Cell Communications Flashcards
where can cellular communication occur?
between cells
-chemical
-electrical
within cells
describe how electrical transmission happens between cells?
direct contact via gap junctions
what do gap junctions allow?
flow of current to go from cell to cell
describe features of electrical transmission between cells.
-rapid transmission in both directions
-linked cells can act as 1 unit (syncytium)
eg. cardiac and some smooth muscle
describe 3 types of chemical transmission.
cell to cell = synapse
cell to many cells = paracrine
many cells to many cells = endocrine
describe 3 types of chemical transmission.
cell to cell = synapse
cell to many cells = paracrine
many cells to many cells = endocrine
describe cell to cell chemical transmission through a synapse.
-effect depends on transmitter and the receptor it acts on
-one way transmission
-common in nervous system
describe the sequence of events in cell to cell chemical transmission through a synapse.
- impulse arrives at terminal of presynaptic cell
- trfansmittwe released from storage vesicle
- transmitter diffuses in synaptic cleft
- transmitter binds to receptor on postsynaptic cell
- alters post synaptic cell
what happens in cell to cell chemical transmission when the transmitter alters the post synaptic cell?
‘excitatory’ eg. impulse generated; muscle contracts; gland secretes
‘inhibitory’ cell is switched off
describe paracrine communication.
- one cell communicates with several cells locally
- often used by defence cells (inflammation)
- can be part of ‘cascade’ of reactions
describe autocrine communication.
chemical acts on cell releasing it (feedback)
describe endocrine transmission.
chemical sent to all parts of body via blood stream
hormone acts only on cells with correct membrane receptor protein (target cells)
which is better for communication in organisms, nerves or hormones?
not have advantages and disadvantages depending on circumstances.
describe communication by nerves.
actions specific or localised.
quick impulse transmission.
suitable for rapid responses.
give examples of communication by nerves.
- control of voluntary muscle contraction
- sensory systems
- salivary gland response
- control of blood pressure