Skeletal System

lamellae

Concentric rings made up of groups of hollow tubes of bone matrix

Epiphysis

End of a long bone

flat bones

These bones are thin, flat, and curved. They form the ribs, breastbone, and skull.

Is there osteoclast activity in both types of ossification?

Yes

Osteoperosis

a condition in which the bones become fragile and break easily, loss of bone mass

periosteum

a dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints. (covering)

spiral fracture

a fracture in which the bone has been twisted apart

stress fracture

a slight bone break caused by repetitive low-impact forces, such as running, rather than single forceful impact

marrow

a soft fatty substance in the cavities of bones, in which blood cells are produced (yellow, fat)

What do parathyroid hormone (PTH) and calcitonin do

adjust the blood calcium levels by removing or depositing calcium in the bones

Osteoblasts

are cells that can form new bone. As the osteoblasts builds the bone matrix, it become trapped and becomes an osteocyte.

appendicular skeleton

arms, legs, pectoral girdle, pelvic girdle

What are the two divisions of the skeletal system

axial and appendicular

greenstick fracture

bending and incomplete break of a bone

simple fracture

bone breaks cleanly but does not penetrate the skin

comminuted fracture

bone breaks into many fragments

osteocyte

bone cell

intramembranous ossification

bone develops from a fibrous membrane (word breakdown=make bone within a membrane)

endochondral ossification

bone forms by replacing hyaline cartilage (word breakdown=making bone inside cartilage)

Wolff's law

bone grows or remodels in response to the demands placed on it

compound fracture (open)

bone is broken and a fragment of bone protrudes through an open wound in the skin

compressed fracture

bone is crushed

rickets

bone soften due to lack of vitamin D, mainly found in children

What is the storehouse for calcium

bones

irregular bones

bones of the vertebrae and face

secondary ossification center

bones ossify here, found in the epiphysis of bones

long bones

bones that are longer than they are wide, ex. femur, humerus, phalanges

What is the skeletal system made up of

bones, cartilage, ligaments

depression fracture

broken bone portion is pressed inward

short bones

carpals and tarsals (square)

What is the original model/template for endochondral ossification

cartilage

contents of bone

compact bone, spongy bone, blood, cartilage, nerves, dense regular etc.

articular

covers the ends of long bones

where does endochondral ossification begin?

diaphysis

When is there a medullary cavity during ossification?

during endochondral ossification

Mesenchyme

embryonic stem cells that create bone and connective tissues

thyroid gland

endocrine gland that surrounds the trachea in the neck

Types of bone formed from intramembranous ossification

flat and irregular

osteogenesis

formation of bone (word breakdown=bone beginning)

pathologic fracture

fracture caused by diseased or weakened bone (osteoporosis)

avulsion fracture

fragment of bone chipped away from the main bone

Where is the spongy bone formed during endochondral ossification?

in the epiphysis

Types of bone formed from endochondral ossification

long and short

four major categories of bone types

long, short, flat, irregular

What is the original model/template for intramembranous ossification

membranes

Endosteum

membranous lining of the hollow cavity of the bone

bone spur

occur when the body produces extra bone tissue

oblique fracture

occurs at an angle across the bone

Bones=

organ

Canaliculi

Hairlike canals that connect lacunae to each other and the central canal. Provides communication and carries nutrients.

compact bone

Hard, dense bone tissue that is beneath the outer membrane of a bone (bullseye)

Hydroxyapatite

Hardy crystals consisting of calcium and phosphate that form the bone matrix.

Where is the spongy bone formed during intramembranous ossification?

In between layers of compact bone

spongy bone

Layer of bone tissue having many small spaces and found just inside the layer of compact bone. (red, blood)

epiphysial plate

Plate of cartialidge in between diaphysis and epiphysis. Where bone growth occurs.

Flow chart when Blood Calcium levels drop below 9-11mg/100ml

parathyroid gland, parathyroid hormone, osteoclast activity stimulated, bone is degraded(broken down), Calcium released to blood, blood calcium levels return to normal

parathyroid gland

parathyroid hormone (PTH), back of thyroid

What does calcium do

"tones the bones" (builds bones)

Osteoclasts

responsible for bone resorption, where bone is dissolved and the calcium released. Bone is constantly being built and then broken down but these cells.

Diaphysis

shaft of a long bone

axial skeleton

skull, vertebae, ribs

Lacuna

small cavities in bone that contain osteocytes (space/house)

Why are proper levels of calcium important?

strong bones/teeth Blood clotting nerve impulses muscle contractions releasing hormones normal heart beat

Osteon

structural unit of compact bone

Functions of skeletal system

support/structure, protection, acts as levers(movement), stores calcium and lipids(storage), blood cell production(hematopoiesis)

Osteogenic cells

the only bone cells that divide, they are stem cells that can mature into osteoblasts.

trabeculae

the spongy bone you can see

Flow chart when Blood calcium levels rise above 9-11mg/100 ml

thyroid gland, calcitonin hormone, osteoblast activity is stimulated, calcium taken from blood, bone built, blood calcium levels return to normal

primary ossification center

where ossification begins, happens in the diaphysis

4 steps in the repair of a fracture

1: Hematoma- blood clot stabilizes fracture bleeding, bruise 2: fibrocartilaginous callus forms between inner layers of spongy bone (soft) 3: Bony callus forms (hard) 4: Remodeling-the bulky callus is remolded back to normal bone shape by osteoclasts

How many bones in the body

206

where does intramembranous ossification begin?

6 weeks after fertilization

how long does it take for the skeleton to form, what is this skeleton made of?

6 weeks after fertilization, made of hyaline cartilage and fibrous membranes

Calcium homeostasis of blood

9-11 mg/100 ml

central canal (haversian canal)

At center of osteon; carries blood vessels, nerves, and lymphatic vessels