ch 6 Flashcards
skeletal cartilage
highly resilient, molded cartilage tissues that consists primarily of water
T/F: skeletal cartilage contains blood vessels and nerves
FALSE
it does NOT contain blood vessels or nerves
perichondrium
layer of dense connective tissue surrounding cartilage like a girdle
resists outward expansion
T/F: perichondrium contains blood vessels
TRUE
allows nutrient delivery to cartilage
what is cartilage made up of
chondrocytes
lacunae
small spaces/cavities
what are chondrocytes encased in
lacunae
what are the three types of cartilage
hyaline
elastic
fibrocartilage
hyaline cartilage
provides support, flexibility, and resilience
contains COLLAGEN FIBERS
joints, ribs, respiratory, nasal cartilage
elastic cartilage
similar to hyaline
contains ELASTIC FIBERS
external ear and epiglottis
fibrocartilage
great tensile strength
THICK COLLAGEN FIBERS
menisci of knee, vertebral disks
what are the two ways that cartilage grows
appositional growth
interstitial growth
appositional growth
growth from the outside
new matrix laid down on surface of cartilage
bone gets thicker
interstitial growth
growth from the inside
chondrocytes within lacunae divide and secrete new matrix
expands from within
bone gets longer
function of bones
support
protection
movement
mineral + growth factor storage
blood cell formation
triglyceride (fat) storage
hormone production
hematopoiesis
production of blood cells in RED MARROW CAVITIES
osteocalcin
protein secreted by bones
regulates insulin secretion, glucose levels, metabolism
how many named bones are in the human skeleton
206
axial skeleton
long axis of body
skull, vertebral column, rib cage
appendicular skeleton
bones of upper and lower limbs
girdles attaching limbs to axial skeleton
long bones
longer than they are wide
limb bones
short bones
cube shaped bones
in wrist and ankles
sesamoid bones
small, round bones embedded in tendons
vary in size
ex patella
flat bones
thin, flat, slightly curved
sternum, scapula, ribs, most skull bonesq
irregular bones
complicated shapes
vertebrae and hip bones
compact bone
dense outer layer on every bone
appears smooth and solid
spongy bone
made up of honeycomb of trabeculae
trabeculae
thin, branching structure found within spongy bone
lightweight and strong
open spaces in it filled with yellow or red bone marrow
periosteum
vascular connective tissue that covers the OUTSIDE of compact bone
fibrous layer (outer)
osteogenic layer (inner)
endosteum
vascular membrane of connective tissue that covers INSIDE portion of compact bone
structure of short, irregular, and flat bones
periosteum
compact bone
spongy bone
endosteum
structure of long bones
diaphysis
epiphysis
membranes
diaphysis
tubular shaft that forms long axis of bone
epiphyses
ends of long bones
compact bone externally
spongy bone internally
epiphyseal line
between diaphysis and epiphysis
remnant of epiphyseal plate
epiphyseal plate
growth plate in long bones
not in adults
red marrow
found within trabecular cavities of spongy bone
what is in the medullary cavities of newborns
red marrow
osteogenic cells
mitotically active stem cells in periosteum and endosteum
aka osteogenic cells
osteoblasts
bone-forming cells that secrete osteoid
made up of collagen and calcium binding proteins
actively mitotic
osteocytes
mature bone cells
no longer divide
act as stress or strain sensors
bone-lining cells
flat cells on bone surfaces
maintenance and repair of bone tissue
periosteal cells (EXTERNAL bone surface)
endosteal cells (INTERNAL surfaces)
osteoclasts
large cells that break down bone tissue via enzymes
another name for compact bone
lamellar bone
what is compact bone consisted of
osteon (Haversian system)
canals and canaliculi
interstitial and circumferential lamellae
osteon (Haversian system)
structural unit of compact bone
surrounded by lamellae
canals and canaliculi
central (Haversian) canal
perforating (Volkman’s) canals
central (Haversian) canal
runs through core of osteon
contains blood vessels and nerve fibers
perforating (Volkman’s) canals
lined with endosteum
connects blood and nerve supply to periosteum
canaliculi
hairlike canals that connect lacunae to each other and to central canal
spongy bone
organized along stress lines to resist stress on bone
T/F: bone is made up of organic and inorganic components
true!!
