Connective and Adipose Tissue Flashcards
What are the 3 main structural components of connective tissue?
Cells- mainly mature fibroblasts/fibrocytes, fixed adipocytes
Fibres- eg collagen, elastin, reticular fibres
Ground substance- proteoglycans (sugars with a protein associated)
What makes up the extracellular matrix?
Ground substance and Fibres
Give 6 functions of connective tissue
1) Binding and supporting (holds organs together)
2) Protecting (Bones protect vital organs and fat acts as a shock absorber)
3) Insulating (fat underlying skin and bone marrow holding warm blood)
4) Storing reserve fuel cells (bone marrow and fat tissue)
5) Transporting substances within the body (blood and interstitium)
6) Separation of tissues (fascia and tendons/cartilage)
Define connective tissue
A tissue that connects, supports, binds or separates other tissues or organs, typically have collagen or other fibres eg elastin.
Describe the structure of loose connective tissue (cell types, fibres, ground substance)
Loose connective tissue has multiple cells type- mast cells, macrophages, fibroblasts, adipocytes
2 main types of fibre are elastin and collagen
It’s ground substance is ‘gel’ like and make up of proteoglycans
What is the function of loose connective tissue (areolar tissue)?
Give 4 examples
1) Holds vessels that supply fluids
2) Permits cell migration
3) INvolved in inflammation pathways
4) act as as packaging around organs
5) Generally holds everything in place
6) Cushions and stabilises organs
List the common cell types found in connective tissue
FIbroblasts, Macrophages, Mast cells, Adipocytes
What is the function of fibroblasts? Why is this important?
They synthesise and secrete the fibres that lie within the ground substance.
Fibroblasts are important in wound healing because these cells are primarily responsible for scar formation
What organelle will fibroblasts have lots of?
RER because they make lots of proteins eg collagen
What are myofibroblasts and what’s there function?
They are modified fibroblasts with actin and myosin. They are responsible for wound contraction when tissue loss has occurred.
What are Mast cells? Where are they found?
Mast cells have a key role in inflammatory response.
They are found in areolar connective tissue near blood vessels.
They are not found in the CNS as they open up blood vessels which would cause oedema on the brain
What do Mast cells look like under the microscope?
They have lots of vesicles surrounding a nucleus
What 3 granules do Mast Cells contain and what is their function?
Histamine (increases blood vessel wall permeability by creating fenestrations which allow cells into the tissue)
Heparin (an anticoagulant) This is important to allow blood flow so macrophages can get to the bacteria
Cytokines (kill pathogens)
What is the function off unilocular adipocytes? What type of adipose tissue does it make up?
It makes up white adipose tissue. Function is padding and shock absorber, insulation and energy reserve
What do white adipocytes look like under the microscope? Why are they hard to see in H&E staining?
The nucleus spreads to the outside of each droplet so look like white circles with pink outlines. They are difficult to see because in H&E the fat is stripped out so the fat doesn’t stain
What is the function of multilocular adipocytes? What type of tissue do they for on?
They form brown adipose tissue. Their function is insulation and energy reserve
Give 3 differences between white and brown adipose tissue
White is single lipid droplet whereas brown is multiple lipid droplets.
White has a normal number of mitochondria whereas brown has lots of mitochondria
In adults, white adipose tissue breakdown is slow and heat only generated after shiver reflex. Whereas only children have brown adipose tissue and the lipid breakdown is accelerated, oxidative phosphorylation is uncoupled to provide heat.