Chapter 6:

1
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

2
Cell to cell communication
connexins
Ca ATP
3
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
4
Examples of paracrine molecules

• Cytokines, peptides (e.g. erythropoietin)
• Eicosanoids, lipid derived (e.g. prostaglandins,
  leukotrienes)

5
Cell to cell communication long distance through
blood vessels
6
Cell to cell communication long distance
through neurons
Neurotransmitter molecules
7
Cell to cell communication long distance
Neurons release product into blood
e.g. oxytocin
8
Signaling pathways in a cell. - receptor proteins
9
Classes of membrane receptors
e.g. Neuromuscular junction
e.g. insulin
e.g. Olfaction Vision Hormones Some
neurotransmitters
e.g. blood clotting -platelets
10
How ion channels participate in cell to cell
communication.
e.g. Neural control of skeletal muscle
contraction.
11
The idea of signal transduction
Can adjust volume
12
Signal amplification, the idea
13

Signal transduction in a cell.
14
The idea that signal transduction is a cascade.
E.g. blood clotting
15
In receptor-enzymes, the amplifier enzyme is in
the cell membrane.
16
The G-protein coupled receptor adenylyl cylcase
cascade.