TEASm A&P Skeletal System

Skeletal System

body’s support systm of structure and protection for internal organs

How many bones are there in the body?

206

Primary function

body support, internal organ protection, reservoir for minerals, produce RBC and WBC and enables movement

What are the two main parts of the skeletal system?

Axial and Appendicular skeletal

Axial Skeletal

forms central axis of our body; facilitates breathing, head and neck movement and is the foundation for the appendicular

Appendicular Skeletal

helps function of all body parts

Long Bone

cylindrical shape, longer than there width and involve movement

Short Bones

resemble cubes, length and width are equivalent, and mobilize muscle contraction and provide stability

Sesamoid Bone

small, round, handle pressure and are imbedded in tendons or muscles

Flat Bone

curved, thin, for body structure and protection

Irregular Bone

defy regular shape classifications, protect against forces and support movement in multiple directions

What is bones composed of?

compact, and spongy

Compact Bone

hard, dense, outer layer of bones that protect and strengthen bones

Spongy/Cancellous/Trabecular Bone

Porous, honey comb like structure containing bone marrow

Red Bone Marrow

contains hematopoetic stem cells that produce RBC, WBC and platelets

Yellow Bone Marrow

contains mesenchymal stem cells producing fat, cartilage and bone; reservoir for long term energy

Cells involved in Bone and Cartilage formation and maintenance

Osteoblasts, osteocytes, and osteoclasts

Osteoblasts

“bone builders”; create new bone, bone synthesis and mineralization

Osteocytes

primary cells in bone tissue and maintain structure

Osteoclasts

bone reabsorbing cells, breaks down bone tissue

Bone Remodeling Steps

1) Resting 2) Reabsorption 3) Reversal 4) Formation 5) Mineralization

Resting

inactive state where remodeling happens

Reabsorption

osteoclasts create acidic environment to dissolve mineral components of bone

Reversal

mononuclear cell appear on surface and transition between reabsorption and formation

Formation

osteoblasts create new osteoid at reabsorption to replenish bone

Mineralization

osteoid mineralization, restoring mechanical strength and support

Chondroblasts

form cartilage, support bone joint connection and are a template

Chondrocytes

maintain structure of cartilage

Closed Fracture

doesn’t penetrate skin

Open Fracture

does penetrate skin

Comminuted Fracture

bone shatters into 3 or more pieces

Impacted fracture

ends of bone driven together

GreenStick fracture

bend and crack, does not break all the way through