Nervou system physiology pt 2

what is the growth process of the neural tube?

ectoderm, neuroectoderm, neural plate, neural groove, neural fold, neural tube, neural crest

how does the neural tube form?

inward folding to converge where the anterior end of the tube forms the brain & the posterior part becomes the spinal cord

what are the secondary vesicles of the prosencephalon?

telecephalon \[cerebrum\] & diencephalon \[thalamus & hypothalamus\]

what are the primary vesicles?

prosencphalon/forebrain, mesencephalon/midbrain, rhombencephalon/hindbrain

what are the secondary vesicles of the mesencephalon?

no vesicles, but is seprated into the tectum & tegmentum

what are the secondary vesicles of the rhombencephalon?

metencephalon \[pons & cerebellum\] & myelencephalon medulla oblongata\]

what are the structures that make up the brain stem?

midbrian, pons, medulla

what part of the brain makes up the most mass?

cerebrum

what is the separation of the cerebral hemispheres?

longitudinal fissure

what is the role of the white matter w/in the cerebrum, the corpus callosum?

major pathway for communication between the 2 cerebral hemispheres

what is the wrinkled portion of the cerebrum?

cerebral cortex

what are the functions of the cerebrum?

memory, emotion, consciousness

what aids the cerebrum w/ its functions?

basal nuclei \[cognitive processing\], basal forebrain \[learning & memory\], limbic cortex \[structures for emotion/memory/behavior\]

what is the gyrus\[gyri\] & sulcus\[sulci\]?

ridge of wrinkles & groove between 2 gyri

what is the purpose of folding in the brain?

to fit in the skull & to fit more gray matter into the limited space

what are the 4 lobes of the brain?

temporal, parietal, frontal, occipital

what separates the temporal lobe from the other lobes?

lateral sulcus

what is superior to the lateral sulcus & separated by the central sulcus?

parietal & frontal lobe

what separates the parietal & occipital lobes?

parieto-occipita sulcus

what are brodmann’s areas 17 & 18 in the occipital lobe?

primary visual perception

what are brodmann’s areas 41 & 42 in the superior temporal lobe?

primary auditory sensation & memory

what are brodmann’s areas 1, 2 & 3 in the postcentral gyrus?

somatosensation \[touch, pressure, tickle, pain, itch, vibration, proprioception, kinesthesia\]

what are brodmann’s areas 4 in the precentral gyrus?

primary motor cortex that instructs the spinal cord to move skeletal muscles

what are the parts of the precentral gyrys?

premotor area, frontal eye fields, broca’s area

what are brodmann’s areas 44 & 45 in the broca’s area?

production of language/controlling movements responsible for speech

what is the role of the prefrontal lobe?

cognitive functions \[personality, short-term memory, & consciousness\]

what is the role of the subcortical nuclei in the basal forebrain?

acetylcholine production

what are the subcorticle structures?

subcortical nuclei, hippocampus, amygdala,

which parts of the brain are involved in long-term memory formation & emotional responses?

hippocampus, amygdala, & adjacent cortex

what is the role of basal nuclei?

comparing cortical processing w/ the general state of activity in the nervous system to influence the likelihood of movement taking place

what are major structures in the basal nuclei that control movement?

straitum \[caudate & putamen\] & globus pallidus

what is the direct pathway of info processing in basal nuclei?

projection of axons from the straitum to globus pallidus internal segement & substantia nigra pars reticulata to the thalamus & back to the cortex

what is the indirect pathway of info processing in basal nuclei?

projection of axons from the straitum to the globus pallidus external segment, to the subthalamic nucleus, to globus pallidus internal segment, & to substantia nigra pars reticulata

what is disinhibition?

inhibition of 1 cell on a traget cell that then inhibits the 1st cell

which pathway disinhibits the thalamus & which reinforces inhibition?

direct \[disinhibition to excite cortex\] & indirect \[normal inhibition, failure to excite cortex\]

what is the substantia nigra pars compacta?

switch between the direct & indirect pathway by projecting to the striatum & releasing dopamine

which dopamine receptors are excitatory & which is inhibitory?

