CT Flashcards
mast cells in secretory granules
heparinocytes- origin, size, shape, granules+stain, metachromatic (acidic radicals), two types of mast cells, F, granules
7-20um +irr shaped, developed from progenitor cells, basophilic granules (STAIN ALCIAN BLUE+ PAS+), nucleus obstructed by secretory granules (e- dense heterogeneous), metachromatic (change colour of basic dye blue to purple/red due to high acidic radicals of GAGs therefore poorly presented)
- numerous near small blood vessels (skin or mesentery called pre-perivascular mast cell; mucosal mast cell along lining of git+resp tract.
- main function- allergic reaction: IgE ginds to mast cells and releases materials of secretory granules (like basophils)
heparines- sulphated GAG act as coagulant
histamine- increase vascular permeability, and increase muscle contraction
phospholipid- precursor for conversion of leukotrines+ prostaglandins
cytokines- polypeptide direct activity of rbc+leokocytes
neutrophilic + eisinophilic chemotactic factors- aggregate + attract other leukocytes
serine protease- activate mediator of inflammation
types of macrophages in diff organs
part of mononuclear phagocytic system:
in liver- kuffer cells; langerhans in skin; microglial; osteoclasts
long living and survive for months
how elastic fibers maintain rubber like property ?
Lysine oxidises on 2 diff elastin and condenses as a desmosine ring which acts as covalent cross-link between polypeptides
reticular fibres function
reticular: type III collagen fibril rich on sugar: glycosylated SILVER IMPREGNANTION+ PAS+. argyrophilic- affinity to silver
- produced by fibroblasts in reticular lamina of basement membrane.
F: characterise the stroma of HEMATOPOETIC tissue tissue+LYMPHOID organs
supports stroma of parenchymal secretory cells + rich in microvasculature of LIVER+ ENDOCRINE GLANDS
CT intro
intro, origin, type of cells (2), F, types of CT
CT provides MATRIX SUPPORTS and PHYSICALLY CONNECTS tissues+cells together in organs
- interstitial fluid provides metabolic support for cells as meeting for diffusion of nutrients + waste
origin:mesenchyme abundance in ECM, two
types of cells:
resident- fibroblast+cystes, myofibroblasts, adipocytes, mesenchymal, reticular, and pigment cells
wandering (migrate to CT for maturation)- macrophage (histocyte), leukocytes, plasma, mast cells (heparinocyte)
main function: support, structure, defense, storage, nutrition and repair
types of CT
- PROPER
- CT w SPECIAL properties
mucous, reticular, elastic and adipose+embryonic: mesenchymal and jelly-like CT
- SUPPORTING CT
cementum,dentin, bone and cartilage
components of ECM
GAGs (long polymer of disaccharide units)-
sulphated (chondroitin, keratan, heparan, and dermatan)
uronic acid: glucuronic+ udoronic acid
hexosamine: glucosamine+ galactosamine
proteoglycans:
decorin (orient fibres y binding to collagen);
perlecan (main protein in basal lamina);
aggrecan (hydrate cartilage of ECM);
versican (cell-cell/cell-ECM); syndecan (cell=ECM linkage)
multi-adhesive glycoprotein
laminin- (anchor cell to basal lamina)
fibronectin- (binding site for collagen IV+ integrin)
tenascin- (modulate cell-ECM attachment)
osteopontin- (bins to osteoblasts)
CT fibers (7)
1) fibroblast- branched +irr basophlic cyto (rer,golgi,mito), active: nucleus large ovoid euchromatic w prominent nucleolus
inactive: smaller+spindle shaped heterochromatin=darker
- main function synthesize ECM components, secrete collagen, elastin, reticular fibres.
2) myofibroblasts: have contractile proteins alpha smooth muscle actin (contract wound to bring closer together)-causes fibrosis (thickening/scarring of CT) excessive production of matrix components
3) pigment cells
neuroectodermal, dark brown granules, stratum basale, melanocytes (melanin for pigment+protect UV)
4) adipocytes: Large fat cell, store lipis, cushion+insulate, less common heat production; types: uniocular+multiocular
5) plasma cells
b-lymphocyte origin, 14-20um, antibody-producing cells
large, ovoid cells w spherical nucleus (w compact peripheral region w HETEROCHROMATTIN+ alter w light areas euchromatin=clockface)
BASOPHILIC cytoplasm (rich RER+GA)
lifespan 10 days+abundant in infected cells
6) leukocytes =wbc
defend against bact/pathogen (by increasing inflammation). diapedesis
neutrophils (phagocytotic), basophils (heparin+histamin), eosinophils (parasite +allergic reaction- lamina propria GIT) , monocyte (precursor for mononuclear phagocytes system) and lymphocyte (lamina propria of GIT+resp tract)
7) histocyte=macrophage
10-30um w eccentrically located nucleus, phagocytic activity (in lysosomes), form mononucleated phagocytic system=monocytes
F: increase in size, GA development, protein synthesis, form lysosomes, actin+microtubules
- in liver- kuffer cells; langerhans in skin; microglial; osteoclasts. long living and survive for months
collagen
- most abundant fibre, eosinophilic glycoprotein, differ in size but avg 300nm long, 1.5nm thick.
