a.ii.7.cells part of this nervous system which respond to stretching which cause the stomach to contract, release acid, release enzymes and release hormones mechanoreceptors – sense stretch chemoreceptors – sense glucose (food)b.Somatic Nervous System b.i.All spinal nerves are mixed nerves b.ii.Alpha motor neurons control the muscle cells2.Neurons a.Properties of neurons a.i.Excitability
a.i.1.-70 mV resting membrane potential a.i.2.can be depolarize (excite – more positive) or hyperpolarize(inhibit - more negative)) most abundant excitatory neurotransmitter – glutamate most abundant inhibitory neurotransmitter – gabba gabba receptors are permissive to chloride ions a.ii.Conductivity a.ii.1.Action potentials a.iii.Secretion a.iii.1.Unique to nerve cells b.Structure of neurons b.i.Cell body is where we find cell organelles b.ii.Dendrites is cytoplasmic projections b.iii.Cell body and dendrites have ligand-gated channel, Na/K pumps and K leak channelsb.iv.Axon have synaptic terminals b.iv.1.Find mitochondria in terminal knobs b.v.Receptors are ligand gated b.v.1.Neurotransmitters are the ligands b.vi.When an action potential hits a terminal knob opens up the volgate gated calcium channels, allowing the calcium to come in b.vii.Volgate gated channels open at -60b.viii.Spike initiation zone – axon hillock + initial segment of axonc.Axonal transport c.i.Anterograde movement (cell body to terminal knob) c.i.1.Use kinesin (moves cargo to positive end of microtubule - MAPS)c.ii.Retrograde movement (terminal knob to cell body)
c.ii.1.Use dynein (moves cargo to negative end of microtubule)d.Classification of neurons d.i.Structural classification d.i.1.Multipolar neurons d.i.1.a. Efferent neuronsd.i.1.b. Many processes d.i.2.Bipolar neuron d.i.2.a. Two processes d.i.2.b. Involved with special senses d.i.2.c. Sensory (afferent)d.i.3.Unipolar neuron d.i.3.a. One process d.i.3.b. Sensory (afferent)d.i.3.c. somatic sensesd.ii.Functional Classification d.ii.1.Sensory d.ii.1.a.Afferent d.ii.1.b.Bipolar and unipolar nerves d.ii.2.Motor d.ii.2.a.Efferent d.ii.3.Interneurons d.iii.Gilal Cells d.iii.1.Most abundant cells in nervous system d.iii.2.6 different types of cells d.iii.3.Astrocytes d.iii.3.a.Most abundant cell in nervous system
d.iii.3.b.Believed that they facilitate neurons formingaction potential d.iii.3.c.Help forms the blood-brain barrier – have pedicals (vascular feet) – wrap around capillaries making it hard to get into the braind.iii.3.d.Scavengers of ions and neurotransmittersd.iii.3.e.Provide structural support d.iii.4.Microglia d.iii.4.a.Macrophagesd.iii.4.b.Doesn’t derive from ectoderm d.iii.5.Ependymal cells d.iii.5.a.Epithetical tissue d.iii.5.b.Does the lining ventricles of your brain and central canal of spinal cordd.iii.5.c.Help from Acorite plexus (ependymal cells + pia matar + blood vessels) - manufacture, secrete, and monitor spinal cord fluid Cerebrum spinal fluid
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