Cell Tissue Flashcards
How is loose connective tissue composed?
Many cells, high content of ground substance, sparse collagen fibres
Describe the structure of a proteoglycan.
A core protein with many side-chain sugars, of which many are glycoaminoglycans
How are glycoaminoglycans charged? What affect does this charge have?
Glycoaminoglycans (GAGs) are negatively charged - this attracts positively charged Na+ ions, drawing with it water
Describe the 2 segments that make up elastin.
A hydrophobic region, which provides the molecules elasticity - an alanine-lysine residue rich region, responsible for cross-linkage of the elastin molecules to make a fibre
What is the basement membrane?
The underlying layer of tissue to which the epithlial cells are anchored - this separates the epithelia from surrounding connective tissue and keeps cells in their proper compartments
What is the role of integrin?
Integrins attach the cell cytoskeleton to the extracellular matrix
How is paracrine secretion different to autocrine secretion?
Paracrine secretion acts on cells locally (ie adjacent cells) while auto crime secretion involves the cell acting on itself
What is endocrine secretion?
Endocrine secretion involves secretion of molecules/hormones into circulation via the blood stream
What process involved the eukaryotic uptake of a prokaryote now known as mitochondria?
Endosymbiosis
What is controlled cell death; apoptosis or necrosis?
Apoptosis
What are the 4 main types of tissue?
Epithelial
Muscle
Nerve
Connective
What type of bond attaches GAGs to the core proteoglycan protein?
Covalent
What are keratan sulphate and chondroitin sulphate?
Sulphated GAGs
How is the ground substance different to the extracellular matrix?
The ground substance is a mixture of proteoglycan and water - the extracellular matrix contains further molecules such as collagen fibrils and extracellular proteins etc
How is dense connective tissue composed?
Few cells, many collagen fibres, low amount of ground substance
What substance does loose connective tissue resemble? What surfaces is loose connective tissue mostly associated with, and how does it impact these surfaces upon infection?
Lost connective tissue resembles a viscous gel - it is mainly associated with the epithelia, and can swell considerably when they become infected
What is the dermis? What is the epidermis?
The dermis is the skin - the epidermis is the outer-most layer of the skin
We know that dense connective tissue has a high abundance of collagen fibres. How does the orientation of these fibres differ in regular and irregular tissue?
In regular tissue, college bundles are all positioned parallel to on another in the same direction - in irregular tissue, collagen fibres are arranged in bundles which are orientated in various different directions
Is the dermis regarded as a regular or irregular dense connective tissue?
Irregular dense connective tissue