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
