peripheral nervous system - nerves, ganglia
- nerve - collections of axons (myelinated/unmyelinated)
- separates into motor/sensory parts at origin
- dorsal root - sensory axons
- ventral root - motor axons
- ganglia - groups of neuron cell bodies outside the central nervous system
- dorsal root ganglia - contains cell bodies of sensory neurons
- motor neuron cell bodies found inside spinal cord
- somatic motor neurons stimulate skeletal muscles to contract
- for each muscle stimulated to contract, its antagonist must be inhibited by hyperpolarizing the motor neuron
autonomic nervous system - contains sympathetic/parasympathetic areas, medulla oblongata
- autonomic neurons control smooth muscles, cardiac muscles, glands
- medulla oblongata - controls the system
- 2 neurons used for each pathway (1 has cell body in central nervous system, other has cell body in autonomic ganglion)
- preganglionic neuron - 1st neuron, releases Ach at synapse
- postganglionic neuron - releases Ach in parasympathetic division, norepinephrine in sympathetic division
- sympathetic division - stimulates the adrenal gland to secrete epinephrine
- prepares the body for fight or flight
- norepinephrine released at postganglionic neuron synapses
- parasympathetic division - slows down heart, increases secretions
- regulates organs by releasing Ach
- ACh causes G proteins to open up ion channels >> hyperpolarization >> slows down cell
neuroglia - cells that support neurons
- supplies neurons w/ nutrients, gets rid of waste, provides immunity
- Schwann cells - produce myelin sheaths in peripheral nervous system
- oligodendrocytes - produce myelin sheaths in central nervous system
Subject:
Subject X2:
