chapter 5 part 1 Flashcards
skeletal system
skeletal bones, cartilage, ligaments, connective tissue to stabalize the skeleton
bones
“dynamic organs” that are made up of severl other tissues
support
the framework for the attachment of other organs
storage of minerals
calcium ions: 98% of the body calcium ions are in the bones and there are also phosphate ions
blood cell production
bone marrow produces erythrocytes, leukocytes, and platelets (thrombocytes); fat is also in the marrow
leverage
muscles pull on the bones to produce movement
protection
ribs protect heart and lungs, skill protects the brain, vertabrae protect the spinal cord and the pelvic bone protects the reproductive organs
bones (osseous tissue) parts
supporting connective tissue, outer linning, and inner linning
connective tissue
specialized cells and solid matrix (material around the cell)
outer linning
periosteum,
inner lining
endosteum
matrix
calcium phosphate eventually converts to hydroxyapatite crystals and the crystals are resistant to compression
collagen fibers
make up 2/3 of the bone matrix, contribute to bone tensile strength, collagen and hydroxyapatite make the bone tissue strong and reinforce it
bone cells
make up 2% of the bone mass
osteocytes
mature bone cells, maintain the protein and mineral content of the matirx
osteoblasts
-immature bone cells, found on the inner and outer surfaces of bone and produce osteoid (involved in making the matrix)
-involved in making new bone (osteogenesis)
-can also convert to osteocytes (when they mature)
osteogenesis
creation of new bone
osteoprogenitor cells
found on the inner and outer surfaces of bone and they differentiate to form new osteoblasts, also involved in repairing broken bones
osteoclasts
secrete acids that dissolve bone and release stored calcium and phosphate ions into blood (osteolysis)
reasons to break down bone
get rid of old cells, make new cells, blood calcium levels are too low the osteoblasts break it down to release calcium and raise levels
osteon
basic unit of skeletal bones including the central canal, canaliculi, osteocytes, lacunae and lamellae
central canal
blood vessels, nerves in it
two types of osseous tissue
compact bone and spongy bone
compact bone (dense bone)
type of osseous tissue, dense and solid, forms the walls of bone outlining the medullary cavity
spongy bone (trabecular bone)
-looks like a sponge, open network of pates and makes the bone light weight
-trabeculae are arranges in parallel struts and form branching plates
-trabeculae also form an open network
red bone marrow
in the spongy bone (makes blood)
compact bone layer
around the spongy bone, has osteons and makes up the dense, solid portion fo the bone
medullary cavity
in the middle under the spongy bone and compact bone
spongy bone cross section
no central canal
support of compact bone
conducts stress from one area of the body to another area, support from end to end and is weak from the sides
support of spongy bone
trabeculae create strength to deal with stress form the side
epiphysis
each end of the long bones
diaphysis
shaft of the long bones
metaphysis
narrow growth zone between the epiphysis and the diaphysis at each end
periosteum
-tendons and ligaments are attached to it
-isolates and protects the bone from surrounding tissue
-route and place for attachment for circulatory and nervous supply
-part of growth and repair
-connects bone to the connctive tissue network of deep fascia
periosteum and tendons
tendons are cemented into the lamellae by osteoblasts (tendons are part of the bone)
children growing
cartilage expands in the metaphysis and becomes bone
endosteum
inner surface of the bone and lines the medullary cavity
-consists of osteoprogenitor cells and are involved in growth and repair
first 6 weeks of development
skeleton made of cartilage
ossification
cartilage cells replaced by bone cells 2 types
-intramembranous ossification
-endochondral ossification
osteogenesis
bone formation
calcification
deposition of calcium ions into the bone tissue
intramembranous ossification
development of the clavicle, mandible, skull and face
-mesenchymal cells differentiate and form osteoblasts that start to secrete matrix where they get trapped
-osteoblasts than differentiate to form osteocytes eventually form compact bone
-OCCURS IN A MEMBRANE
-MEMBRANE BECOMES BONE
endochondral ossification
involved in the development of limbs, vertebrae and hips
-cartilage becomes bone
-cartilage matrix grows inward (interstitial growth)
-cartilage matrix growth outwards (appositional growth)
-blood vessels grow around the cartilage
-perichondrial cells concert to osteoblasts that develop the superficial layer of the bone around the cartilage
-blood vessels penetrate cartilage
-osteoblasts develop spongy bone in the diaphysis
-becomes the primary center of ossification
intersitial growth
cartilage matrix grows inward
appositional growth
cartilage matrix grows outward (diameter of bone gets larger)
-blood vessels running parallel to bone become surrounded by bone cells
-“tunnels” form that have blood vessels in them
bone development
-cartilage shaped like bone
-blood vessls grow into epiphysis which becomes the secondary oss center
-osteoclasts break down bone in the center and make it hollow then build one on the sides
-hollowed out bone turns to spongy bone
-epishyseal cartilage grows wider and turns to bone during late teens
-layer of cartilage left around the bone
endochondrial ossification continued
-cartilage near the epiphysis concerts to bone
-blood vessels penetrate the epiphysis
-osteoblasts begin to develop spongy bone in the epiphysis
-epiphysis becomes the secondary center of ossification
epiphyseal plate
area of cartilage in metaphysis also called epiphyseal cartilage (near the diaphysis)
-width gets narrower with age
enlarging bone diameter (appositional growth)
-osteoblasts produce matrix and create concentric rings
-osteoblasts are laying down more bone material, osteoclasts are dissolving the inner bone and creating marrow cavity
