Neuro Flashcards
What is meant by neocortex?
A cerebral cortex with 6 layers of grey matter
Give the 4 main subdivisions of the brain
Cerebrum
Diencephalon
Brainstem
Cerebellum
What is meant my gyrus?
Ridge
What is meant by sulcus?
Groove
What are the functions of the frontal lobe?
Personality Behaviour Movements (motor cortex) Planning (pre-motor cortex) Emotion *Broca's area (dominant hemisphere)
What are the functions of the parietal lobes?
Body sense and position (somatosensory cortex)
Calculations
Reading and writing
Object and space perception
What are the functions of the temporal lobe?
Auditory cortex
Memory
*Wernickes area (dominant hemisphere)
What is the function of the occipital lobe?
Visual processing
What are the function of the insular cortex?
Emotion, self-awarness
What are the functions of the limbic system?
Emotion, memory, olfaction, behavior
Name 3 parts of the diencephalon
Thalamus
Hypothalamus
Pineal gland
What is the function of the thalamus?
Processes and relays sensory information
What is the function of the hypothalamus?
Homeostatic regulation
What structure is the pineal gland apart of? And what is its function?
Epithalamus
Circadian regulation
What are the 3 components of the hindbrain?
Pons
Medulla oblongata
Cerebellum
Where is Broca’s area located?
Frontal lobe of the dominant hemisphere
What is the role of Broca’s area?
Speech production - Constructive aphasia
In which Brodmann’s area is Broca’s area found?
44 (45)
In which lobe is Wernicke’s area located?
Temporal lobe of the dominant hemisphere
What is the role of Wernicke’s area?
Speech comprehension - receptive aphasia (can say words fluently but lack meaning)
In which Brodmann’s area is Wernickes area located?
22
What is the tectum?
The dorsal aspect of the midbrain, made up of the superior and inferior colliculi (aka corpra quadrigemina)
Where are the mamillary bodies found?
Ventral aspect of the midbrain
Where are the red nuclei and substantia nigra located
Midrain (ventral portion)
What is the ventral portion of the midbrain?
Cerebral peduncles and tegmentum
What is the obex?
Inferior aspect of the IV ventricle
What is the tentorium cerebelli?
Fold of dura mater over lying the cerebellum (tent like)
What are the functions of the cerebellum?
Co-ordination of voluntary movements
Balance and equilibrium
Posture/muscle tone
(learning)
Where in the skull does the cerebellum lie?
Posterior cranial fossa
What is the falx cerebelli?
Fold of dura which projects in between the two cerebellar hemispheres
What are folia? (of the cerebellum)
Ridges
What are the main concerns of the flocculonodular lobe?
Vestibular information/balance
Vision
?Smell
Give the signs of cerebellar dysfunction (DANISH)
Dysdiadochokinesia (unable to perform rapid alternating movements)
Ataxia (uncontrolled movements/lack of balance)
Nystagmus (uncontrolled eye movements)
Intention tremor (increases as approach object)
Slurred speech
Hypotonia
Give the three layers of the cerebellar cortex
Molecular
Purkinje
Granular
Where does the cerebellum receive inputs from? And via what type of fibres?
Cerebral cortex (mossy fibres) Brainstem nuclei and sensory receptors (climbing fibres)
What is the output of the cerebellum? And what is its journey?
Purkinje fibres
To dentate nucleus (deep w/i cerebellum), then to red nucleus and thalamus. Info then sent from thalamus to cerebral cortex
True or false the (dorsal) spinocerebellar tract remains ipsilateral
True
How many neurones are involved in the spinocerebellar tract?
2
What information does the spinocerebellar tract carry?
Unconcious proprioception
Where does the (dorsal) spinocerebellar tract enter the cerebellum?
Inferior cerebellar peduncles
What does the telencephalon refer to?
The cerebral hemispheres
What gives rise to the forebrain?
Prosencephalon
What does the rhombencephalon give rise to?`
The hindbrain
Name the two parts of the forebrain
Cerebrum (telencephalon)
Diencephalon
What does the mesencephalon give rise to?
Midbrain
What is the metencephalon part of? And what does it give rise to?
Rhombencephalon
- Pons
- Cerebellum
What is the myelencephalon part of? And what does it give rise to?
Rhombencephalon
-Medulla oblongata
From which germ layer is the CNS derived?
