Tissues 1: Epithelial cells Flashcards
(47 cards)
Define Cytoskeleton
A system of filaments formed by the polymerisation of protein monomers
Summarise the 3 main components which constitute the cytoskeleton
Microtubules Intermediate Filaments Microfilaments.
How are microtubules formed?
Polymers of a and b tubulin heterodimers, ~20nm thick.
What is the function of microtubules?
Involved in cell shape, and act as “tracks” for the movement of organelles and other cytoplasmic components within the cell.
What is the major component of cilia and flagellae
Microtubules
Where are microtubules located within a cell
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What is the Microtubule organising centre (MTOC)
The microtubule-organizing center (MTOC) is a structure found in eukaryotic cells from which microtubules emerge. MTOCs have two main functions: the organization of eukaryotic flagella and cilia and the organization of the mitotic and meiotic spindle apparatus, which separate the chromosomes during cell division.
What constitute of the cytoskeleton forms the mitotic spindle
Microtubules form the mitotic spindle The microtubular mitotic spindle is the target for many antimitotic cancer drugs
What is an Intermediate filament?
A group of polymers of filamentous proteins which form rope-like filaments, with diameter in the range 10-15 nm. `
What is the function of Intermediate filaments
IFs give mechanical strength to cells. Desmosome cell-cell adhesions are connected by intermediate filaments
Why can Intermediate Filaments be used to differentiate between cell types?
The type of IF a cell has is characteristic of cell type, epithelia have cytokeratins; mesenchymal cells have vimentin; neurones have neurofilament protein. muscle cells have desmin.
What part of the nuclear envelope is made up of Intermediate Filaments and what is the function of this structure made up of IFs?
Nuclear lamins (mentioned earlier) are intermediate filaments found forming a network on the internal surface of the nuclear envelope, being involved in stabilising the envelope.
Where are intermediate filaments located within a cell?
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What are Microfilaments?
Polymers of the globular protein, actin; associate with adhesion belts in epithelia and endothelia, and with other plasma membrane proteins. 5-9nm diameter
What are Microfilaments made up of?
Polymers of the globular protein, actin;
What is the function of Microfilaments?
Involved in cell shape and cell movement (crawling of cells; cell contractility esp. muscle).
Name an accessory protein which is assciated with microfilaments?
Accessory proteins, e.g. myosin, act with actin to control actin organisation and cell movement.
What is the monomer for Actin filaments?
Monomer = globular actin, G-actin
What type of actin makes up microfilaments?
Microfilaments = filamentous actin, F-actin
Where is microfilaments located in a cell?
Typically present in the cortical (peripheral) regions of a cell. add pic
List the main cell type groups?
Epithelial
Mesenchymal
Haematopoetic
Neural
What are epithelial cells
cells forming continuous layers, these layers line surfaces and separate tissue compartments and have a variety of other functions.
What are nueral cells and what are the two main types of nueral cells?
cells of the nervous system having two main types; neurones (carry electrical signals) and glial cells (support cells).
What are Haematopoietic cells?
Haematopoietic cells: blood cells, tissue-resident immune cells, and the cells of the bone marrow from which they are derived.
