Neuroanatomy & Function II Flashcards
where are the respiration centers located within the brain
respiration center controls: for inhalation and exhalation are controlled in the pons and the medulla
thus, injury to the pons and medulla in these specific locations can result in respiratory issues such as dyspnea
where are cardiac control centers located wtihin the brain
responses from the baro and chemoreceptors are taken in by the rostral and caudal ventrolateral medulla
where is the reticular activating system of the brain
what is it responsible for
what does this connect (areas/structures within the brain)
The Retiuclar Activating System (RAS) is the system within the brainstem (areas of nuclei found throughout the midbrain, pons and medulla) responsible for arousal/consciousness and wakefulness
Lesions in the RAs can lead to obtunded pts, stupor, and coma presentations
Nuclei Names
- pedunculpontine nuclei
- locus cercules
- raphe nuclei
- reticualr nuclei
- parvocellular nuclei
the RAS connects the brainstem to the thalmus & then to the cortex through a series of NT connections
RAS is seen as the connection between the thalmus and the cortex
What is the Hippocampus
how is memory related to this area
what are the two memory pathways
Hippocampus: a struture (swirled) that sits just below the pre-hippocampal gyrus in the temporal lobe
Hippocampus: is the area of memory retrevial and consolidation not memory storage!!
subbreakdown of the hippocampus
CA1, CA2, CA3 & CA4
Memory Pathways
1. Tri-synaptic Circuit: encoding, consolidation & retrevial of memories
2. Circuit of Papex: Connects the hippocampus to limbic, ANS and other systems (which is why memories can be emotional!)
Explain the Tri-Synaptic Circuit of Hippocampal Memory
Explain the Circuitof Papez of Hippocampa Memory
Tri-Synaptic Circuit (tri think CA3 before CA1)
- entorhinal cortex –> dentate gyrus
- dentate –> CA3
- CA3 –> CA1
Circuit of Papez
- subiculum (in hippocamp) –> travel to the Mamillary Bodies via the Fornix
- mamillary bodies –> anterior nucleus o the thalamus
- anterior nucleus to the cingulate gyrus
- cingulate gyrus to parahippocampal gyrus
- parahippo. to the entorhinal cortex
what is the Limbic System
what strucutres are involved
Limbic System: involved in emotion, drive and basic behaviors
- the emotion, memory and autonomic regualtion related
- related to other pathways (reason for memories being related to stress, fear, anger, etc.)
Structures
- Amygdala (near hippocampus)
- hippocampus
- Olfactory Blub (smells = memorie!)
- Fornix
- Hypothalmus
CNS: Blood Supply
2 origins of the blood supply from what arteries
three main branches to know
where does the MCA run? the ACA?
Origins of Supply
- the two internal carotid arteries (from common carotids)
- the two vertebral arteries
Branching
- the vertebral arteries come together to form the basilar artey: the main posterior blood supply of the brain
- the internal caroitd arteris give rise to the MCA (middle cerebral artery) and the ACA (anterior cerebral artery) which are the main supplies of the anterior brain
MCA: runs within the lateral fissure
ACA: runs within the longitudinal fissure
Circle of Willis
- the basilar artery (supplied by the vertebral arteries)
- Basilar: gives off arteries which supply the cerebellum (the superior cerebellar, the anterior inferior cerebellar and the posterior inferior cerebellar) & pontine arteries
- the posterior cerebral artery: connects to basialr and to the posterior communicating artery
- the middle cerebra artery: gives rise to the opthalmic artery
- the anterior cerebral artery: gives rise to the anterior communicating
the arteries which make up the circle
- basilar artery
- posterior cerebral artery
- internal carotid/middle cerebral artery
- anterior cerebral artery
- posterior communicating artery (allows for collateral blood supply)
- anterior communicating artery
what areas are supplied by the MCA and ACA
what about the posterior circulation of the brain
MCA: supplies the lateral aspects of the brian’s cortex
ACA: suppleis the medial aspect of the brain’s cortex
Posterior Circulation
- PCA: supplies parts of the occipital, superior cerebellum
- cerebellum: superior cerebellar a, anterior inferior & posterior inferior
- thalmus: PCA, ICA (internal carotid)
- midbrain: PCA, SCA, BA
- Pons: BA, PICA
- MEdulla: VA, PICA
Venous Drainage of the Brain
Venous Drainage occurs through the Venous Sinuses
- no valves (meaning the flow is natrual and gravity dependent) but this means back flow can occur (like standing on your head for too long)
- eventually all draiins to the internal jugular vein and into the SVC
Sinues
- Left and Righ Cavernous Sinuses
- Superior Sagittal
- Inferior Sagittal Sinuses (connects via Straight sinus)
- Confluence of sinuses
- into the transverse sinuses
- to the sigmoid sinus
- to the internal jugular
what is the cavernous sinus
what NV strucutres pass through it
risk of infection
Cavernous Sinus: an area of blood which pools in the brain sinuses for a moment, used as a cooling system in order to cool down incoming arterial blood through the internal carotid artery
- lined with dura
- risk of infection and thrombosis: infection because the facial vein also drains here: “danger zone” of infection on the face can get to the brain
Strucutres which pass WITHIN the Cavernous Sinuses
- internal carotids
- CN V1 and V2 (opthalmic and maxillary nerves of the trigem.)
- Abducens (VI) and Trochlear (IV)
- Occulomotor III
(in sum, internal caroitd, III, IV, VI and V1 and V2)
lacunar Infarcts
- where will the impact be
Lacunar Infarcts: common because they are infarcts of smal vessels deeper in the brain which can be asymptomatic
- uncontroleld HTN plays a big role here
- internal capsule and thalamus can be affected with these
Meninges
3 layers and their order
where are vessles (arteries? veins?)
Mengines: outer coverings of the brain
- Dura Mater: hard outer most layer
- Arachnoid Mater: middle
- Pia Mater: inner most (almost glued to the brain itself)
Arachnoid Mater Specifics
what is within
Arachnoid Mater
- subarachnoid space: CSF flows here
- continuous with the SC
- more arteries can be found in teh subarachnoid space
Dura Mater Specifics
what is above and below
septa?
innervation and blood supply
Dura Mater
- makes up the folds within the brain (the sinuses)
- EPidural (above dura): this space contains fat, arteries, lymph, etc.
- SUBdural (below the dura): this space contains veins
- dura not continuous with the SC
Dural Septa (Divisions)
- Falx Cerebri (divides the cerebral cortex) (cignulate gyri under here in herniation)
- tentorum cerebelli: divides teh cerebral cortex from the cerebellum (uncal herniation under this)
Innervated : trigeminal n.
blood: middle meningeal artery
the dura splits to creat sinues, allowsing scalp drainge here too & risk for infection to occur