Ectoderm
What is the name given to the dorsal portion of the neural tube?
Alar plate
From which part of the neural tube is the diencephalon derived?
Basal plate (ventral aspect)
True or false the telencephalon is derived from the alar plate of the neural tube?
True
Folding of the rhombencephalon gives rise to what structure?
IV ventricle
Where is the III ventricle found?
Diencephalon
Dilation of the neural tube within the telencephalon gives rise to what?
Lateral ventricles
How are the choroid plexi of the ventricles formed?
Invaginations of capillary tufts from the prosencephalon (lateral and III) and rhombencephalon (IV)
What is the role of choroid plexus?
Secrete CSF
Name the basal ganglia
Caudate nucleus Putamen Globus pallidus (internal and external) Subthalamic nucleus Substantia nigra
Which basal ganglia make up the lentiform nucleus?
Globus pallidus and putamen
Together the caudate nucleus and the putamen make up what?
Striatum
Which of the basal ganglia are affected during Parkinson’s disease?
Substantia nigra
Parkinson’s disease is associated which too or too little dopamine?
Too little
What are the symptoms of Parkinson’s disease?
Tremor
Rigidity (increased muscle tone)
Bradykinesia (reduced/slow movements)
What are the symptoms of Huntington’s disease?
Chorea (twitching) Overshooting movements Decreased muscle tone Dementia Personality changes
Which part of the basal ganglia does Huntington’s disease affect?
Striatum
What is the treatment for Huntington’s disease?
Dopamine receptor blockers
What is the result of increased stimulation of the subthalamic nucleus?
Increased inhibition of the thalamus, decreased output back to the cerebral cortex
Describe the different states of the Striatum, Globus Pallidus and Thalamus when the body it not moving (at rest)
Striatum - inactive
GP - active
Thalamus - inactive
To which regions of the cerebral cortex does the thalamus relay the outputs of the basal ganglia?
Pre-frontal cortex, pre-motor cortex and primary motor cortex
As well as the coordination of voluntary movements what else is the basal ganglia involved with?
Cognition, behaviour, decision making
True or false the rostral basal ganglia are excitory
False, the rostral basal ganglia consist of the striatum and globus pallidus which are inhibitory
What neurotransmitter is released from the striatum?
GABA
Is GABA an excitatory or inhibitory neurotransmitter?
Inhibitory
Define what is meant by a motor unit
A single motor neurone and all the muscle fibres it innervates
Why can’t action potentials propagate directly from neural to muscular tissue?
Because neural and muscular tissues are structurally and physiologically different
What are the 5 key processes in synapses
Manufacture Storage Release Interaction with post-synaptic receptors Inactivation
What type of neurotransmitter is glutamate?
Excitatory
What neurotransmitter is used at neuromuscular junctions?
ACh
How is it the middle ear is maintained at atmospheric pressure?
It it connected to the pharynx by the eustachian tube (auditory tube) which opens during to yawning, swallowing and sneezing
True or false the middle ear is fluid filled
False, it is the inner ear that is fluid filled
Name the 3 ossicles of the middle ear in order moving towards the inner ear
Malleus
Incus
Stapes
What fluid fills the cochlear duct?
Endolymph
Describe the concentrations of potassium and sodium in endolymph
High concentration of potassium
Low concentration of sodium
(This is atypical of ECF)
What fluid fills the scala tympani and scala vestibuli?
Perilymph
Which of the scala tympani and scala vestibuli lies above the cochlear duct
Scala vestibuli
What is the helicotrema of the cochlear
The end of the cochlear, where scala tympani and scala vestibuli are continuous
What does the amplitude of a sound wave indicate?
Loudness
What does the frequency of a sound wave indicate?
Pitch
At the membrane of which window does the stapes attach?
Oval window
What is the role of the stereocilia of the inner hair cells?
Transduce waves of endolymph into receptor potentials
How many layers of inner hair cells are there at the organ of Corti?
1
How many layers of outer hair cells are there at the organ of Corti?
3
What happens in the ear in order to protect it from damage due to loud continuous sound?
Contraction of the tensor tympani (attached to malleus) and stapedius (attached to stapes). This results in the dampening of bone movement and therefore reduces conduction of vibrations
Also efferent nerve fibres from brainstem regulate the activity of outer hair cells
What is temporary hearing loss caused by?
Damage to stereocilia (stereocilla can regenerate)
What is permanent hearing loss caused by?
