neuro extra Flashcards
Which nerve innervates the posterior 1/3 of the tongue for taste?
Glossopharyngeal nerve (IX)
which tract does motor
corticospinal
which tract is pain and temp
spinothalamic
which tract doesFINE TOUCH, VIBRATION,
PROPRIOCEPTION, 2-POINT
DISCRIMINATION
DCML
4 folds of dura mater
Falx cerebri
Falx cerebelli
Tentorium cerebelli
Diaphragma sellae
effects of UMN lesions
Hypertonia/spasticity
Hyperreflexia
+ve Babinski sign (plantar upgoing)
Pyramidal weakness (flexors > extensors in UL)
Ankle clonus
effects of LMN lesions
Hypotonia
Hyporeflexia
Muscle fasciculations (small involuntary twitching)
Muscle atrophy
A stroke of the right posterior cerebral artery would result in which visual defect?
Left homonymous hemianopia with macular sparing
what nerve is affected in wrist drop
radial
Which spinal tract transfers information regarding perception of self-movement and
body position of our lower limbs to the medulla oblongata?
Fasciculus Gracilis - DCML
What is the function of the Pia Mater and what cell type aids with this function?
Forms the blood brain barrier; Astrocytes
What is the resting membrane potential of a neuron?
-70mv
What is the definition of temporal summation?
Occurs when multiple subthreshold excitatory postsynaptic potentials (EPSPs) from one neuron
occur close enough in time to combine and trigger an action potential at the axon hillock (one to
one)
what is a motor unit
A single alpha motor neuron + all the muscle fibres it innervates
What is the definition of a muscle fasciculus?
A bundle of several muscle fibres
what is a muscle fibre
A thread-like structure of myofibrils
what is a myofibril
A basic unit of muscle containing actin and myosin filaments
what is a sarcomere
The functional unit of striated muscle
Which nerve type innervates intrafusal muscle fibres?
gamma motor neurones
Which cranial nerve is the afferent nerve of the carotid sinus?
glossopharyngeal
which part of ascending tracts control uppper and lower limb movements and where do they synapse rescpectively
fasciculus cunneatus = upper limb 1st order synapse in nucleus cunneatus
fasciculus gracilis = lowwer limb 1st order synapse in nucleus gracilis
2nd order synapse in thalamus
3rd orser travel to sensory cortex
what part of brain is associated with awareness of pain
prefrontal cortex
function of lentiform nucleus
putamen and globus pallidus - controlling voluntary movements and involved in memory
what occurs in damage to left meyers loop
contralateral homonymous superior quadrantanopia - upper right quadrant of both eyes
what CN is responsible for pupil reflex
3
what descending tract is responsible for fine control of hand movement
rubrospinal
what losses would one suffer with brown sequard syndrome
contralateral loss of pain crude touch pain and temp 1-2 lvls below lesion (spinothalamic)
ipsilateral hemiparesis and loss of of fine touch, vibration and propioception below lesion (DCML)
where does 1st order neuron of spinothalamic tract synapse in CNS
substantia gelatinosa of relaxed laminae
what % of corticospinal tract decussate forming contralateral lateral corticospinal tract
85
what muscle does trochlear innervate
superior oblique
what is efferent nerve of corneal reflex and what muscle is responsible
facial and orbicularis occuli
where does dcml decussate
medulla oblongata
where does spinothalamic tract decussate
spinal cord
posterior cerebellar tracts function
proprioceptive info from lower limbs to ipsilateral cerebellum
anterior cerebellar tract functiom
proprioceptive info from upper limbs to ipsilateral cerebellum (decussate twice)
the base of the basilar membrane is more sensitive to what freq of sound
high
what is scala media filled with
endolymph
what CN does general sensation for anterior 2/3 tongue
mandibular branch of trigerminal ( through foramen ovale)
where does corticospinal tracts decussate
medulla
where in trilaminar disc is CNS formed
ectoderm
Via which cranial nerve do afferent impulses from the carotid sinus baroreceptors reach the CNS?
glossopharyngeal
Which of the following nerves supplies sensory innervation to the frontal sinus?
Ophthalmic division of the trigeminal nerve (CN V1)
Via which of the following foramina does the nerve that carries sensory afferents from the forehead traverse the cranium
opthalmic division of trigerminal through superior orbital fissure
Stapedius and tensor tympani function
stiffen the ossicular chain to protect against loud noises. Stapedius is innervated by the facial nerve (VII) and tensor tympani is innervated by a branch of the mandibular nerve (V2).
where is primary auditory cortex located
In the superior temporal gyrus of the temporal lobe just inferior to the lateral sulcus
layers of dura mater
outer endosteal, inner meningeal
foramen luschka
where csf exits 4th ventricle
foramen magendie
medial of lushka
Foramen of Monro
another name for the interventricular foramen linking the lateral ventricles to the third ventricle.
Oligodendrocytes function
myelinating cells of the CNS
Briefly explain the process of neurotransmitter release across the synapse, starting from the action potential arriving at the presynaptic neuron
Calcium ion channels open when an action potential reaches the pre-synaptic terminal (1)
- Ca2+ ions cause vesicles containing neurotransmitter to fuse with the membrane and release their contents (1)
- Neurotransmitter diffuses across the synaptic cleft and attaches to receptor sites on the post-synaptic membrane
Which artery does the middle meningeal artery usually directly arise from?
