Nervous System Flashcards
spatial summation
postsynaptic neuron stimulated or inhibited simultaneously by large number of presynaptic axon terminals
resulting EPSP or IPSP add together
EPSP
depolarization
IPSP
hyperpolarization
temporal summation
postsynaptic neuron stimulated or inhibited in quick succession by on or more presynaptic neurons
resulitng EPSPs or IPSPs add together
at threshold
depolarization opens more voltage gated sodium channels
What are the two processes that break the loop of the positive feedback??
inactivation of sodium channels, voltage sensitive gate
activation of K channels (out of cell), slow responders, become fully activated ager action potential reaches its peak
repolarization
K leaving and less Na coming in
hyperpolarization
K continues to leave after resting potential has been reached
absolute refractory period
a neuron cannot generate another action potential while it is doing one
relative refractory period
stronger stimuli have to arrive at the axon hillock
conduction velocity
how fast the nerve impulse travels down the axon
the larger the diameter, the faster the AP
saltatory conduction
myelinated axon AP
action potential
all or none
charge inside cell
-70mV
what make the sodium channel inactive?
a time sensitive arm
for every 3 Na out
2 K in
transports both sodium and potassium ions across the membrane to compensate for their constant leakage
sodium potassium pump
mobilizes body systems during activity
sympathetic division
conserves energy
promotes house keeping functions while at rest
parasympathetic division
sensory
afferent
motor
efferent, impulses from CNS
sympathetic, parasympathetic
somatic, autonomic
somatic
voluntary
autonomic
involuntary
From most anterior to most posterior, what is the order of the secondary embryonic brain vesicles?
Telencephalon Diencephalon Mesencephalon Metencephalon Myelocephalon
The telencephalon becomes…
the two cerebral hemispheres, cerebrum
The diencephalon becomes…
the hypothalamus, thalamus, epithalamus, and retina of eye
Mesencephalon becomes…
midbrain
Metencephalon becomes…
pons and cerebellum
Myelocephalon becomes…
medulla oblongata
brain stem
midbrain, pons and medulla oblongata
Important areas of the frontal lobe
primary motor cortex
premotor cortex - helps plan movements, basic movement to accomplish complex tasks
Broca’s area - speech production
prefrontal - personality, cognition
parietal
somatosensory cortex (just posterior to primary motor) and somatosensory association cortex just posterior to the somatosensory cortex
temporal
auditory, olfactory
occipital
visual
insula
taste and visceral stimuli
Multimodal association area
general interpretive areas throughout temporal, occipital, parietal, frontal lobes
• Flow of info: sensory receptors primary sensory cortex sensory association area multimodal association areas
premotor cortex
Basal nuclei
gray matter deep within white matter
Input from cerebral cortex • Project into premotor & prefrontal cortex • Influence muscle movements (starting/stopping) • Role in cognition & emotion
thalamus
mailroom
ALL sensory input comes to thalamus first - Sorts impulses and sends similar ones out in “bulk”
hypothalamus
controls ANS
Response to emotions –Regulate body temperature –Regulate food intake/water balance –Regulate biological clock –Endocrine control
epithalamus
Pineal gland, secretes the hormone melatonin which regulates wake/sleep cycles
Cerebellum
Muscle coordination
ventral roots
fused axons of neurons whose cell bodies in ventral & lateral horns
– Only transmits efferent (motor) impulses
dorsal roots
axons of sensory (afferent) neurons
– Only transmits afferent (sensory) impulses
ascending tracts
afferent, sensory
descneding tracts
efferent, motor
ascending tracts
spinocerebellar
spinothalamic
dorsal column-medial lemniscal
Spinothalamic
coarse touch, pressure, pain, & temperature (spinal cord to thalamus)
Spinocerebellar
muscle/tendon stretch
(spinal cord to cerebellum
Dorsal column-medial lemniscal
fine touch
(spinal cord/medulla to thalamus
Descending tracts can be
indirect or direct pathways
direct pathways (desceding tracts)
do not synapse before reaching spinal cord
pyramidal, corticospinal, fine movements, cerebrum to spinal cord
tectospinal
eyeball and neck movements, midbrain to spinal cord
rubriospinal
controls flexor muscles, red nucleus to spinal cord
vestibulospinal
posture muscles, medulla to spinal cord
reticulospinal
pons/medulla to spinal cord
What is so bad about polio?
Destroys ventral horn neurons
Remember, the ventral horn neurons are motor neurons
proprioceptors
are sensors that provide information about joint angle, muscle length, and muscle tension, which is integrated to give information about the position of the limb in space.
Midbrain
hearing, eyeball movement, vision, body movement
Medulla
maintaining vital body function, autonomic function, breathing and heart rate, other reflexes like sneezing an domiting
Pons
motor control and sensory analylsis
What is the largest of the midbrain nuclei?
corpora quadrigemina
Which part of the corpora quadrigemina of the midbrain controls visual reflexes?
superior colliculi
Which part of the corpora quadrigemina of the midbrain controls auditory reflexes?
inferior colliculi
Where is the substantia nigra?
just ventral to the red nuclei, which are all located in the midbrain
The substantial nigra produces dopamine.
The red nucleus is a relay for limb flexion.
Only two structures of the pons mentioned…what are they?
projection fibers into both the higher brain and spinal cord
ventral fibers into cerebellum, connecting it to it
from superficial to deep, what are the layers of the meninges?
dura, arachnoid, pia
What do the dorsal, posterior horns of the spinal cord contain?
interneurons
What do the anterior horns, the ventral horns, contain?
motor neurons
sympathetic NS
fight or flight
parasympathetic
rest and digest
What do microglia do?
little housekeeper, clean up dead neurons and microorganisms
What is the functional equivalent of an astrocyte in the PNS?
satellite cells
CNS doesn’t have nerves, it has…
tracts
Gray matter of the PNS?
ganglia
depolarization
to make RMP more positive, to bring closer to threshold potential