Death of hair cells
The middle ear, cochlear and vestibular apparatus are all found in which bone of the skull?
Temporal bone
Which part of the basilar membrane has the greatest response to high pitched tones?
The part nearest the middle ear. There membrane here is narrower and more stiff and so vibrates more easily
Describe the auditory pathway from the vestibulocochlear nerve to the cotex
Cochlear nucleus (ventral) Superior olive Inferior colliculus Medial geniculate nucleus (thalamus) Auditory cortex (temporal lobe)
What do the semicircular canals detect?
Angular acceleration and rotation
What does the utricle detect?
Horizontal acceleration
What does the saccule detect?
Vertical acceleration
The frequency of action potentials generated in the vestibulocochlear nerve from the semicircular canals indicate what?
The force and direction of rotational movement
Give 3 uses of vestibular information
Control of eye movements
Balance
Proprioception
Where is the vestibular centre located?
Parietal lobe
What is meant by chronic pain?
Pain lasting for more than 12 weeks (or longer than expected e.g. surgery)
Give the two different types of pain
Nociceptive
Neuropathic
Define pain
An unpleasant sensory or emotional experience associated with either actual or potential tissue damage
Define nociceptive pain
Pain cause by actual or threatened damaged to non-neural tissue and is due to the activation of nocioceptors
Define neuropathic pain
Pain caused by a primary lesion or dysfunction of the nervous system/ somato-sensory cortex
What are the two types of nociceptor? And what afferent fibres are each associated with?
Mechanoreceptors e.g. meissener’s/pacinian corpuscles - A-delta fibres
Polymodal receptors e.g. thermo/chemo - C fibres
Describe A-delta fibres and their transmission of pain stimuli
Myelinated
Fast
Sharp pain
Well localised
Describe C fibres and their transmission of pain stimuli
Unmyelinated
Slow
Dull
Poorly localised pain
Name the neurotransmitters released by the A-detla/C-fibre afferent neurones. What type of potential do theses substances generate
Substance P and glutamate
Excitatory post-synaptic stimuli
What is hyperanalgesia? And how does it occur?
Increased sensitivity to pain stimuli. Substances released from damaged tissue e.g. histamine lower the nociceptive threshold
How do descending pathways reduce the effects of painful stimuli?
Release opoids that inhibit synaptic transmission between the primary and secondary afferent neurones of the ascending/spinothalamic tract
Where does decussation of the spinothalamic tract occur?
1 or 2 levels above the spinal segment at which it enters
Give the Brodmann areas of the somatosensory cortex
3, 1, 2
In terms of pain what is the role of the somato-sensory cortex?
Localisation and discrimination of pain
In terms of pain what is the role of the insular cortex?
Detects the degree of pain
In terms of pain what is the effect of stimulating the periaqueductal grey (PAG)? And what receptors are found here?
Analgesic effect
Opoid receptors
Give an example on non-pharmacological treatment of pain
Accupuncture
CBT
Physio/massage
True or false some antibiotics can damage the stereocillia of hair cells
True
What is meant by a portal vein system?
Veins leading from one capillary bed to another
Define a hormone
A signalling molecule secreted by specialised endocrine tissue
Where does the DCML tract synapse
1) Gracile(lower limb)/Cuneate (upper limb) nuclei
2) Ventral posterolateral nucleus of the thalamus
Where does the DCML decussate?
Medulla
What does the DCML carry?
Fine touch, proprioception and vibration
Give 3 signs of someone w/ a lesion of their DCML tract
Wide gait
Downward gaze
Stamping action
What sensory information does the spinothalamic tract carry?
Pain, temperature and crude touch
In which part of the spinothalamic tract are pain and temperature carried?
Lateral
In which part of the spinothalamic tract is crude touch carried by?
Anterior
Where does the spinothalamic tract decussate?
1-2 levels above where it enters the spinal cord
How many neurones are involved in the corticospinal tract?
2
Which part of the body does the anterior corticospinal tract carry fibres from and where does it decussate?
Axial skeleton
At the level (anterior white commissure)
Which part of the body does the lateral corticospinal tract carry fibres from and where does it decussate?
Limbs
Medulla
What does the corticospinal tract carry?
Motor (voluntary)
What is the function of the dural venous sinuses?
Drain cerebral veins -> internal jugular veins (-> SCA ->SVC)
What structures are located w/i the carvernous sinus?
