Life 45- Neurons And Nervous Systems Flashcards
Spatial summation
In the production or inhibition of action potentials in a post synaptic cell, the interaction of depolarisations and hyper polarisation produced at different sites on the post synaptic cell.
Patch clamping
A technique for isolating a tiny patch of membrane to allow the study of ion movement through a particular channel.
Motor end plate
The modified area on a muscle cell membrane where a synapse is formed with a motor neuron
Neuron
A nervous system cell that can generate and conduct action potentials along an axon to a synapse with another cell.
Presynaptic neuron
The neuron that transmits information to another cell at a synapse
Neuromuscular junction
Synapse (point of contact) where a motor neuron axon stimulates a muscle fibre cell.
Voltage-gated channel.
A type of gated channel that opens or closes when a certain voltage exists across the membrane in which it is inserted.
Depolarization
A change in the resting potential across a membrane so that the inside of the cell becomes less negative, or even positive, compared with the outside of the cell.
Long-term potentiation (LTP)
A long-lasting increase in the responsiveness of a neuron resulting from a period of intense stimulation.
Refractory period
The time interval after an action potential during which another action potential cannot be elicited from an excitable membrane.
Central nervous system (CNS)
That portion of the nervous system that is the site of most information processing, storage, and retrieval; in vertebrates, the brain and spinal cord.
Saltatory conduction
The rapid conduction of action potentials in myelinated axons; so called because action potentials appear to “jump” between nodes of Ranvier along the axon.
Glia
Cells of the nervous system that do not conduct action potentials.
Electrochemical gradient
The concentration gradient of an ion across a membrane plus the voltage difference across that membrane.
Schwann cell
A type of glia cell that myelinated axons in the peripheral nervous system
Temporal summation
In the production or inhibition of action potentials in a postsynaptic cell, the interaction of depolarisations or hyperpolarisations produced by rapidly repeated stimulation of a single point on the postsynaptic cell
Neural network
An organised group of neurons that contains three functional categories of neurons- afferent neurons, inter neurons, and efferent neurons- and is capable of processing information.
Interneuron
A neuron that communicates information between two other neurons.
Microglia
Glia cells that act as macrophages and mediators of inflammatory responses in the central nervous system
Node of Ranvier
A gap in the myelin sheath covering an axon; the point where the axonal membrane can fire action potentials.
Axon
The part of a neuron that conducts action potentials always from the cell body
Ganglion
A cluster of neurons that have similar characteristics or function.
Acetylcholine (ACh)
A neurotransmitter that carries information across vertebrate neuromuscular junctions and some other synapses
Peripheral nervous system (PNS)
The portion of the nervous system that consists of neurons that extend or reside outside the brain or spinal cord and their supporting cells.
Membrane potential
The difference in electrical charge between the inside and the outside of a cell, caused by a difference in the distribution of ions
Afferent
Carrying to, as in a neuron that carries impulses to the central nervous system, or a blood vessel that carries blood to a structure.
Astrocyte.
A type of glial cell that contributes to the blood-brain barrier by surrounding the smallest, most permeable blood vessels in the brain
Dendrite
A fibre of a neuron which often cannot carry action potentials, is usually much branched and relatively short, and commonly carries information to the cell body of the neuron
Action potential
An impulse in a neuron taking the form of a wave of depolarisation or hyperpolarisation.
Threshold
The level of depolarisations that causes an electrically excitable membrane to fire an action potential.
Synapse
A specialised type of junction where a neuron meets its target cell (which can be another neuron or some other type of cell) and information in the form of neurotransmitter molecules is exchanged
Mechanically gated channel
A molecular channel that opens or closes in response to mechanical force applied to the plasma membrane in which it is inserted.
Myelin
Concentric layers of plasma membrane that form a sheath around some axons; provides the axon with electrical insulation and increases the rate of transmission of action potentials.
Nerve
A structure consisting of many neuronal axons and connective tissue.
Electrical synapse
A type of synapse at which action potentials spread directly from presynaptic cell to postsynaptic cell.
Hyperpolarization
A change in the resting potential across a membrane so that the inside of a cell becomes more negative compared with the outside of the cell.
Oligodendrocyte
A type of glial cell that myelinated axons in the central nervous system
Sodium-potassium pump
Antiporter responsible for primary active transport; it pumps sodium ions out of the cell and potassium ions into the cell, both against their concentration gradient.
Axon terminals.
The endings of an axon; they form synapses an release neurotransmitter.
Metabotropic receptor
A receptor that indirectly alters membrane permeability to a type of ion when it combines with its ligand
Nernst equation
A mathematical statement that calculates the potential across a membrane potential permeable to a single type of ion that differs in concentration on the two sides of the membrane.
Brain
The centralised integrative centre of a nervous system
Sensory neuron
A specialised neuron that transducers a particular type of sensory stimulus into action potentials
Efferent
Carrying outward or away from, as in a neuron that carries impulses outward from the central nervous system, or a blood vessel that carries blood away from a structure
Ionotropic receptors
A receptor that directly alters membrane permeability to a type of ions when it combines with is Ligand.
Resting potential
The membrane potential of a living cell at rest.
Axon hillock
The junction between an axon and its cell body, where action potentials are generated.
Chemically gated channel
A type of gated channel that opens of closes depending on the presence or absence of a specific molecule, which binds to the channel protein or to a separate receptor that in turn alters the three-dimensional shape of channel protein.
Neurotransmitter
A substance produced in and released by a neuron (the presynaptic cell) that diffuses across a synapse and excites or inhibits another cell (the postsynaptic cell)
Chemical synapse
Neural junction at which neurotransmitter molecules released from a presynaptic cell induce changes in a postsynaptic cell.
Blood-brain barrier
A property of blood vessels in the brain that prevents most chemicals from diffusing from the blood into the brain.
