Lecture 10 - Connective Tissue (proper) Flashcards
What is the definition of connective tissue?
Tissue that connects, supports, binds or separates other tissues or organs
What are the 3 components of the structure of connective tissue?
Cells
Fibres
Ground substance
What are the main cells of connective tissues?
Fibroblasts
Chondrocytes
Osteocytes/osteoblasts/osteoclasts
Stem cells/progenitor cells/bone marrow/blood/adipocytes
What are the main products produced by connective tissues?
Fibres
Ground substance
What 2 components of connective tissue make up the extracellular matrix (ECM)?
Fibres + Ground substance
What fibres are commonly found in connective tissues?
Collagens
Elastin
Reticular fibres
What is ground substance made of?
Proteoglycans like Hyaluronic acid (a type of glucosaminoglycan)
What is the function of connective tissue??
Binds and supports tissues
Protection (fat as shock absorber)
Insulation (bone marrow holding warm blood)
Storing reserve fuel and cells (bone marrow and fat)
Transporting substances
Separating tissues (fascia and tendons/cartilage)
What are the 2 types of Connective Tissue Proper?
Loose connective tissue
Dense connective tissue
What is the strucutre of loose connective tissue?
1.) Multiple cell types: Fibroblast, macrophages, other WBCs, mast cells and adipocytes
2.) 2 main fibres = collagen and elastin
3.) Lots of Gel like ground substance made of: proteoglycans, Hyaluronic acid…..
What is the name given to macrophages in connective tissues?
Histiocytes
What is the function of loose connective tissue?
Acts as packing around organs
Cushions and stabilises organs
Holds vessels and everything in place
Involved in inflammation pathways (mast cells)
Where is loose connective tissue found?
Under all epithelial layers (Called the Lamina propria)
Around glands, capillaries , nerves and sinusoids
What do the cells and fibres all lie in in connective tissue?
Ground substance
What are fibroblasts?
The cells that synthesis and secrete the fibres that lie within the ground substance
Why are fibroblasts important in wound healing?
Produce scar tissue
What are myofibroblasts and what is special about them?
Modified fibroblasts
Contain actin and myosin
Responsible for wound contraction
What type of cells are the hisitocytes/macrophages?
Dendritic cells
They present foreign material to the T lymphocytes
What is the function of mast cells?
Important in the immune response
What substances to Mast cells release when activated?
Histamine (inc blood vessel permeability)
Heparin (anticoagulant)
Cytokines (attract eosinophils and neutrophils)
When do mast cells become activated?
Infection by bacteria, parasites and allergens
Get coated by IgE
Where are Mast Cells not found an why?
CNS
avoid damaging effects of oedema
What are unilocular adipocytes called?
White adipocytes
What is the structure of a white adipocytes?
Single large lipid droplet
Nucleus, cytoplasm and organelles all squeezed to one side of cell (peripheral)
What is the function of white adipocytes?
Shock absorber
Insulation
Energy reserve
What are mulitlocular adipocytes called?
Brown adipocytes
What is the structure of brown adipocytes?
Lots of small lipids droplets
Nucleus, cytoplasm and organelles squeezed to CENTER of cell
What is the function of brown adipocytes?
Insuliton
Energy reserve
How does the number of mitochondria differ between white and brown adipose?
Brown has more mitochondria
In neonates, the ETC and ATP synthesis are uncoupled to generate lots of heat
How many types of collagen are there?
Type I
Type II
Type III
Type IV
What is the structure of Type 1 collagen?
Fibrils form Fibres
What is the structure of Type II collagen?
Fibrils do NOT FORM FIBRES