Flashcards in Nervous System Deck (75):
postsynaptic neuron stimulated or inhibited simultaneously by large number of presynaptic axon terminals
resulting EPSP or IPSP add together
postsynaptic neuron stimulated or inhibited in *quick succession* by on or more presynaptic neurons
resulitng EPSPs or IPSPs add together
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
K leaving and less Na coming in
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
how fast the nerve impulse travels down the axon
the larger the diameter, the faster the AP
myelinated axon AP
all or none
charge inside cell
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
promotes house keeping functions while at rest
efferent, impulses from CNS
From most anterior to most posterior, what is the order of the secondary embryonic brain vesicles?
The telencephalon becomes...
the two cerebral hemispheres, cerebrum
The diencephalon becomes...
the hypothalamus, thalamus, epithalamus, and retina of eye
pons and cerebellum
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
somatosensory cortex (just posterior to primary motor) and somatosensory association cortex just posterior to the somatosensory cortex
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
gray matter deep within white matter
Input from cerebral cortex • Project into premotor & prefrontal cortex • Influence muscle movements (starting/stopping) • Role in cognition & emotion
ALL sensory input comes to thalamus first - Sorts impulses and sends similar ones out in “bulk”
Response to emotions –Regulate body temperature –Regulate food intake/water balance –Regulate biological clock –Endocrine control
Pineal gland, secretes the hormone melatonin which regulates wake/sleep cycles
fused axons of neurons whose cell bodies in ventral & lateral horns
– Only transmits efferent (motor) impulses
axons of sensory (afferent) neurons
– Only transmits afferent (sensory) impulses
dorsal column-medial lemniscal
coarse touch, pressure, pain, & temperature (spinal cord to thalamus)
(spinal cord to cerebellum
Dorsal column-medial lemniscal
(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
eyeball and neck movements, midbrain to spinal cord
controls flexor muscles, red nucleus to spinal cord
posture muscles, medulla to spinal cord
pons/medulla to spinal cord
What is so bad about polio?
Destroys ventral horn neurons
Remember, the ventral horn neurons are motor neurons
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.
hearing, eyeball movement, vision, body movement
maintaining vital body function, autonomic function, breathing and heart rate, other reflexes like sneezing an domiting
motor control and sensory analylsis
What is the largest of the midbrain nuclei?
Which part of the corpora quadrigemina of the midbrain controls visual reflexes?
Which part of the corpora quadrigemina of the midbrain controls auditory reflexes?
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?
What do the anterior horns, the ventral horns, contain?
fight or flight
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?
CNS doesn't have nerves, it has...
Gray matter of the PNS?