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Flashcards in Connective Tissue Deck (61):
0

What tissue is the most abundant and widespread in the body?

-Connective tissue

1

What are the main functions of connective tissue?

-Join to underlying tissues and provide support
-Protect underlying organs
-Defend against infection
-Provide a medium for diffusion

2

What three general features make up connective tissue?

-Cellular components
-Ground substance
-Fibres

3

What is ground substance?

-amorphous ECM consisting of linear aggregates of hyaluronic acid with many proteoglycan monomers (glycoaminoglycans attached to a core protein)
-Link proteins attach the proteoglycan monomers to the hyaluronic acid molecules

4

Why does ground substance form a hydrated gel?

-The high density of gags gives the ground substance a high negative charge which attracts water

5

What type of fibres can be found in connective tissue?

-Collagen
-Reticular
-Elastic

6

What protein is the most abundant in the body?

-Collagen (specifically Type 1)

7

What secretes collagen?

-Fibroblasts secrete procollagen which are then arranged into fibres

8

What is type 3 collagen and where is it found?

-Reticulin
-Lymphatic tissues

9

What do reticular fibres look like?

-Messy network of fibres
-Thin
-Branched

10

Where is type 4 collagen found?

-Basal lamina in basement membrane

11

What is type 2 collagen?

-Elastic and hyaline

12

Name the two types of embryonic connective tissue?

-Mesenchyme
-Mucous

13

Where is mucous connective tissue found? Describe its features

-Wharton's jelly of the umbilical cord
-Gelatin-like ground substance
-Large intercellular spaces
-Spindle-shaped cells

14

Where is mesenchyme derived from?

-Mesoderm

15

Describe mesenchymal cells

-Pluripoent
-Tapered/spindle appearance due to cytoplasmic processes

16

What 5 things are derived from mesenchyme?

-Bone
-Fibroblasts->ligaments/tendons/supporting tissues
-Adipocytes
-Cartilage
-Skeletal muscle

17

What are the types of connective tissue proper?

-Loose
-Dense->regular/irregular

18

What are the specialised types of connective tissue?

-Bone
-Blood
-Cartilage
-Fibrocartilage
-Adipose tissue
-Lymphatics
-Haematopoetic tissue

19

Why does mesenchyme persist in the adult?

-To give rise to new connective tissue during healing

20

Where would you find elastic fibres?

-Dermis
-Artery walls
-Elastic cartilage

21

Describe the structure of elastic fibres, and it's appearance under a TEM

-Primarily elastin surrounded by a microfibril protein called fibrillin
-Elastin is less electron dense than fibrillin ->lighter on the inside with surrounding darker area

22

Name the three layers of arterial walls and what do they consist of?

-Tunica intima -> epithelia
-Tunica media -> elastic lamella capable of being stretched, smooth muscle, collagen and ECM
-Tunica adventitia -> collagen

23

What is the inheritance pattern of marfans syndrome?

-Autosomal dominant

24

What is special about the smooth muscle of the aorta wall?

-Secretes elastic, collagen and matrix

25

What do elastic fibres look like?

-Thin
-Usually black
-Branched network (not as messy as reticular)

26

What causes marfans syndrome?

-Abnormal fibrillin gene leading to abnormal elastic tissue

27

What is the clinical picture of marfans syndrome?

-Abnormall tall
-Arachnodactyly
-Frequent joint dislocations
-Abormally stretchy skin
-Risk of aortic rupture

28

Describe the connective tissue of the mammory gland

-loose connective tissue with wispy collagen and many fibroblasts surrounds the glandular epithelium
-Dense irregular connective tissue lies further away from the glandular epithelium with thick and abundant collagen and few fibroblasts

29

What is the main function of loose connective tissue?

-Attach epithelium to underlying tissues
-Allow diffusion of nutrients to cells

30

Which layer of epithelial tissue is normally loose connective tissue?

-Submucosa (eg, in colon)

31

What type of fibres does loose connective tissue contain?

-Collagen and elastic

32

What is a specialised loose connective tissue?

-Blood

33

What type of connective tissue are organ capsules?

-Loose or dense irregular depending on anatomical location

34

What is the purpose of organ capsules?

-To provide protection

35

What are the main purposes of dense irregular connective tissue?

-Withstand tension
-Provide structural support

36

What type of connective tissue is the dermis?

-Dense irrgular

37

What is the general organisation of dense irregular connective tissue? How does its structure relate to its function?

-Collagen bundles which are densely packed but irregularly arranged
-The different orientations of the fibres allows the connective tissue to resist force in multiple directions and prevents tearing

38

What is the function of the elastic fibres in the dermis?

-Allows a degree of stretch and restoration

39

What are the colours of the dermis with silverstain?

-Collagen bundles - pink
-Elastic fibres - dark red

40

What is the main function of dense regular connective tissue?

-To have high tensile strength to resist high force in one direction

41

Where is dense regular connective tissue found?

-Tendon
-Ligaments

42

What is the structure of tendons and how does this relate to its function?

-Very dense collagen bundles tightly packed arranged in parallel lines to the direction of the exerting force
-Rows of elongated flattened fibroblasts between bundles
-Provides high tensile strength of the tendon which is needed to attach muscle to bone

43

What is the function of ligaments?

-Attach bone to bone

44

How does the structure of ligaments differ from tendons?

-Arranged in fascicles of dense connective tissue separated by loose connective tissue

45

What 4 cell types are found in connective tissue?

-Fibroblasts
-Macrophages
-Mast cell
-Adipocyte

46

What is the most common cell type in connective tissue?

-Fibroblasts

47

What are the function of fibroblasts?

-Provide and maintain ECM
-Synthesise and secrete collagen, elastin, proteoglycans and gags

48

Describe the appearance of a fibroblast?

-Slightly spindle nuclei
-Tapered cytoplasm
-Abundant rER

49

What other function are fibroblasts important in?

-Wound healing

50

In what connective tissue are macrophages found?

-Loose

51

What are the functions of the macrophages in connective tissue?

-Degrade foreign organisms
-Remove cell debris and dead cells

52

Where are mast cells found in connective tissue?

-Near blood vessels, absent from CNS

53

What are mast cells involved in?

-Hypersensitivity
-Anaphylaxis

54

What causes mast cells to release their granules?

-Become coated in IgE
-Bind allergen
-Release granules

55

What do the granules contain?

-Histamine
-Heparin
-Chemoattractants

56

What are the two types of adipocytes?

-Brown and white

57

Describe the features of a white adipocyte

-Numerous lipid droplets merge to form one large droplet
-Displaces all other cell contents to the side

58

Describe the features of a brown adipocyte

-Lipid droplets remain separate
-Central nucleus
-Abundant mitochondria (non-shivering thermogenesis)

59

Why do adipocytes look empty when stained with H and E?

-Preparation with toluene and xylene dissolves the lipid

60

Where is brown adipose tissue found?

-Scapula, sternum, axillae