L9 - Intercellular Communication
Terms
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- Communication Types
-
between cells - short and long range
electrical and chemical -
Communication Types
-Paracrines -
-local hormones
-when released from one cell , they have effect on cell next door (diff. cell type)
-endothelium lines vasculature--> relataxion of vascular smooth muscle -
Communication Types
-neurotransmitters -
-specific for each neuron
-NTs bind as released--> short distances
-released by exocytosis--> neurons, muscles, and endocrine cells
-removal involves digestion (chemically destroyed), diffusion, reuptake, and recycling -
communication types
-endocrine -
-cells derived from epitholium
-release hormones into blood--> hormones(H) go everywhere -
communication types
-neurohormones -
-H's released from neurons
-faster release than simple endocrine H's
-effect is like other hormones: depend on receptors on different cells - hydrophilic/hydrophobic hormones
-
hydrophilic (water soluble)
-amino acids/small peptides
-bind to membrane receptors---> 2nd messengers
hydrophobic(not very water soluble)
-bound to protein in plasma
-diffuse into cells in nucleus: raise protein synthesis
-many side effects - Second Messengers
-
-produced by hydrophilic H's which bind to membrane receptors
-receptor activate enzyme produces intracellular product-2nd messenger
-2nd messenger will alter cell functions -
Second messengers
-cAMP -
-cyclic AMP
-activate kinases(add phosphate to molecules)
-kinases amplify signal to activate cascade pathways. 1-10-100--> -
Second Messengers
-cGMP -
GTP-->cGMP
activate kinases -
Second Messengers
-IP3 -
-causes release of Ca(2+) from sarcoplasmic reticulum
-SA derived from ER - Nuclear Receptors
-
-bind hydrophilic H's
-form interface between H's and your genes
-presence of particular N. Rec. cause activation of specific genes
-variations in gene activation basis for different effects and side effects - Calcium
-
-released by IP3 from SR
-bind proteins-> alter protein activity often, raise enzyme activity
-Ca(2+) gap junctions coordinate ciliary motion in oviduct/lungs
-muscle contraction, exocytosis, WBC movement, phagocytosis - G Proteins
-
-connect receptor to an enzyme
-G protein binds GTP - [whole system is active]
-stay active until GTP->GDP->[not active]
-timing element - vision, growth, vesicle movement - Neural-Endocrine Comparisons
-
-neurons are rapid, precise, brief, and produce virtually no side-effects
-H's have long duration, slow, widespread effects receptor dependent
-H's have side effects especially the H-phobic H's
-neurohormones like other hormones-release is faster from neurons