CN III, IV, V(1), V(2), VI and the internal carotid artery
Name the lateral foramen of the IVth ventrical
Foramina of Luschka
Name the medial foramen of the IVth ventrical
Foramen of Magendie
Name the foramen connecting the lateral ventricles to the 3rd ventricle
Interventricular foramen (of Monroe)
Describe the main differences between the somatic and autonomic nervous system
Somatic nervous system
- innervates skeletal muscle (voluntary movements)
- always excitatory
- single neurone between CNS and effector(upper and lower motor neurone)
Autonomic nervous system
- innervates smooth muscle, cardiac muscle, abdominal viscera and glands (involuntary responses)
- can be either excitatory or inhibitory
- two neurone chain between CNS and effector (pre-ganglionic and post-ganglionic neurone)
Give the sympathetic outflow
T1-L2 (later horns of the grey matter)
Give the parasympathetic outflow
CN 3, 7, 9, 10
S 2, 3, 4
What venous sinus does the great cerebral vein drain into?
Straight sinus
Where does the straight sinus lie?
Midline of tentorium cerebelli
Which cerebral veins to the venous sinuses drain? Internal or external?
External (deep and superficial) (internal cerebral veins drain in to the external cerebral veins)
Where do the venous sinuses drain into?
Internal jugular vein > subclavian > SVC
Where are the superior and inferior sagittal sinuses found?
Superior and inferior borders of the falx cerebri, respectively
Where does the transverse sinus lie?
In the posterior fix margin of the tentorium cerebelli
Which cerebral artery supplies Broca’s area?
Middle
Which cerebral artery supplies Wernicke’s area?
Middle
How is CSF reabsorbed?
By the arachnoid villi/granulations in the dural venous sinuses
In which lobe is the hipppcampus located?
Temporal
In which lobe is the amygdala located?
Temporal
What is the blood supply to the corpus callosum?
Anterior cerebral artery
What bones make up the anterior cranial fossa?
Frontal
Ethmoid bone
Lesser wings of sphenoid bone
What type of white matter fibre is the corpus callosum?
Commissural fibre
What is meant by a commissural fibre?
Connects similar functional areas of the two hemispheres
What is the name of the aspect of the lesser wing of the sphenoid bone?
Anterior clinoid process
Which arteries travel through foramen magnum
Vertebral
Spinal
Where does the facial nerve emerge from the skull? (after travelling through the internal acoustic meatus)
Stylomastoid foramina
What are the actions of the superior oblique muscle?
Depress
Intort
Abduct
What are the actions of the inferior oblique muscle?
Elevate
Extort
Abduct
The cornea is avascular, where does it receive its nutrients from?
Tear film
Aqueous humour
How of the refraction power does the cornea contribute
2/3
How much of the refraction power does the lens contribute to?
1/3
What is the innervation of the cornea?
Trigeminal nerve
What are the 3 layers of the cornea?
1) Epithelium (continually replaced by limbal stem cells)
2) Stroma
3) Endothelium (for life)
Name the fibrous component of the eye
Sclera
Cornea
What is the conjunctiva
Clear covering over the sclera (2 cells thick)
Name the vascular layers of the eye
Choroid
Ciliary
Iris
Between which two layers of the eye is the choroid found?
Retina and sclera
What are the function of the ciliary bodies?
Accomodation (adjust refracting power of the lens)
Produce aqueous humour
How is C7 vertebra different to the rest (not inc C1/C2) of the cervicle vertebra?
Not bifid
Which vertebra does the ‘vertebra prominent’ refer to?
C7
At what level is the highest point of the iliac crest?
L3-L4
What is the name given to the outer part of an intervertebral disc?
Annulus fibrosis
What is the name given to the inner part of an intervertebral disc?
Nucleus pulposus
At what level is the conus medullaris?
L1-L2
At what level should you take a lumbar puncture?
L3/4
What are the 3 covering of a spinal nerve
Epineurium
Perineurium
Endoneurium
What type of Glial cells are responsible for regulation of CNS production/flow
Ependymal
What in terms of pain what is the function of the somatosensory cortex?
Localisation and descrimination of pain
In term pain what is the role the insular cortex?
Detects the degree of pain
Which part of the brain is activated by acupuncture
Cingulate gyrus (anterior)
Where are opoid receptors found?
Periaqueductal grey