CARTILAGE Specialized connective tissue Rigid, Elastic, Resilient - RESISTS COMPRESSION AVASCULAR – nutrients diffuse through matrix

Hundreds of Eyes Staring Back at YOU!

PERICHONDRIUM Dense irregularly arranged connective tissue (type I collagen) Ensheaths the cartilage Houses the blood vessels that nourish chondrocytes

CHONDROBLAST Progenitor of chondrocytes Lines border between perichondrium and matrix Secretes type II collagen and other ECM components Chondroblasts build

CHONDROCYTE Mature cartilage cell Reside in a space called the lacuna Clear areas = Golgi and lipid droplets

Chondrocytes completely fill their lacunae RER and euchromatic nuclei Synthetically active, secrete matrix N RER ? Cartilage matrix

MATRIX Provides the rigidity, elasticity, & resilience FIBERS Collagenous and elastic GROUND SUBSTANCE Glycosaminoglycans (chondroitin sulfates, keratin sulfate, hyaluronic acid) Proteoglycans: GAGs + core protein Water Basophilic Territorial matrix - high [ ] of sulfated proteoglycans Territorial matrix surrounds lacuna (space in which chondrocyte lives)

CARTILAGE GROWTH Appositional Interstitial Increasing in WIDTH; chondroblasts deposit matrix on surface of pre-existing cartilage Interstitial Increasing in LENGTH; chondrocytes divide and secrete matrix from w/in lacunae

TYPES OF CARTILAGE HYALINE ELASTIC FIBROUS

HYALINE CARTILAGE FUNCTION MATRIX LOCATION Support tissue and organs Model for bone development MATRIX Type II collagen (thin fibrils) Chondroitin sulfate, keratin sulfate, hyaluronic acid Water LOCATION Tracheal rings, nasal septum, larynx, articular surfaces of joints Trachea

ELASTIC CARTILAGE FUNCTION MATRIX LOCATION STAINS perichondrium Support with flexibility MATRIX Normal components of hyaline matrix plus ELASTIC fibers LOCATION External ear, external auditory canal, epiglottis STAINS Elastic fibers stain BLACK with Weigert stain Ear perichondrium

FIBROCARTILAGE Intervetebral disk – Anulus fibrosus – High compression, shear Surrounds nucleus proposus Orcein van Giesen Elastic stain - fibrocartilage - reddish brown hyaline cartilage - yellow

FIBROCARTILAGE FUNCTION MATRIX LOCATION Support with great tensile strength MATRIX Type I collagen - Oriented parallel to stress plane LOCATION Intervertebral disks, pubic symphysis

FIBROCARTILAGE Chondrocytes align between collagen fibers Collagen fibers lie parallel to lines of stress

How many types of cartilage do you see? All 3: Collagen fibrils stain intensely pink in intervertebral disk

SYNOVIAL (DIARTHRODIAL) JOINTS

JOINT DEFINITIONS SYNOVIAL CAVITY SYNOVIAL FLUID SYNOVIAL MEMBRANE Fluid filled space b/t 2 bones SYNOVIAL FLUID Water and GAGs; provides nutrients for cartilage SYNOVIAL MEMBRANE Continuous with the perichondrium

SYNOVIAL “MEMBRANE” Not a true membrane - Why? Specialized secretory CT Loose (areolar) CT Formed by layers of collagen and fibroblasts Highly vascular Not lined by epithelium, directly in contact with synovial fluid of joint; fibroblasts secrete synovial fluid

Joint capsule composed of DIACT No perichondrium Joint capsule composed of DIACT Why does the cartilage at the joint stain so acidophilic (i.e. pink)? Especially high concentration of collagen

Question 1 Panel C is a low magnification micrograph of the tissue shown in Panel B. Provide the letter or letters (A and/or B) (or none) of the panel to which the following apply. normally calcified vascularized collagen type II cells capable of division matrix contains proteoglycans lacunae present A C B

C A Questions 2 and 3: 2. The three tissues shown have all of the following properties in common EXCEPT: a. They contain capillaries. b. They contain proteoglycans. c. They can increase in size by interstitial growth. d. They can increase in size by appositional growth. 3. Which tissue is the most highly specialized to resist compression? a. A b. B c. C B

Question 4 4. What cartilage nourishing tissue is missing at the interface shown? Synovial fluid Perichondrium Synovial membrane Chondroblasts