Neurons & Neurotransmission Flashcards
Describe the basic anatomy of a neuron and the functions associated with each part.
Cell Body (soma) – nucleus with chromosomes
Dendrites – receive information from other neurons
Axon – transmits information to other neurons, muscles and glands
Name three different types of neurons? What is their function?
Sensory - Carry messages from the body’s tissue and sensory receptors inward to the brain and spinal cord for processing
Motor - Carry instructions from the central nervous system out to the body’s muscles
Interneurons - Between the sensory input and the motor output, information is processed in the brain’s internal communication system via interneurons
Much more of these than the other 2 types
What are mirror neurons?
A neuron that fires both when an animal acts and when the animal observes the same action performed by another
What is the resting membrane potential?
High concentration of K+ (potassium) inside neuron, Higher concentration of Na+ (sodium) outside the neuron, Ultimately the electrical voltage of inside a neuron at rest is -70mV
Considered a hyperpolarized state
What is an action potential?
Stimulation from other neurons can lead to neuronal firing
What are the roles of sodium and potassium ions during this period?
To leave rest, NA+ enters the axon and depolarizes the K+ ions to +40 mV and then lets the neuron fire, then they expel the Na+ ions
Describe the process of neural transmission down the axon?
Electrical charge reaches a threshold, Na+ Channels open, Na+ flows into the neuron, + charge increases in the neuron
Charge reaches +40 mV, Depolarized
What is the sodium-potassium pump?
A pump in the cell membrane of an axon that sends Na+ ions out of the cell
What is myelin?
Insulating layer made of fatty material composed of glial cells
How does myelin impact neural transmission?
Helps efficient transmission of signals to other cells
How does myelin impact neural transmission?
The junction between one neuron’s axon and another’s dendrites/cell body, fundamental in communication between neurons
Describe the process by which neural impulses cross the synapse.
When an action potential reaches the terminal at the end of an axon, it triggers the release of chemical messengers called neurotransmitters. Within 1/10,000th of a second, the neurotransmitter molecules cross the synaptic gap and bind to receptor sites on the receiving neuron. Then the neurotransmitters unlock tiny channels at the receiving site and electronically charged atoms flow in, exciting or inhibiting the receiving neuron’s readiness to fire. Then in a process called reuptake, the sending neuron reabsorbs excess neurotransmitters
Explain excitatory and inhibitory transmission.
Excitatory, like pushing on the gas and Inhibitory, like pushing the brakes
If there are more excitatory signals than inhibitory, the combined signals trigger an action potential
What happens to neurotransmitters in the synapse to stop neural communication?
Reuptake – absorbed
Enzyme Deactivation – broken down by enzymes in the synapse
Acetylcholine (Ach)?
Enables muscle action, learning and memory
Deteriorates with Alzheimer’s
