Biopsychology - Neurons Flashcards
What are the three types of neurons?
- Sensory neurons: Carry messages from PNS to CNS. Long dendrites, short axons.
- Relay neurons: Connect sensory and motor neurons. Short dendrites, short axons.
- Motor neurons: Connect CNS to effectors (e.g., muscles). Short dendrites, long axons.
What are the key structural features of a neuron?
Cell body (soma), dendrites, axon, myelin sheath, and nodes of Ranvier.
What do dendrites do in a neuron?
Carry nerve impulses toward the cell body.
What is the function of the axon?
Transmits impulses away from the cell body.
How does the myelin sheath aid transmission?
Protects and insulates the axon, speeding up electrical impulses.
What are nodes of Ranvier, and why are they important?
Gaps in the myelin sheath where impulses jump, speeding up transmission.
What happens during the resting state of a neuron?
Inside of the neuron is negatively charged compared to the outside.
Define synaptic transmission.
Neurons communicate by releasing neurotransmitters into the synaptic gap, which bind to receptors on the postsynaptic neuron.
What happens when an electrical impulse reaches the presynaptic terminal?
Electrical impulses trigger neurotransmitter release from vesicles into the synaptic gap.
What are neurotransmitters, and how do they work in synaptic transmission?
Chemicals that transmit signals across the synapse. They bind to postsynaptic receptors, converting chemical signals back into electrical impulses.
What are the two main effects neurotransmitters can have on a neuron?
- Excitatory: Increases likelihood of firing.
- Inhibitory: Decreases likelihood of firing.
What is summation, and how does it influence the postsynaptic neuron?
Combines excitatory and inhibitory signals. If excitatory signals outweigh inhibitory signals, the neuron fires.
What happens if the net effect on a neuron is inhibitory?
Reduces likelihood of firing; the neuron remains inactive.
What happens if the net effect on a neuron is excitatory?
Increases likelihood of firing; action potential is triggered.
What triggers an action potential?
An electrical impulse triggered when combined signals reach the firing threshold.
