Week 5- CT- Downing Flashcards
CT components
- Cells
- fibers
- amorphous intercellular substance (ground substance)- what the fibers are imbedded in
CT characteristics
abundant matrix: fibers and amorphous ground substance
-proportion of cells to intercellular substances (matrix) varies greatly
origin of CT
mesoderm ⇒ mesenchyme ⇒ CT
differences b/t CT and epithelium
ep: have litter intercellular material
- ep: basil lamine is present
- ep: cover surfaces/line cavities
collagenous fibers
origin: fibroblasts
- 1-2 um in diameter but made up of smaller fibrils
- microfibril bundles to ⇒ fibril which bundles to ⇒ fiber which bundles to ⇒ a bundle of fibers
- inelastic
- leather industry: this is what they are tanning
- can stain with acid dyes: thus CT must have a neutral or slightly acidic charge
- can see microfibrils with an electron microscope
- have a cross banding pattern of 64 nm
- thick band is where the heads/tails are lining up
- this doesn’t allow heavy metal stains to get in ⇒ shows up very light
- AA variations produce different types of collagen that can wrap around each other ⇒ triple helix held together with H bonds
collagen types
1) I: ordinary CT (loose and dense) and bone
2) II: hyaline and elastic cartilage
3) III: loose CT, blood vessel wall, skin, lung
4) IV: basement membranes: network forming
reticular fibers
type III collagen
- very small
- branch to form networks
- staining: PAS (+) (because have excess carbs)
- have more carbs than other collagens
- origin: fibroblasts, reticular cells
elastic fibers
- physical characteristics:
- SUPER THIN
- can form sheets- picture: long wavy lines held together
- need a special stain to see them
- 2 distinct components: microfibrils and amorphous components (elastin)
- super stretchy: can be stretched up to 150% of original length
- sheets are held together by cross-links made up of elastin moelcules
- elastin is made up of: desmosine and isodesmosine
-origin: fibroblasts and smooth muscle cells
Marfan’s syndrome:
when you have too much elastin in your aorta ⇒ rupture
Amorphous intercellular substance (ground substance)
physical characteristics
- can vary b/t a viscous (very thick) and a thin gel - transparent- all the white space on pics
chemical composition:
water binds to it
glycosaminoglycans- repeating sugars
proteoglycans
functions:
- space filler
- permits passage of gases
- can immobilize larger objects (ie bacteria)
origin: fibroblast
HYALURONIC ACID
very viscous
- plays a HUGE role - alternating glucosamine and glycouranate units - barrier to bacteria (because so large) - but bacteria that produce hyaluronidase can get thru - present in joints- good lube
fibronectin
adhesive glycoproteins
- 2 forms: cellular and plasms
- monomers connected by disulfide links
- fxn: organize extracellular matrix and bind to macromolecular species
- can bind to RGD (like epithelial)
- have multiple binding sites
laminin
-
adhesive glycoproteins
confined to BM
-structural AND adhesive fxns
-binds cell surface receptors, type IV collagen,
Fibroblasts
most common CT cell
- can be active or nonactive
- oval nuc and enlarged golgi (when active)
- fxns: produce CT fibers and ground substance
macrophages
cytoplasm stains lightly
- larger nuc and many granules
- capable of amoeboid movement
- move to sites of inflation
- fxns: phago, formation of foreign body giant cells
- phago- doesn’t allow it to take up dyes
- have receptors of Fc and C3- where stuff comes in to get phago
- antigen presenting cells- process antigens and present them in a more antigenic fashion to other cells
plasma cells
not very common
- # s increase for inflammation
- wagon wheel chromatin; egg shape
- large golgi body
- origin: B-lymphocytes
- fxn: production of humoral antibodies
distubances related to PM
– Hyperglobulinemia: high concentrations of plasma cells with excessive circulating antibodies
– Agammaglobulinemia: complete failure of antibody synthesis; plasma cells do not develop at sites of antigenic stimulation
– Multiple myeloma: tumor of plasma cells
mast cells
appearance: large, small nuc, many granules
- origin: mesenchymal-like cells-fxn:
- heparin- no significant anticoagulant fxn
- histamine-
- causes smooth musch of bronchi to contract
- dilates blood caps increasing their permability
- anaphylaxis
anaphylaxis
with mast cells
occurs when host receives an antigenic insult the second time
- ppl are too good at responding
- antigen binds to mast cell ⇒ everything explodes out
fat cells
occur singly or in small groups
- ring shaped, large lipid droplet
- origin: from undifferentiated mesenchymal-like cells
- wax and wane in size- can grow 4x larger
- fxns: storage of fate and TG, carb/fat metabolism, endrocrine fxns
what are the visitors from the blood
monocytes, lymphocytes, eosinophils, neutrophils
monocytes
ameboid
-when leave the blood they are considered macrophages
lymphocytes
ameboid
- small and round
- dark nucleus fills cells
- fxn: make T and B lymphocytes and NK lymphocytes
eosinophils
amoeboid
- bi-lobed nuc
- numerous, large granules
- fxn: increase in number when there are infections, can phago, control of allergic responses
neutrophils
ameboid
- present in site of inflammation
- multi-lobed nuc and granular cyto
- fxn: first line of defense, actively phago, form pus when die
Loose CT
fills in otherwise unoccupied spaces
- forms part of framework for organs
- surrounds blood vessels and nerves
Dense irregular CT
irregularly arranged fibers
- components:
1) Fibers: coarse collagenous fibers (very dominate), elastic fibers and reticular fibers
2) cells: fibroblasts and macrophages
3) ground substance
- ex: dermis of skin
Dense regular CT
2 forms:
- predominately collagenous - ligaments, tendons, sheet like - predominately elastic: ligament flaca, vocal cords - fibers are lined up parallel - well suite for withstanding tension - major cell: fibroblast
reticular CT
provides a fine fibrillar network in lymph tissues
-components: reticular cells and fibers
need special dye to see
2 causes of edema
1) increase formation of tissue fluid
- hydrostatic pressure (impeded venous return)
- increase capillary permeability (heat and cold)
2) decreased resorption of tissue fluid
- decreased blood colloid (starvation, renal diseases, burns)
- decreased lymphatic drainage (cancer, elephantiasis)
