Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013
Typical Signal Transduction Pathway Typical Signal Transduction Pathway
Endocrine & Cell Communication Part III: Hormonal Communication
Phase 1: Reception Ligand = Chemical Messenger The target cell detects the ligand
• Enduring Understanding 3.D Cells communicate by generating, transmitting and receiving chemical • Three major classes of molecules function as • Membrane proteins signals. hormones in vertebrates (ligands) • EK 3D2: Cells communicate with each other through –G-protein linked receptors Polypeptides (proteins and peptides) direct contact with other cells or from a distance via – Ion channel receptors chemical signaling – Amines derived from amino acids – c. Signals released by one cell type can travel long distances – Steroid hormones –Tyrosine Kinase to target cells of another cell types. 1. Endocrine signals are produced by endocrine cells that • Intracellular receptor release signaling molecules, which are specific and can travel long distances through the blood to reach all parts of –Steroid hormone receptors the body.
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The Process of Communication: Signal-Transduction Pathway Ligands Type of Receptor : G-protein linked
Three stages of the Signal- Transduction Pathway 1. reception LIGAND: 2. transduction a molecule that binds to a larger 3. response molecule
1 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013
Name three types of receptors in the signal Type of Receptor: Ion Channel transduction pathway Transduction
• G-protein-linked receptors • Binding changes the receptor protein. • Ion channel receptors • Can set off a cascade reaction • Intracellular receptors
Action of G-Protein Linked Receptor Response • Set any of a variety of Type of Receptor: cell activities in motion. Intracellular Receptor –Activation of an enzyme –Rearrangement of cytoskeleton features –Activation of a specific gene
2 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013
Recap Which Is A Receptor Through Which Ions Would Pass?
EXTRACELLULAR CYTOPLASM FLUID Plasma membrane
1 Reception
Receptor
Signaling molecule
Recap Types of Receptors Which Of These Acts As A Second Messenger?
EXTRACELLULAR CYTOPLASM FLUID Plasma membrane
1 Reception 2 Transduction
Receptor
Relay molecules in a signal transduction pathway +
Signaling molecule
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Water-soluble (hydrophilic) Lipid-soluble (hydrophobic) Recap Which is the receptor? G-Protein? Ligand? Polypeptides Steroids
EXTRACELLULAR CYTOPLASM FLUID Plasma membrane
1 Reception 2 Transduction 3 Response
Receptor 0.8 nm Activation Insulin Cortisol of cellular response Amines Relay molecules in a signal transduction pathway
Signaling molecule
Epinephrine Thyroxine
3 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013
Cellular Response Pathways Pathway for Water-Soluble Hormones Pathway for Lipid-Soluble Hormones
• Water- and lipid-soluble hormones differ in their • Binding of a hormone to its receptor initiates a signal • The response to a lipid-soluble hormone is usually a paths through a body transduction pathway leading to responses in the change in gene expression • Water-soluble hormones are secreted by exocytosis, cytoplasm, enzyme activation, or a change in gene • Steroids, thyroid hormones, and the hormonal form of travel freely in the bloodstream, and bind to cell- expression vitamin D enter target cells and bind to protein surface receptors receptors in the cytoplasm or nucleus • Lipid-soluble hormones diffuse across cell • Protein-receptor complexes then act as transcription membranes, travel in the bloodstream bound to factors in the nucleus, regulating transcription of transport proteins, and diffuse through the membrane of target cells specific genes
SECRETORY CELL Pathway for Water-Soluble Hormones Pathway for Lipid-Soluble Hormones
Water- Lipid- soluble soluble hormone hormone
VIA BLOOD Transport Signal receptor protein
TARGET CELL Signal receptor
NUCLEUS (a) (b)
SECRETORY CELL Specific Example Steroid Hormone Example: Testosterone
Water- Lipid- soluble soluble hormone hormone Notice the presence of the second messenger VIA BLOOD Transport Signal receptor protein
TARGET OR CELL Signal receptor
Cytoplasmic response Gene regulation Cytoplasmic response Gene Click here regulation to view the NUCLEUS animation (a) (b)
4 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013
Compare protein and steroid hormones by completing this T chart
Characteristic Protein Hormone Steroid Hormone
Speed of response Rapid response, cascade Response is slower, gene expression Primary biomolecule Amino acid cholesterol composition
Method of leaving secretory Exocytosis diffusion cell
Location of receptor Membrane bound Intracellular
Example Epinephrine Testosterone
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Same receptors but different Different receptors Multiple Effects of Hormones intracellular proteins (not shown)
Different cellular Different cellular • The same hormone may have different effects on responses responses Model Steroid Hormone Action target cells that have – Different receptors for the hormone Epinephrine Epinephrine Epinephrine β β α using the Testosterone – Different signal transduction pathways receptor receptor receptor Glycogen Manipulative deposits
Vessel Vessel Glycogen dilates. breaks down constricts. and glucose is released from cell.
(a) Liver cell (b) Skeletal muscle (c) Intestinal blood blood vessel vessel 38
Compare protein and steroid hormones by completing this T chart Multiple Effects of Hormones Did you know…
Characteristic Protein Hormone Steroid Hormone • The hormone epinephrine has multiple effects • One reason that kittens sleep so much is because a growth Speed of response in mediating the body’s response to short-term stress hormone is released only during sleep.
Primary biomolecule The levels of two stress hormones, cortisol and composition • Epinephrine binds to receptors on the plasma • membrane of liver cells epinephrine which suppress the body's immune system, Method of leaving secretory will actually drop after a dose of laughter. cell • This triggers the release of messenger molecules that Location of receptor • Chocolate is associated with the release of serotonin, the activate enzymes and result in the release of glucose hormone that makes you feel relaxed, calm, and happy. Example into the bloodstream So are hugs.
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5 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013
Created by:
Debra Richards Coordinator of Secondary Science Programs Bryan ISD Bryan, TX
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