d1-type receptor \[excitatory for direct pathway\] & d2-type receptor \[inhibitory for indirect pathway\]

what is the diencephalon?

brain, spinal cord, & peripheral nervous system sends info to the cerebrum through it & the cerebrum output passes through it after

what is the only system exception to diencephalon passage?

olfaction bc it connects directly to the cerebrum

what are the thalamus subunits in the diencephalon?

epithalamus \[pineal gland\] & subthalamus \[subthalamic nucleus part of basal nuclei\]

what is the role of the thalamus?

collection of nuclei that relay & processes sensory info between the cerebral cortex & periphery, spinal cord, or brain stem

what type of info does the cerebrum typically send to the thalamus?

motor commands

what is the hypothalamus?

nuclei involved in regulating memory & emotion through limbic system, & homeostasis through autonomic nervous system & endocrine system through anterior pituitary gland regulation

what is the role of the midbrain/mesencephalon?

coordinates sensory representations of the visual, auditory, & somatosensory perceptual spaces

what do the pons & medulla regulate?

cardiovascular & respiratory systems and rates

what do the cranial nerves do?

connects through brain stem & provides brain w/ sensory input & motor output associated w/ the head & neck \[special senses

what is the tectum?

4 concolliculi bumps consisting of the inferior colliculus & superior colliculus

what is the role of the inferior colliculus?

auditory brain stem pathway that sends auditory info to the cerebrum for conscious perception of sound

what is the role of the superior colliculus?

combines sensory info ab visual/auditory/somatosensory space

what is the tegmentum?

continuous w/ gray matter & contains nuclei that receive & sends info through cranial nerves while regulating functions in cardiovascular & respiratory systems

what is known as the connection between the cerebellum & brain stem?

pons

what is known to process cranial nerve info?

gray matter w/in the medulla

what is reticular formation?

diffuse region of gray matter throughout the brain stem related to sleep & wakefulness

what is the cerebellum?

covered w/ gyri & sulci that compares info from the cerebrum w/ sensory feedback from the periphery through the spinal cord

what is the pathway of sensory info messages to the cerebellum ?

cerebrum fibers connect to pons neurons & projects into cerebellum, motor commands sent to spinal cord, sensory feedback to periphery \[spinal/cranial nerves\], to medulla nucleus, to cerebellum & compared to descending commands from cerebellum

What is the pathway of output messages from the cerebellum?

cerebellum, to midbrain, then descending input to spinal cord to correct the messages going to the skeletal muscles

how does the posterior part of the neural tube develop?

the spinal cord maintains tube structure & is specialized in certain regions

what are some anatomical features along the spinal cord?

anterior median fissure & posterior median sulcus

where do axons enter the spine?

dorsal/posterior nerve root & ventral/anterior nerve root, both are marked by the posterolateral sulcus

what are the posterior regions \[alar plate\] of the spinal cord responsible for?

sensory functions

what are the anterior regions \[basal plate\] of the spinal cord responsible for?

motor functions

how are the regions of the spinal cord divided?

lvl at which spinal nerves pass through the intervertebral foramina & as the vertebral column grows it forms the cauda equina

what are the regions of the gray matter?

posterior horn \[sensory processing\], anterior horn \[skeletal muscle motor signals\], lateral horn \[motor neurons of autonomic nervous system cell bodies\]

what are the regions of the white matter?

ascending tracts \[carry sensory info to brain\], descending tracts \[carry motor commands from brain\], posterior columns \[between 2 posterior gray horns\], anterior columns \[between 2 anterior gray horns\], lateral columns \[between posterior horn & axons on anterior horn neurons\]

where does blood enter the brain from?

from the aorta, it is supplied through the internal carotid arteries & vertebral arteries

what is the circle of willis?

confluence of arteries that can maintain perfusion of the brain even if narrowing/blockage limits flow through 1 part

what are the arteries in the circle of willis from superior to inferior?

anterior cerebral, middle cerebral, ophthalmic, anterior choroidal, internal carotid, posterior communicating, posterior cerebral, superior cerebellar, pontine, anterior inferior cerebellar, vertrbral

what are the arteries in the circle of willis in the center from superior to inferior?

anterior communicating, basilar, & anterior spinal

what happens after the blood circulates through the CNS?

blood drains from the brain through a series of sinuses that connect to the jugular veins

what is the pathway of sinuses that drains cerebral spinal fluid?

superior sagittal, occipital, straight, transverse, sigmoid, jugular veins, blood pumped to the heart to be pumped to the lungs for reoxygenation

what are the meninges?

connective tissue on the outer surface of the CNS to protect the brain

what is the dura mater?

thick fibrous layer & strong protective sheath over the brain & spinal cord; anchored to cranium inner surface & vertebral cavity

what is the arachnoid mater?

membrane of thin fibrous tissue; forms a loose sac around CNS

what is the pia mater?

thin fibrous membrane following the convolutions of gyri & sulci in the cerebral cortex & fits in grooves & indentations

what are the meningeal layers of the brain from superficial to deep?

dura mater, arachnoid mater, pia mater

what is the role of the dura mater?

encloses/protects the CNS, major blood vessels, & venous sinuses that enter the cranium & vertebral cavity

what is the role of the arachnoid mater?

filled w/ circulating cerebrospinal fluid emerges into dural sinus as arachnoid granulations to filter fluid back into blood for drainage & is a liquid cushion to brain & spinal cord

what is the role of pia mater?

gentle covering for every convolution of CNS & blood vessels between it & nervous tissue provides nourishment

what is the role of ventricles in the CNS?

open spaces w/in the brain when cerebrospinal fluid circulates

how is cerebrospinal fluid produced?

filtering of the blood by the choroid plexus through ependymal cells surrounding blood capillaries consisting of water, small molecules, & electrolytes

where do the 4 brain ventricles develop?

hollow central canal w/in the central canal

what is the pathway of cerebrospinal fluid from the lateral ventricles?

lateral ventricles, third ventricle, fourth ventricle, central canal of the spinal cord

what happens as the cerebral spinal fluid is circulating out?

constant filtering & replacement production; picking up metabolic wastes from nervous tissue & liquid cushion for brain & spinal cord

how does blood from dural sinuses get filtered out of the head & neck?

jugular veins & w/ the rest of the circulation for blood is reoxygenated by lungs & filtered by kidneys

what is the role of dorsal/posterior root ganglion?

unipolar cell neurons w/ axons that are sensory endings in the spinal nerve & extend into the CNS through the dorsal nerve root

what is the role of the cranial nerve ganglion?

similar to dorsal root ganglion but associated w/ cranial nerves w/in the cranium

what are the ganglia in the ANS?

sympathetic chain ganglia, paravertebral ganglia, prevertebral ganglia, & terminal ganglia

what is the role of the thoracic & lumbar ganglia in the ANS?

multipolar w/ dendrites radiating out around the cell body where synapses from the spinal cord neurons& project into the organs to regulate the sympathetic aspect of homeostatic mechanisms

what is the role of cranial & sacral ganglia in the ANS?

receives input from cranial or sacral spinal nerves & are responsible for regulating the parasympathetic aspect of homeostatic mechanisms

what is the plexus?

netweork of fibers/vessels; enetric \[small & large intestines\], gastric, esophageal

what makes the enetric nervous system unique from other body systems?

does nor require CNS input to funciton & operates indipendently to regulate the digestive system

what are nerves?

bundles of axons in the peripheral nervous system

what are the layers of a nerve from superficial to deep?

epineurium, axons bundled into fascicles, surrounded by perineurium, individual axons surrounded by endoneurium tissue

what is the role of the cranial nerves?

12 in total responsible for sensory &/or motor functions of the head & neck

how many cranial nerves have sensory fibers, motor fibers, or both sensory & motor fibers?

3, 5, 4

what is cranial nerve i?

olfactory for sense of smell

what is cranial nerve ii?

optic for sense of sight

what is cranial nerve iii?

oculomotor for eye movement through the 4 extraocular muscles, lifting the upper eyelid when eye looks up, & pupillary constriction

what is cranial nerve iv?

trochlear for eye movement to look down & look to/away from nose

what is cranial nerve v?

trigeminal for cutaneous sensations of the face & controlling the muscles of mastication