- formed by three alpha chains= triple helix
- type I: accounts for 90% of collagen, in loose, dense CT+ bone- type II: hyaline and elastic cart
- type III: forms reticular fibers. in loose, smooth muscle+ endoneurium (around myelin sheath)
- type IV: basal lamina of epithelial cells
elastin
elastic: outer fibrillin+ inner elastin core. has fenestrated sheets=lamellae
- non coding AA (desmosine+ isodesmosine).
- AA (lysine, glycine +proline)
- to maintain rubber-like property: lysine oxidised on 2 diff elastin= condense as desmosine ring and covalently cross-link between polypeptide
- ALDEHYDEFUCHSIN(magenta) , ORCEIN (red-brown) AND RESORCINFUCHSIN (blue-black)
in elastic CT- densely packed bundles of elastin
elastic tissue in lig flava in vertebral column=yellow lig
CT proper
1) CT proper
loose CT- irregular fibrillar component that is loosely arranged fibres flexible but not very resistant to stress, abundant matrix w wandering cells, type I, elastin+reticular fibres , well vascularized
- function: supports epithelial tissue, provide environment for exchange of compounds, involved in immune reactions
- in lamina propria of mucosa, interstitial fluid of glands and stratum papillae dermis(papillary layer of dermis)
dense CT- fewer cells+ground substance, poorly vascularized, type I
-->reg- fibers oriented in one direction, fibroblasts arranged in parallel orientation to collagen fibres - tendon, lig, aponeurosis
--> irr- oriented in many directions - function: less flexible but more resistance due to dense collagen - periosteum, perichondrium, stratum reticulare dermis (reticular layer of dermis), and sclera
in tendons: tendinocytes
- densely, closely packed bundles of collagen separated by little ground substance
- fibrocytes have elongated nuclei that lie parallel to fibres;
- cytoplasm has portion of collagen bundles. cyto stains same as fibres:yellow lig of vertebral column=lig flavum has abundant parallel elastic fibres
- poor vascularization (repair low)
- some tendons: dense irr CT has synovial cells secrete hylauron
structure:
inner peritendinum: dense reg CT
outer epitendinum: dense irr CT
adipose CT
2) Adipose CT
white adipose tissue
- 50-150um spherical when isolated; polyhedral when closely packed
- uniocular: one large droplet of triglyceride; surrounded by rim of cytoplasm w nuclei; has mitoch, cistern in rer, golgi and polyrib
- surrounded by thin submembranous layer (collagen IV) has pinocytotic vesicles .
- found: neurovascular bundle and subcutaneous tissue around kidneys
- f: store energy, cushion of vital organs + insulation, secrete organs
brown adipose tissue
- polygonal; subdivided by partitions of CT into lobules- makes more pronounced and delineated
- multiocular: smaller w many lipid droplets; abundant in mitochondria (why brown) scattered around lipid droplet of fat cell+ in capillaries
- f: heat production+ thermogenin in mitochondrial membrane (produce heat by non shivering using uncoupling proteins+ bc has many mitoch protects against oxidation stress- neutralise reactive oxygen species )
beige adipose tissue
- similar to brown morphologically; in insulated cells dissipated in white adipose tissue
embryonic CT
3) embryonic CT STAIN: H&E
mesenchymal: small stellate/spindle shaped cell, interconnected by gap j, forms 3D network. ECM has sparse collagen+reticular fibres
- developed in lymphatic+ circulatory tissue+ musculoskeletal (bone, cartilage)
Mucous: found in umbilical cord: Warton’s Jelly- dispersed fibrocyte-like cellular portion between ECM. also in tooth pulp. High abundance of ground substance (fibroblasts, collagen+reticular fibres,HA and glycoproteins)
cartilage intro
cartilage is supporting CT, mesenchymal in origin. Made from dense CT; avascular (low metabolic activity+low regeneration) and aneural and nutrition supplied by diffusion from perichondrium (double layer dense irr CT (type I collagen fibrils) inner layer: contains chondroprogenitor cells and outer layer is fibrous layer)=EOSINOPHILIC
matrix: sparse fibrillar component
sulfated GAGs (keratan+chondroitin+ hylauronic acid), proteoglycans
multiadhesive glycoproteins: chondronectin binds to GAGs, integrin and collagen to help w adherence of chondrocytes to ECM
basophilic: STAIN ALCIAN BLUE, NUCLEAR RED H&E
cells:
- chondroblasts (help w development of cartilage, is in perichondrium and proliferate due to somatotrophin released (GH)
- chondrocyte (help w maturation +maintain structure by secreting metalloproteinase to degrade cartilage )
each type of cartilage
hyaline cartilage: type II collagen fibers. most common, and it’s the skeletal model for endochondrial oss.
