Fundamental Principles of Cell Signalling Flashcards
What are the two kinds of synapses?
ELECTRICAL (endothelial cells, cardiac myocytes and epithelia) and CHEMICAL (neurons in the brain).
What are the 3 different cell-to-cell signalling techniques?
The three are PARACRINE (cell to cell direct), ENDOCRINE (cell to cell via the bloodstream) and SYNAPTIC (synapse to synapse).
List the receptor categories and types of receptors in those categories.
There are cell surface receptors (G-protein coupled, tyrosine kinase couples and ligand-gated ion channel receptors) and intracellular receptors (nuclear receptors).
Name 4 voltage-gated ion channels.
The Na+, Ca2+, K+ and Cl- channels.
Name 3 ligand-gated ion channels.
The neurotransmitter receptor (Na+ and K+ switching), the Ca2+ activated K+ channel and the cyclic nucleotide-gated channel (Na+ and K+ switching).
What are the 5 mechanisms of maintaining calcium levels in the cytoplasm?
- The NA+/Ca2+ exchanger on the cell membrane
- The Ca2+ pump on the cell membrane
- The Ca2+ pump on the ER
- The Ca2+ binding molecule
- The Ca2+ importer on mitochondria
Give an example, using acetylcholine, of signalling molecules being versatile in their induced responses.
In salivary glands, acetylcholine induces secretion. In heart muscle, it induces decreased rate and force of contraction. In skeletal muscle, it induces contraction.
This is due to the different receptors expressed on the different cells.
Describe the role of Na+/K+ ATPase.
It is used to regulate the levels of sodium in the cells. Examples of drugs that act upon it are Oubain and Digoxin. They are prescribed for heart failure.
How does Digoxin work?
It works on the Na+/K+ ATPase to increase the levels of Na+ in the cell. The Na+/Ca2+ exchanger now works backwards, bringing more Ca2+ into the cell. Ca2+ increases cardiac contraction.
Digoxin helps make the heart beat stronger and with a more regular rhythm.
