Extracellular Signalling - Basics Flashcards
What is remote signalling?
When cell secretes chemicals that signal to far away cells
What are steps involved from signalling to cellular response?
- Reception - reception of extracellular signal by cell through interaction with receptor
- Transduction - transduction of signal from outside to inside of cell
- Response - activation of cellular response
What are 2 types of contact signalling?
Involves plasma membrane-bound molecules (juxtacrine –> requires close contact)
OR
Involves gap junctions
What type of signalling is T-helper cell activation by APCs an example of?
Contact signalling
What occurs during T-helper cell activation by APCs?
- APCs display bits of bacteria on cell surface to see if an immune response is needed
- T cells recognise these bits of pathogen
What are gap junctions?
Directly join the cytoplasms of interacting cells, allowing the passage of chemical and electrical signals
Form when connexin proteins expressed by 2 adjacent cells form a channel that allows movement of cytoplasmic contents and allows rapid electrical coupling
What type of signalling is a cardiomyocyte contraction an example of?
Contact signalling - adjacent myocytes coupled through connexin-43 gap junctions
What is endocrine signalling?
Secreted into duct then enters blood stream for FAR AWAY target
What is paracrine signalling?
Signalling molecule affects target cell CLOSE TO cell
What is autocrine signalling?
Cell responds to molecule that it has produced ITSELF
What is neuronal signalling?
Stimulus (nerve impulse) leads to electrical signal which is converted to chemical signal which affects another cell type
What are hormones?
Chemical messengers released by a cell, gland, or organ that transport a signal from one cell to another
Where are receptors located for hydrophilic (soluble) hormones?
On the cell membrane
Where are receptors located for lipid-based hormones (hydrophobic and able to cross membrane)?
Inside cell
What type of hormones are catecholamines?
Hydrophilic
