Neurology Flashcards
where are the rostral & caudal directions
rostral = angled up toward forehead
caudal= angled down toward neck
where are the dorsal and ventral directions
dorsal = above rostral caudal & rhs of brainstem
ventral = below rostral caudal direction and lhs of brainstem
what is the coronal plane
frontal plane
what is the sagittal plane
longitudal plane (separating left & right)
what is the diff. between neurons & neuroglia
neurons send and receive signals while neuroglia support & protect the neurons
what are the (5) functions of the nervous system
monitor the internal & external environment
monitor sensory input & initiate responses
regulate & coordinate internal environment
control mental activity
control muscles & glands
what organs are in the PNS
cranial nerves
spinal nerves
enteric plexuses in small intestine
sensory receptors in the skin
what is in the CNS
brain & spinal cord
what is contained within the brain & spinal cord (CNS)
neural tissue
connective tissue
blood vessels
describe & point to the 4 lobes
frontal, temporal, parietal & occipital are visible from the exterior surface
visible deep within the groove is the insular cortex/lobe
what is myleination
insulation like a cord
insulated for electrical forces to travel through the axon
what are cell membranes made of
phospholipids
what is the difference between demyelination and unmyelination
demyelination is a disease because it implies the myelination has been stripped off e.g. autoimmune disease like multiple sclerosis
Unmyelination is fine because about 5% of axons are unmyelinated
what is the difference between white & grey matter
grey matter contains the cell bodies of the neurons (unmyelinated)
white matter contains the myelinated axons
what is the function of the CNS
sensory data: internal & external
motor commands: control peripheral organs
higher functions: intelligence, memory, learning, emotion
what is conus medullaris
cone like structure where the spinal cord terminates
where does the spinal cord terminate (vertebrae numbers)
between L1 & L2 (12th rib)
how is the spinal cord different from the brain in terms of matter
the white matter is on the outside and they grey matter is on the inside because the neurons are travelling toward the brain
what is cervical enlargement
nerves of shoulders & upper limbs
what is lumbar enlargement
nerves of pelvis & lower limbs
what is conus medullaris
termination of spinal cord, cone like [finish this]
what is filum terminale
fibrous tissue (ligament) that runs down from conus medullaris to coccygeal ligament.
it’s like a bungee cord because it stops the vertical movement of the spinal cord off the coccyx
what is cauda equina
looks like a horse’s tail, nerve roots extending below conus medullaris
what is a collection of axons in CNS
tract
what is a nerve
collection of axons in PNS
what is the name for a collection of cell bodies in the CNS
nucleus (not the nucleus within a cell)
what is ganglia
collection of cell bodies in the peripheral nervous system
where do dorsal and ventral roots exit between successive vertebrae
through intervertebral foramen
explain the naming of the spinal nerves & numbers
31 spinal nerves
cervical region: 7, get their name from vertebrae caudal to them
thoracic region: get their name from the rostral vertebrae e.g. t1 below vertebrae t1, t2 below vertebrae t2
why are there 8 cervical nerves when there are only 7 cervical vertebrae
there is a nerve between c7 & t1 hence c8 because they get their names from the vertebrae caudal to them
what is a tract, and what are the names of 4 tracts
HONDA CRVS
C = CORTICO
R = RUBRO
V = VESTI
S = SPINO
- corticospinal
- spinothalamic
- rubrospinal
- vestibulospinal
what is in the PNS
- nerves: cranial & spinal (12 & 31)
- enteric plexuses in small intestine
- plexus = nerves that come together & form network
- ganglion
- sensory receptors in the skin
what are cranial nevers
nerves that exit from the brain stem (they are peripheral).