ossification
bone tissue formation
another name for ossification
osteogenesis
endochondral ossification
bone forms by replacing hyaline cartilage
forms most of skeleton
bones are called cartilage bones
intramembranous ossification
bone develops from fibrous membrane
bones are called membrane bones
endochondral ossifcation
forms most bones inferior to base of skull except clavicles
requires breakdown of hyaline cartilage prior
begins at primary ossification center in shaft
five steps in process of ossification
- bone collar forms around diaphysis of cartilage model
- central cartilage in dialysis calcifies and then develops cavities
- periosteal bud invades cavities, formation of spongy bone
- diaphysis elongates and medullary cavity forms
- epiphyses ossify
intramembranous ossification
forms flat bones (ex. frontal, parietal, occipital, temporal, clavicle)
1. mesenchymal cells cluster and become osteoblasts
2. osteoid secreted and calcified
3. woven bone formed when osteoid is laid down around blood vessels
4. lamellar bone replaces woven bone, red marrow appears
five zones of epiphyseal plate
resting
proliferation
hypertrophic
calcification
ossification
resting (quiescent) zone
area of cartilage on epiphyseal side of epiphyseal plate that is relatively inactive
proliferation (growth) zone
area of cartilage on diaphysis side of epiphyseal plate that is rapidly dividing
new cells move and push upward, causing lengthening
hypertrophic zone
area with older chondrocytes closer to diaphysis
interconnecting spaces form
calcification zone
surrounding cartilage matrix calcifies
chondrocytes die and deteriorate
ossification zone
chondrite deterioration leaves calcified cartilage
osteoclasts erode spicules and are covered with new bone
ultimately replaced with spongy bone
medullary cavity enlarges
growth hormone
stimulates epiphyseal plate activity
thyroid hormone
moderates activity of growth hormone
testosterone
adolescent growth spurts in men
ends growth by inducing epiphyseal plate closure
estrogen
adolescent growth spurts in women
ends growth by inducing epiphyseal plate closure
bone remodeling
bone deposit and resorption
old bone broken down and new bone is formed
bone resorption
osteoclasts break down bone tissue
bone formation
osteoblasts deposit new bone matrix
osteoid seam
band of unmineralized bone matrix that marks area of new matrix
calcification front
abrupt transition zone between osteoid seam and older mineralized bone
parathyroid hormone
produced in response to LOW blood calcium levels
stimulates osteoclasts to resorb bone
calcium released into blood
calcitonin
produced by parafollicular cells of thyroid gland
produced in response to HIGH blood calcium levels
leptin
hormone released by adipose tissue
inhibits osteoclasts
seratonin
regulates mood and sleep
interferes with osteoblast activities
Wolf’s Law
bones grow or remodel in response to demands placed on them
fractures
breaks
nondisplaced fracture
ends remain in normal position
displaced fracture
ends are not in normal alignment
complete fracture
broken all the way through
incomplete fracture
not broken all the way through
open (compound) fracture
skin is penetrated, broken
closed (simple) fracture
skin is not penetrated, broken
reduction
alignment of broken bone ends
closed reduction
manipulated to the correct position
open reduction
surgery
pins or wires to secure end
four major stages of bone repair
hematoma formation
fibrocartilaginous callus formation
bony callus forming
bone remodeling
hematoma formation
clotted blood at site of break
fibrocartilaginous callus formation
capillaries grow into hematoma
phagocytic cells clear debris
fibroblasts secrete collagen fibers to span break
fibrocartilaginous callus formed (cartilage matrix of repair tissue)
bony callus formation
trabeculae form in fibrocartilaginous callus
callus is converted to bony (hard) callus of spongy bone
lasts 2 months
bone remodeling (bone repair step)
starts during bony callus formation
excess material removed
compact bone laid down to reconstruct shaft walls
fixed!
osteomalacia
soft, weak bones
poorly mineralized
rickets
osteomalacia in children
bowed legs
vitamin D or calcium deficiency
osteoporosis
bone resorption exceeds deposit
bone mass declines
older women
Paget’s disease
excessive and haphazard bone deposit and resorption
bone grows fast and develops poorly
Pagetic bone
