Unit 3: Nervous Flashcards
Dendrites (neuron anatomy)
Receive Signal
Axon (neuron anatomy)
Transmits Electric Signal
Synaptic Terminals (neuron anatomy)
Releases Chemical Signal
Myelin Sheath (neuron anatomy)
Partially coats axon, speeds up transmission
Nodes of Ranvier (neuron anatomy)
Gaps in myelin sheath, where ion exchange occurs (saltatory conduction)
Synaptic Cleft (neuron anatomy)
Gap between giving and receiving neurons
Central Nervous System
Processes stimuli
Peripheral Nervous System
Sensory input/motor output
Sensory Input
Detecting stimuli, signaling CNS, sensory neurons- PNS
Integration
Processing information in response to stimuli, interneurons- CNS
Motor Output
Response to stimuli, muscle movement, motor neurons- PNS
Na/K Pump
3 Na+ out, 2 K+ in
Gated Ion Channel
Opens in response to stimulus, graded potential (depends on stimulus intensity)
Voltage-Gated Ion Channel
Respond to voltage threshold
Resting Potential
Outside is positive, inside is negative (relative to outside), Na/K pump active
Stimulus (Depolarization)
Na+ ion channels open, inside is less negative, outside is less positive
Rising Phase of Action Potential
Voltage-gated Na+ channel opens, Na+ channel open, charges swap (outside is negative, inside is positive)
Falling Phase of Action Potential (Hyperpolarization)
Voltage-gated Na+ channel deactivates, Voltage-gated K+ channel opens, outside positive, inside negative)
“Reset” Phase
Na/K pump regulates level (3 Na+ out, 2 K+ in)
When AP reaches synaptic terminal
Voltage-gated Ca2+ channels open and influx of Ca2+ ions forces vesicles to fuse with membrane and release neurotransmitters into synapse
After neurotransmitters are released into synapse
They bind to Ligand-gated ion channels on dendrites, causing ions to flow in or out of the receiving cell’s membrane
