What is proper or generalised connective tissue contain?
Tendons and ligaments, Fascia and reticular networks and Adipose Tissue(Fat)
How is adipose tissue different to fascia?
Adipose tissue is where fat is stored under a deep layer of skin, while fascia is connective tissue around muscles
What are the 3 basic components all connective tissue shares?
1) Specialised Cells
2) Protein Fibers
3) Ground substancce (fluid)
What is a fibroblast and what are its 3 functions?
Most abundant type of cell in the body that:
1)secrete proteins that complex together to form fibers,
2)secrete molecules => ground substance e.g. hyaluronan: acts as a cement between cells, and
3)proliferate(increase in number) and migrate in response to injury
What is the difference between a fibroblast and fibrocyte?
Fibrocytes are less active fibroblast that produce scar tissue
What is a fixed macrophage and what does it do?
A phagocyte that phagocytoses(eats) pathogens and damaged cells
What is a mast cell and what does it do?
A leucocyte(white blood cell) that stimulates inflammation after injury and secrete/degranulate inflammatory mediators histamine(capillary permeability) and heparin(prevents blood clotting)
What are Mesenchymal cells and what do they do?
Stem cells that differentiate to replace old or damaged connective tissue cells
What are Monocytes and Neutrophilis and what do they do?
Phagocytic cells that migrate from vascular compartment => generalised connective tissue in response to signal from mast cells & macrophages i.e. chemotaxis
What is a lymphocyte and what does it do?
A type of white blood cell that also migrates from vascular compartment
What would be the physical sign of increased vascular permeability to plasma fluid and proteins at site of injury?
Explain the 4 steps of injury healing?
1) Immune mediators are released(histamine and heparin) and immune cells are activated (mast cells and macrophages) to pump blood to area (vasodilate/vascular permeability)
2) Neutrophilis migrate and phagocytose damaged tissue, monocytes finish job
3) Fibrocytes produce scar tissue
4) Mesenchymal cells re-establish receded scar tissue
How are collagen fibres formed?
Rough endoplasmic reticulum synthesis procallegen chain=> triple helix and create subunit tropocollagen that complexes together to form fibrils and then fibers.
What are reticular fibres and what do they do?
Network of interwoven fibers(stroma) that are thinner than collagen fibers but can resist forces in many directions
What are elastic fibers?
Branched and wavy fibers made up of an elastin core and microfibrils that can increase their length by 150% and return to original configuration
Where are elastic fibres found?
Structures that must withstand repeated stretching e.g. blood vessel walls, skin, lungs
What is connective tissues ground substance?
Fluid that fills spaces between Connective Tissue cells and fibers that is made up of Proteoglycans and Glycoproteins.
What is the difference between Proteoglycans and Glycoproteins?
-Proteoglycans are hydrators that stabilise collagen networks and resist compressive forces(glue)
-Glycoproteins link extra cellular matrix components and facilitate movement of cells through Connective Tissue
What is the difference between loose (aerolar), adipose and dense regular connective tissue?
-Loose(aerolar) tissue is found in dermis of skin and is composed of widely scattered cells that support and stabilise structures
-Adipose tissue is loose(aerolar) tissue with adipose cells that swells when filled with fat and shrinks when fat is used for energy.
-Dense tissue is tightly packed glue that holds it shape