Midterm 1 Flashcards
What is the difference between afferent and efferent neurons?
Afferent carries info toward CNS and efferent carries info away from CNS
What is functional neuroanatomy?
Defining language and concepts needed to describe nervous system and it’s function
What makes up the CNS?
Brain and spinal cord
What makes up the PNS?
Cranial and spinal nerve fibers, ganglia
What are the functional divisions of the PNS?
Autonomic, somatic
What does the somatic NS control?
Voluntary and conscious movement
What does the autonomic control?
Unconscious or involuntary movements
What does the enteric NS control?
GI tract, works without intervention from CNS
What are to parts of the autonomic NS?
Sympathetic, parasympathetic, enteric
What is the sympathetic NS associated with?
Fight/flight
What is the parasympathetic NS associated with?
Rest/digest
Are sensory neurons afferent or efferent? Motor neurons?
Sensory is afferent
Motor is efferent
What part of the neuron receives input?
Dendrites
What direction do axons send signals?
Away from soma
Where is white matter and grey matter in the brain?
Grey matter is on outside of white matter
Where is white matter and grey matter in spinal cord?
White matter is on outside of grey matter
What do ependymal cells do?
Line the ventricles in brain and central canal in spinal cord and make CSF via making the choiroid plexus
What are the 3 major subtypes of macroglia?
protoplasmic astrocytes, oligodendrocytes, fibrous astrocytes
What are protoplasmic astrocytes?
primarily found in grey matter, support blood brain barrier
What are fibrous astrocytes?
support neruons and their functions, primarily found in white matter (similar function to protoplasmic)
What are oligodendrocytes?
found in CNS, myelinate multiple axons
What are schwann cells?
found in PNS, myelinate axon
How many places can be myelinated by 1 schwann cell?
1
What is the function of microglia?
macrophages, immune response
What are the primary division of the spine?
cervical, thoracic, lumbar, saccral
What are columns in the spinal cord? Where are they found?
long connections up and down the spinal cord, in white matter
What parts of the NS help maintain homeostasis?
Sympathetic, parasympathetic, enteric
What are the effector organs?
Skeletal, smooth, and cardiac muscle and glands
Where are ependymal cells and macroglia derived from?
Cells of the neural tube
Where are microglial cells derived from?
Monocyte precursors of the bone marrow
How do astrocytes assist neurons in transmitting impulses?
Regulating the presence of neurotransmitter substances as well as releasing gliotransmitter substances
What are gliotransmitters?
Chemicals released from glial cells that modulate synaptic transmission and neural excitability
Ex. ATP and glutamate
What is the telencephalon?
Cerebral hemispheres of brain
What is the diencephalon?
Epithalamus, thalamus, hypothalamus, subthalamus
What is the mesencephalon?
Cerebral peduncles and tectum
What is the metencephalon?
Pons and cerebellum
What is the myelencephalon?
Medulla oblangata
Where are the nerves responsible for somatic motor function in the spinal cord located?
Ventral horn, their axons leave via the ventral rootlets, inner area skeletal muscle
What regions is the lateral horn found in?
Thoracic, upper lumbar and sacral regions
What is the function of lateral horn?
Central component of the sympathetic division of autonomic NS
What is the function of the dorsal horn?
Where sensory info is brought in by dorsal root ganglia
What do interneurons do?
Connect two types of neurons to each other
What is an example of a connection interneurons make? Hint motor and sensory
Unipolar sensory neurons of DRG to motor neurons of ventral horn
What are the two major categories of neurons?
Those with axons that leave the CNS and those whose axons remain in CNS
How many pairs of spinal nerves are there?
31
8 cervical, 12 thoracic, 5 sacral, 5 lumbar, 1 coccygeal
Where is the boundary between sensory and motor more ambiguous the CNS or PNS?
