Lecture 3: Connective tissue Flashcards
What are the two components of connective tissue?
CT is made up of extracellular matrix and cells
What are the two types of connective tissue?
Embryonic and mature
What are the functions of connective tissue?
Binds, supports strengthens body structures
Transport system of body - blood
Site of stored energy reserves - adipose tissue
Is CT vascular or avascular?
CT is vascular unlike epithelial tissue meaning it contains blood vessels
Does CT have a supply of nerves?
Yes, all CT contain nerves except cartilage
Is CT found on body surfaces?
No
What are the components of the ECM?
Ground substance and protein fibres
What are the components of the ground substance?
1) water
2) protein
3) polysaccharide (glycosaminoglycans)
What are glycosaminoglycans?
GAGS are long unbranched polysaccharides made up of amino sugar and uronic sugar (disaccharides)
There are two types: sulphated and non-sulphated
What are proteoglycans?
Formed by the long polysaccharide chains binding to core proteins
These molecules have lots of sugar and less protein
What is hyaluronic acid?
Type of non-sulphated GAGS therefore not bound to a core protein
Highly polar therefore can attract and trap water becoming sort of slippery
Viscous slippery substance that binds cells together
What is the function of hyaluronic acid?
Lubricates joints
Maintains shape of eyeball
What is hyaluronidase?
Enzyme that breaks down hyaluronic acid
Produced by sperm, white blood cells and bacteria
It allows species to navigate connective tissue by making ground substance more liquid
What is the chondroitin sulphate?
Type of sulphated GAGS that support and provide the adhesive features of cartilage, bone, skin , blood vessels
What is keratan sulphate?
Sulphated GAGS found in bone, cartilage and cornea of eye
What is dermatan sulphate?
Sulphated GAGS found in skin, tendons, blood vessels, heart valves
What is exophthalmos?
A disorder related to abnormal ECM causing the bulging of the eyes.
Occurs when the immune system attacks tissue in the thyroid gland causing over-activation and production of hormones. The extra hormones stimulate fibroblasts in the eye causing an influx of water and pushing eyes forward
What are the three types of protein fibres?
1) Collagen
2) Reticular fibre
3) Elastic fibre
What is collagen
A protein fibre that makes up the ECM of CT.
Strong and flexible allowing to resist pulling forces
Common in bone, cartilages, tendons and ligaments
What is reticular fibre
A protein fibre that makes up the ECM of CT
Made up of fine bundles of collagen + glycoprotein coating
Made by fibroblasts (like reticular lamina of basement membrane)
Provides strength and support
Found in basement membrane, vessels, adipose tissue, nerve fibres, smooth muscle tissues
What is elastic fibre
A protein fibre that makes up the ECM of CT
Made up of elastin surrounded by fibrillin giving strength and stability
Allows tissue to be stretched
Found in skin, blood vessles, and lung
Symptoms of marfan syndrome
Abnormal growth of limbs caused by defect in fibrillin of elastic fibres
Stability of heart valves and arterial walls are decreased.
How is marfan syndrome caused?
Hereditary defect on chromosome 15 for the coding of fibrillin, a glycoprotein that usually binds to TGFbs regulating growth. Fibrillin cannot bind to TGFbs causing abnormal growth.
What is fibrillin?
A type of glycoprotein that makes up elastic fibres along with elastin. It forms a scaffold for elastin and also binds to transforming growth factor betas controlling growth.
What are the two most common types of cells that make up CT?
Fibroblasts and adipocytes
What are fibroblasts?
Cells of CT
Secretes components of matrix (eg secretes reticular fibres forming reticular lamina of basement membrane)
Migratory
What are adipocytes?
Cells of CT
store fat (energy reserves)
found under skin and around organs