cell signalling Flashcards
(75 cards)
why do cells communicate
- Respond to immediate environment – including danger signals
- Respond to central commands
- Respond to local commands
- Respond accordingly
- Coordinate cellular responses
- Integrate signals from multiple sources
- Induce / decrease growth (division) if the need arises
what are the 3 types of intercellular signalling
chemical
physical
gaseous
what is intercellular signalling
between cells
what are signalling molecules that bind and activate receptors
agnosits/ligands
what are signaling molecules that bind to and inactivate receptors
antagonists/blockers
what are transmembrane/ cell surface receptors
Respond to signals on the outside of the cell by interacting with molecules on the inside
what are the types of transmembrane / cell surface receptors
G protien coupled receptors (GPCRs)
ion channel linked receptors
enzyme receptors
why are transmembrane receptors important
- Most signalling molecules are too large or too hydrophilic to cross the membrane
- Ligand binding changes the activities of the intracellular domains of the receptor, which initiates the response
- The signalling molecule itself doesn’t need to enter the cell
what kind of receptor is this
cytoplasmic and nucelar
what are cytoplasmic and nuclear receptors
- Small molecules and hydrophobic molecules can cross the cell membrane
- Bind directly to receptors in the cytosol or the nucleus
what kind of receptor is this
transmembrane
what determines how different cells can respond differently to the same signal
The sets of receptors the cell has
The intracellular machinery
This explains why drugs sometimes have additional unwanted effects
what are the 5 modes of intercellular signalling
endocrine
paracrine
neuronal
autocrine
juxtacrine
which types of intercellular signalling is long range
endorcine
which types of intercellular signalling are short range
paracrine
neuronal
autocrine
juxtacrine
what is a hormone
a compound produced by an endocrine gland and released into the bloodstream where it acts on target cells at a distance location
what is endocrine signalling
- low chemical communication
- Hormones are released and circulate in the blood, coming into contact with most cells within the body (hence long distance)
why can only a limited number of cells respond to a hormone?
must express the correct receptor to interpret the signal
what do hormones do during intercellular signalling
Hormones regulate cell reactions by affecting gene expression
what is paracrine signalling
- Signalling molecules are released from one cell and diffuse locally to neighbouring cells
what are kinds of paracrine signals
proteins
amino acid derivatives
dissolved gas
what kind of signalling is this?
paracrine
what is neuronal/ neurocrine signalling
- Deriving from a nerve
- Neurotransmitters travel only across the synaptic gap to the adjacent target cell only (e.g. nerve cell, muscle cell)
what is an example of neuronal signalling
noradrenaline, secreted form sympathetic nerve terminal to act at adrenoceptors to contract blood vessels