Connective Tissue Flashcards
What are the functions of connective tissue? (6)
CONNECTS, TRANSPORTS (diffusion medium), PROTECTION (provides a cushion and insulation), STORAGE (fats), DEFENCE (against infection) and WOUND HEALING
What are the 4 basic types of tissue?
Epithelial, muscle, nerve and connective
What are the 6 specialised types of connective tissue?
Adipose, Lymphatic, blood, haemopoietic, cartilage and bone
What does general connective tissue (CT proper) consist of?
Cells, Fibres and ground substance
What are the 3 types of fibres found in connective tissue?
Collagen, reticular and elastin
How is collagen produced?
Fibroblasts secrete procollagen which is converted into collagen outside the cells. The collagen molecules then aggregate together to form collagen fibrils, which group together to form collagen fibres.
What are the types of fixed cells found in connective tissue? (6)
Fibroblasts, macrophages, mast cells, melanocytes, adipocytes and mesenchymal stem cells
What are the wandering cells found in connective tissue? (5)
Leucocytes, plasma cells, eosinophils, basophils and monocytes
What do fibroblasts do?
Synthesise and secrete ground substance, procollagen and fibres.
What is the function of reticular fibres?
Provides a supporting framework
What is reticular fibres made of?
Type III collagen
What is ground substance?
Viscous, clear fluid
What is ground substance composed of?
Proteoglycans
What is loose connective tissue composed of?
Lots of cells and ground substance. Sparse collagen fibres.
What is dense connective tissue composed of?
Few cells (only fibroblasts present) or ground substance. Lots of collagen fibres densely packed.
What are the 2 types of dense CT?
Regular and irregular
What is the structure of regular dense CT?
Collagen fibres are arranged in parallel bundles which densely packed fibroblast cells between bundles. Therefore, they can withstand stress from one direction.
Where is regular dense CT found?
In tendons, ligaments and aponeurosis
Where is loose CT found?
Beneath epithelia, around small blood vessels (where pathogens can get in)
What is the structure of irregular dense CT?
Bundles of collagen fibres arranged in various directions so can withstand stress from various directions
Where is irregular dense CT found?
In the dermis
What conditions results in a lack of vitamin C?
Scurvy as procollagen production requires vitamin C and so there is a poor bone formation without it.
What are the roles of elastin fibres?
Allows tissues to stretch and recoil
Where do you find elastin fibres?
At the dermis, artery walls and lungs
What condition results from abnormal type 1 collagen?
Osteogenesis imperfecta
What are elastin fibres composed of?
Elastic fibres but itself enfolds and is surrounded by microfibrils called fibrillin.
How would elastin fibres appear on a TEM?
Elastin fibres are amorphous (no clear shape/form)
What condition arises due to an abnormality in the fibrillin gene?
Marfan’s syndrome
What are the symptoms of marfan’s syndrome?
Sufferers are abnormally tall, exhibit arachnodactyly, have frequent joint dislocation and can be at risk of catastrophic aortic rupture.