CNS, especially in brain
PNS is defined and also spinal cord
If someone injured their C6 dorsal root ganglion what would happen to them?
loss of sensation in the area of C6 dermatome (arm, thumb, index finger)
b/c dorsal is sensory
What is the function of the dorsal root ganglion?
contains the cell bodies of sensory neurons
What is the function of the dorsal column?
aka. dorsal column medial lemniscus pathway (DCML)
deals with fine touch, proprioception, two-point discrimination, and vibration sensations from everywhere but head
If patient injures their left dorsal column which leg will show symptoms?
left leg, damage is ipsilateral
if it was right leg, right side is damaged
What is the lateral funiculus?
aka. lateral white column
contains lateral spinothalamic tract and the lateral corticospinal tract
What is the function of the lateral spinothalamic tract?
an ascending sensory pathway that transmits pain sensations, temperature, and potentially itching
damage typically is contralateral
What is the function of the lateral corticospinal tract?
largest descending motor pathway in body, responsible for voluntary movement of the contralateral (opposite) upper and lower limbs
What is the function of myelin?
speeds up transmission of nerve impulses
What part of the spinal cord contains motor neurons?
ventral horn
What is contained in the anterior root of spinal cord?
the axons of motor neurons that exit that spinal cord
What is contained in the lateral horn?
neurons involved in the autonomic nervous system
What is anterograde transport?
movement of materials (neurotransmitters, proteins, organelles) from the soma to the axon terminal
What is retrograde transport?
movement of materials (neurotransmitters, proteins, organlles) from the axon terminals to the soma
What is the vestibulospinal tract involved with?
balance and posture
What is the conus medullaris?
tapered end of the spinal cord
What is the coccyx?
bone at base of spinal cord
aka. tailbone
Who is Ian Waterman?
contracted a viral illness which attacked his NS, leaving him without proprioception from neck down
despite his motor neurons being unaffected he couldn’t move, pain and temperature was intact
managed to relearn to walk
What is sacrum?
shield shaped bone located between hipbones, base of lumbar vertebrae and connected to pelvis
What is a three neuron reflex arc?
made up of receptor sensory, interneuron, motor
reflex can be overidden when interneurons receive input from brain
What is a two neuron reflex arc?
made up of sensory and motor neuron, automatic and only involve part of body
ex. patellar reflex
Where do action potentials originate?
axon hillock
Collectively, anterograde and retrograde transport are referred to as?
axonal transport
What is axodendritic?
one of the potential synapse configurations
where axon of 1 neuron synpases w/dendrites of another
What is axon proper?
long part of axon that you usually think of when thinking of axons
Why is the axon hillock where actiona potentials start?
high density of Na+ channels
What are bipolar neurons?
possess an axon and dendrites
found in retina, roof of nasal cavity, inner ear
What is cilia? Where is it found in the NS and why?
short hairlike filaments
spinal canal and ventricles, b/c they help circulate CSF
How do presynaptic membranes stay the same size when vesicles have to fuse with it to deliver their contents?
form clathrin coated pits, which eventually form clathrin coated vesicles, then recycled by SER to be used in forming new vesicles
What are schmidt-lantermann clefts/incisures?
small pockets of cytoplasm in myelin sheaths made by schwann cells
What is the function of shcmidt-lantermann clefts/incisures?
believed to help sustain the growth and function of compact myelin
What are dendritic spines?
tiny protrusions from dendrities, form contacts with axons of other neurons
very plastic, have diff shapes and size
(filopodia, mushroom, etc)
What are docking complexes?
oblong electron dense, protein structures located at presynaptic membrane, form presynaptic grid
What is the purpose of docking complexes?
some synaptic vesicles are bound by them near the active site so they are ready when an action potnetial comes
What type of synapse is faster?
electrical
Are electrical synapses found in mammals?
only in retina, cerebral cortex, and brainstem
What is a type I synapse?
aka. asymmetric synapse b/c postsynaptic density is thicker than presynaptic density, round vesicles, excitatory
What is a type II synapse?
aka. symmetric synapse b/c 2 densities are = thickness, flattened vesicles, inhibitory
What are G-proteins?
specialized proteins with the ability to bind GTP and GDP
used in metabotropic receptors
What are gap junctions?
continuous channels that connect two molecules together
electrical synapse uses these
What is the glial-limiting membrane?
formed by astrocytes (end-feet) at interface of brain and pia mater, barrier against unwanted things entering CNS
What are glioblastoma?
type of neuroglial tumor, malignant and highly fatal, formed by astrocytes
What is the initial segment?
transition between axon hillock and axon proper, repsonsbile for intiial and propagation of action potential, membrane is thicker
What is inner mesaxon?
when schwann cells myelinate they wrap around axon, inner mesaxon is the part of schwann cell membrane that connects to the innermost wrapping around axon
beginning of intraperiod gap
What are internodes?
between 2 nodes of ranvier, the myelinated part
WHat are intraperiod gaps?
gaps betweeen the membrane of shcwann cell wrapping around axon
beleived to be so small molecules can reach axon
What are ionotropic receptors?
ligand gated channels, when neurotransmitter binds it changes shape to open the channel
direct, rapid
What is plasmalemma?
cell membrane
What are metabotropic receptors?
bind neuromodulators/ neurohormones, binds to a receptor molecule which triggers a signaling cascade
indirect, slow
What are microfilaments?
mostly actin filaments
associated with cell membrane and aid in dendrites/axon elongation, and movement of membrane
What do microtubules do?
create a scaffold-like structure to maintain cell shape and aid in transport of materials
What are multipolar neurons?
