Skeletal system

parts of the skeletal system

Bones (skeleton) Joints Cartilages Ligaments

Two subdivisions of the skeleton

axial skeleton appendicular skeleton

Functions of Bones

Support the Body, Protect soft organs, Allows movement due to attached skeletal muscles, stores minerals and fats

Examples of the Functions

Small and vertebrae for brain and spinal cord, Ribcage for thoracic cavity organs

What minerals/fats are stored

calcium and phosphorous, fat in the internal marrow cavity, blood cell formation [Chematopoiesis]

How many bones in the adult body?

206 bones

Two basic types of bone tissue

Compact bone Homogeneous,

Spongy bone

Small needle

How are bones classified?

Long, short, flat, irregular

long bone

typically longer than they are wide shaft with heads situated at both ends contain mostly compact bone (solid) all of the bones of the limbs (except wrist, ankle, and kneecap bones)

Examples of Long bones

femur, humerus ( funny bone)

Short bones

Generally cube

Sesamoid bones

are a type of short bone which form within tendons (patella)

Examples of short bones

carpals, tarsals

Flat bones

thin, flattened, and usually carved two thin layers of compact bone surround a layer of spongy bone

Examples of flat bones

ribs, skull, sternum

Irregular bones

do not fit into other bone classification categories

Examples of irregular bones

Vertebrae, Hip bones

Diaphysis

shaft of long bone, composed of compact bone

Epiphysis

ends of the bone composed mostly of spongy bone

Periosteum

Outside covering of the diaphysis Fibrous connective tissue membrane

Arteries

supply bone cells with nutrients

Perforating (Sharpey's) fibers

secure periosteum to underlying bone

articular cartilage

Covers the external surface of the epiphyses Made of hyaline cartilage, Decreases friction at joint surfaces

epiphyseal plate

flat plate of hyaline

Marrow (medulary cavity)

cavity inside of the shaft contains yellow marrow (mostly flat) in adults contains red marrow for blood cell formation in infants *in adults, red marrow is situated in cavities of spongy bone and epiphyses of some lone bone*

Formation of the skeletal system

In embryos, the skeleton is primarily HYALINE CARTILAGe, during DEVELOPMENT, cartilage is REPLACED by BONE

Where does cartilage remain?

Bridge of the nose, Parts of ribs, Joints

Bone Growth (Ossification)

Epiphyseal plates allow for lengthwise growth of long bones during childhood, New cartilage is continuously formed, Bone replaces cartilage through the action of osteoblasts

Bones are remodeled in response to two factors

1. Blood calcium levels 2. Pull of gravity and muscles on the skeleton

Osteoclasts

Giant bone destroying cells, breaks down matrix for remodeling and release of calcium

bone remodeling is performed by both

osteoblasts and osteoclasts

Types of fractures

comminuted, compression, depressed, impacted, spiral, greenstick

Comminuted

Bone breaks into many fragments

Compression

Bone is crushed

Impacted

Broken bone ends are forced into each other

Spiral

Ragged break occurs when excessive twisting fores are applied to a bone

Greenstick

Bone breaks incompletely, common in kids

Hematoma

bone fracture repair, blood-filled swelling is form

repair bone fractures

Break is spindled by fibrocartilage to form a callus, fibrocartilage callus is replaced by a bony callus, bony callus is remodeled to form a permanent

axial skeleton has

vertebral column, bony thorax, skull

How many bones are in the appendicular skeleton

126

how many bones in axial skeleton

80

how many bones in thoracic cage

25

where is the hyoid bone located?

In front of your neck (cervical region)

the only movable bone in the skull

the mandible

the tail bone is the

coccyx

the skull has two sets of bones such as

cranium, facial bones

Functions of paranasal sinuses

lighten the skull, give resonance and amplification to voice (make it higher)

the hyoid bone

that does not articulate with another bone, serves as a movable base for the tongue, aids in swallowing and speech

fetal skull

large compared to the infants total body length, ¼ body length compared to adult skull which is 1/8 body length

Fontanels

Fibrous membranes connecting with the cranial bones, allow the skull compression during birth, allow the brain to grow during later pregnancy and infancy, convert to bone within 24 months after birth

how many vertebral bones are there, and what are they separated by?

24, separated by intervertebral discs (7 cervical vertebrae in the neck, 12 thoracic vertebrae are in the neck, 5 lumbar vertebrae are associated with the lower back)

Joint inflammation is known as

arthritis

Diarthroses joints have

a greater degree of mobility and flexibility than synthroses joints

The last two pairs of ribs are called

false Ribs/floating ribs because they have no anterior attachments

The intervertebral discs that cushion the spine and absorb shock are composed of

fibro cartilage

SAD acronym

syntharsis joints cannot move, amphiarthrosis joints, diarthrosis joints freely movable with synovial joints

Nine vertebrae fuse to form two composite bones such as

sacrum and coccyx

First curvature is ___ and primary curvature

C shaped, newborn

Adults have a ___ shaped curvature

S shaped

Ribs

true ribs, false Ribs, floating ribs

thorax forms a cage to protect major organs such as

sternum, ribs, and thoracic vertebrae

Two girdles

Pectoral girdle, pelvic girdle

Appendicular skeleton consists of

Limbs, Pectoral Girdle, and Pelvic girdle