CT Flashcards
Fxn of CT
support- physical and metabolic
nutrition
thermoregulation - adipose tissue
protection/defence- immunological and abrasion defence
repair- CT responsible for granulation tissue
CT is derived from embryonic CT called?
Mesenchyme - derived from the mesodermal germ layer
CT is classified on the basis of?
its ECM organization and cells within
Characteristics of CT
basic tissue type
mesodermal origin
minimum cell to cell contact
abundance of ECM relative to cells
The cells of CT secrete?
both the fibres and the ground substance
The fibroblast
fxn: synthesis of CT fibres and ground substance
fibrocyte=inactive form
oval to elongate basophilic nucleus
will find nuclei surrounded by collagen fibres
Ground substance
supports cells and fibres of CT, transport of substances
- composition changes with the type of CT fibroblast produces
- pink in masson’s trichrome
Collagen fibres
fxn: tensile strength, resistance
most abundant protein in the body 30%
consists of type I, II or III collagen
Elastic fibres
strength, stretch, recoil
thick tubular fibres
eosinophilic and slightly refractive
Reticular fibres
- Visualized easily with PAS and silver impregnation
- 3D support network- espeically in organs that change in volume - ex lymph nodes
- made of collagen III and IV
Basement membranes
fxn= anchor epithelium to the lamina propria (CT); separate epithelium from CT
- thin,fibrous, sheet like arrangements
- separates epithelium, mesothelium, endothelium from underlying CT
- formed of 2 layers of basal lamina
Embryonic CT types
mesenchymal
mucous
Mesenchymal cells are?
stem cells
Mucous CT
fxn support
found in umbilical cord
whartons jelly matrix
Types of proper CT
loose
dense -regular vs irregular
Loose CT
function: support
found in- tunica adventitia surrounding BV, serosa surrounding oragans, lamina propria beneath epithelial
abundant ground substance (greater portion of this than cells and fibres)
Dense irregular CT
function: support and protection
unorganized, haphazard arrangement of interwoven fibres
collagen fibres predominate
-dermis, organ capsules
Dense regular CT
function: support, facilitate body movement
structural framework
tendons, ligaments
fibres have organized and parallel arrangement
what are the special CTs
blood
adipose
bone
carilage
what are the 3 types of cartilage
elastic
fibrous
hyaline
Hyaline cartilage
function: connect bones together; reists compression; cushioning and low-friction surface for joint movement
- chondrocytes located in lacunae
- perichondrium (dense CT) surrounds hyaline cartilage (except at joints)
Elastic cartilage
flexible support
elastin is the predominant fibre in the matrix (not usually seen in H&E)
perichondrium usually surrounds the cartilage
How can you tell hyaline cartilage from elastic cartilage
hyalin matrix often appears somewhat basophilic and smooth vs elastic which has a more eosinophilic matrix
FIbrous cartilage
Function: tensile support, resists deformation; shock absorber
combination of dense regular CT and hyaline cartilage
chondrocytes and fibroblasts
-chondrocytes dispersed among collagen fibres singly or in rows or groups
Bone (osseous tissue)
-mineralized ECM
-collagen is predominant along with other proteins
-solid, hard, tensile strength-dynamic
support- axial and appendicular skeleton and muscle, tendon, and ligament insertion
protection- skull, ribs, long bones
Types of bone cells
osteoblasts
osteocytes
osteoclasts
Osteoblasts
basophilic cytoplasm
formation and mineralization of bone matrix
osteocyte
mature osteoblast surrounded by osteoid
reside in lacunae
principle cell in mature bone
Osteoclast
chew bone
large, multinucleated cells
located on surface in howships lacunae or resorption bay
eosinophilic cytoplasm
Types of bone
compact- cortical
trabecular -spongy
Osteon
concentric layers of bony matrix
centered around haversian canal
osteocytes reside in lacunae between lamellae
canaliculi connect lacunae
_____ _____ connect haversian canals
volkamann’s canal
____ and ____ extend into volkmanns from the ____
blood vessels and lymphatics
periosteum