1 axon and 2 or more dendrites
ex. motor neurons in spinal cord
What are neurites?
any protrusion form neuron
ex. axon, dendrite
What do neurofilaments do?
help with regenaration and development of axons/dendrites
aka. intermediate filaments
What is neurolemma?
outermost layer of the Schwann cell that surrounds an axon in the peripheral nervous system
not same as myelin sheath (multple layers)
protects neurons, support repair
Compare neurotransmitters and neuromodulators?
NT act locally at synapse, cause immediate effects, short lived
ex. glutamate, gaba,
NM affect larger area, slower more prolonged changes, modulate overall state of neuron
ex. neuropeptides like oxytocin, endorphins, some NT like dopamine/serotonin
What is outermesaxon?
the outermost wrapping of the outer cell membrane to the myelin sheath
What is pervivascular covering?
formed by astrocytes around blood vessels
What are psudounipolar neurons?
start out bipolar, then axon and dendrite fuse before later spliting
What is collapse fusion?
permanent fusion, vesicle fuses to membrane after emptying contents
What is kiss and run fusion?
temporary fusion, vesciles contact presynaptic membrane empties its content and then leaves
What is the anterior spinal artery?
located in ventral median fissure, from cranial cavity through entire spinal cord, has small branche sthat supply white and grey mater, only 1
small in thoracic area
What do ascending tracts transmit?
sensory info to brain
What is the cauda equina?
nerve fibers at end of spinal cord, within the lumbar cistern
area for lumbar puncture
What is the central canal?
continuous with 4th ventricle, CSF filled in spine, entire lenght of cord in young adults
What is dermatome?
strip of skin a aprticular spinal nerve is responsible for
What do descending tracts do?
relay motor info from brain to rest of body
What is the dorsal median sulcus?
runs entire lenght of spine, less deep than anterior
What is dorsal primary ramus?
after spinal nerve exits the spinal cord, it splits into two primary branches, dorsal and ventral ramus
The dorsal primary ramus innervates the deep muscles of the back, carries sensory information from the skin and tissues along the back
Where is the dorsointermediate sulcus?
located between dorsomedian sulcus and dorsolateral sulcus, only in cervical and upper thoracic
Where is the dorsolateral sulcus?
on either side of dorsomedian sulcus, can be distinguished by presence of dorsal rootlets of spinal nerves
What is the dorsolateral tract of lissauer
small bundle of nerve fibers located in the spinal cord lateral to dorsal horn
carries pain, temperature, and light touch information from the body to the spinal cord, modulates sensory input before it enters the central pathways
What is foramen magnum?
base of skull, where spinal cord starts
What is GSA?
general somatic afferent
snesory info (touch, pressure, proprioception, pain, temperature) that is perceived in body and transmitted to spinal cord
What is GSE?
genereal somatic efferent
provide motor innervation to skeletal muscles
What is GVA?
general visceral afferent
sensory info perceived in viscera (organs, glaands, membranes) that is transmitted to spinal cord
What is GVE?
general visceral efferent
motor innervation to glands, cardiac muslce, smooth muslce
What is the gray commisure?
strip of gray matter that connects the “wings” of spinal cord together
subdivided into posterior and anterior gray commisure, associated w/autonomic
What is gray ramus communicans?
connects a spinal nerve to the sympathetic chain, carries postganglionic fibers
What is great ventral radicular artery? (artery of adamkiewicz)
arises from the left side in most people, supplies the anterior spinal artery in the lower two-thirds of the spinal cord, arises from L2 to T9 usually
What are intersegmental tracts?
convey info between spinal segments
help with intersegmental spinal refelxes
What are intervertebral foramen?
gaps in the vertebrae of spinal cord where spinal nerves and blood vessels pass through
What is lumbar cistern?
