lecture 6 bones and skeletal tissues Flashcards
-found throughout the body
cartilage
- surrounds cartilages
- resists outward pressure
- functions in growth and repair of cartilage
- consists primarily of water
- resilient tissue
- springs back to original shape
perichondrium
- all cartilages share some similarities
- cell type is chondrocyte
- chondrocytes are located within lacunae
- matrix contains fibers and jelly like ground substance
characteristics of all types of cartilage
- most abundant cartilage
- chondrocytes appear spherical
- collagen unit fibril is the only type of fiber in the matrix
- ground substance holds a large amount of water
- provides support through flexibility
hyaline cartilage
- contains many elastic fibers
- able to tolerate repeated bending
- locations ;
- epiglottis and cartilage of external ear
elastic cartilage
- resists strong compression and strong tension
- intermediate between hyaline and elastic cartilage
- location ;
- pubic symphysis, menisci of knee, annulus fibrosus
fibrocartilage
-chondroblasts in surround perichondrium produce new cartilage
appositional growth
chondrocytes within cartilage divide and secrete new matrix
interstitial growth
- bones contain several types of tissues
- dominated by bone connective
- contains nervous and blood connective tissue
- contains cartilage in articular cartilages
- contatins epithelial tissue lining blood vessels
tissues in bone
provide hard framework for function of bones
support
skeletal muscles use bones as levers for function of bones
movement
underlying organs for function of bones
protection
reservoir for importnat minerals
mineral storage
bone contains red marrow
blood cell formation
osteoblasts secrete osteocalcin
energy metabolism
- organic components
- cells, fibers, and ground substance
- inorganic components
- mineral salts that invade bony matrix
bone tissue characteristics
- unique composition of matrix
- gives bone exceptional properties
- 355 organic components
- -contribute to flexibility and tensile strength
- 65% inorganic components
- provides exceptional hardness, resist compression
extracellular matrix
3 types of cells that produce or maintain bone
- osteogenic cells
- osteoblasts
- osteocytes
stem cells that differentiate into osteoblasts
osteogenic cells
actively produce and secrete bone matrix
osteoblasts
bone matrix called
osteoid
keep bone matrix healthy
osteocytes
- found in bone tissue
- responsible for resorption of bone
- are derived from a line of white blood cells
- secrete hydrochloric acid and lysosomal enzymes
osteoclasts
longer than wide ; a shaft plus ends
long bones
roughly cube shaped bones
short bones
thin and flattened; usually curved
flat bones
various shapes; do not fit into other categories
irregular bones
dense outer layer of bone
compact bone
internal network of bone and trabeculae
spongy bone
little beams of bone
-open spaces between trabeculae are filled with marrow
trabeculae
shaft of a bone
diaphysis
ends of a bone
epiphyses
well vascularized
blood vessels
hollow cavity filled with yellow marrow
medullary cavity
periosteum, perforating collagen fiber bundles (sharpeys fibers) and endosteum
membranes
3 broad categories of bone markings
- projections for muscle attachments
- surfaces that form joints
- depressions and opening
- cancellous bone of the skeleton is replaced every 3-4 years
- compact bone replaced every 10 years
- bone matrix and osteocytes are continually removed and replaced
bone remodeling
- accomplished by osteoblasts for bone remodeling
- osteoblasts lay down osteoid and the calcium salts crystallize in about a week.
bone deposition
- accomplished by osteoclasts for bone remodeling
- osteoclasts are giant cells with many nuclei
- take up dead osteocytes and collagen by phagocytosis.
bone resorption
- characterized by low bone mass
- bone reabsorption outpaces bone deposition
- occurs most often in women after menopause
osteoporosis
-occurs in adults ; bones are inadequately mineralized
osteomalacia
occurs in children ; analogous to osteomalacia
rickets
-form of bone cancer
osteosarcoma
- skeleton grows until 18-21
- in children ; bone formation exceeds rate of bone reabsorption
- in young adults, bone formation and bone reabsorption are in balance
- in old age; reabsorption predominates
- bone mass declines with age
skeleton throughout life
a membrane around the bone. has 2 layers ; superficial and deep
periosteum
-dense irregular connective tissue to help resist tension
superficial layer
is osteogenic makes osteoblasts and osteoclasts the site for bone remodeling
deep layer
-connected or anchored to the bone by perforating collagen fiber bundles
sharpeys fibers
inside the bone; covers the trabeculae and lines the central canals of the osteons.
endosteum
also called “Haversian systems” ; long cylindrical structures that run parallel to the long axis of the bone.
osteon
tubes inside tubes
lamella
-also called Haversian canals; runs through center of each osteon, contains arteries, veins and nerves. lined with endosteum
central canal
-also called “volksmanns canal” -makes right angles to the central canal.
perforating canal
small tubes that connect to the lacunae that the osteocytes sit in
canaliculi
leftover osteon that have cut apart by bone remodeling
interstitial lamellae
occur on internal and external surface of the compact bone. extend over the entire circumference of the diaphysis
circumferential lamellae
bones heal in 4 steps. reduction is the realignment of the bones. closed reduction is the coaxing of bone back into place. open reduction is using pins and wires to set the bones
bone fractures
bone fracture steps
- hematoma formation
- fibrocartilaginous callus formation
- bony callus formation
- bone remodeling
