Cartilage and Bone Flashcards
cartilage is simply described as a
specialized form of fibrous connective tissue
a main feature of cartilage compared to the rest of the body is that it is
avascular
Cartilage contains ________ embedded in the extracellular matrix
chondrocytes
Three types of cartilage
hyaline cartilage, elastic cartilage, fibrocartilage
3 primary functions of cartilage
support soft tissues
guide the development
growth of long bones
the temporary skeleton for the fetus until replaced with bone is primarily
hyaline cartilage
location of hyaline cartilage
articular ends of long bones in adults, walls of respiratory system (nose, larynx, trachea, and bronchi) and ventral ends of ribs
In the hyaline cartilage matrix, the area adjacent to chondrocytes is called
the territorial (capsular) matrix
the territorial (capsular) matrix is
poor in collagen, but rich in glycosaminoglycans
Components of hyaline cartilage matrix
homogenous, amorphous ground substance with proteoglycan aggregates and chondronectin embedded type II collagen
layer of dense irregular connective tissue-surrounds hyaline cartilage except at articular surfaces
Perichondrium
perichondrium provides
blood supply for the avascular cartilage
Components of perichondrium
outer fibrous layer( containing type I collagen, fibroblasts, and blood vessels)and – inner cellular layer (containing chondrogenic cells- source of new cartilage cells)
mature cartilage cells embedded in lacunae
chondrocytes
cartilage is made and maintained by
chondrocytes
chondrocytes may occur in groups of 2-8 cells because
when cells divide they stay in the same lacunae
this type of cartilage is less prone to degeneration than hyaline cartilage
elastic cartilage
Elastic cartilage matrix
contains a network of elastic fibers– gives a yellowish color to elastic cartilage
type of collagen with no perichondrium
fibrocartilage
elastic cartilage is located
where flexible support is required (external ear, Eustachian tube, and epiglottis, larynx)
fibrocartilage has properties between
connective tissue and hyaline cartilage
Where is fibrocartilage found?
fibrocartilage is found where support and tensile strength are needed in conjunction with hyaline cartilage, other fibrous tissues, or both
In fibrocartilage, chondrocytes may align along
lines of stress
fibrocartilage has alternating rows of___________ and thick bundles of ____________
fibroblast derived chondrocytes and type I collagen
main component of adult skeleton
BONE
dynamic tissue-constantly undergoes shape change, absorption and resorption in response to biomechanics forces
BONE!
specialized CT-calcified EM with osteocytes embedded in the matrix
Bone
Bone matrix consists primarily of
hydroxyapatite crystals
organic portion of bone is primarily made of
type I collagen
ground substance of bone contains
chondroitin sulfate and keratan sulfate
______ are 50% of the dry weight of bone
minerals
inorganic (Calcified) portion of bone is made up of
calcium, phosphate, bicarbonate, citrate, magnesium, potassium, and sodium
first bone formed in fetal development
primary bone
primary bone has a ________ mineral content than secondary bone
lower
2 types of secondary bone
compact bone and spongy bone
dense, outer portion of bone
compact bone
meshwork of trabecular in bone interior
spongy bone
compact bone is organized with
outer circumferential lamellae below the periosteum and inner circumferential lamellae adjacent to the marrow cavity
other than compact bone, rest of bone is organized around
haversian canal systems (osteons)
Osteons are connected to each other by
Volkmann’s canals
bone periosteum distributes
blood vessels to bone
layer of non calcified CT covering bone on external surfaces, except at synovial articulations
Bone periosteum
Sharpey’s fibers
(type I collagen) - attach periosteum to the bone
thin specialized CT which lines marrow cavities
endosteum
Endosteum is the source of _________________ and ________ for bone growth and repair
Endosteum is the source of osteoprogenitor cells and osteoblasts for bone growth and repair
osteoprogenitor cells can differentiate into
osteoblasts
flatttened/spindled shaped . inner layer of periosteum and endosteal cells that line marrow cavity
osteoprogenitor cells
osteoblasts regulate
mineralization of bone
this cuboidal/polygonal bone cell secretes collagen, ground substance and osteoid
osteoblast
osteocytes maintain
bone matrix
osteocytes reside in
lacuna
to a limited extent osteocytes are capable of
synthesizing and resorbing matric
osteocytes communicate with other osteocytes and osteoblasts via
processes that extend through canaliculi and gap junctions with other cells
osteoclast
multinucleate cell - acidophilic. macrophage lineage- phagocytic. Actively resorb bone
osteocLasts release
lysosomes into extracellular space
Howship’s lacuna
depression in bone created by osteoclast. cell seals off area, acidifies and secretes acid hydrolyses to resorb bone.
decrease in bone mass associated with a normal ratio of mineral to matrix. Due to decreased bone formation, increased bone resorbtion or both
Osteoporosis
osteoporosis occurs primarily in old age because of diminished secretion of
growth hormone
osteomalacia is due to _______ ________ in adults
calcium deficiency
osteomalacia in children
Rickets. Primarily due to vitamin D deficiency but calcium deficiency can be a contributing factor
Osteomalacia is characterized by ________ ___________ of newly formed bone and _________ of calcified bone
deficient calcification
decalcification
Acromegaly
excess pituitary growth hormone in adults
Acromegaly is characterized by _____________ in extremities and in parts of facial skeleton
very thick bones
osteomalacia is usually accompanied by deformation of bone spicules in epiphyseal plates which causes
bones to grow more slowly and allows bone deformation
Sharpeys fibers attach
Periosteum to bone
Fibrocartilage easily confused with
Dense regular connective tissue
