Lecture 2.3 Connective Tissue Flashcards
What develops from ectoderm, endoderm and mesoderm?
Ectoderm: skin, neural tissue, epithelium
Mesoderm: muscle, connective tissue, epithelium
Endoderm: epithelium
What makes up connective tissue and what are its roles?
Cells, fibres, ground substance - lots of ECF. Provides structure, strength, defence, space filling
Types of connective tissue proper?
Loose: irregular
Dense: regular or irregular
Features of fibroblasts?
Elongated/spindled nuclei, synthesise ECM
What are the features of collagen fibres?
Abundant, strong, wavy on LM, 3 alpha chains, need vit c to form, organised, slow healing (low BS)
Types of collagen fibres?
– I: connective tissue proper, bone, tendon, ligament
– II: cartilage, intervertebral disc
– III: reticulin (thin, delicate support, not seen on LM – need silver stain)
– IV: basement membranes
– VII: anchoring fibrils that link to basement membranes
What are the features of elastin?
Sheets or branching fibres, need silver stain, found in aorta, lung and skin, surrounding microfibril network
What is marfan syndrome?
Lack of fibrilin to produce elastin, present in tall people, risk of aorta dilating or rupturing
What is ground substance?
Clear, high water, 4/5 of ECF, takes up haemotoxilin, made up of GAGs and glycoproteins, negative charge, links cells and matrix
What is special about myofibroblasts?
Contract (have actin and myosin) and reduce area to heal
What do mast cells have?
Granules with histamine
Why is cartilage flexible and what are its cells?
Flexible due to ground substance (water), chondrocytes are cells, main cartilage is hyaline which is avascular
What are the features of the basement membrane?
Interface b/w support and parenchyma, produced by cells being supported, 3 layers on EM, too thin for H&E, linked to connective tissue via collagen VII
Functions: support, control epithelial growth, link epithelium to underlying tissues, selective barrier
Why does adipose look white under stain?
Alcohol and xylene remove lipids
What are the features of white and brown fat?
White: yellow to naked eye, one droplet on LM
Brown: more present in babies, multiple lipid vesicles, adult retroperitoneum