diagram for branches of the nervous system
what are the branches of the spinal nerves
ventral root = contains axons of motor neurons
dorsal root = contains axons of sensory neurons
how do axons get their energy supply / oxygen
axons can’t store enegry so they recieve it from the large blood vessels (arteries) that serve the brain
how do axons get their energy supply / oxygen
axons can’t store enegry so they recieve it from the large blood vessels (arteries) that serve the brain
define nerve, and it’s more specific name
bundles of axons with connective tissues & blood vessels, aka peripheral nerves. they carry sensory information & motor commands in the pns
what are the functional divisions of the PNS
afferent = carries sensory info from PNS to CNS
efferent = carries motor commands from CNS to muscles & glands
what is the difference between an effector & a receptor
receptor = detects changes in environment, complex sensory organs e.g. ears & eyes, neurons & specialised cells
effector = responds to efferent signals, cells & organs
what is SNS and it’s functions
controls skeletal muscle contractions (voluntary & involuntary i.e. reflexes, not autonomic because it has a stimulus)
what is the motor division of the PNS
ANS = autonomic nervous system
contains visceral motor neurons that carry info from CNS to all other peripheral receptors e.g. glands, skin, muscle
what are the 3 ANS divisions
sympathetic = fight or flight, from thoracic & lumbar SpC (thoracolumbar)
T1 –> L2
increase heart rate, respiratory rate
parasympathetic = rest or digest from cranial nerves and sacral SpC (carniosacral)
C1 –> S4
enteric nervous system =
explain the role of the ganglia in the autonomic nervous system [EXAM Q]
there are pre and post ganglionic fibres
the pre fibres are short, while the post are very long in the sympathetic nervous system so they can travel all the way to the organ
in the parasympathetic, the pre ganglionic fibres are very long, while the post are very short
when neurons exchange info and the membranes fuse together are the synaptic vesicles released?
no, only the neurotransmitters are released
how are nerve pain signals blocked
administering a small amount of anaesthetic
what are dermatomes
bilateral region of skin monitored by specific pair of spinal nerves
what is the diff. between pre & post synaptic cells
pre = neuron bringing information
post = neuron receiving information
synapse = point of info. exchange
what is the synaptic cleft
the gap between two synaptic membranes where the neurotransmitters are released, and then bind to receptors on the post synaptic cells. if they don’t bind the information won’t be received.
it also contains enzymes to break down the neurotransmitter
what are the features of neurotransmitters
- chemical messengers
- released at presynaptic membrane
- affect receptors at postsynaptic membrane
- broken down by enzymes
- reassembled at synaptic knob
what is an anaxonic neuron
can’t tell where the axon is, can only see cell body
what is a bipolar neuron
two poles from body, seen in retina
what is a unipolar neuron
sensory neurons in dorsal root ganglia, only one pole
what is a multipolar neuron
2+ processes, single axon, multiple dendrites
what are the 3 functional classifications of neurons
sensory, motor, inter
inter = ability to stop information from travelling to motor
what are the functions of sensory neurons
afferent neurons of the PNS i.e. they bring info into the CNS
what are the types of sensory receptors
based on stimulus:
- inter
- exter
- proprio = postition & movement of muscles & joints
what are afferent fibrres
sensory & ascending pathways
what are efferent fibres
motor & descending pathways
what are the functions & types of neuroglia
CNS = astrocytes = regulate substances that reach CNS from blood e.g. blood brain barrier
they also regulate inflammatory processes by wrapping themselves around blood vessels
CNS = ependymal cells = cerebrospinal fluid
CNS = microglia = clean up debris, waste, pathogens
CNS = oligodendrocytes = myelinate axons of CNS neurons
what is the choroid plexus
a collection of ependymal cells (CNS) that secrete cerebrospinal fluid
what are ependymal cells
cell that lines the brains ventricles (holes) to take blood vessels and squeeze out blood to make cerebrospinal fluid
what are microglia
type of neuroglia that cleans up cellular debris. the only cell that can move in the nervous system.
their chemicals can impede the regeneration of axons
what are oligodendrocytes
type of neuroglia that myelinate CNS axons
one can myleinate multiple axons
explain nodes vs internodes
internodes are myelinated segments of an axon
nodes are the gaps between internodes for conduction of messages between the neuron
what are schwann cells
cells that myelinate axons in the PNS. only myelinates one segment of one axon
name the ventricular system of the brain
picture
name the ventricular system of the brain
picture
95% of sensory information is filtered by the?
