A: Histology of connective tissue Flashcards
Functions of connective tissue
- Structure
- Protection
- Storage
- Transportation
- Defense
Fibroblasts
- Flat cells with elongated nuclei.
- Produce fibres + ground substance
- Help in wound healing (mesenchymal cells develop into fibroblasts and enter a wound site. They secrete ground substance + fibres to make a collagenous scar which replaces damaged tissue).
What are the dark blue things
Fibroblasts
Mast cells
- Common beneath membranes + along small blood vessels
- In their cytoplasm there are granules with histamine (causes capillaries to leak, causing oedema which dilates blood vessels causing warmth + redness) and heparin (inhibits blood clotting)
Identify
Mast cells
Plasma cells
- Derived from B cells
- Large, granular + round nucleus
- Secrete specific antigens.
Identify
Plasma cell
Adipocytes
- Synthesise + store fat
- Release cytokines
White adipocytes
large lipid droplets push nucleus to edge of cell
Brown adipocytes
found in newborn mammals, used for thermoregulation. Are smaller, central nucleus + many small lipid globules.
Identify
White adipocyte
Identify
Brown adipocyte
Collagen
- Strong + inelastic
- Produced by fibroblasts
- Tropocollagen (3 collagen a-fibres) come together to make collagen microfibrils which make collagen fibres
What is E, L and Ma?
Elastin
Collagen
Mast cells
Ehlers-Danlos syndrome
Mutated gene forming abnormal collagen.
- Hypermobile ligaments
- Hyperelastic skin bruises easily
Osteogenesis imperfecta
- Mutation in gene for collagen synthesis –> abnormal collagen
- Extremely fragile bones
- More likely to be deaf.
- Blue sclera
Elastin fibres
- Branched fibres, can stretch + recoil
- Synthesised by fibroblast
- Made of protein elastin + fibrillin (which forms scaffolding for elastin)
Marfan’s syndrome
- Mutation in fibrillin gene
- Makes skeleton tall + thin with arachnodactyly
- Risk of developing aortic dilation or aortic aneurysm
- Leaky heart valves
- Myopia in eyes
Reticular fibres
- Fine, highly branched collagen fibres
- Form structural framework
- Found in lymph nodes + spleen
Ground substance:
- Semi-fluid gel in between cells + fibres
- Made of glycosaminoglycans (polysaccharides), proteoglycans (bind water, giving gel-like properties), water and salt
- Size of spaces between glycosaminoglycans determines permeability of tissue
- Delays spread of infection through tissue
Types of general connective tissue
- Loose connective tissue: low density of fibres
- Dense connective tissue: dominated by fibres
Dense connective tissue:
Dominated by fibres
Dense regular: fibres run parallel
Dense irregular: fibres have no clear orientation
Identify
Areolar connective tissue
Loose connective tissue:
Low density of fibres
- Areolar
- Adipose