CSF filled space at bottom of spinal cord where there is no cord
What are myotomes?
groups of muscles innervated by same spinal nerve
What is a neuropil?
any area in the nervous system composed of mostly unmyelinated axons, dendrites and glial cell processes that forms a synaptically dense region containing a relatively low number of cell bodies
How does the spine receive blood flow?
from anterior and posterior spinal arteries as well as small segmental radicular arteries
How many posterior spinal arteries are there?
2
Where do the anterior and posterior spinal arteries originate from?
vertebral arteries
How many pairs of radicular arteries are there?
32
What is a sclerotome?
the ligaments and bones that are innervated by same spinal nerve
What is spina bifida?
developmental disroder where neural tube doesn’t close fully, 1-2% prevalence, different types depending on the severity
What is spina bifida anterior?
when it occurs along the ventral surface of the vertebral column
What is spina bifida cystia? (aka aperta)
more serious, involves herniation of spinal and/or meninges, potnetially can rupture the skin resulting in leaking CSF and miningitis
What is spina bifida occulta?
least serious and most common, may not have symptoms, someotimes able to see tuft of hair on area
What is a spinal segment?
region of the spinal cord associated with a particular pair of spinal nerves
What is subarachnoid space?
between arachnoid mater and pia mater, filled with csf, protects spinal cord from injury
What is substantia gelatinosa centralis?
layer of neuroglia intersperesed with nerve fibers and nerve fibers, surrounding ependymal cells of central canal
What is syringomyelia?
spinal cord disroder marked by loss of the sense of pain/temperature at levels involving several consecutive spinal cord segments
can be caused by a cleft or an increased central canal size
What are ventral primary rami?
carry sensory and motor fibers for the innervation of the muscles, joints, and skin of the lateral and ventral body walls and the extremities, also autonomic
What is ventrolateral sulcus?
in spinal cord, btwn posterolateral sulcus and anterior median fissure, where ventral rootlets emrege from cord
What is white ramus communicans?
contains preganglionic fibers of the sympathetic system, a structure that anteriorly connects the spinal nerve to the sympathetic trunk
What is the archicortex? aka allocortex
oldest region, three layers, in limbic system
What is mesocortex? aka juxtallocortex
younger than archicortex, 3 to 6 layers, predominantly located in insula and cingulate gyrus
What is neocortex? aka isocortex?
youngest, 6 layers, bulk of cerebral cortex
What do association fibers do?
connect regions of hemisphere to other regions of the same hemisphere
aka arcuate fibers
the axons of pyrimidal cells and fusiform neurons
What is the basal nuclei?
used to be called basal ganglia
composed of caudate nucleus, putamen and globus pallidus (lenticular nucleus), subthalamic nucleus of ventral thalamus, substantia nigra
What are input, output, and intrinsic nuclei of basal nuclei mean?
input receive input, output project to other neurons, intrinsic means they receive input, project and have local interconnections
What is the calcarine fissure?
sulcus in occipital lobe, marks where the primary visual cortex is (cuneate gyrus and lingual gyrus)
What is the central sulcus?
separates the frontal lobe from the parietal lobe
How is the cerebellum connected to brain?
connected to brainstem via the superior, middle, and inferior cerebral peduncles
What does the cerebral aqueduct do?
connects the fourth ventricle to the third ventricle
What is the cingulate gyrus?
located above corpus callosum, separated from it by the callosal sulcus, continues as the isthmus, included in limbic lobe
What is the cingulate sulcus?
borders the frontal lobe medially, forms the superior boundary of the cingulate gyrus
What are commissural fibers?
bundles fo axons that connect the left and right hemispere
What are the four bundles of commissural fibers?
corpus callosum, anterior commissure, posterior commissure, hippocampal commissure
What does the anterior commissure connect?
right and left amygdalas, olfactory bulbs, several regions of temporal lobes
What does the posterior commissure connect?
right and left pretectal regions and related cell gorups of mesencephalon
What does the hippocampal commissure conenct?
aka commissure of the fornix, left and right hippocampi
What are the regions of the corpus callosum?
anteriormost rostrum, curved genu, the body, and the posteriormsot spenium
What are corticofugal fibers?
efferent fibers that transmit info from cerebral cortex to lower centres of the brain and spinal cord
consist of corticobulbar, corticopontine, corticospinal, corticothalamic fibers
What are corticopetal fibers?
afferent fibers that bring info from thalamus to the cerebral cortex
consist thalamocortical fibers
Where is the cuneate gyrus?
