Lecture 6

Question 1

Fibroblast

Answer 1

Produces the extracellular fibres (collagen, elastic and reticular fibres) and produce/maintain ground substance. Active fibroblasts have more mitochondria and euchromatin than inactive fibroblasts

Question 2

Ground substance

Answer 2

Glycosaminoglycans, proteoglycans, multi-adhesive glycoproteins

Question 3

Glycosaminoglycans

Answer 3

sugar, highly-charges, rigid, strong, attract H2O to form hydrated gel, provides cushioning and strength, resist compression, allows diffusion

Question 4

proteoglycans

Answer 4

Glycosaminoglycans attach to core proteins.

Question 5

multi-adhesive glycoproteins

Answer 5

e.g fibronectin, stabilise extracellular matrix and link it to cell surface

Question 6

collagen fibres

Answer 6

most abundant of connective tissue fibres. Flexible, extremely high tensile strength. With LM appear thick and wavy. In EM, you can see collagen fibrils. Due to structural organisation of component molecules, regular transverse collagen fibrils are made of an array of collagen molecules. Cpllagem molecules = 3 peptide chains intertwined to form tight rope-like molecules.

Question 7

reticular fibres

Answer 7

provide supporting meshwork for cells in certain organs (e.g kidney, liver, lymph nodes). Adds mechanical strength to these tissues. Difficult to see in LM section. silver stains highlight them. T3 collagen fibres produced by reticular cells (specialised fibrils)

Question 8

Elastic fibres

Answer 8

allows tissues to return to shape after stretching. Thin fibres in branching 3D network. interspersed in collagen = limits degree of stretching. Made of elastin molecules joined together. Have natural tendency to coil up causes contraction of fibres. Elastic material also present in arteries.

Question 9

sectioning

Answer 9

cut in thin slices of tissue, so thin you can see through it.

Question 10

spread

Answer 10

whole tissue is thin enough to spread over slide. You can see path of blood vessels and fibres through tissue.

Question 11

mesentary

Answer 11

thin layer of loose connective tissue between 2 layers of simple squamous epithelium. Already thin enough

Question 12

loose connective tissue

Answer 12

provides medium for gas, nutrient, metabolic waste diffusion. Mainly found beneath epithelia. Susceptible to invasion of immune systems

Question 13

Dense irregular CT

Answer 13

Few cells, mosly fibroblasts. Little ground substance. Lots of collagen fibres (strength). Firbres arranges in bundles and oriented in range of directions (structural strength in multiple directions to prevent tearing).

Question 14

Sense regular CT

Answer 14

Few cells, mostly fibroblasts (squashed fibres). Little ground substance. Mainly collagen fibres (tightly packed). Collagen fibres arranged in parallel to obtain maximum strength in one direction. Main component of tendons and ligaments