Cartilage Flashcards
Describe the skeletal system functions. (Bone)
- Bone = frame, protect, support soft tissues
Describe the skeletal system functions. (Cartilage)
Cartilage = shock absorber in menisci & intervertebral disks
A. semi rigid support for:
-bones
-joints
-ligaments
-respiratory tree
-intervertebral discs
B. Protects ends of bone
C. 3 types: based on amount of collagen/elastic fibers in extracellular matrix & amount of GAGs
-hyaline, elastic, & fibrocartilage
Describe the skeletal system functions. (Ligaments)
-provide stability of joints
-connects bone to bone
-can get strained
Describe the skeletal system functions. (Tendons)
-strong, flexible connection between muscle & bone
-can get strained
Describe the skeletal system functions. (Joints)
-space with fluid between bones
-lubricated
-movement & flexibility
Describe the skeletal system differentiation.
-originates from undifferentiated mesenchymal cells
-differentiate into: cartilage, bone, fibrous tissue
Describe cartilage differentiation.
-center = differentiation & maturation
-immature at periphery = perichondrium (condensed CT)
>elongated fusiform cells that looks like fibroblasts
>gives rise to chondroblasts
-completion of growth = chondrocytes in ECF
Describe cartilage.
-avascular (young animals have blood vessels)
-CT
-lymphatic vessels
-nerves (adults)
-supports soft tissues (ex. Ear, eyelid, trachea, bronchi)
-longitudinal growth = endochondral ossification
-chondrocytes
Describe chondrogensis. (Picture)
A = embryonic mesenchyme
B = proliferation & early differentiation
C = chondroblasts separate from each other due to production of matrix
D = multiplication of cartilage cells in aggregates
mature cartilage = slow cell turnover & replacement of cells
Describe isogenous group.
-cluster of chondrocytes formed through division of progenitor cell
-found in hyaline cartilage, elastic cartilage, & fibrocartilage
Describe endochondral ossification.
-cartilage in physes matures, dies, mineralized & forms scaffold to form bone = longitudinal growth of bones
-primary ossification centers form first at epiphyses
Growth plate (physis) picture.
Hyaline cartilage picture.
Elastic cartilage picture.
Ear, epiglottis
flexibility needed
Fibrocartilage picture.
-menisci disc
-insertion of tendon & ligaments
Describe the locations of hyaline cartilage.
-growth plate/physes
-articular cartilage covers joint surfaces at Costco-chondral junctions of ribs, nasal septum, larynx, tracheal rings, bronchi
-fetal axial & appendicular skeleton
Describe elastic cartilage.
-perichondrium, chondroblasts, chondrocytes in large lacunae
-elastic fibers that stain dark
-flexible tissue
-found in epiglottis & corniculate & cuneiform processes of the arytenoid cartilage in external auditory canal in ear pinna
Describe fibrocartilage.
-lacks a perichondrium = no regen
-chondrocytes & lacunae
-intermediate between cartilage & dense CT
-type 1 collagen
>tendons, ligaments, skin, fascia, scar tissue
-support & strength:
>intervertebral discs (annulus fibrosus)
>menisci
>insertions of tendons & ligaments
>mandibular symphysis
>pubic symphysis
Fibrocytes (picture).
-mature & inactive fibroblasts
Describe perichondrium.
-outer layer of dense fibrous CT
-resembles mature fibroblasts
-inner layer = hyaline cartilage (not on articular surfaces/cartilage)
>chondrogenic, chondroblasts
Describe cartilage matrix.
-collagen, elastic fibers, proteoglycans (GAGs)
-basophilia = high concentration of GAGs
-matrix near chrondrocytes (territorial) is more basophillic bc of greater amount of GAG than the matrix further away from the chondrocytes (interterritorial)
Describe GAGs
-sulfated polysaccharide units
-GAG = glycosaminoglycans
-EX: HCl in joint fluid
-GAGs bound to a protein core from macromolecules = proteoglycans = shock absorption (strong/flexible cartilage)
-within matrix GAGs = in collagen & elastic fibers giving rise to hyaline, elastic, fibro-cartilage
Describe tendons.
-muscle to bone
-85% collagen
-parallel bundles of Type I collagen
-elastic
-limited regen in mature tendon
-injury = type III collage (scar tissue = stronger but less elastic)
>prone to re-injure due to less flexibility
What are the different types of joints?
fibrous joints = synarthroses
>bones/cartilage united by fibrous tissue
1. Sutures (cranial)
2. Syndesmosis (tibia-fibula)
3. Gomphosis (ex. Tooth socket)
Describe cartilaginous (amphiarthrosis) joints.
Bones/cartilage united by hyaline cartilage (ex. Costrochondrol joints) or fibrocartilage (ex. Pelvic & mandibular symphysis)
Describe synovial (diarthrosis/true joints).
-Unite 2 bone ends
-covered by articular cartilage
-surrounded by thick articular capsule
(Ex. Synovial joints of appendicular skeleton & vertebral joints)
Describe the morphologic types of joints.
- Fibrous (synarthrosis)
>ex. Sutures in skull - Cartilaginous (amphiathrosis)
>ex. Ribs - Synovial (diarthrosis)
>ex. Limbs
Describe synovial joints.
-bone surfaces in joint cavity = covered by hyaline cartilage (articular)
-joint cavity = consists of a capsule with a fibrous portion
>vascularized synovial membrane lined by:
1. Type A cell = phagocytic function - remove debris
2. Type B cell = secret HCl & protein complex (mucin) into synovial fluid -> lubricant, protectant, & nutrition to joints
Describe articular cartilage.
-formed by type II collagen & proteoglycans
-avascular
-lacks nerves & lymphatic vessels
-limited regen (nourishment from synovial fluid)
-attached to subchondral bone
-articular capsule = thick sac of CT (joint stability)
Describe synovial membrane.
-thin membrane
-villi
-lined by continuous layer of specialized cells >synoviocytes
—type A = phagocytic
—type B = produce synovial fluid
Describe synovial fluid.
-clear, viscous, colorless
-produced by synoviocytes (low cellularity & low protein)
FUNCTION:
-reduce friction
-increases in joint diseases (effusion)
Normal synovium epithelium picture.
