Ch 1-4 Flashcards
What is a Gilia
A cell in the nervous system that supports the activities of neurons.
Neuron
A cell of the nervous system that specializes in information processing and communication
Macrogilia
Large glial cells including astrocytes, ependymal cells, oligodendrocytes, and Schwann cells.
Microglia
Tiny, mobile glia cells migrate to areas of damage and digest debris.
Astrocytes
A large-shaped gilia cell of the central nervous system, responsible for structural support, isolation of the synapse, control of the extracellular chemical environment at the synapse, and possibly communication. located in CNS
ependymal cells
Glial cells lining the ventricle and the central canal of the spinal cord. located in the lining of the ventricles central canal of the spinal cord.
oligodendrocytes
a glial cell forms the myeline on the central nervous system axons.
Schwann cell
a glial cell that forms the myelin of the axiom in the peripheral nervous system.
synapse
the junction between two neurons, at which information is transferred from one to another.
Blood-brain barrier
an impertinent to the transfer of molecules from the circulation into the brain formed by the astrocytes.
Form follows function
Frank Loyd, the nervous system has been shaped by the course of evolution
FOUR TYPES OF MACROGLIA
Astrocytes, Epedemymal cells, oligodendrocytes and Shwann cells.
Astrocytes - TWO TYPES- a most common type of glial cell.
Protoplasm- fine branches found in grey matter, and Fibrous Astrocytes- long fibers found in white matter.
they provide the structural matrix for the neuron.
Organelle
a small thin cell that carries out a specific function
A negatively charged ion has-
more electrons than protons, whereas a positively charged ion, has fewer electrons than protons.
Extracellular fluid is-
like sea water
intracellular fluid-
of the resting neuron contains large numbers of potassium ions, in addition, within the intracellular fluid there are some large proteins in ion form that are negatively charged.
Diffusion
The force that moves molecules from areas of high concentration to areas of low concentration.
Concentration gradient
an unequal distribution in the concentration of molecules across a cell membrane.
electrical pressure
the force that moves molecules like electrical charges apart and molecules with opposite electrical charges together.
depolarization
A change in membrane potential in a more positive direction.
threshold
the level of depolarization at which an action potential is initiated.
hyperpolarization
a change in membrane potential in a more negative direction
Absolute refractory period
the period following an action potential will not occur in a particular location of an axon regardless of input.
relative refractory period
the period following an action potential in which larger than usual input will produce a second action potential in which normal input will be insufficient.
Typical human myelinated fibers can conduct action potentials at about-
268 miles per hour.
Resting potential
inactive segments of axons> equilibrium between diffusion and electric static pressure exists for K+ and CL-> Na+ is actively prevented from entering the neuron
Action potential - HOW?
begins at the initial segment and propagates down the length of the axon > Depolarization to the threshold triggers the opening of Na+ channels> entering Na+ ions make voltage inside neurons more positive>opening k+ channels near the peak of action potential allows K+ to leave the neuron > less of K+ returns neuron to the resting potential.
Neurochemicals fall into three categories-
Neurotransmitters, neuromodulators, and neurohormones. they engage in wiring and volume transmission.
neuromodulators
influence more global functions, including attention and assessments of threats, saliency, novelty, and reward. Released from varicosities located along thin unmyelinated axons rather from axon terminal along with a classic neurotransmitter.
synapses have two types
chemical and electrical
Small molecules
one of a group of neurochemicals that include amino acids and amines. typical synthesized in the axiom terminal.
neuropeptides
a peptide that acts as a neurotransmitter, neuromodulation, and a neurohormone. chains of amino acid.
amino acid
an essential component of proteins.
