1. Announcements Pick up & keep Quiz 1 from piano Pick up copy of Androstenedione paper for Lab next week Monday Quiz on Endocrine Chapter and Case Studies Lab Check email & website over weekend for updates and sample quiz questions

2. Endocrine disorders Hypersecretion –Primary –Secondary Hyposecretion –Primary –Secondary CRH ACTH Cortisol hypothalamus Anterior pituitary Adrenal Cortex

3. Endocrine System Nervous System Common features Major differences

4. Ch 6 Nervous SystemPart A and B Ch 6 Part A: Basic terms Cell types of Nervous Tissue Components of a neuron Components of a reflex arc Axonal regeneration: PNS and CNS Ohm’s Law Origin of resting membrane potential Equilibrium Potentials (Nernst potentials)

5. Important Terms (we’ll know these and many more as we move through Chapter 6 Myelin Axon Terminal Node of Ranvier Cell Body (soma) Astrocyte = Astroglia Microglia Ependymal cell Schwann cell Dendrite Neurotransmitter Oligodendrocyte Axon with axon hillock Axonal pathfinding Synapse Afferent Neuron Efferent Neuron Interneuron

6. Nervous tissue = Neurons (for electrical signalling) and Glial cells (for…..) Know relative numbers (neurons:glia) and various functions of CNS Glial cell types. Schwann cells wrap axons in PNS CNS = Brain + Spinal Cord

7. Membrane Potential & Structure make Neurons good Electrical Communicators } receiving } sending ligand-gated ion channels in membranes of dendrites and soma…. Graded potentials voltage-gated ion channels in membrane of axon hillock and axon….. Action potentials = “all or nothing!” Axon hillock “integrates.” Decremental conduction in dendrites and somatic membranes Unidirectional Non-decremental conduction in axons Synapse on other neurons, skeletal muscle, smooth muscle, cardiac muscle, glands

8. Fig. 06.02 In PNS In CNS Nodes of Ranvier ~1mm apart Not all axons are myelinated, although all axons are enveloped by Schwann cells in CNS or Oligodendrocytes in PNS What are the advantages of myelination? Lightly myelinated axon

9. Communication in The Vertebrate NS Signalling over short and long distances Blood pressure Blood gases and pH Muscle stretch Skin temperature Hair movement Light Taste Odor Touch Pain Etc. Dimensions of neurons Reflexes require some part of the CNS (i.e. frog lab) Peripheral nerves are “mixed” (have sensory & motor axons)

10. Descending neurons (interneurons) from brain to spinal cord Sensory (afferent) neurons from hoof to brain Nodes of Ranvier are 1 mm apart. How many Schwann cells to myelinate the 2 meters of a sensory axon from hoof to dorsal root ganglion near spinal cord?

11. Fig. 06.03

12. Axonal Transport Orthograde = Anterograde = from soma to terminals –slow……1-2 mm/day –fast …..200-400 mm/day (kinesin) Retrograde = from terminals to soma –fast….200-400 mm/day (dynein) What gets transported and why? Axonal transport is too slow for rapid signalling, so…

13. Who Cares?

15. Alayna Davis October 1992 Age 5 October 31, 1992 October 1998

17. Regeneration in CNS?