Skeletal System Basics

Functions (5)

-protection

-support

-hematopoiesis (making BCs)

-fat storage

-mineral storage and pH balance

Microanatomy of the bone

-a ground substance (calcium phosphate mineral; strong; dissolves in acid)

-fibers (collagen; flexible; denatures in heat)

Bone growth

-epiphyseal plate (growth plate): new cartilage → new bone

-epiphyseal line: show place where bone once grew from

Compact bone

-hard, calcified

-function: supports/protects, provides levers for muscles to act on, stores calcium + other minerals

Spongy bone

-bone mesh

-osteocytes

-red bone marrow

How many bones do we have as adults?

206+

Axial skeleton

skull, vertebral column, ribs, sternum, hyoid

Appendicular skeleton

upper limb bones + pectoral girdle, lower limbs + ox coxae of the pelvic girdle

Short bones

cube or sphere-shaped

(ex: carpals)

Flat bones

bony sandwich

(ex: sternum)

Long bones

longer than they are wide

(ex: femur)

Irregular bones

have characteristics of more than one bone

(ex: vertebra)

sesamoid bones

form inside tendons 

(ex: patella)

Red bone marrow

-in epiphysis

-makes blood cells

Yellow bone marrow

-in medullary cavity

-stored fat

Periosteum

outside layer of connective tissue coverings

Endosteum

inside layer of connective tissue coverings

Articular cartilage

on the bone ends at the joint