some resilience or give

comprises most skeletal cartilage (thyroid, cricoid, nasal, costal, shoulder, elbow, wrists, fingers, hips, feet, ankles)

Function of elastic cartilage.

Where would you find it?

Flexible and tolerates bending

Location: external ear, epiglottis

Function of fibrocartilage.

What is it made of?

Where would you find it?

-Has great tensile strength and can withstand heavy compression

-Consists of rows of chondrocytes alternating with rows of collagen fibers

-Intervertebral discs, meniscus of knee, pubic symphysis

Compact: looks smooth and homogeneous

Spongy: lots of open space; many trabeculae (bars)

List six groups of bones.

How are they classified?

Classified based on gross anatomy

Long bones

Short bones

Flat bones

Irregular bones

Sesamoid bones

Wormian or Sutural bones

Describe long bones

Where would you find them?

-Much longer than they are wide, generally consisting of a shaft with heads at either end

-Femur, phalanges, humerus, radius, ulna, tibia, fibia, metatarsals

Describe short bones.

Where would you find them?

-Typically cube shaped; contain more spongy bone than compact

-Tarsals, carpals

Describe flat bones.

Where would you find them?

-generally thin with two waferlike layers of compact bone sandwiching a layer of spongy bone; many are curved

-skull

Describe irregular bones.

Where would you find them?

Not long, short, or flat :)

Vertebrae

What are sesamoid bones?

Where are they formed?

Where would you find them?

-Special types of short bones formed in tendons

-Patellas (kneecaps)

What are Wormian bones?

What is another name for them?

Are they included in the 206 bones in the body? Why/why not?

-Tiny bones b/w cranial bones

-Sutural bones

-No - they vary in number + location in individuals

-Projections: processes that grow out from the bone and serve as sites of muscle attachment or help form joints

-Depressions/cavities: indentations or openings in the bone that often serve as conduits for nerves and blood vessels

Tuberosity

Crest

Trochanger

Line

Tubercle

Epicondyle

Spine

Process

head

facet

condyle

ramus

groove

fissure

foramen

notch

what is a tuberosity?

is it a projection or depression?

example.

projection

large rounded projection; may be roughened

ex: coxal bone - ischial tuberosity

what is a crest?

projection or depression?

example

projection

narrow ridge of bone; usually prominent

ex: coxal bone - iliac crest

what is a trochanter?

depression or projection?

example.

very large blunt irregularly shaped process

ex: femur - trochanters

What is a line bone marking?

projection or depression?

example.

narrow ridge of bone; less prominent than a crest

projection

ex: intertrochanteric line

What is a tubercle?

projection or depression?

example

small rounded projection or process

ex: femur - adductor tubercle

what is an epicondyle?

projection or depression?

example.

raised area on or above a condyle

projection

ex: medial epicondyle of the femur

what is a spine bone marking?

projection or depression?

example

sharp slender often pointed projection

ex: spinous process of vertebrae

what is a process bone marking?

depression or projection?

example

any bony prominence

projection

ex: spinous process of vertebra

what is a head bone marking?

projection or depression?

example

bony expansion carried on a narrow neck

projection

ex: head of a rib

what is a facet bone marking?

projection or depression?

example

small nearly flat articluar surface

projection

facets of a rib

what is a condyle bone marking?

depression or projection?

example

rounded articluar projection

ex: condyle on mandible

what is a ramus bone marking?

projection or depression?

example

armlike bar of bone

projection

ex: ramus in mandible

what is a groove bone marking?

projection or depression?

example

furrow (like a long narrow trench)

depression

ex: groove in mandible

what is a fissure bone marking?

depression or opening

example

narrow slitlike opening

ex: inferior orbital fissure

what is a formen bone marking?

opening or depression?

example

round or oval opening through a bone

ex: foramen magnum of skull

what is a notch bone marking?

depression or projection?

example

indentation at the edge of a structure

depression

ex: notch in mandible

what is the diaphysis of a long bone?

compact/spongy bone?

shaft

compact bone

periosteum

many fibers penetrate the bone

what are perforating fibers?

what is another name for them?

fibers penetrating the periosteum that blood vessels and nerves travel through

aka Sharpey's fibers

compare osteoblasts and osteoclasts.

where are they found?

bone-forming  cells; bone-destroying cells

found on the inner, or osteogenic, layer of the periosteum

what is the epiphysis?

describe the bone tissue structure

the end of the long bone

composed of thin layer of compact bone that encloses spongy bone

what is articular cartilage composed of?

where would you find it?

what is its function?

glassy hyaline cartilage

covers the epiphyseal surface (in place of periosteum)

provides a smooth surface to prevent friction at foint surfaces

plate: see in growing animals - thin area of hyaline cartilage that provides for longitudinal growth of bone

line: replaces epiphyseal plate when bone growth is stopped

in adults, what is the central cavity of the shaft called?

what is it composed of?

how does it differ in an infant?

medullary cavity

composed of adipose tissue, or yellow marrow

in infants, the medullary cavity is made of red marrow and forms blood cells

lines the diaphysis and covers trabeculae of spongy bone and lines canals of compact bone

contains osteoblasts and osteoclasts

describe endochondral ossificaion

where does it begin?

what bones do NOT form in this manner?

all bones of the body inferior to the sull form in the embryo by this process which uses hyaline cartilage "bones" as patterns for bone formation

primary ossification center of the shaft

clavicles

1-fibrous membrane covering hyaline cartilage is vascularized and converted to periosteum

2-osteoblasts at the inner surface of the periosteum secrete bone matrix around the hyaline cartilage forming a bone collar

3-cartilage in the shaft center calcifies and then hollows out forming an internal cavity

4-perisoteal bud (vessels, nerves, red marrow elements, osteoblasts + clasts) invade internal cavity to become medullary cavity --center =primary ossification center

5-bones grow from primary ossification center and medullary cavity enlarges

6-chondroblasts lay down new cartilage matrix on epiphyseal plate