Lecture 8 - Connective Tissue Flashcards Preview

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Flashcards in Lecture 8 - Connective Tissue Deck (39):
1

Connective Tissue made of

ECM (ground substance, fibers, structural glycoproteins) and and cells

2

Functions

Structural Support; Site of Exchange of nutrients/waste between tissues; defense/protection from foreign bodies; storage of fat

3

Ground substance

glycosaminoglycans (GAG, long carb chains), proteoglycans (many gag chains attached to protein core, mostly carbohydrate in composition). V. negative so retains lots of salt and water

4

Types of GAGs

Hyaluronic acid --> not sulfated or bound to protein, so not negative so proteoglycans bound to them. The other gags fill the space between the proteoglycan bound; keratin sulfate (skin); heparan sulfate (basement membrane, stain positive PAS); dermatan sulfate (skin); chondroitin sulfate (cartilage)

5

Three types of connective tissue

Collagen fiber, reticular fiber, elastic fiber

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Type I collagen

tendon, ligaments, bone, fibrous cartilage, dermis of skin; forms fibrils

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Type II collagen

Hyaline cartilage, elastic cartilage; forms fibrils

8

Type III collagen

Also called reticular fibers, thinner than type I/II; lymphoid organs, muscle cells, blood vessels, liver, endocrine glands, lung, kidney; forms fibrils

9

Type IV collagen

Basement membrane (found around epithelium, endothelium, muscle, nerve axons); forms mesh like structure

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Properties shared by Types I-III

Mechanical support, gives tensile strength to tissue, resistance to stretching when pulled

11

Fibril under EM

Can see alternating dark and white bands at 64 nm periodicity, specific to collagen

12

fibril vs. fiber

Many fibrils make up one fiber

13

Silver stain

Stains Type III collagen black

14

Type IV collagen

basement membrane (heparan sulfate), mesh like structure, so do not see banding. PAS positive

15

Elastic fiber components

Elastin (desmosine and isodesmosine) and microfibrils (fibrillin)

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Structure of elastic fibers

Thin branched forming irregular networks in connective tissue

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Properties of elastic fibers

Stretchable as rubber bc of desmoseine and isodesmoseine; elastic recoil

18

Cells that make elastic fibers

Fibroblasts in CT, smooth muscle cells, chondroblasts and chondrocytes found in elastic cartilage

19

Classification of connective tissue

1. Loose connective
2. Dense connective tissue --> two types, regular and irregular

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specialized types of CT

Reticular Tissue; Elastic Tissue; Adipose Tissue

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Embryonic CT

Mesenchyme; Mucous

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Loose CT, what and where

More Cells than collagen fibers, seen in most tissues and organs,
Largely type III collagen/lining of mucous membranes called lamina propria

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Dense Irregular CT

More collagen fibers than cells, irregularly arranged.
Largely types I and III, some elastic fibers
Dermis

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Dense regular CT

Parallel bundles of collagen fibers, separated by linear rows of fibroblasts
Type I collagen
Tendon and ligaments

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Reticular Tissue

Loose network Type III
Forms suportive tissue for tissue/organs, seen in lymphatic tissue

26

Elastic Tissue

Seen in wall of aorta, elastic ligaments
Stained by resorcin fuschin stain

27

Types of adipose tissue and functions

White --> All over body; for thermal insulation, storage of energy, visceral fats correlated to obesity
Yellow --> Bone marrow

28

Mesenchyme CT

Embryonic
Stellate/spindle shaped, delicate branching of mesenchymal cells, surrounded by ground substance
Unspecialized, can differentiate into all CT types

29

Mucous CT

Umbilical cord, also called whatron's jelly

30

Cell Types of CT

Fibroblasts, mast cells, macrophages, plasma cells, lymphocytes, neutrophils, eosinophils, adipocytes

31

Fibroblasts

Splindle shaped, nuclei and cytoplasm elongated
Cytoplasm slightly basophilic --> RER
Produces ECM (collagens, elastic fibers, ground substance)

32

Mast Cells

Single round dark purple nucleus, strongly acidophilic cytoplasm
Finely granular (seen in EM)
Have IfE receptors that bind antibodies, trigger allergic rxns

33

Where are Macrophages found

Found in CT, lungs, lymphoid organs and bone marrow. Some types are tissue specific (ex. microglia in CNS)

34

Monocytes

pre-cursor to macrophages, develop in bone marrow, circulate in the blood. After leaving blood for CT, diff. into macrophages

35

Macrophages unique properties

Lysosomes, which contain acid phosphotase (stain red under azo dye)
Phagocytosis
secrete cytokines which are signals to other immune cells
present antigens on cell surface to T-cells

36

Where are lymphocytes found

Develop in bone marrow; two types (T & B); leave circulation for CT, live 2-3 years

37

Plasma Bodies/Cells

Created from B lymphocytes; Make antibodies; live in loose CT; nucleus off center; depends on RER (protein synthesis) --> slightly basophilic cytoplasm;

38

Neutrophils

Multilobed nucleus (3-5 lobes); slightly pink cytoplasm; usually in circulation, found in CT in cases of acute infection for 2-3 days. Defunct neutrophils are pus cells

39

Eosinophil

Bilobed nucleus, strongly pink cytoplasm, seen in parisitic infection and allergic rxn; seen in loose CT in chronic inflammation