Anatomy- The Skeletal System

Functions of the skeletal system

Support

Storage ( calcium, lipids)

Blood cell production

Protection of vital organs

Leverage- skeletal muscles pull the bones in a particular direction

How many bones are in the skeleton?

206

Major divisions of the skeleton

axial and appendicular

axial skeleton

80 bones

Bones in the:

Skull

Vertebral column

Thorax

Hyoid

appendicular skeleton

126 bones

Bones in the:

Shoulders

Upper limbs

Lower limbs

Pelvic girdle

Osteon

contains rings of bone cells with a central canal

Lacuna

small cavities in bone that contain osteocytes

Haversian, or central canal (compact bone )

central channel containing blood vessels and nerves

4 types of bone cells

osteogenic cells, osteoblasts, osteocytes, osteoclasts; stem cells

Osteoprogenerator

make immature bone cells, called osteoblasts

Osteoblasts

cells responsible for making bone matrix, which is called osteoid

osteoclytes

an osteoblast that is completely surrounded by the matrix; mature bone cells

Osteoclasts

bone- resorbing cell

Osteoperosis

calcium deficiency, vertebrae collapse into each other; can also be caused by an overproduction of PTH

PTH (Para Thyroid Hormone)

tells osteoclasts to increase activity, antagonistic

How does calcium enter the bloodstream?

via osteoclasts

Calcitonin

a hormone made by the thyroid glands that helps store calcium in the matrix of the bones, makes bones stronger

Long bones

compact bone, arranged in cocentric layers

Red blood cells

red marrow

Stores lipids

yellow marrow

Medullar Cavity

space where bone marrow is contained

Endosteum

the lining of the medullary cavity, protects the delicate bone marrow

Epiphysis

End of a long bone where mitosis occurs

Pox epiphysis

growth plate

Shaft (Middle) of the Bone

diaphysis, ends covered with cartilage

Short bones

-Cube-shaped bones of the wrist and ankle

-Bones that form within tendons

Coxae

hip bones, have an irregular shape

Ossification

process of bone formation

somotropin

growth hormone, increases glucose levels

Gland that makes growth hormone

pituitary

Gigantism

overproduction of growth hormone

Dwarfism

underproduction of growth hormone

Rickets

Vitamin D deficiency, causes bow-leggedness

acromegaly

When an adult makes too much growth hormone, bones get wider and thicker

How are fractures classified?

cause and nature of the break

simple

broken bone is not exposed and protected by unbroken skin

Compund

broken bone exposed to the outside by an opening in the skin

Communiated fracture

complete break with 3 or more fragments

Greenstick fracture

bending and incomplete break of a bone; most often seen in children

transverse fracture

complete horizontal break

fissured fracture

incomplete longitudinal break

impacted/compression fracture

results in crushed bones

Pott's fracture

fracture of both the fibula and the tibula

collies fracture

when the distal parts of the radius smashes into the wrist bones

epiphesial fracture

break through the growth plate

depressed fracture

when a bone is passed inward in the skull, can reach the brain

oblique fracture

complete break at an angle

spiral fracture

caused by a twisting motion

Process of healing a fracture

-Hematoma (blood-filled swelling) is formed

-Break is splinted by fibrocartilage to form a callus

-Fibrocartilage callus is replaced by a bony callus

-Bony callus is remolded to form a permanent patch

Tuberosity

Large rounded projection; may be roughened

Crest

Narrow ridge of bone; usually prominent

Trochanter

Very large, blunt, irregularly shaped process

Line

Narrow ridge of bone; less prominent than a crest

Tubercule

small rounded projection or process

Epicondoyle

raised area on or above a condoyle

Spine

sharp, slender, often pointed projection

Process

any bony prominence

Projections that help form joints

head, facet, condyle, ramus

head

bony expansion carried on a narrow neck

facet

smooth, nearly flat articular surface

Condoyle

rounded articular projection

ramus

armlike bar of bone

Meatus

canal-like passageway

sinus

Cavity within a bone, filled with air and lined with mucous membrane

Fossa

Shallow, basinlike depression in a bone, often serving as an articular surface

groove

furrow

fissure

Narrow, slitlike opening

Foramen

Round or oval opening through a bone

Joint

where two or more bones meet

immovable joints

joint that allows little or no movement, interlocked and help together by connective tissue or they are fused together

semi-movable joint

permit limited movement

pubic symphysis

cartilaginous joint at which two pubic bones fuse together

vertebral discs

cartielege in the vertebral column

gliding joint

allows one bone to slide over another

hinge joint

Joint between bones (as at the elbow or knee) that permits motion in only one plane

pivot joint

rotating bone turns around an axis; i.e. connection between radius/ulna and humerus

ball and socket joint

An articulation (as the hip joint) in which the rounded head of one bone fits into a cuplike cavity of the other and admits movement in any direction

synovial joints

freely movable joints

Ligament

Connective tissue that connects bone to bone

articular cartilage

covers the surfaces of bones where they come together to form joints

Cartilege cells

condrocytes

synovial fluid

thin lubricating film over the surface of a joint and protects the ends of the bones from function