Connective tissue

71
Connective tissue

description

Connective tissue. What is connective tissue? As the name suggests, it connects the various tissues of the body and gives them support. 1.       General features: 1)   small number of cells and large amount of extracellular ground substance - PowerPoint PPT Presentation

Transcript of Connective tissue

Page 1: Connective tissue

Connective tissue

Page 2: Connective tissue

What is connective tissue? As the name suggests, it connects the vari

ous tissues of the body and gives them support.

Page 3: Connective tissue

1.       General features:

1)   small number of cells and large amount of extracellular ground substance

2)  extracellular is composed of fibers and amorphous ground substance-matrix

3)   all of them originate from mesenchyme-embryonal CT

4) have functions of connection, supporting, protecting, nutrition, defence and repairing

Page 4: Connective tissue

mesenchyme---mesenchymal cell: /structure: stellate/star in shaped with

processes a large nucleus,with clear n

ucleoles slight basophilic cytoplasm /function: a.    undifferentiated cell b. multiple developmental pot

ential→CT cell, SM and endothelial cell

---matrix

Page 5: Connective tissue
Page 6: Connective tissue
Page 7: Connective tissue

2.       Classification ---CT in narrow sense means connetive prop

er which include loose CT, dense CT, adipose T and reticular tissue

---CT in wide sense includes cartilage, bone and blood

Page 8: Connective tissue

3.  Loose connective tissue(areolar tissue)

features: have more types of cells and less fibers

functions: connection, supporting, defence and repairing

consists of cells, fiber and ground substance

Page 9: Connective tissue

cells

extracellular

matrix

Major con

stituen

ts

Fiber

Ground substance

Page 10: Connective tissue
Page 11: Connective tissue
Page 12: Connective tissue

1) cells: seven types of cells are present in LCT

Page 13: Connective tissue

cells

of

CT

Fixed cells

Transient cells

Fibroblasts

Adipose cells

Mast cells Macrophage

s

Undifferentiated mesenchymal cell

Plasma cell

Blood cell

Macrophage

Page 14: Connective tissue
Page 15: Connective tissue

① fibroblast

---structure: LM: large,flattened cell with processes- stellate in sha

ped Large ovoid pale nucleus-contain more fine chro

matin, with clear one-two nucleoli Weakly basophilic cytoplasm-homogeneous

Page 16: Connective tissue

EM: rich in RER, Golgi appatatus and free riboso

me---function: synthesize fibers and ground substa

nce

Page 17: Connective tissue

Synthesis of collagenous fiber

Three steps: a.synthesis of procol

lagen(RER) → process(Golgi) → out of cell

b.procollagen→ tropocollagen → fibril

c.fibril → collagenous fiber

Page 18: Connective tissue

*fibrocyte: still state or inactive fibroblast---structure: spindle-shaped, small N:small,dark stained Acidophilic cytoplasma EM: less organelles

---function: become into fibroblast for repairing

Page 19: Connective tissue
Page 20: Connective tissue
Page 21: Connective tissue

EM:

RER

Golgi

Page 22: Connective tissue
Page 23: Connective tissue

②macrophage---structure:

LM: round or ovoid-irregular in shape when it

have short blunt processes_pseudopodium Small and dark nucleus Acidophilic cytoplasm

Page 24: Connective tissue

EM: rich in a.  lysosome b. Phagosome← phagocytosis and pinosome ←pinocytosis c.  Remnant d.  Microfilament and microtubule

Page 25: Connective tissue
Page 26: Connective tissue
Page 27: Connective tissue

---function: a.    Chemotaxis: chemotactic factor(TNFα 、 I

FN (interferon) or interleukin) b. phagocytosis: Special phagocytosis: recognize Bacterium, vi

rus and foreign cell non special: carbon particles, dust and dead c

ells *Phagosome(pinosome) + primary lysosome

→secondary lysosome →remnants

Page 28: Connective tissue

c.  secretion: lysozyme, complement and interleukin-I (IL-1)and interferon(INF)

b.  antigen presenting function:

*capture antigen→processes→+ MHC II molecule (major histocompatibility complex molecules) →antigen-MHC II complexes→ TLC/BLC

Page 29: Connective tissue
Page 30: Connective tissue

③plasma cell---structure:

LM: round or ovoid Round eccentrically-located nucleus with

more spot-liked heterochromatin Basophilic cytoplasm

Page 31: Connective tissue
Page 32: Connective tissue

EM: rich in parallelly arranged RER, free ribosome and Golgi complex

---function: synthesize and secrete immunoglobulin, Ig-antibody

Page 33: Connective tissue
Page 34: Connective tissue

④mast cell

---structure:

LM: round and large cell Small dark-stained nucleus Basophilic secreting granules

Page 35: Connective tissue
Page 36: Connective tissue
Page 37: Connective tissue

Basophilic secreting granules: heparin:an anticoagulant Histamine: cause cap. permeability↑, cap.

leakage to form oedema and contraction of SM

Eosinophil chemotactic factor

Cytoplasm contain: leukotriene- slow reaction substance

Page 38: Connective tissue

Function: Mast cells degranulation r

esults in the release of histamine a

nd other vasoactive mediators whic

h induce the immediate hypersensit

ivity response (characteristic of urti

caria ( wheal-itch ) , allergic rhinit

is (sneeze) and asthma (cough)) an

d anaphylactic shock.

