Connective Tissue Flashcards
What are the three things connective tissue is made of?
Cells
Fibres
Ground substance
What are the three main types of fibre in connective tissue?
Collagen
Elastin
Reticular fibre
What is the extracellular matrix made up of?
Ground substance
Fibres
What is the ground substance?
What is it main component?
Viscous, slippery substances
Proteoglycans
What are the main cells in connective tissue?
Fibroblasts
Myofibroblasts
Macrophage
Mast cells
White adipocytes
Brown adipocytes
What do reticular cells do?
What type of cell are they?
Synthesise collagen alpha-I - which it uses to produce reticular fibres
So provide structural support
Fibroblast
What is the instersitium space?
Space between tissues and organs
What are some of the functions of connective tissue?
- binding and supporting
- protecting (bone protecting organs)
- insulating (fat)
- store reserve fuel and cells (fat and bone marrow)
- transport substances (blood)
- separation of tissue (tendons)
What is the function of fibroblasts?
Synthesise and secret fibres within the GS
Reponsible for scar formation
What is the function of Myofibroblasts?
What are they derived from?
What do they contain?
Responsible for wound contraction when tissue loss has occured
Modified fibroblasts
Actin and myosin
What is the function of macrophage? (2)
What are they derived from?
Phagocytic - degrade foreign organisms and cell debris
Antigen presenting - present foreign material to T lymphocytes
Blood monocytes
What three things do mast cells contain? Explain briefly what they all do
Histamine - increases blood vessel wall permeability
Heparin - anticoagulant
Cytokines - attract eosinophils and neutrophils
What do mast cells have on their membrane?
What is their function?
IgE
IgE bind to allergens
Releasing the contents of the mast cell
What is the function of unilocular adipocytes?
What are they also known as?
What are two key features?
Padding
Shock absorber
Insulation
Energy reserve
White
One single large lipid droplet
Nucleus and organelles to the side
What is the function of brown adipocytes?
What are they also known as?
What are two key features?
Insulation
Energy reserve
Brown
Small lipid droplets
Nucleus and organelles are central
What are adipocytes derived from? (2)
Immature fibroblasts
Mesenchymal stem cells
What is the function of collagen?
What two properties allow this?
Structural support
Flexible
High tensile strength
What is the function of elastin?
Responsible for elastic recoil after stretch or distension
What is the function of reticular fibres?
What is a key fact about them?
Provides a supporting framework
Non in lose tissue
What is the most common type of collagen?
Type I
Briefly describe the structure of collagen I
Where is it found?
Fibrils aggregate into fibres and fibre bundles
Within tendons and liagments
Briefly describe the structure of collagen II
Where is it found?
Fibrils do not form fibres
Cartilage
Briefly describe the structure of collagen III
Where is it found?
What is it also known as?
Fibrils form fibres around muscle and nerve cells
The bone marrow, lymphatic tissue and tendons
Reticulin
Briefly describe the structure of collagen III
Where is it found?
Unique form
Basement membrane
What are the two types of connective tissue?
Loose
Dense
What is loose tissue also known as?
Areolar
What is dense tissue also known as? (2)
Fibrous
Collagenous
How many different cell types loose tissue have in comparison to dense
Name the most common (4)
Many
Fibroblasts
Macrophages (and other WBC)
Mast cells
Adipocytes
What are the two main fibre in loose tissue?
Collagenous
Elastic
How much ground substance does loose tissue have in comparison to dense?
A lot
Name four functions of loose tissue
- Holds vessels that supply fluid - so highly vascularised
- permits cell migration (due to gaps)
- packaging around organs
- holds everything in place
Name three key places loose tissue is
- under epithelial cell layers
- around glands
- surround capillaries, nerves and sinusoids
What is the main component of ground substance?
What are covalently bound to?
What are they composed of?
Proteoglycans
Glycosaminoglycans
Polysaccharides
What is responsible for hydrating the ground substance?
Glycosaminoglycans (bound to the proteoglycans )
GAGs are attached to hyluronate
The sugar moieties attract water
What are the two types of dense connective tissue?
Irregular - fibres run in different directions
Regular - fibres run in parallel
What are the two main things to look out for in mucoid connective tissue?
Mucoid connective tissue
Collagen fibres (blue)
Name some symptoms of scurvy
- gum disease and tooth loss
- poor wound healing
- weakness and fatigue
Name some symptoms of marfan’s syndrome
- abnormally tall
- arachnodactyly
- joint dislocation
- risk of aortic rupture
Name some symptoms of osteogenesis imperfecta
- weak bones
- blue sclera
- hypermobility
- short stature
What causes scurvy?
- Vitamin C deficiency
- causes disruption to collagen fibril production
What causes marfan’s syndrome?
Autosomal dominant
- fibrillin 1 gene is affected
- elastic tissue is abnormal - as elastin is surrounded by microfibril fibrilin
What causes osteogenesis imperfecta?
Mutated COL1A gene
Either/both:
- collagen fibres do not knit together
- not enough collagen produced
Define connective tissue
A tissue that connects, supports, binds or separates other tissue or organs
typically having relatively few cells embedded in an amorphous matrix
Often with collagen or other fibres
