Week 6 Flashcards
What separates the frontal from the parietal lobe
central sulcus
where is the motor cortex
pre central girus
where is the somatosensory cortex
post central girus
what separates the occipital from the parietal lobe
parietal occipital sulcus
what separates the temporal, parietal and frontal lobes
lateral sulcus
where is the primary auditory cortex
temporal lobe
where is speech produced
brocus area
where is speech understood
audicus area
what is white matter
myelinated axons, transmission tissue
what is grey matter
unmyelinated cell bodies, thinking tissue
what dips into the transverse fissure
the tentorium cerebeli
what do ventricles contain
CSF
what is the lateral ventricle called
hypocampus
what do association fibres allow
impulses to go from front to back
what does the internal capsule allow
projection capsule, brings info up and down
what is a fornex
white fibre (axon tract) which connects multiple limbic nuclei together
what is the corpus callosum made up of
commisual fibres (transmission from left to right hemispheres)
what is the thalamus composed of
lots of nuceli, relay station for information, intermediate mass between the 2 thalamus (one in each hemisphere)
what do mamillary bodies do
play a role in smell
what are the 3 parts of the brainstem
- midbrain
- pons
- medulla oblongata
what are the 3 parts to the diancephalon
- thalamus
- hypothalamus
- epithalamus
what happens at the pyramids of medulla
descending motor fibres cross
What is the clinical term for a stroke
cerebrovascular accident
If a patient had a stroke in their right internal capsule what would their face look like
- paralysed left face (apart from eyelid and forehead)
- paralysed left upper and lower limb
- tongue moves slightly to the left
where is the thalamus
grey matter deep in the brain at the midline called the dicencephalon
what happens at the thalamus
relay station on the sensory pathways where the 3rd order sensory neurons are
what are the 4 basal ganglia
- lentiform nucleus
- caudate nucleus
- substantia nigra
- subthalamus
which of the basal ganglia has the role to smooth out muscle contractions
lentiform nucleus
what does the lentiform nucleus do
smooth out muscle contractions
where is the internal capsule
in between the lentiform nucleus and thalamus
what happens in the internal capsule
the corticospinal pathway and corticonuclear tracts converge
is the internal capsule white or grey matter
white
what is the corona radiata
white matter further up from the internal capsule
what is the corpus callosum
tells brain what is happening on the other side
Describe the corticospinal pathway
Thousands of axons coming from these cells in the motor cortex for the upper and lower limb.
- they come from the corona radiata and converge in the internal capsule
- the corticospinal tract comes down and through the midbrain, the pons and medulla
- when it reaches the motor decussation at the bottom of the medulla, the fibres cross over
- they carry on until they meet the motor neurons they are going to synapse with to make the muscles in the limbs of the trunk contract
Which of the cranial nerves supply muscles (really important)
3 4 5 6 7 9 10 11 12
what muscle(s) does CN3 supply
extraocular muscles
what muscle(s) does CN4 supply
superior oblique muscle
what muscle(s) does CN5 supply
muscles of mastication (and others)
what muscle(s) does CN6 supply
lateral rectus muscle
what muscle(s) does CN7 supply
muscles of facial expression (and others)
what muscle(s) does CN9 supply
stylopharyngeus muscle
what muscle(s) does CN10 supply
muscles of pharynx and larynx
what muscle(s) does CN11 supply
(CN) - pharynx and larynx
(spinal) - sternocleidomastoid and trapezius
what muscle(s) does CN12 supply
muscles of the tongue
what are the two different kinds of nuclei from which the cell bodies of the motor neurons for the cranial nerves are found
- those which supply muscles formed by somites
- those which supply muscles formed by pharyngeal arches
what are somites
blocks of nerves on either side of the developing system
what are pharyngeal arches
arches in the embryo which give rise to certain muscles
what nerve supplies muscles derived from the 1st pharyngeal arch
CN5
what nerve supplies muscles derived from the 2nd pharyngeal arch
CN7
What nerve supplies muscles derived from the 3rd pharyngeal arch
CN9
What nerve supplies muscles derived from the 4th and 6th pharyngeal arches
CN10
the trigeminal nerve supplies muscles from which pharyngeal arch
1st
the facial nerve supplies muscles from which pharyngeal arch
2nd
the glossopharyngeal supplies a muscle from which pharyngeal arch
3rd
the vagus nerve supplies muscles from which pharyngeal arches
4th and 6th
is there a 5th pharyngeal arch
kind of, it’s rudimentary (ignore it)
where are the neurons which supply muscles from somites in relation to the midline
near the midline
where are the neurones which supply muscles from pharyngeal arches in relation to the midline
out to the side
what cranial nerves share the nucleus ambiguus
9th, 10th and 11th
what nuclei are in the midbrain
- occulomotor nucleus
- trochlear nucleus
what nuclei are in the pons
- trigeminal motor nucleus
- abducens nucleus
- facial nucleus
what nuclei are in the medulla
- nucleus ambiguus
- hypoglossal nucleus
how does the pathway for spinal nerves differ from the pathway for cranial nerves
- spinal nerves all cross over (nothing from the same side)
- cranial nerves fibres go to all nuclei on the opposite side BUT also to most of the nueclei on the same side
what is the type of input for cranial nerves called
bilateral input
what are the exceptions to the general pathway for cranial nerves
- Facial nerve
- Hypoglossal nerve
How does the facial nerve differ from the general cranial nerve pathway
Bilateral input to the opposite side and ONLY to the upper most part of the face on the same side (i.e. motor neurons for the lower face only receive from the opposite side)
How does the hypoglossal nerve differ from the general cranial nerve pathway
input is only to the opposite side
Explain why someone who has a stroke in their right internal capsule has a paralysed lower left face, upper and lower left limb and their tongue points to the left but everything else works
Most of the motor nuclei recieve input from both motor cortexes (right and left) so if one pathway is damaged the muscles will still be able to work as the other pathway also supplies the nuclei and is able to therefore keep those muscles working.
Motor neurons for the lower face and tongue only recieve input from the opposite motor cortex so if you have damage to one side you get a paralysed tongue and lower face.
What arteries supply the cerebellum
- Superior cerebral artery
- anterior inferior artery
- posterior inferior artery
what artery is continuous with the internal carotid artery
middle cerebral artery
what is the tortuous course of the internal carotid artery designed to do
smooth out the waves of the pulse
Blockage at different points in the cerebral circulation result in different groups of symptoms. What are these known as
stroke syndromes
what are the vessels visible further up in the brain along the falx cerebri in the midline
veins, moving upwards to drain into the saggital sinus
where does the internal carotid artery enter the cranial cavity
through the carotid canal in the temporal bone
what arteries branch from the basilar artery
- anterior inferior cerebellar arteries
- superior cerebellar arteries
- posterior cerebral arteries
what is the pathway of the right and left vertebral arteries
- right much bigger than left
- curve round the axis (C2 vertebra)
- enter the foramen magnum
