PHED-2506EL Chapter Notes - Chapter 11: Schwann Cell, Myelin, Autonomic Nervous System
25 Jun 2018
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Lecture 11A class objectives
1. Name the branches of the nervous system:
Central Nervous system
I
Peripheral Nervous system
_______________I____________________
I I
Autonomic Nervous System Somatic Nervous System
I
Parasympathetic
I
Sympathetic
2. Name the two types of cells of the nervous system and give a function for each:
Neurons: Excitable cells that transmit electrical signals.
Supporting Cells: Cells that surround and wrap neurons.
3. Give functions for each of the 3 parts of a neuron.
Dendrites: Short, tapering, and diffusely branched processes
Receptive, or input, regions of the neuron
Electrical signals are conveyed as graded potentials (not action potentials)
Axons:
Structure: Slender processes of uniform diameter arising from the hillock, and usually
there is only one unbranched axon per neuron.
Function: Generate and transmit action potentials, secrete neurotransmitters from the
axon terminals, movement along axons occur in two ways: Anterograde (towards axonal
terminal) and retrograde (away from axonal terminal).
Myelin Sheath: Whitish, fatty, segmented sheath around most long axons (protects the axon,
electrically insulate fibers from one another, increase the speed of nerve impulse transmission)
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Document Summary
Lecture 11a class objectives: name the branches of the nervous system: Sympathetic: name the two types of cells of the nervous system and give a function for each: Supporting cells: cells that surround and wrap neurons: give functions for each of the 3 parts of a neuron. Electrical signals are conveyed as graded potentials (not action potentials) Structure: slender processes of uniform diameter arising from the hillock, and usually there is only one unbranched axon per neuron. Function: generate and transmit action potentials, secrete neurotransmitters from the axon terminals, movement along axons occur in two ways: anterograde (towards axonal terminal) and retrograde (away from axonal terminal). Myelin sheath: whitish, fatty, segmented sheath around most long axons (protects the axon, electrically insulate fibers from one another, increase the speed of nerve impulse transmission) Nodes of ranvier: gaps in the myelin sheath between adjacent schwann cells, cites where axon collaterals can emerge: explain the importance of myelination.
