Chapter 6: “Communication, Integration and Homeostasis Cell to cell communication –Gap junctions –Paracrines and autocrines –Long distance communication Signaling pathways –Receptors –Ion channels –Signal transduction

Cell to cell communication connexins Ca++ ATP

Cell to cell communication Diffuse to targets through interstitial fluid e.g. Histamine leaves damaged cell  capillary cell (endothelial cell) becomes more permeable  fluid accumulates around damaged cell  swelling

Examples of paracrine molecules: Cytokines, peptides (e.g. erythropoietin) Eicosanoids, lipid derived (e.g. prostaglandins, leukotrienes)

Cell to cell communication: long distance through blood vessels

Cell to cell communication: long distance through neurons Neurotransmitter molecules

Cell to cell communication: long distance Neurons release product into blood e.g. oxytocin

Signaling pathways in a cell. - receptor proteins

Classes of membrane receptors e.g. blood clotting -platelets e.g. Neuromuscular junction e.g. insulin e.g. Olfaction Vision Hormones Some neurotransmitters

How ion channels participate in cell to cell communication. e.g. Neural control of skeletal muscle contraction.

The idea of signal transduction Can adjust volume

Signal amplification, the idea

Signal transduction in a cell. **

The idea that signal transduction is a cascade. E.g. blood clotting

In receptor-enzymes, the amplifier enzyme is in the cell membrane.

The G-protein coupled receptor adenylyl cylcase cascade.