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Histology Lecture 5 (Packet #2 - Page 1-19)
Connective Tissue (Packet #2 - Page 1-19)
Terms in this set (62)
_____ percent of dry weight of body is made up of ____
30 percent of dry weight of body is made up of collagen
what are the components of connective tissue?
1. Ground substance
matrix that allows difffusion and binds fibers and other elements together
components of ground substance
2. Extracellular fibers
provide strength and flexibility
3. cellular elements
cells will secrete fibers and ground substance
components of ground substance:
- heparan sulfate
- dermatan sulfate
- keratan sulfate
- chondroitin sulfate
components of ground substance:
what are the glycosaminoglycans made up of and what do they do?
disaccharaides that form polysacharides
what is a polysaccharide attached to a protein called?
what are the ground substances synthesized by?
fibroblats, ostepblasts, chondroblasts, and adipocytes
what do polysaccharide chains attached to?
long protein core and form a bottle brush protein
what is the funciton of gags:
- gags have negative charge and the bottle brush are evenly distributed which will maximize the volume of the tissue
- trap water to make a gel
- electrostatically binds to collagen for strength
what are the other functions of gags?
matrix for cells and blood vessels and a diffusion medium
gel like substance enables tissuees to withstand compression
great tensile strength and is major fiber component of CT
only one type of collagen?
no variety of types
ONLY one that stains with H and E
(only one seen in LM)
Which fibers form distinctive banded fibers in Electron micrographs?
how is collagen secreted?
by cells found in extracellular matrix
collagen types form?
fibrils with a banded pattern
we see gaps in collagen, what do they fill with
electron EM stain that makes dark bands in EM
type I collagen
only one that stains with H and E and forms huge fibers
type II collagen
found in catilage (made by chondroblasts
form reticular fibers (form nets)
what do reticular fibers form?
supporting framework for bone marrow, lymph glands, spleen, thymus
what are reticular fibers made by
Type IV collagen in regards to position
important in lamina densa of basal lamina
secreted by epithelial cells
Type VII collagen fnx?
anchors the basal lamina to underlying CT, expecially type II fibers
where is elastin found
in loose and dense irregular CT, elastic cartilage, and ligament
they are stretch rubber band like fibers where tissue elasticity is important
what is elastin secreted by
secreted by fibroblasts as proelastin that assembled on secreted fibrillin fibers
what is elastin also secreted by?
smooth muscle cells in arteries WITHOUT fibrillin to form elastic SHEETS instead of fibers
loose connective tissue
loose CT components
abundant ground substance, few fibers
loose CT: diffuse in ground substance
diffuseion in ground substance of loose CT will faciliate waste and nutrient exchange with caps
what is unique about loose CT
immune cells to fight bacteria
how does fluid produced by ground substance?
water leaking out from lumen of blood vessels into rground susbstance
fetal loose CT filled with cells derives from all 3 germ cell layers
stem cells for specific cell types
remain throughout life to replenish cells as needed
associated with vascular system which are associated with CT stem cells
what can pericytes form?
fibroblats and other CT cells
cells are also dervied from_________________ involved in_______
cells derived from hematopoetic stem cells involved in inflammation
what do mast cells mediate?
allergic and inflammatory respons
what do mast cells react to?
antigens and degranulate
heparin, histamines, and chemotactctic factors)
purpose of maste cell is to
controll capillay beds and modulate amount of edema via histamine
allergic reaction is
two types of loose connective tissue cells
general (mast cells)
Mucosal CT cells of GI, Upper resp tracts
what do reactions of these mucosal CT cells of GI and upper resp tract cause
ashtma, rhinitis, vomitng
similar cells to loose CT but found elsewhere
langerhan cells skin
dendritic lymph node
microglia in brain
white blood cells enter loose CT as
how to white bloocells get into loose CT
through capillaries and they are attracted to inflammaton site
plasma cells produce
antibodies during humeral immune response
what are plasma cells derived from
activated b lymphocye
what are plasma cells referred to as
clock dial cells
dense irregular CT components
same as loose CT (type I collagen and GAGS) ecept the fibers are much loarger and tightly packs
DICT fibers specialzed for
irregular fibers specialized for strength such that it resists stress in all direcitons
DICT: ground substance?
less ground substance because all fibers and less cells
examples where DICT is found
Dense regular CT
tendons... (tendon sheath made of DICT) but tendon itself made of dense regular CT
Type I and GAGS
minimal ground substance
where do collagen fibers run in dense regular CT
along the axis of the tendon
ligments: dense regular CT?
ligaments are mae up of dense regular CT however now as much as tendons... ligaments are made up of more elastin