Topography of the brain Flashcards
Name the 3 parts of the brainstem
midbrain, pons and medulla
What is connected to the brain via the brainstem?
cerebellum
What cranial nerves emerge from the brainstem?
3-12
3 functions of the brainstem
pathway for tracts running between higher and lower centres
brainstem nuclei involved with 10 out of 12 cranial nerves
Centres produce rigidly programmed autonomic behaviours
What cavity is the medulla in relation to?
4th ventricle
After the foramen magnum what does the medulla continue as?
spinal cord
What are the pyramids?
midline swellings which are caused by white matter motor tracts from the motor complex
What peduncle connects the cerebellum to the medulla?
inferior cerebellar peduncle
Where are the superior and middle cerebellar peduncle in relation to the inferior peduncle?
middle - lateral and biggest
inferior and superior on the inside with superior above and inferior below
cranial nerves emerging from the medulla
9-12
What part of the medulla is open and closed?
open cranial and closed caudal
pons peduncle
middle
cranial nerves emerging from ventral surface of pons
5-8
What does the midbrain develop from?
mesencephalon
Central cavity of the midbrain
cerebral aqueduct
4 midbrain surface features
CN 1-4
superior cerebellar peduncle
cerebral peduncle
superior and inferior colliculus for visual and auditory reflex
On which part of the brainstem are the olives found?
medulla
What is the dessucation of the pyramids?
where the tracts cross over
What is the only cranial nerve to originate posteriorly?
trochlear - CN 4
Are cerebellar peduncles formed from grey or white matter?
white
Describe the surface findings of the cerebellum (anatomy)
anterior, posterior and flocculonodular lobes hemispheres separated by vermis tonsils sulci and folia 3 cerebellar peduncles
ataxia
lack of voluntary co-ordination of muscles
2 main functions of cerebellum?
posture maintenance
fine tuning motor activity
3 clinical tests for ataxia
finger-nose test
knee-heel test
walking in a straight line
3 inputs to cerebellum
proprioceptors - ipsilateral periphery
pyramidal tracts - motor intention of the brain
vestibular nuclei re balance and posture
Cerebellum - what does it calculate?
best way to make smooth co-ordinated movements
output of cerebellum
back to cerebrum with what to do - via cerebellar peduncle
What ventricle is the diencephalon found and is it a superficial or deep structure?
deep into cerebrum - 3rd ventricle
What does the diencephalon develop from?
diencephalic vesicle - from forebrain vesicle
Name the paired structures which make up the diencephalon
thalamus, hypothalamus (pituitary gland), epithalamus (pineal gland)
What is the function of the thalamus?
sensory relay station
What is the thalamus mainly made up of?
group of nuclei - grey matter
anterior medial and lateral
What is the lateral group of nuclei of the thalamus responsible for?
processing sensory information
How are the thalamus and hypothalamus separated?
by the hypothalamic sulcus
What Is the hypothalamus role in homeostasis - a few examples
water balance and thirst
sleep cycle
temperature
endocrine
blood supply to the brain - main arteries and how they enter
2 ICA and 2 vertebral
ICA via carotid canal and vertebral via foramen magnum
What are the vertebral arteries a branch of?
subclavian arteries
ICA branches
ophthalmic, ACA, MCA, P communicating artery
What do the 2 vertebral arteries fuse to give and what does this further give off?
basilar artery –> PCA
What do the vertebrobasilar system branches supply?
cerebellum and brainstem
Circle of willis - how is it protective and where do the problems come in?
anastomoses - occlusion can still receive blood supply
cerebral arteries are end arteries and an occlusion here will result in a stroke
What doe each of the cerebral arteries supply?
ACA - medial portion exc. occipital lobe
medial - lateral aspect
PCA - occipital lobe and inferior aspect
Name the venous sinuses you should know
superior and inferior sagittal, lateral, straight, confluence of sinuses, cavernous, inferior and superior petrosal
What layers of mater are venous sinuses found between?
dura mater
When the dural venous sinuses join where do they drain into?
IJV
Where is the cavernous sinus found and what does it drain?
on either side of sella turcica of sphenoid bone
eye venous drainage - ophthalmic veins
cavernous sinus relations
ICA, abducens nerve, CN 3,4,1,V2
