Brain + Neurons Flashcards
Nervous System
The highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body.
Parasympathetic Nervous System
A network of nerves that relaxes your body after periods of stress or danger. It also helps run life-sustaining processes, like digestion, during times when you feel safe and relaxed.
Sympathetic
A network of nerves that helps your body activate its “fight-or-flight” response. This system’s activity increases when you’re stressed, in danger or physically active.
Neurons
They are information messengers. They use electrical impulses and chemical signals to transmit information between different areas of the brain, and between the brain and the rest of the nervous system.
Glial Cells
These cells are non-neuronal cells in the central nervous system and the peripheral nervous system that do not produce electrical impulses. They provide supporting functions to the nervous system.
Astrocytes
exchange materials between neurons and cappilaries
Dendrites
Dendrites are appendages that are designed to receive communications from other cells.
Microglial Cells
Immune defense against invading microorganism
Ependymal Cells
Create, secrete and circulate cerebrospinal fluid
Oligodendrocytes
Produce insulating barrier called myelin sheath, CNS
Satellite Cells
Surround and support neuron cell bodies
Schwann Cells
Produce insulating barrier called myelin sheath, PNS
Dendrites
Appendages that are designed to receive communications from other cells.
Cell Body (Soma)
The information received via the dendrites from thousands of other neurons is collected and integrated.
Axon
Tube-like structure that carries neural signals away from the cell body via the axon terminals.
Terminal Buttons
The small knobs at the end of an axon that release chemicals called neurotransmitters.
Myelin Sheath
This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells.
Resting Potential
The imbalance of electrical charge that exists between the interior of electrically excitable neurons (nerve cells) and their surroundings.
Action Potential
The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.
Depolarization
A change occurs inside a cell that causes the distribution of electric charges to alter, leaving the cell with a less negative charge than the outside.
Hyperpolarization
A change in a cell’s membrane potential that makes it more negative.
Refractory Period
The refractory period of a neuron is the time in which a nerve cell is unable to fire an action potential
Nodes of Ranvier
Microscopic gaps found within myelinated axons. Their function is to speed up propagation of action potentials along the axon via saltatory conduction.
Synapse
The site of transmission of electric nerve impulses between two nerve cells or between a neuron and a gland or muscle cell (effector).
Neurotransmitters
A chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.
Synaptic Vesicles
In a neuron, they store various neurotransmitters that are released at the synapse.
Excitatory Influence
Excitatory neurotransmitters have excitatory effects on the neuron. This means they increase the likelihood that the neuron will fire an action potential.
Inhibitory Influence
Inhibitory neurotransmitters have inhibitory effects on the neuron. This means they decrease the likelihood that the neuron will fire an action.