Chapter 2a Activity Within the Brain Flashcards
What are Neurons?
The building blocks of brain activity are neurons: the cells that facilitate communication within the nervous system.
What are Sensory Neurons?
Sensory neurons carry information to your brain from your senses (sight, hearing, smell, taste, touch).
What are Motor Neurons?
Motor neurons carry messages from your brain to your muscles.
What’s a Reflex?
An automatic motor response to sensory input.
What is the Myelin Sheath?
In many neurons, the axon is covered with a layer of insulation called the myelin sheath: a protective sleeve of fatty material that surrounds the axon
The myelin sheath is a protective sleeve of fatty material that surrounds the axon. The myelin sheath makes sure that communication between neurons happens at maximum speed and with minimal loss
What are Glial cells
Cells that support and protect neurons throughout the brain
What is a Synapse?
A gap between two connecting neurons
When a signal from a neuron makes it successfully through the axon, the message travels from an axon terminal of one neuron to a dendrite of the next neuron. That trip is a vital part of neuronal communication. Between the axon terminal and the dendrite—the space that needs to be crossed—is the synapse
What are Neurotransmitters?
The substances that actually travel across the synapse are neurotransmitters: chemical messengers that travel across synapses from one neuron to the next
What are Synaptic vesicles?
Until they reach the synapse, neurotransmitters travel in synaptic vesicles: tiny, sacklike containers for neurotransmitters
What are Receptor sites?
To complete their journey across the synapse, the neurotransmitters emerge from the synaptic vesicles and find their way to receptor sites: Openings in dendrites that match specific neurotransmitters like a lock fits a specific key.
What is Reuptake?
To handle some of these excess neurotransmitters, the first neuron carries out reuptake: the process when a neurotransmitter is taken back up by the sending neuron after failing to land in a receptor site in the receiving neuron
What is the Action Potential?
What is the Threshold?
Another important part of communication between neurons is how a neuron initiates the transmission of a signal. This start is called an action potential: the release, or firing, of an electrical impulse that travels through the axon
The neuron shifts from rest into action when the electrical charge reaches a certain Threshold: the level of electrical charge required to trigger an action potential
How do Neurons and their connections work?
The cell body (or soma) is the centerpiece of each neuron and keeps it functioning. Farther from the center, axons carry information away from the neuron and toward the next neuron in the chain. (In this illustration, as the arrow indicates, the movement is from left to right.).
Toward the end of each axon, it splits into axon terminals, the small branches that form connections with the next neuron. In that next neuron, the dendrites are the receiving branches that accept what the axon terminals deliver.
What is the Resting Potential?
Most of the time, a neuron is not firing, but is at rest. In those moments, the neuron is in a state of resting potential: the low-level electrical charge in a neuron that is not firing
What is the Refractory Period?
Each action potential is followed by a Refractory Period: a waiting time before another action potential can begin, during which the neuron is reset.
