L6 - cell communication Flashcards
(17 cards)
Types of cell to cell communication
cell-cell contact
autocrine signalling
paracrine signalling
endocrine signalling
neeuronal signalling
Cell-cell
Through gap junctions
Ions and small molecules move between cells
Autocrine
Cell signals to itself
Paracrine
Cell signals to neighbouring cell
Chemical diffuses through the intersitial fluid
Endocrine
Cells singals to many distant and diverse cells via circulatory system
Features of endocrine glands
Highly vascular
Sevretory cells are arranged in groups around blood vessels
Hormones secreted directly into circulation
Neuroendocrine
Hormones synthesised in specific neurons in hypothalamus
Released from vesicles adjacent to capillaries
Travels to anterior pituitary»_space; act on receptors»_space; stimulate anterior pituitary cells to secrete other hormones
Neuronal
Signalling at junction between nerve and its target
Nerve makes chemical message (neurotransmitter)»_space; action potential arrives»_space; message is released»_space; neurotransmitter diffused to act on target»_space; generates response
Chemical classifications of hormones
Water soluble
Lipid soluble
Water soluble
Hydrophilic
Unable to cross cell membrane unaided
Lipid soluble
Lipophilic
Can cross cell membrane
Steroid and thyroid hormones
Hydrophilic hormones
Synthesised and stored in vesicles
Secreted via exocytosis
Transported dissolved in blood plasma
Faster release and metabolism
Hydrophobic hormones
Synthesised and secreted on demand (not stored)
Transported in blood by carrier proteins
Slower release, stable
Hormone action
Each hormone has a specific receptor
Receptors can be on the surface membrane or inside the cell
Hormone binds to receptor»_space; causes effect of hormone
Hydrophilic hormone action
- Binds to receptor
- Activated receptor activates a second messenger (cAMP)
- cAMP activates protein kinases in cytoplasm
- Protein phosphorylation switches on/off a protein function
- cAMP gets degraded and signalling ends
Hydrophobic hormone action
