Chapter 3 Flashcards
(47 cards)
What are neurons?
Individual cells in the nervous system that receive, integrate and transmit information
What is the soma?
Cell body- Contains the nucleus and most of the chemical machinery common to most cells
What is a dendrite?
Tree- The part of a neuron that receives information
What is an axon?
Axle- A long thin fiber that transmits signals to other neurons, muscles or glands
What is the myelin sheath?
Insulating material that encases some axons
What is the terminal button?
Small knobs that secrete chemicals called neurotransmitters
What is a synapse?
A junction where information is transmitted from one neuron to another
What is glia?
Glue- Cells found throughout the nervous system that provide various type of support for neurons
What are some functions of Glia?
Supply nourishment to neurons, remove waste products and provide insulation around many axons
What are two theories about the role of Glia?
1- Glia modulates the signaling of neurons
2-Glia shield synapses from surrounding neuronal activity
What is a Schwann cell?
How many steps are there in a neural impulse and what are they?
Four
1- The resting Potential
2- The action potential
3- The absolute refractory period (rest)
4- The All-or-None law
Describe the resting potential of a neuron
Stable, negative charge when the cell is inactive or at rest (-70 mV)
What are the chemicals inside of a neuron at rest?
Sodium (NA+), Potassium (K+), and Chloride (Cl-)
What is an action potential?
A very brief shift in a neurons electrical charge that travels along an axon
What is the refractory period?
A 1-2 ms break where an action potential cannot happen
What is the all or none law?
-A Neuron either fires or it doesn’t
-All action potentials are the same size
-Neurons convey strength of a stimuli through the rate at which it fires action potentials.
What is a synaptic cleft?
The location where the terminal buttons and neurons cell membrane communicate
What is the transmitting neuron called?
The Presynaptic neuron
What is the receiving neuron called?
The postsynaptic neuron
What are neurotransmitters
Chemicals that transmit information
What are synaptic vesicles
Small sacs where neurotransmitters are stored in the terminal button
What are the 5 steps of synaptic transmission?
1- Synthesis of neurotransmitters and storage in synaptic vesicles
2- Synaptic vesicles touch the membrane of the presynaptic cell and release its contents into the cleft
3- Contents bind with special molecules in the postsynaptic membrane (Lock and key)
4-Unused neurotransmitters go through inactivation (convert) or removal (drift away)
5 Reuptake: when neurotransmitters are “sponged up” from the synaptic cleft by the presynaptic membrane
What is a neural network?
Interconnected neurons that frequently fire together or sequentially to perform certain functions