located above calcarine sulcus, primary visual cortex
What is gyrification?
the process by which the brain undergoes changes in surface morphology to create sulcal and gyral regions
What is hydrocephalus?
abnormal buildup of cerebrospinal fluid in the ventricles in the brain, puts pressure on brain
What is the insula?
forms the floor of the lateral sulcus, surrounded by circular sulcus
beleived to be associated with taste and potentially other viscera functions
What is the interventricular foramen?
connects the lateral hemispheres to the third hemisphere
What is ataxia?
lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements
contralateral to lesion
What are the autonomic centers?
in the medulla, controls respiratory, cardiovasuclar, and gastrointestinal functions
What is the basal pons?
anterior portion of pons, facilitates communication between the cerebral cortex and cerebellum, role in coordinating voluntary motor activity
The corticospinal and corticobulbar tracts are essential for motor control of the body and face
What are projection fibres?
restricted to a single hemisphere and connect the cerebral hemispheres with lower centers (corpus striatum, diencephalon, spinal cord, brainstem)
subdivided into corticopetal and corticofugal
What is the septum pellucidum?
non-nervous membranes that adhere to each other, separate lateral ventricles
What are splitbrain patient?
people whose corpus callosum has been partially or fully removed
What is the superior parietal lobule involved with?
association area for somatosensory function
What is the inferior parietal lobule involved with?
has 2 regions
supramarginal gryus, involved with integrating info from somatosensoyry, auditory and visual sensese
angular gyrus, receives visual input
Where is wernicke’s area located?
superior temporal gyrus
Where is broca’s area located?
inferior frontal gryus
What is the basilar artery?
main artery that supplies blood to brainstem, cerebellum, and occipital lobes mainly
What is bradykinesia?
slowness of movement and difficulty initiating movements, reduced facial expression
What does the inferior cerebellar peduncle connect?
cerebellum to medulla
What does the middle cerebellar peduncle connect?
cerebellum to pons
What does the superior cerebellar peduncle connect?
cerebellum to midbrain
Where is the midbrain located?
Above the pons, below the thalamus
What role does the midbrain play?
vision, hearing, motor control, sleep and wakefulness, arousal, and temperature regulation
Astrocytosis is involved with?
many disroders, like ALS, parkinson, huntington, autism, schizophrenia
What are extrafusal fibers?
contract to produce the movements of skeletal muscles, receive alpha fiber projections
Where are intrafusal muscle fibers found?
inside muscle spindles
WHat is contained in intrafusal muscle fibers?
nuclear chain intrafusal fibers and nuclear bag intrafusal fibers
What are nuclear chain and nuclear bag fibers innervated by?
gamma motor neurons in spinal cord
What is type 1a?
Annulospiral endings, primarily wrapped around non-contrcticle regions and spinal length and quick changes in length
What are the symptoms of lateral medullary (wallenberg) syndrome?
vertigo, nystagmus, ataxia, ipsilateral pain/temperature loss on face, contralateral in body, dysphagia, dysphonia, diminshed gag refelx
What is the cause of lateral medullary (wallenberg) syndrome?
Occlusion of the posterior inferior cerebellar artery (PICA) or vertebral artery
What are the symptoms of medial medullary syndrome?
contralateral hemiparesis, contralateral loss proprioception and fine touch, ipsilateral tongue deviation, dysarthia (slurred speech cause tongue weak)
What is the cause of medial medullary syndrome?
Occlusion of the anterior spinal artery or paramedian branches of the vertebral arteries
What are corticobulbular tracts?
Descending fibers from the cerebral cortex to cranial nerve nuclei
Who is Jean-Dominuqe Bauby?
man with locked in syndrome, wrote a book by blinking his left eyelid, could only move left eye and left eyelid
What is MPTP related to?
in 1980s bunch of college kids presetned with parkinsons symtpoms, accidently make mptp which is taken up by substantia nigra and causes parkinsons
What are the symptoms of medial midbrain syndrome?
ipsilateral CN III palsy (oculomotor) causes ptosis, mydriasis (dialted pupil unreactive), contralateral hemiparesis
What is auto genic inhibition?
Prevents muscles from exerting more force than bone/tendon can handle
What is areflexia?
Absence of tendon reflexes
What is flaccid paralysis?
Weakness or paralysis and reduced muscle tone with no obvious cause
What is Golgi tendon organ?
Sensory receptor loactaed near tendon and muscle junction
Responds to muscle tension
