Chapter Pgs Objective: I can describe the basic categories of the endocrine system and relate them to various feedback mechanisms I’ve learned.

 Nervous System involves  Electrical Signals & Chemical Neurotransmitters  Fast and Immediate response (transient)  Endocrine System involves  Chemical Hormones & Endocrine Glands  Secreted into extracellular fluid & carried by circulatory system (remains internal)  Hormones only act on target cells (receptors)  Slow response but longer-lasting…AND…  Two systems NOT exclusive (often work together)  Neurosecretory cells receive neural (electrical impulse) and secrete hormone (Ductless) neuro confined widespread FYI, pheremones are external

 Endocrine: long distance  Paracrine: short distance: local signal  nearby cells  Autocrine: signal itself externally…wha..?  Para/Auto-crine use local regulators (not hormones)  Synaptic: nervous (elec/chem)  Neuroendocrine: combination of the two Classify by distance neurotransmitters

 Growth factors (i.e. cytokines)  For cells: promote division  Nitric Oxide (NO)  Vasodilation (increase blood flow)  Viagra works on NO pathway…  Prostaglandins  First found in prostate gland (added to semen)  Uterine walls (aides conception/contractions)  Promote fever/inflammation/pain  Ibuprofen inhibit prostaglandin (relieves pain)

 3 chemical classes; 2 soluble classes  Small proteins (peptides): at most ~30 amino acids  Amines dervied from amino acids  Steroids (type of lipid…)  Hormones signal a change in target cell by 1) Reception: 2 possibilities  On cell membrane or Within cell/nucleus 2) Signal Transduction (chain reactions) 3) Response: 2 possibilities  Cytoplasmic or Nuclear  If nuclear, regulation of gene Water-soluble Lipid-soluble Review Ch. 11 Why different reception?

 If water-soluble hormone…  Receptor on surface of cell membrane  Response can be cytoplasmic or nuclear  If lipid-soluble hormone…  Receptor in cytoplasm or nucleus  Response can be either May need to make second messengers cAMP, IP 3

 Hormones will circulate throughout entire body and only affect cells with receptor  But can have different cells with same receptor, resulting in different responses How?

 Review Control Pathway (w/Feedback) Ch.40 1) Receptor or Sensor (located on ) 2) Control Center (Endocrine Gland/Cell) 3) Effector (Target Cell)  For Endocrine system, control center sends out hormone (efferent signal)  Pathways can be simple or complex (figure)  Pathways can be classified as  Negative Feedback  Positive Feedback

 Negative  Failure in this results in…  Diabetes (2 types)  Type 1 = immune system destroys pancreas ability to make insulin  Type 2 = cells stop responding to insulin