thalamus. if it let this information through it would result in information overload
what are basal nuclei, their functions & input/outputs
4 subcortical nuclei the sequence movement (don’t start or stop)
the death of a basal nuclei results in parkinson’s disease, huntington’s, some forms of cerebral paulsy
input = cortex
output = via thalamus to prefrontal, premotor & motor cortex
what is the limbic system
a functional grouping of:
- emotional states
- linking of conscious functions of cerebral cortex with autonomic functions of brain stem
- memory storage & retrieval
what are the components of the limbic system
amygdaloid body
limbic lobe
fornix
anterior nucleus
reticular formation
hypothalamus
what is unique about the brain from a coronal or horizontal view of the brain
are neurons mytotic
no
why do we lose neurons
we don’t use all of them, so they are discarded ~ 18 months
what is an axon
conducting region of a neuron
only one per neuron
how many body systems do we have
10, 11 with the integument
what body system communicates with all other systems
nervous system
what organelles are in neurons & what is the function of each
mitochondria: respiration & energy production
rough endoplasmic reticulum: synthesises lipids to create proteins
golgi apparatus: modifies and sorts proteins & lipids made in the endoplasmic reticulum –> looks like a stack of pancakes
what is exocytosis
release of proteins from the cell membrane
what is synapse
when one neuron communicates with another neuron
what is the purpose of dendrites & dendritic spines
dendrites are for synapse with other neurons & dendritic spines increase the surface area for communication
what are synaptic terminals
knobs that secrete neurotransmitter chemical
why are there grooves and bumps in the brain
they increase surface area to store all the neurons
groves = sulcus
bumps = gyrus
where is the central sulcus
top of the brain from a lateral view
what is a fissure
point where you can separate two parts e.g. the lateral fissure to separate both parts of the brain
what is corticospinal
tract from cortex to spinal cord
what is spinothalamic
tract from spinal cord to thalamus
label the thoracic cross-section of the spinal cord
in the spinal cord, where are the somatic motor neurons
anterior
in the spinal cord, where are the autonomic motor neurons
lateral
what is contained within the spinal nerve
sensory neurons, autonomic neurons & somatic motor neurons
what is the dorsal root innervated by [& LABEL DIAGRAM]
sensory neuron
what is the ventral root innervated by [& LABEL DIAGRAM]
autonomic & somatic motor neuron
what are (spinal) meninges & their layers
meninges surround the spine & brain continuously
they are forms of connective tissue
pathologies = meningitis
3 layers:
outer = dura mater = toughest
middle = arachnoid mater = spider web like network
inner, stuck and has to be peeled = pia mater
what are denticulate ligaments
ligaments that look like teeth holding the spinal cord in place laterally
what is the subdural space?
space between dura mater and arachanoid mater
explain the importance of interneurons
most are located in brain, spinal cord & autonomic ganglia
they are responsible for distribution of sensory information (if it should be distributed) and coordination of motor activity
they are also involved in higher functions such as memory, planning & learning
what is the name for gaps between axons myelinated by Schwann cells, and the purpose of these gaps
nodes of Ranvier
regulate the speed at which the signal can travel down an axon (action potential)
what is the normal colour of cerebrospinal fluid
clear, cloudy indicates bacterial meningitis
where is a lumbar puncture and where is it taken
extraction of cerebral fluid, taken from L3-L4 to avoid the spinal cord
what does cerebrospinal fluid look like in an MRI
white
what is the purpose of cerebrospinal fluid and what is it’s process of flowing through ventricles
cushions the brain & spinal cord & provides nutrients
flows from lateral ventricles
what would happen if there was a block in the inter-ventricular foramen?
it’s an emergency and will cause a build up in the lateral ventricle. can cause permanent damage
[EXAM Q]
is it true that the limbic system links conscious functions of the cerebral cortex with autonomic functions of the brain stem
true e.g. the voice example from holsinger
what does the amygdaloid body in the limbic system do
interfaces limbic system with cerebrum & sensory systems
where do the releasing factors of the hypothalamus go
the pituitary gland
what is reticular formation
stimulation or inhibition affects emotions
what is the function of the hypothalamus
controlling functions such as hunger, thirst, emotions, body, temperature etc
what does the fornix do
links the hippocampus to the hypothalamus
what does the hippocampus do
consolidates information from short term to long term memory e.g. associated with dementia & alzheimers
what is the purpose of the superior colliculs
preliminary visual processing & control of eye movements
what is the purpose of the inferior colliculs
auditory processing
does the tegmentum run from the mid brain to the medulla
yes
why is substantia nigra black
pigmented grey matter
what are cranial nerves 1 & 2 myelinated by that is different from the other 10 nerves
they’re myelinated by oligodendrocytes while the others are myelinated by Schwann cells
[EXAM Q] what is the purpose of cerebral peduncles vs cerebella penduncles
The cerebral peduncle of midbrain connects the cerebrum with the brainstem (mainly, pons), while the cerebellar peduncle connects the cerebellum with the brainstem (mainly, pons)
The main function of the cerebral peduncle is to transfer motor signals from the brain down to the brainstem.
