3 - Connective Tissues

Question 1

Three embryological germ layers

Answer 1

Ectoderm, endoderm,

mesoderm

Question 2

Germ layers from which epithelium develops from

Answer 2

All germ layers

Question 3

Germ layers that connective tissue develops from

Answer 3

Mesenchymal stem cells from mesoderm

Question 4

Common layout of connective tissue

Answer 4

Few cells to a large mass of extracellular matrix which consists of fibres embedded in ground substance containing tissue fluid: extracellular fluid

Question 5

Dominant component that determines type of connective tissue

Answer 5

Extracellular matrix

Question 6

Cell that produces most fibres in the body (EG: collagen, elastin)

Answer 6

Fibroblasts

Question 7

Molecular makeup of collagen

Answer 7

3x alpha polypeptide chains that form a helix.

Question 8

Type I collagen

Answer 8

Connective tissue proper, bone, tendon, ligament

Question 9

Type II collagen

Answer 9

Hyaline cartilage, intervertebral disc

Question 10

Type III collagen

Answer 10

Reticular collagen.

Forms framework in certain tissues (EG: liver, bone marrow)

Question 11

Type IV collagen

Answer 11

Forms basement membrane

Question 12

Type VII collagen

Answer 12

Anchoring fibrils that link to basement membranes

Question 13

How are type III collagen fibres stained?

Answer 13

Not with H&E.

With silver stains

Question 14

Shape of elastin fibres

Answer 14

Branching fibres or sheets

Question 15

Where is elastin most commonly found?

Answer 15

Lung, skin, aorta

Question 16

Ground substance

Answer 16

Viscous, clear substance.
Glycosaminoglycans bound to core protein (forms proteoglycan).
Negative charge attracts Na+, which attracts water.

Question 17

Examples of glycosylated proteins that can be found in ground substance

Answer 17

Fibronectin, fibrillin, laminin

Question 18

ECM

Answer 18

Fibres + ground substance

Question 19

Resident cells

Answer 19

– Fibroblasts, myofibroblasts
– Macrophages
– Mast cells
– Mesenchymal stem cells
– Adipocytes
– Cells of specific CT: adipocytes, osteoblasts, chondroblasts,
haematopoietic cells

Question 20

Wandering cells

Answer 20

Lymphocytes, eosinophils, plasma cells, basophils

Question 21

Example of dense connective tissue

Answer 21

Tendon

Question 22

Why doesn’t ground substance stain in H&E?

Answer 22

Water is removed from it during slide preparation

Question 23

Composition of cartilage
1)
2)
3)
4)

Answer 23

1) Predominance of
proteoglycan ground
substance
2) Collagen type II
3) Connective tissue cells are
chondrocytes
4) Main type of cartilage is
hyaline which is avascular

Question 24

Composition of bone
1)
2)

Answer 24

1) Predominantly collagenous (type 1) matrix called osteoid which becomes mineralised
2) Connective tissue cells are osteoblasts and osteocytes

Question 25

Basement membrane

Answer 25

Interface between support tissues and parenchymal cells e.g. epithelia Mainly produced by the cells being supported EG epithelia

Question 26

``` Basement membrane composition 1) 2) 3) 4) ```

Answer 26

Composed of extracellular matrix: 1) Predominantly collagen IV 2) Heparan sulphate 3) Structural glycoproteins: laminins, fibronectin. 4) Collagen VII attaches basement membrane to underlying connective tissue Laminins and fibronectin are involved in linking integrins of epithelial cells to extracellular matrix

Question 27

Example of basement membrane

Answer 27

Basal lamina around muscles

Question 28

Basement membrane functions

Answer 28

– Structural support – Control of epithelial growth – Links epithelium to underlying tissue – Selective barrier to nutrients