MIDTERM LEC 2: BONE AND CARTILAGE Flashcards
● Part of/surrounded by connective tissue
● Tough, durable form of supporting
connective tissue, characterized by its
extracellular matrix (ECM)
● Lacks nerves
CARTILAGE
CARTILAGE ORIGNATED FROM?
EMBRYONIC MESENCHYME
ECM of cartilage:
➢ Has high concentrations of ___and __________, interacting with collagen and elastic fibers
GAGs, proteoglycans
- is a SHEATH OF DENSE CONNECTIVE TISSUES that surrounds cartilage in most places
- forming an interface between the cartilage and the tissues supported by the cartilage
- HARBORS THE BLOOD SUPPLY serving the cartilage and a small neural component
PERICHONDRIUM
THE PHYSICAL PROPERTIES OF CARTILAGE DEPEND ON ELECTROSTATIC BONDS BETWEEN:
● ECM TYPE II COLLAGEN
● HYALURONAN/ HYALURONATE/ HYALURONIC ACID
- COVERS THE ENDS OF BONE in
movable joints - erodes in the course of arthritic
degeneration, - LACKS PERICHONDRIUM and is
sustained by the diffusion of
oxygen and nutrients from the
synovial fluid
ARTICULAR CARTILAGE
● (Gr. chondros, cartilage + kytos, cell)
● Cartilage cells
● Cells of the cartilage embedded in the
ECM which unlike connective tissue
proper contains no other cell types
SYNTHESIZE ANDMANTAIN ALL ECM COMPONENTS
● Exhibit LOW METABOLIC ACTIVITY
● Location: cavities (LACUNAE)
CHONDROCYTE
- HYALOS: glass; glassy appearance,
bluish - MOST COMMON TYPE OF CARTILAGE
● Fresh state: HOMOGENOUS and
SEMI TRANSPARENT
● Location in adult:
1. Articular surfaces of movable joints
2. Walls of larger respiratory
passages - (nose, larynx, trachea,
bronchi)
3. Ventral ends of ribs - where they articulate with the sternum, and
4. Epiphyseal plates of long
bones - where it makes possible longitudinal bone growth
HYALINE CARTILAGE
hyaline cartilage that forms the temporary skeleton and later on replaced by bones
EMBRYO
● Nearly 40% collagen (mostly type II)
● Embedded in a firm, hydrated gel of
proteoglycans and structural
glycoproteins
ECM OF HYALINE CARTILAGE
make the matrix generally BASOPHILIC (negative) and the thin collagen fibrils are barely discernible.
PROTEOGLYCANS
- MOST ABUNDANT PROTEOGLYCAN OF HYALINE CARTILAGE
- bound noncovalently by link proteins to long polymers of hyaluronan
AGGRECAN
- a form of structural MULTIADHESIVE GLYCOPROTEIN
- Binds specifically to GAGs, collagen, and integrins, mediating the adherence of chondrocytes to the ECM.
CHONDRONECTIN
CHONDROCYTES OF HYALINE CARTILAGE
● Chondrocytes respire under________
tension because cartilage matrix is
AVASCULAR
LOW - OXYGEN
Cell metabolism: Glucose metabolized
mainly by
ANAEROBIC GLYCOLYSIS
young chondrocytes that has an elliptic
shape, with the long axes parallel to the
surface; may appear in groups of up to
eight cells that originate from mitotic
divisions of a single chondroblast and
are called ISOGENOUS AGGREGATES
CHONDROBLAST
most collagen in hyaline cartilage
TYPE II COLLAGEN
metabolize glucose
ANAEROBIC GLYCOLYSIS
DRY WEIGHT OF HYALINE CARTILAGE (40% collagen embedded in firm, hydrated gel of proteoglycans and structural glycoproteins)
MATRIX
- elliptic shape, with long axes parallel to the surface
- Round and may appear in groups of up to 8 cells (Isogenous aggrefates)
- Secretes collagen and other ECM
components
CHONDROBLAST
- a PITUITARY -DERIVED protein
- major regulator of hyaline cartilage growth
- acts INDIRECTLY, promoting the
endocrine release from the liver
of insulin-like growth factors,
or somatomedins, which directly
stimulate the cells of hyaline
cartilage
SOMATOTROPHIN
- Source of nutrients
- Dense connective tissue
- Essential for growth and maintenance of cartilage
PERICHONDRIUM
OUTER REGION OF PERICHONDRIUM is consists largely of collagen ______ fibers and ____
TYPE I, FIBROBLASTS
OUTER REGION OF PERICHONDRIUM contains ________ which provide a SOURCE FOR A NEW CHONDROBLASTS hat divide and differentiate into chondrocytes
MESENCHYMAL STEM CELLS