Nervous system Flashcards
what produces myelin in the CNS
oligodendrocytes
what produces myelin in the PNS
schwann cells
when does depolarization occur
when Na+ channels open and Na+ influx into the neuron occurs
when do K+ channels open
when the cell reaches +35 mV
what happens when K+ channels open
repolarization
how does hyper-polarization happen
opening and closing of the K+ channels can be slow
what is the refractory period and when does it occur
a period of time after the action potential in which new action potentials are very hard to initiate, occurs during hyperpolarization
is white matter myelinated or unmyelinated
myelinated
is grey matter myelinated or unmyelinated
unmyelinated
what type of neurons are neurons that carry sensory information
afferent neurons
what direction to afferent neurons travel
from external environment to the spinal cord or brain
what direction to efferent neurons travel
from the brain or spinal cord to various parts of the body
what type of neurons are efferent neurons
motor neurons
what are the neuroglia in the CNS
astrocytes, oligodendrocytes, microglia, ependymal cells
what are the neuroglia in the PNS
satellite cells, schwann cells
what do astrocytes do
maintain the integrity of the blood-brain barrier, regulate nutrient and gas concentrations, degrade NTs
what do microglia do
remove cellular debris
what do ependymal cells do
line the brain ventricles and aid in the production, circulation, and monitoring of cerebral spinal fluid
what do satellite cells do
surround the neuron cell bodies in the ganglia
what is another name for the forebrain
prosencephalon
what does the forebrain consist of
telencephalon and diencephalon
what does the telencephalon contain
the cerebral cortex and the olfactory bulb
what does the cerebral cortex do
processes and integrates sensory input and memory responses, also important for memory and creative thought
what does the olfactory bulb do
it is the center for reception and integration of smell
what does the diencephalon contain
the thalamus and hypothalamus
what does the thalamus do
it is a relay and integrate center for the spinal cord and cereal cortex
what does the hypothalamus do
controls visceral functions such as hunger, thirst, sex drive water balance, blood pressure, and temperature regulation, also plays important role in the endocrine system
what is another name for the midbrain
mesencephalon
what does the midbrain do
it is a relay center for visual and auditory impulses, also plays a role in motor control
what is another name for the hindbrain
rhombencephalon
what does the hindbrain consist of
the pons, the medulla, and the cerebellum
what does the cerebellum do
modulates motor impulses initiated by the cerebral cortex and is important in the maintenance of balance, hand-eye coordination and the timing of rapid movements
what does the pons do
acts as a relay center to allow the cortex to communicate with the cerebellum
what does the medulla do
controls breathing, heart rate, and GI activity
what does the outer white matter of the spinal cord contain
motor and sensory axons
what does the inner grey matter of the spinal cord contain
nerve cell bodies
where does sensory information enter the spinal cord
through the dorsal horn
where does motor information exit the spinal cord
through the ventral horn
what is the primary neurotransmitter in the sympathetic nervous system
norepinephrine
what is the primary neurotransmitter in the parasympathetic nervous system
acetylcholine
what does the choroid layer of the eye do
supplies the retina with blood , it also reduced reflection in the eye
what does the cornea of the eye do
bends and focuses light rays
what is the central section of the retina called
the macula
what is the central section of the macula called
the fovea
does the fovea contain rods or cones
cones only
what is the visual pathway
photoreceptor cells synapse on bipolar cells which synapse on ganglion cells which form the optic nerve which transmits visual information to the brain
what is myopia
nearsightedness, occurs when the image is focused in front of the retina
what is hyperopia
farsightedness, occurs when the image is focused behind the retina
what is astigmatism caused by
an irregular shaped cornea
what is glaucoma
an increase in the pressure of the eye because of blocking of the outflow of the aqueous humor which results in optic nerve damage
what are the 3 bones of the middle ear
malleus, incus, and stapes
what does the inner ear consist of
cochlea and vestibule
