Integrating Cells Into Tissues Flashcards
At what temperature are packed red blood cells usually stored at? How long can they be kept at this temperature for?
6 degrees Celsius.
42 Days.
What is the lateral domain?
Refers to the side-to-side attachment of cells to each other.
What are the 3 types of cell junctions? Where are cell junctions found?
Tight junctions, desmosomes and gap junctions.
Found between adjacent epithelial cells.
What is a tight junction? Give an example of where they are found.
Fused plasmalemma forming a seal between 2 cells (selective barrier).
Epithelium of the intestines.
What is a desmosome? Give an example of where they are found.
They further strengthen the connection between adjacent cells, through interlocking proteins. Found under/next to tight junctions.
Found between epithelial cells that need to resist stress e.g. Skin
What is a gap junction?
Allow cells to communicate effectively together. Protein channels called connexons allow messages between cells.
What does the basal domain refer to?
Refers to cells sitting on a basement membrane
The basement membrane is the structural site for…
Overlying (epithelial) Cells and underlying connective tissue.
What are 2 ways in which cells can be attached to the basement membrane?
Hemidesmosomes.
Focal Adhesions.
What are hemidesmosomes? Where are they found?
Attach cells to the basement membrane through integrins and intermediate keratin filaments.
Found in tissues subject to abrasion. Skin. Oral cavity.
What are focal adhesions?
Anchor cells to the basement membrane using integrins and intracellular actin filaments.
What is function of focal adhesions?
Help in cell movement. For example migration of epithelial cells in wound repair.
What are integrins?
Transmembrane glycoproteins used in the formation of hemidesmosomes and focal adhesions.
Give 2 functions of integrins.
Attachment of the cell to the ECM.
Signal transduction from the ECM to the cell.
Give 2 ways in which cells can be separated from tissues to produce a cell culture?
Using collagenase.
Using microdissection.
What are the disadvantages of using cultured cells? (3)
1) Cultured cells behave and look different to the same cells in tissues.
2) They demonstrate contact inhibition (stop growing once they touch each other)
3) Limited life span (senescence)
What two processes do cells die by?
Apoptosis.
Necrosis.
Define apoptosis.
Programmed cell death.
What is apoptosis controlled by? Give an example of a protein that inhibits apoptosis.
Molecular signals.
Bcl-2 protein in the outer mitochondrial membrane.
What are the basic steps of apoptosis once it has been initiated?
Catabolic processes begin (e.g enzymes digest cell components)
Cell shrinks and fragments into apoptotic bodies.
Phagocytised by adjoining cells.
What are the 3 types of cell renewal?
Static
Stable
Renewing
Give examples of cells that show static cell renewal.
Cardiac, CNS and skeletal muscle.
Give examples of cells that show stable cell renewal.
Fibroblasts, endothelium, smooth muscle.
Give examples of cells that show renewing cell renewal.
Blood, skin, gut epithelium.
