The Brain Flashcards
what are the gyri and sulci of the brain?
gyrus = lump sulci = groove
what is the central sulcus and what are on each side?
sulcus in the middle of the brain, runs from medial to lateral motor cortex (pre-central gyrus) anteriorly sensory cortex (post-central gyrus) posteriorly
where is the lateral fissure and what does it contain?
between the temporal and parietal lobes
contains the middle cerebral artery
where is the longitudinal fissure and what does it contain?
sulcus through the midline of the brain, dividing the hemispheres
contains the anterior cerebral arteries
what is the corpus callosum?
white matter tracts that connect the cerebral hemispheres
where are association tracts found?
between gyri of the same hemisphere
where do commissural tracts/fibres run?
from one hemisphere to the corresponding region of the other hemisphere
where do the projection fibres arise from?
cerebrum to thalamus, brainstem etc.
what is the function of basal ganglia?
regulate initiation and termination of body moments, also thought to be involved with memory, planning and emotional response (via limbic system)
what forms the lentiform nucleus?
globus palladus and putamen
what does the substansia nigra in the mid-brain communicate with and what is its role?
caudate and putamen
control sub-conscious muscle action
what does the sub-thalamic nuclei communicate with?
the globus palladus
what does the diencephalon contain?
thalamus
hypothalamus
pineal gland
what is the role of the thalamus?
sensory relay station involved in motor pathways with connections to the hypothalamus and limbic systems
what is the role of the hypothalamus?
regulates ANS and homeostasis and produces hormones
what is the role of the pineal gland?
produces melatonin to regulate body clock
it’s epithelium contians the habenular nucleus whihc is responsible for olfaction and emotional response
what cranial nerves originate in the midbrain?
III and IV (oculomotor and trochlear)
what does the midbrain connect?
pons and medulla to diencephalon
where is the superior colliculi and what is its role?
in the midbrain
visula tracking, scanning
where is the inferior colliculi and what is its role?
in the midbrain
auditory startle reflex
where are red nuclei and what is it’s role?
in the midbrain
co-ordinate muscle movement
what cranial nerves originate in the pons?
V, VI, VII and vestibular part of VIII (trigeminal, abducens, facial and part of vestibulocohlear)
what does the pons contain and what are their roles?
pontine nuclei: coordination and maximising voluntary motor output
tracts e.g. pneumotaxic: helps control breathing
what cranial nerves originate in the medulla?
IX, X, XI, XII (glossopharyngeal, vagus, spinal accessory and hypoglossal)
what does the medulla contain and what are their roles?
pyramids (motor tracts)
cardiovascular centres (rate/force of heartbeat and diameter of vessels)
breathing centres
nuclei concerned with touch, pressure and vibration
what is the role of the olives in the medulla?
proprioception (joint and muscle position)
what divides the cerebellum into lobes?
cerebral vermis
what is the role of the cerebellum?
controls sub-conscious aspects of skeletal muscle movements and coordinates complex sequences
regulates posture and balance
what do the superior, middle and inferior peduncles connect?
superior: midbrain to cerebellum
middle: pons to cerebellum
inferior: medulla to cerebellum
what does the pituitary gland release?
growth hormone (GH) follicle stimulating hormone (FSH) luteinising hormone (LH)
what is the circle of willis and what is it formed from?
is a circulatory anastomosis that supplies blood to the brain and surrounding structures formed from: - anterior communicating - L+R anterior cerebral - L+R internal carotid - L+R posterior cerebral - L+R posterior communicating note: middle cerebral, basilar and vertebral arteries also supply the brain but aren't part of the circle
what does the middle cerebral artery supply?
temporal loves
what does the posterior cerebral artery supply?
occipital lobe and base of brain
what are the branches of the basilar artery?
cerebellar, pontine and medullary arteries
what does the anterior cerebral artery supply?
frontal and parietal lobes
where do the vertebral arteries arise from?
the subclavian
what are the layers of the meninges surrounding the spinal cord?
pia mater: innermost layer
arachnoid mater: middle layer, fine ‘spiderweb’ of CT
dura mater: outermost layer, tough CT sheath
what is the space between the pia and arachnoid mater and what does it contain?
subarachnoid space
contains cerebrospinal fluid
what lines the skull, what is its role and what does it form?
dura mater
protects the brain
forms the dural venous sinuses
what covers the surface of the brain and what does it carry?
arachnoid mater
carries blood vessels
what is the covering of the brain beneath the arachnoid mater?
pia mater
adheres to surface, goes into the sulci and around the gyri
what does the anterior meningeal artery arise from and what does it supply?
ethmoid branches of the internal carotid
supplies the dura of the anterior fossa
what does the middle meningeal artery arise from, what does it pass through and what does it supply?
from maxillary artery
passes through the foramen spinosum
supplies the dura with blood (major vessel supplying it, if damaged causes extra-dural haematoma)
what does the posterior meningeal artery arise from and what does it supply?
from occipital artery
supplies dura of posterior fossa
what nerves supply the dura?
anterior and posterior ethmoidal nerve
anterior meningeal branches of ethmoidal nerve (CN V1)
meningeal branch of maxillary (CN V2)
meningeal branches of mandibular (CN V3)
tentorial nerve (recurrent meningeal branch of opthalmic, CN V1)
fibres from C2+3, some of which are distributed by CN X
what is the role of the dural venous sinuses and what are they found between?
drain blood from the brain and channel it into the IJV
between either the periosteum and dura (e.g. sigmoid sinus) or between two of the layers of dura (e.g. inferior sagittal sinus)
what are the names of the four ventricles of the brain and where are they found?
lateral ventricles x2 (one in each hemisphere) 3rd ventricle (inside the thalamus) 4th ventricle (in the pons or upper part of medulla)
how does the third ventricle connect to the lateral ventricles?
inter-ventricular foramina of Monro
what is the 4th ventricle connected to?
subarachnoid space via lateral (x2) and median (x1) apertures
central canal of the spinal cord
what is the role of CSF and where does it circulate?
provides mechanical and physical protection to the brain and spinal cord
circulates through the ventricles and into the subarachnoid space
how is CSF lost from the body?
through arachnoid villi (aka arachnoid granulations) which are protrusions of the arachnoid mater into the dura mater
protrude into the DVS allowing CSF to exit from the subarachnoid space into blood
where are ependymal cells found and what is their role?
found in choroid plexi present in the lateral, 3rd and 4th ventricles (hang from roof in lateral ventricles!)
filter blood plasma to produce CSF