Maxillary artery
describes the anatomical region called the
asterion
Where the temporal, parietal and occipital bones meet
what passes through cavernous sinus
Oculomotor nerve
Trochlear nerve
Internal carotid artery
Abducens nerve
branches 1 and 2 of trigerminal nerve
Which artery typically supplies Broca’s area?
Left middle cerebral artery
What is an important differential diagnosis of Bell’s palsy?
stroke
Vagus nerve lesions can often result in a hoarse voice. This arises as a result of damage to
which branch of the Vagus?
recurrent laryngeal
is GABA inhibitory or exitatory
inhibitory (glutamate exitatory)
What is the function of the hippocampus?
short-term memory to long-term memory.
amygdala function
produces feelings of anger and fear.
thalamus function
relay station for sensory inputs.
hypothalamus function
regulates the autonomic nervous system.
A patient comes to the acute neurology ward with a suspected lesion of the CN IV.
What would you expect to find on examination?
a defective downward gaze and vertical diplopia,
how does CSF drain into subdural space
via arachnoid granulations, which are projections of arachnoid mater into the
subdural space.
What type of neurons are found in the substantia nigra?
Dopaminergic
In the rostral lower regions of the brain, you may find a blue pigmented area which
has many serotonergic neurons. What is this location known as?
locus coeruleus
On a visual field test, you note a left homonymous hemianopia. Where is the visual
pathway lesioned?
right
Which vein do all dural venous sinuses drain into?
internal jugular vein
where are dopamine receptors
pars compacta in sub nig
Pyramidal tracts function
These tracts originate in the cerebral cortex, carrying motor fibres to the spinal cord and brain stem. They are responsible for the voluntary control of the musculature of the body and face.
extrapyrimidal tracts function
These tracts originate in the brain stem, carrying motor fibres to the spinal cord. They are responsible for the involuntary and automatic control of all musculature, such as muscle tone, balance, posture and locomotion
do descending tracts synapse
no they synapse with LMN so all are classed as upper motor neurons
medullary pyrimidal tracts function
These pathways are responsible for the voluntary control of the musculature of the body and face.
Corticospinal tracts – supplies the musculature of the body.
Corticobulbar tracts – supplies the musculature of the head and neck.
where does corticospinal split
caudal medulla
where does corticospinal synapse with LMN
ventral horn in medulla
where does corticobulbar originate
lateral aspect of the primary motor cortex
where do corticobulbar terminate and synapse with LMN
motor nuclei of the cranial nerves.
extrapyrimidal tract function
originate in the brainstem, carrying motor fibres to the spinal cord. They are responsible for the involuntary and automatic control of all musculature, such as muscle tone, balance, posture and locomotion.
Vestibulospinal Tracts facts
They arise from the vestibular nuclei, which receive input from the organs of balance. The tracts convey this balance information to the spinal cord, where it remains ipsilateral.
Fibres in this pathway control balance and posture by innervating the ‘anti-gravity’ muscles (flexors of the arm, and extensors of the leg), via lower motor neurones.
reticulospinal facts
The medial reticulospinal tract arises from the pons. It facilitates voluntary movements, and increases muscle tone.
The lateral reticulospinal tract arises from the medulla. It inhibits voluntary movements, and reduces muscle tone.
rubrospinal facts
The rubrospinal tract originates from the red nucleus, a midbrain structure. As the fibres emerge, they decussate and descend into the spinal cord. Thus, they have a contralateral innervation.
Its exact function is unclear, but it is thought to play a role in the fine control of hand movements
How does the visual pathway from the temporal and nasal retina differ?
Nasal fibres decussate (0.5 marks) at the optic chiasm (0.5 marks) to pass to the opposite cortex, temporal fibres pass to cortex of the same side (0.5 marks)
Where do nerve fibres synapse on their path from the retina to the cortex?
lateral geniculate body
Which two nerves carry the impulses of the pupil reflex?
CN2 and 3
tectospinal facts
This pathway begins at the superior colliculus of the midbrain. The superior colliculus is a structure that receives input from the optic nerves. The neurones then quickly decussate, and enter the spinal cord. They terminate at the cervical levels of the spinal cord.
The tectospinal tract coordinates movements of the head in relation to vision stimuli.
Which type of
communication involves chemical messengers between cells, which are released into
the extracellular fluid and travel short distances, such as at neuromuscular
junctions?
paracrine
What are the largest and most numerous glial cells found in the central nervous
system?
astrocytes
The three primary brain vesicles found in the early embryo are the prosencephalon, mesencephalon and the rhombencephalon. By which week of embryonic development can these three vesicles be identified?
5
The inner eye is made up of three layers of tear film. What is the most posterior
(outermost) layer and what type of cell or gland secretes this?
mucous layer by goblet cells
describes a
loss of vision in his temporal visual fields (bitemporal hemianopia). What is the most
likely site of damage?
optic chasm
Which nerve provides both the motor and sensory innervation to the larynx?
vagus
What triad of
symptoms is seen in Horner’s syndrome?
Ipsilateral ptosis, miosis & anhidrosis