The cerebellar peduncles contain the afferent and efferent tracts of the cerebellum. The inferior cerebellar peduncle contains four afferent tracts (posterior spinocerebellar, vestibulocerebellar, olivocerebellar and reticulocerebellar) and one efferent tract (the cerebellovestibular tract). The middle cerebellar peduncle is the largest and contains only afferent fibres from the pontine nucleus. This pontocerebellar tract provides an important connection between the cerebral cortex and cerebellum and modulates skilled activities of hands and fingers. The superior cerebellar peduncle contains one afferent, anterior cerebellar tract and one efferent tract from the cerebellar nuclei to the red nucleus, thalamus and medulla.
[EQ] what do the pons link
linke cerebellum with mesencephalon, diencephalon, cerebrum & spinal cord
[EQ] what do the descending tracts do
carry motor commands from higher centres to nuclei of cranial/ spinal nerves
[EQ] what do the ascending tracts do
carry sensory info from the brain stem nuclei to the thalamus
[EQ] what do the transverse fibres do
interconnect cerebellar hemispheres
[EQ] what do the apneustic & pneumotaxic centres do
adjust activities of the respiratory rhythmicity centres in the medulla oblongata
[EQ] what do the cranial nerve nuclei do, and what nerves are they
V, VI, VII, VIII (part)
relay sensory info & somatic motor commands
[EQ] what do other nuclei/relay centres in the grey matter do
relay sensory & motor info to the cerebellum
what does the medullary reticular formation contain
cell groups that influence hr and respiration
what does a leison in the right pons cause
and what does a leison in the left pons cause
what happens if it’s on the spinal cord
motor weakness on the lhs of the body
left pons affects rhs of the body
then it’ll be on the same side (ipsilateral), but in the brain stem or brain they’ll be contralateral
how many pairs of spinal and cranial nerves
31/12
what are the classes of cranial nerves
sensory, special sensory, motor, mixed (like spinal they have sensory & motor)
what is another name for the posterior column pathway and what does it do
dorsal column
carries sensations of fine touch, pressure, vibration & proprioception
what information synapses at fasciculus gracilis and where do the neurons go
sensations from inferior half (below T6)
synapse on second order neurons which go to opposite side of spinal cord (left) to the thalamus
then they synapse on 3rd order neurons that carry information to the sensory cortex
what info synapses at fasciculus cuneatus
superior half sensations (T6+)
what does the anterolateral pathway do & what are the paths of it’s neurons
provides conscious sensations of poorly localised crude touch, pressure, pain, temperature
1st, 2nd 3rd order
1st synapse immediately and crossover immediately, then travelling to thalamus, seperate pain and temp neurons
considering the posterior column pathway and the lateral spinothalamic tract, what would happen if there was a leison on the RHS of the spinal cord
fine touch would be lost because the 1st order neurons in the posterior column pathway travel a while up the rhs before synapsing, whereas crude temperature & pain will still be felt because the neuros in the lateral spinothalamic tract cross over to the lhs immediately and synapse immediately. but pain and temp from the lhs will not get through
what is the diff in neuron numbers for the ascending and descending systems
ascending = 3 neuron system
descending = 2 neuron system
is the cerebellum an automatic or autonomic processing centre
automatic
what is ataxia
cerebellum
damage from trauma or stroke, temporary disturbance from intoxication, disturbs muscle coordination
lack of coordination in muscle movements
what is dysmetria
cerebellum
loss of ability to gauge distance, speed, power of movement resulting in over/undershooting
what is decomposition of movement
cerebellum
disturbs fluidity of movement
how much time of lost blood flow results in irreversible neuronal damage
how long for neurological symptoms
2.5-3 minutes (neurons are post mytotic & don’t divide)
20 sec
what are the main arterial blood supplies
ica = internal carotid artery = forebrain
ba = vertebral artery = occipital, brain stem, cerebellum
what is the path from the aorta to ICA
aorta –> common carotid –> internal carotid (for brain) & external carotid at about C4 –> branches
branches = hypophyseal, ophthalmic, anterior choroidal artery, posterior communicating artery
what is the path from the aorta to the VA
aorta –> subclavian –> vertebral
what vertebrae have the transverse foramen for arterial blood supply
cervical vertebrae 1 - 6
what is the circle of willis
what are cerebrovascular accidents
strokes = blood loss from the brain
what causes strokes/ cerebrovascular accidents
ischemia
arterial embolism
hemmorrhage
how do strokes occur
suddenly or in a step wise manner e.g. mini stroke via ischemia, resolves by itself, <24hrs, but indicative of a larger stroke
