click below
click below
Normal Size Small Size show me how
HSO109 pt 9
Question | Answer |
---|---|
What are the anatomical divisions of the nervous system? | - The peripheral nervous system - The central nervous system |
What is the central nervous system comprised of? | - Brain - Spinal cord |
What is the peripheral nervous system? | - Afferent division (sensory) - Efferent division (somatic motor & autonomic motor: sympathetic & parasympathetic) |
What makes up a neuron? | - Cell membrane - Dendrite - Cell body (soma) - Nucleus - Axon - Myelin sheath - Synaptic terminals |
What is the function of myelin sheath? | - Electrical insulation increases the speed at which electrical signals (action potentials) traveel along the axon |
What is a transmembrane potential? | - Is the electrical potential of the cell's interior relative to its surroundings |
What is the resting potential? | - Is the transmembrane potential of an undisturbed cell |
What are action potentials? | - Are nerve impulses - Are propagated changes in the transmembrane potential that, once initiated, affect an entire excitable membrane |
Describe the all-or-none principle: | - A stimulus either triggers a typical action potential, or it does not produce one at all |
What is the refractory period? | - From the time an action potential begins until the normal resting potential is stabilised, the membrane will not respond normally to additional depolarising stimuli |
How does an action potential work? | 1. An action potential is generated in a small portion of the membrane 2. A local current depolarises the adjacent portion of the membrane 3. Same events take place over and over 4. Action potential is propagated through the entire excitable membrane |
How does an action potential work? pt 2. | 5. An action potential only moves forward because previous segment is in refractory period |
What affect the speed of action potentials? | - Myelin - Axon diameter: large = fast, small = slower |
What is the synapse comprised of? | - Telodendron - Synaptic terminal - Synaptic vesicles - Synaptic cleft - Neurotransmitters - Ligand-gated channels (receptors w/ neurotransmitters) - Post synaptic neuron |
What is a chemical synapse? | - Involves a neurotransmitter |
What is an electrical synapse? | - Direct physical contact between cells (gap junctions) |