Page 39: Connective tissue

⑤adipose cell(fat cell)

---structure: large, round or polygonal flattened ovoid nucleus located on one side of cell thin layer of cytoplasm a large lipid droplet

---function: synthesize and store fat

Page 40: Connective tissue
Page 41: Connective tissue

This is a higher

magnification of fat

cell with a large

lipid droplets and

cytoplasm pushed to

the periphery

membrane, nucleus

is flattened against

the membrane also.

Page 42: Connective tissue

⑥undifferentiated mesenchymal cell

---structure:similar to fibrocyto

---function:multidifferentiating potential

⑦leukocytes: neutrophil,acidophil and lymphocyte

Page 43: Connective tissue

2) fibers

Page 44: Connective tissue

①collagenous fiber(white fiber)

LM: Main fiber 1-20 um in diameter Belt-liked wave and branch to form a network Eosinophilic

Page 45: Connective tissue

EM: parallel-arranged fibrilsFibril: 20-200nm in diameter Have periodic cross striation at 64nm interval*formation: Extracellular polymerize

collagen(type I and III) →collagenous fibril → collagenous fiber

Page 46: Connective tissue
Page 47: Connective tissue
Page 48: Connective tissue
Page 49: Connective tissue

② elastic fiber (yellow fiber) LM: thinner and less, 0.2-1.0 um Slight red(HE), purple(aldehyde fuchsin) or brow

n(orcein) Branch and form a network EM: core: elastin-low electron density Peripheral: microfibril 10-12 nm, electron dense ↑ fibrillin

Page 50: Connective tissue
Page 51: Connective tissue
Page 52: Connective tissue

Physical properties:

As their name implies elastic fibers can

be stretched (like a rubber band ) and

return to their original length when

tension is released.

Page 53: Connective tissue
Page 54: Connective tissue

③reticular fiberLM: thin and less,0.2-1.0 um in diameter Branch to form network Argyrophilic fiber(silver impregnation method)EM: type III collagen 64nm cross striation---distribution: reticular tissue connecting portion, e.g.reticular lamina

Page 55: Connective tissue
Page 56: Connective tissue

3) ground substance

---amorphous colloidal substance

---consists of proteoglycan, glycoprotein and tissue fluid

Page 57: Connective tissue

①proteoglycan Large molecular complex (polysac

charide)

---glycosaminoglycans: chondroitin sulfate keratin sulfate dermatan sulfate heparin sulfate hyaluronic acid: 2.5um long

--protein

*molecular sieve

Page 58: Connective tissue

② glycoprotein: proteins---fibronectin cells←fibronectin→collagen

↓ proteoglycan---laminin---chondronectin---function: Connection affect the differentiation and movement of cells

Page 59: Connective tissue

③ tissue fluid

tissue

artery → Tissue fluid → vein →blood steam

cells dehydration edema

Page 60: Connective tissue

4.    Dense connective tissue

---more fiber

---connection and supporting

Page 61: Connective tissue

1) regular DCT: parallelly-arranged collagenous fibers tendon cells: /special fibroblast

/wing-liked processes

---distribution: tendons, ligament and cornea

Page 62: Connective tissue
Page 63: Connective tissue

2) irregular DCT: Fiber arranged in bundles,runing in different d

irection Fibroblast less ground substance---distribution: dermis, sclera and capsule of so

me organs

Page 64: Connective tissue
Page 65: Connective tissue

3) elastic T: elastic fiber in bundles or in membrane ligament and large artery

Page 66: Connective tissue

5.       adipose tissue---LCT+fat cells---white fat T: single fat cell distribution in subcutaneous tissue, mesenteriu

m---brown fat T: fat cell contain many small lipid droplets, rich in large mitochondria centrally-located nucleus rich in cap. distribution: neonate

Page 67: Connective tissue
Page 68: Connective tissue
Page 69: Connective tissue
Page 70: Connective tissue

6.    reticular tissue---reticular cells: stellate with processes-form network round, ovoid and pale nucleus with 1-2 nucle

oli EM: rich in RER---reticular fiber: connect to form network---distribution: hemopoietic tissue and lymphatic

tissue

Page 71: Connective tissue