(9) TOB L4.1 CONNECTIVE TISSUE Flashcards
What are the three components which make up connective tissue?
cells, extracellular fibres (elastic, reticular and collagen) and ground substance (Hyaluronate proteoglycan aggregates).
Give three functions of connective tissue and examples
Provide a medium for dffusion of nutrients and waste - Blood
Attach muscle to bone and bone to bone - Tendons and Ligaments
Provide substance - Alimentary Canal
Name two constituents of embryonic connective tissue
Mesenchyme (gives rise to myriad types connective tissue)
Mucous connective tissue
Give example of where mucous connective tissue can be found
Whartons Jelly, in umbilical chord
Two types of normal connective tissue
- Loose connective tissue
* Dense connective tissue (irregular or dense)
Name four types of specialised connective tissue
Adipose tissue, blood, cartilage, bone.
Name three common cells found in connective tissue
Fibroblasts
Mesenchymal cells
Macrophages
Function of fibroblasts
Synthesise collagen, elastic and reticular fibres and ground substance
Function of Mesenchymal cells
Undifferntiated cells which differentaite into other cells and maintain exracellular material
Macrophages
Ingest foreign, dead or unneeded material.
What is a macrophage called in the liver?
Kupfer Cells
What is a macrophage called in Bone?
Osteoclast
What is a fibrocyte
Mature and less active Fibroblasts
What is a mast cell? (visitant)
Release pharmacologically active molecules in response to histamine and heparine.
What are fat cells? (visitant)
Store lipids and act as an insulate and shock absorber
What does the extracellular matrix determine in connective tissue?
Whether function of connective tissue mechanical or support (loose packing material)
Which type of collagen is most common, and how much of body protein is made up of it?
I, 25%
Where is type II collagen present?
Hyaline and elastic cartilage
Where does the synthesis of collagen take place?
Rough endoplasmic reticulum
What is a collagen fibre made up of?
Collagen fibrils, in triple helix of alpha chains.
What amino acid is the most common in collagen fibrils and why?
Glycine appears every third amino acid and allows close association of collagen fibres
What is responsible for production of collagen fibrils?
Fibroblasts, secrete procallagen
What type of collagen is found in reticular fibres?
Type III
Name three places reticular fibres form delicate network?
Smooth muscle cells, epithelial cells and blood vessels
Name four places reticular fibres make up structural framework?
LSLB
Liver, Spleens, Lympoid organs, bone marrow
Why are elastic fibres elastic?
Due to high lysine content
What is the structure of an elastic fibre?
Elastin surrounded by microfibrils called fibrillin.
Give three places elastic fibres are structurally important
Dermis, artery walls and sites with elastic cartilage
What is ground substance?
Gel like matrix in which fibres and cells are embedded
What three things are ground substance made up?
GAGs, proteoglycans and glycoproteins
How does GAG form a hydrated gel?
Highly negative, so attracts water
Define loose connective tissue
Wispy collagen and many fibroblasts separated by ground substance.
What two cell structures are made up of loose connective tissue?
Walls (septa) and trabeculae (rods)
Name four types of loose connective tissue and two examples of where found (only one for fat)
Mucous connective tissue
Aereolar connective tissue
Adipose tissue
Reticular tissue
Where find adipose tissue (LCC) 1
Fat cells connected by loose connective tissue
Where find mucous connective tissue? 2
Umbilical cord and subdermal connective tissue of embryo
Where fine aereolar connective tissue? 4
Deep under skin, submucosa,below mesothelium of peritoneum, parenchyma of glands
Wherwe would you find reticular tissue? 2
Lymphoid tissue and the liver
Define dense connective tissue
Close packing of fibres with fewer cells and less ground substance
Two functions of dense connective tissue?
Achieve mechanical support and transmit forces
Name two types of dense connective tissue
Regular and irregular
How are fibres arranged in dense regular tissue?
Fibre bundles orientated in parallel to provide maximum tensile strength
Name two places you could find dense regular connective tissue
Ligaments and tendons
How are fibres arranged in dense irregular connective tissue
Interwoven bundles of collagen which criss cross each other in many directions. Counteracts multi-directional forces.
Name three places where dense irregular connective tissues found?
Dermis, dura mater and large septa
What happens in systemic sclerosis?
all organs have excessive accumulation of collagen (fibrosis)
Name three places sclerosis occurs in sytemic sclerosis and what happens as a result
Skin, digestive tract, muscles and kidney - hardening and functional impairment
What are keloids?
Abnormal scars caused by abnormal amounts of collagen
How does scurvy occur?
Vitamin C defiency causes defective collagen synthesis resulting in degeneration of connective tissue.
What is the main symptom of scurvy?
Loosening of teeth in sockets and subsequent loss
What is the cause of Marfans syndrome?
Autosomal dominant inherited genetic disease. Causes defective fibrilin to be produced
What is the result of defective fibrilin in Marfans syndrome?
Elastic fibres underdeveloped and hyperelastic. Aortic rupture, high blood pressure and dislocation.
What is the name of the disease which causes defiency in collagen type III causing ruptures in tissues containing high reticullin content?
Ethlers-Danlos Disease