territorial: basophilic (less fibrils-collagen)
inter-territorial: eosinophilic (more fibrils)
- chondrocytes on surface more elongated and deeper are oval; form isogenic lineages (cluster)
- resp system +nose+larynx , coastal cartilage, growth plate (epiphysial plate for growth of long bones); articular surface of bone don’t have perichondrium has synovium (secrete synovial fluid for nutrition- no perichondrium)
elastic cartilage: type II collagen. Similar to hyaline but has branching elastic fibres (elastin+fibrillin)= fibrillar component more abundant. more flexible. Has perichondrium
- chondrocyte= alone/isogenic groups
ALDEHYDOFUCHSIN, RESORCINBUCHSIN (black) ORCEIN
- auricle, eustachian tube, epiglottis, and small cartilage of larynx
fibrocartilage: mix of hyaline+dense reg CT= type I+II , not visible perichonderium. less vascularized bc has dense bundles of type I collagen fibers that alternate w cartilage matrix. EOSINOPHILIC (low GAGs)
- chondrocyte= alone/linear groups
interstitial growth= diff from preexisting chondroblast
apposition is from new chondroblast
damage= perichondrium produce scar of dense CT to form new cartilage (low repair bc bad vascularization)
- f: provide tensile strength+ bear weight+ resist compression
- in intervertebral disc+ menisci at knee+ pubic symphysis
AZAN/MASON TRICHROME
bone
bone specialised CT, main constituent of skeletal tissue, protects vital organs, acts as reservoir for Ca+PO4 ions, lever for body mov= mechanical+metabolic functions
Layers: dense CT, blood vessels, collagen fibres and fibroblasts
periosteum
inner cellular. Osteoprogenitor cells. responsible for appositional bone growth+repair
outer - fibrous layer, dense irr CT+perforating sharpy’s fibres (bundles of periosteum collagen fibres w purpose to bind periosteum to bone by penetrating matrix)
endosteum- lines marrow cavity, and surface of trabeculae of compact bone. same as periosteum but thinner
cells
1) osteoblasts: mesenchymal active form cuboidal/columnar cells with high basophilic cyto; inactive-flattened and less basophilic. Majority inactive form on surface between endosteum+periosteum.
- secrete osteoid-layer of matrix components between osteoblast+preexisting bone surface and now in contact w preexisting bone matrix: euchromatin, nuclei, abundant GER +GA
- osteoid essential for apposition growth completed by deposition of calcium salts into newly formed matrix.
comm w gap j. stimulated by parathyroid hormone (bone remodeling)
osteocyte- flat almond-shaped, diff array of genes than blast; less GER, smaller GA and more condensed nucleus. enclosed within lacunae, w blood supply that runs through canaliculi (250-300nm). Organized in isogenic groups/lines. Also comm gap j. produce sclerostin+cytokines= bone remod
- help w Ca hemostasis+ sensors detect mechanical stress
osteoclasts: not mesenchymal in origin, hematopoietic (comes from projenitor cells in bone marrow). Large motile cells 50-100um, multinucleated, lie within reabsorption cavities. Active ones are at surface against matrix, has irregular projection= ruffled border surrounded by AF;
- formation: two polypeptide osteoblasts secrete: MCSF macrophage colony stimulating factor + rankl receptor-activated of nuclear factor kb ligands
bone remodelling: osteoclasts secrete lysosomal enzymes (collagensa+cathepsin k) cause protein pumps to secrete H, increase acidity. Dissolved crystals+digest matrix. Endocytosis occurs, infoldings of PM going to ECM.
- osteopetrosis condition: overly dense w abnormal growth, very brittle fracture easily. No ruffled border so reabsorption is low
