connective tissue Flashcards
what are connective tissues?
they connect and support the other three types of tissues in the body
the ECM of connective tissue is composed of what two components?
- ground substance
2. fibers
the GS has?
proteoglycans and glycoproteins
the three types of fibers are?
- collagen
- reticular
- elastic
what are the functions of connective tissues?
- provision of structural support.
- role as medium for exchange
- role in defense and protection
- storage of fat
what are the types of connective tissue cells?
migrant cells
resident cells
examples of migrant cells?
plasma cells, macrophages, mast cells and various types of WBC
examples of resident cells?
fibroblast, myofibroblast, adipocytes, mesenchymal stem cells
what constitutes the most abudant type of connective tissue cells?
fibroblast
what are the 2 types of fibroblast?
inactive
and active
describe the inactive fibroblast and its nucelus
small ovoid shaped cells with condensed rod shaped nucleus
the cytoplasm of fibrocytes is acidophilic or basophilic?
acidophilic
describe the shape of active fibroblast and its nucleus?
spindle shaped cell with ovoid nucleus, radiating processes and prominent nucleolus
the cytoplasm of active fibroblast is acidophlic or baso? and what does EM shows is present in the cell?
highly basophilic
and contains large amount of RER and ribosomes
what is the function of fibroblast?
it secretes protein elastin and collagen
and also secretes components of ground substances
list down organelles and other stuff myofibroblast contains?
RER and golgi apparatus
bundles of actin filaments
dense bodies like the smooth muscle cells
function of myofibroblast?
wound healing (contraction)
explain unilocular adipocyte ?
they have one large fat globule and aggregation constitutes of white adipose tissue
expl multilocular adipocyte?
they have small many fat droplets and aggregation constitutes of brown adipose tissue.
unilocular adipocyte gives appearance of?
signet-ring appearance.
describe the appearance of an inactive macrophage?
they are fusiform or stellate in shape, the nucleus is prominent that fibroblast and has granules (lysosomes)
describe the appearance of active macrophage?
spherical, oval in shape, kidney shaped prominent eccentric nucleus, it seems irregular and has numerous folds.
what does ANTIGEN PRESENTING CELLS do?
they phagocytose antigen proteins and transfer them to the macrophages and presented in combination with MHC II
describe what does cytokines do?
they belong to interleukin 1 fam
they initiate proliferation and maturation of lymphocytes so immune response is amplified
the active macrophage releases what,which calls cancer cells are called?
tumor necrosis factor-alpha
what is MULTINUCLEAR GIANT CELL?
sometimes the foreign body is to large to be engulfed so the macrophage fuse to form a large multinucleated cell that engulfs the foreign cell
what type of macrophages are made at the site of chronic infection?
epithelioid cell
what cells are resistant to macrophages?
tuberculosis and syphilis
an organized colection of epitheloid macrophages cells are called?
granuloma
from where are the macrophages derived from
monocytes
what comprises of mononuclear phagocytic system
macrophages, monocytes, kupffer cells of liver, langerhans cells of skin, microglia of neruons alveolar macrophages of lungs and osetoclasts of bones
what is the characteristic feature of mast cell?
large secretory granule in the middle
what special fixator is used on mast cells?
aniline (toluidine) blue
what stain does mast cells pick up?
purple (metachromasia)
why causes the metachromasia in mast cells?
heparin cause’ it is highly sulfated proteoglycan
what secrete the mediators of inflammation?
mast cells
where primary mediators of inflammation are stored?
basophilic granules of mast cells
what are Primary mediators of inflammation?
Heparin, histamine, 2 proteolytic enzymes (chymase and tryptase) 2 cytokines neutrophil chemotactic factor
eosinophili chemotactic factor
what are Secondary mediators of inflammation
leukotrienes D4 E4 and C4, tumor necrosis factor, porstaglandin D2 and interleukins
functions of mast cells in development of allergic reactions is called>?
immediate hypersensitivity reaction
cell membrane of mast cells contains receptors for?
antibody of the immunoglobin E
the IgE antibodies are made when?
the plasma cells are exposed to an allergen which may be a protein antigen (pollen, bee sting etc)
what happens with the IgE Is exposed to the allergen?
the IgE antibody binds to the receptor on the surface of the plasmalemma of the mast cellss
what happens on subsequent exposure to same allergen?
antigen-antibody reaction takes place on the surface of tghe mast cells, that causes the discharge the PMI AND SMI
what is local immediate hypersensitivty reaction?
skin rash, rhinitis or asthma
what happens in systemic IHR
it is known as anaphylactic shock, happens when substantial amount of IgE Are poduced in hyperallergic people, like histamine which can cause anaphylactic shocks and death
role of histamine?
vasodialation
bronchospams
increase secretion of mucous in respiratory tract
from which type of lymphocytes are plasma cells made from?
B lymphocytes
what happens when plasma cells engulf the antigen?
the represent the epitome to helper T cells
what does helper t cells do?
release protein that make B lymphocytes to differentiate into plasma cells
where does plasma cell formation occurs?
in germinal centres of lymphoid follicles of lymphoid organs
e.g tonsils and lymph nodes
ground substance of connective tissue composed of?
glycosaminoglycans and glycoproteins
all GAG are sulfated except?
hyaluronic acid
the sulfated GAG are covalently bonded to small proteins to form
proteoglycans
how many sulfated and non sulfated GAG present?
one non sulfated
and 5 sulfated
name the 5 sulfated
chondroitin sulfate, dermatan sulfate, keratan sulfate, heparan sulfate and heparin
what does glycoprotein in the ground substance do?
act as adhesive and bind the components of connective tissues together
major adhesive glycoproteins are?
fibronectin and laminin
chondronectin
osteonectin
what cells make up the connective tissue fiber
fibroblast
structure of collagen?
triple helical molecule, with 3 polypeptide chains winded around each other giving rope like appearance
3 commonest types of amino acids in collagen?
proline, hydoxyproline and glycine
collagen are made by what cells?
fibroblast, chondrocytes and osteoblast
functions of collagen?
structural support, scaffolding, integrity and provides tensile strength cell adhesion and migration
the 3 main groups of collagen are?
fibrillar collagen
sheet forming collagen
anchoring collagen
length of fibrillar collagen
12 to 500nm
fibrillar collagen has what type of collagens?
collagen type I II III V XI
diameter of collagen type I is
20 to 90 nm
collagen type I is found where?
the make up the collagen fibers that make up the connective tissue of the body
collagen type II makes up the?
ECM of cartilage
collagen type III makes up the ?
reticular fibers
collagen type V make up the?
it is in association with type I and makes up the cornea, placenta skin and bone
collagen type XI makes up the?
it is in association with type II
which type makes up the sheet forming collagen?
type IV
sheet forming collagen makes up the/ present in the?
Basement membrane of the epithelial tissue
external laminae of adipocytes, schwann cells, smooth muscle cells, skeletal muscle cellls
what does anchoring collangen do?
it anchors the fibrillar collagen together or anchors sheet forming collagen with each other
types of anchoring collagen?
type VII IX XII XIV
