Test 1 Shit Flashcards
What is the CNS composed of?
Brain and Spinal Cord
Different cortices that make up the cerebral cortex?
Frontal Cortex Parietal Cortex Temporal Cortex Occipital Cortex Insular Cortex
The brain stem is composed of?
Midbrain
Pons
Medulla
Spinal Cord is composed of?
Cervical Thoracic Lumbar Sacral Coccygeal
Central Sulcus
Separates the frontal cortex from the parietal cortex
Lateral Fissure
AKA Sylvia Fissure
Separates the frontal and parietal cortices from temporal cortex
Preoccipital notch
Divides the temporal and occipital cortices
Operculum
Region of cerebrum bordering the lateral fissure
EX: Frontal, parietal, and temporal operculum
Caudal
Towards tail
Rostrum
Toward Head
Distal
Away
Proximal
Closer
Midbrain
Hidden by temporal lobe
-top part of brain stem
Medulla Oblongata
Inferior most portion of the brain stem
-continuous with the spinal cord at the foramen magnum
Pons
Below the Midbrain
Above the Medulla Oblongata
Parieto-occipital sulcus
Separates the parietal cortex from the occipital cortex
Corpus Callosum
White Matter
- composed of myelinated axons that connect L and R brain together
- axons run right to left/left to right in corpus callosum
- medial cut=axons look like dots
White Matter definition
Large myelinated fiber tracts/axons
Grey Matter
Portion of the CNS containing high density of neuronal cell bodies
Thalamus
- AKA diencephalon; reflects embryonic function
- Subcortical Structure
- involved in relay of info to and from the cerebral cortex
- bilateral structure (gap between sides)
Cerebellum
Superior and dorsal to the brain stem
-involved with coordination
CSF-containing ventricular system composed of:
3rd ventricle
Cerebral Aqueduct
4th Ventricle
Hypothalamus
No anatomical boundary
Cerebral Aqueduct of midbrain
Connects 3rd and 4th Ventricle
-aka Cerebral aqueduct of Sylvius
3rd Ventricle
Space between thalami
- continuous with cerebral aqueduct
- located on the midline of the brain
Lateral Ventricles
2 of them
- located in cerebral hemispheres
- drain into the 3rd ventricle via interventricular foramen (AKA foramen of monro)
Interventricular Foramen
AKA Foramen of Monro
-Connects the 2 lateral ventricles to 3rd ventricle
How much CSF does an adult make on average per day?
150 cc (or mL)
4th Ventricle
Located between the pons-medulla and cerebellum
How does CSF flow from the 4th ventricle:
By 1 of 3 routes:
- Median Aperture (foramen of Magendie)
- Lateral Aperature (Foramen of LUSHKA)
- Central Canal of medulla and spinal cord
Median Aperature
AKA foramen of Magendie
- unilateral (not bilateral)
- CSF flow from 4th ventricle through this (one of 3)
- empties into cistern magna (located at the base of the occipital bone)
Lateral Aperature
AKA Foramen of LUSHKA
- bilateral (R and L Sides)
- located at the pons/medulla junction
- empties into the Pontine Cistern
Choroid Plexus
Produces CSF
-located in the lateral (body and inferior horn) ventricles, third ventricles, and fourth ventricles
Circulation of CSF
Lateral Ventricles-> interventricular foramen-> 3rd ventricle-> cerebral aqueduct-> 4th ventricles-> median and lateral Aperature-> Transverse subarchnoid space-> arachnoid granulation-> absorbed into the venous circulation
Stenosis
Squeezing/making smaller
-impeding flow
0can be caused by a tumor, bacteria, or debris
Arachnoid Villus
AKA arachnoid granulation
- protrude into the superior Sagittarius sinus (Dural sinus)
- takes CSF and absorbs into venous circulation through the dura mater that forms the walls of the superior sagittal sinus
Superior Sagittarius Sinus
Between 2 layers of Dura Mater
- Dural Sinus
- venous blood
Meninges
3 membranes that cover the brain and spinal cord
1) Dura mater
2) Arachnoid
3) Pia Mater
Dura Mater
- Outermost layer of meninges
- thickest membrane
- doesn’t follow contour of brain
2 Layers:
-layers aren’t easily separable except where venous sinuses occur between them
Inner (meningeal) layer
-folds of meningeal layer form 4 fibrous partitions or septa that divide cranial cavity: 1) Falx cerebri, Tentorium cerebelli, falx cerebelli, diaphragma sellae
Outer (periosteal/endosteal) layer
-stops at the foramen magnum where it fuses with the occipital bone
Falx cerebri
- located between the 2 cerebral hemispheres
- top of cranium
Tentorium cerebelli
- located superior to the cerebellum
- covers the cerebellum within the posterior cranial fossa
Falx cerebelli
extends vertical between the two cerebellar hemispheres
-bottom of cranium near cerebellum
diaphragma sellae
- extends between the anterior and posterior crinoid processes
- covers the pituitary gland
Arachnoid Membrane
Middle layer of meninges
-does not follow the contour of the brain (like dura mater)
Subarachnoid Space
- Found between the Arachnoid membrane and Pia Mater
- contains CSF, blood vessels (arteries and veins)
Pia Mater
- Inner most layer of meninges
- Vascularized
- areolar membrane
- extends into every contour of brain
- very thin/transparent
CSF
- constant circulation of 150 cc
- complete turnover 3-4 times/day
Diploic Vein
Drains into Superior Sagittal Sinus
-valveless
Emissary Veins
- passes through foramina (Foramen) of skull
- connects superficials veins with deep venous structures (i.e. dural sinuses)
Bridging Vein
- easily ruptured In elderly
- blood will split dura resulting in subdural hematoma
- slow forming
Galea Aponeurosis
CT b/w skin and skull
Subgaleal Hematoma
bleed under galea aponeurosis
- trauma
- common in babies during birth when MD uses suction; pulls up aponeurosis
- don’t let pt sleep bc unsure of LOC
Epidural space
- not normally present
- b/w dural and skull
- can be opened up by ruptured meningeal artery (ex: middle meningeal artery) which run in the periosteal layer of dura resulting in Epidural hematoma
- Arterial blood is under High pressure-> Large V of blood can be lost into the epidural space fast-causing severe brain compression
- unless bleeding is quickening controlled surgically
- DEATH can happen quickly
Meningeal artery
ex: Middle meningeal artery
- run in the periosteal layer of dura
- can result in epidural hematoma
- supplies blood to bone and dura mater
- High Pressure
Subdural Space
- not normally present
- near the Jan between dura and arachnoid membrane
- may be opened by blood from a vein; typically cerebral vein as it enters a dural sinus
- Subdural Hematoma
Trigon area
calcified area of choroid plexus=glomus
- common for adults
- opaque, will show up on x-ray
Cisterna Magna
inferior to the cerebellum
-median aperture empties into
Pontine Cistern
Lateral aperture empties into
Disturbances of circulating of CSF
- most common blockage of ventricles that leads to increase inn ICP
- due to malfunction of absorption
- can be caused by clogging by debris, bacterial etc
Middle Meningeal artery
- Enters cranium via foramen spinosum then bifurcates into anterior and posterior
- anterior goes through pterion (very vulnerable area)
Pterion
Intersection of sutures
-vulnerable area
Aneurysms
- Categorized by shape
- involves all 3 layers of artery
- unless aneurysm is pressing on something that is innervated=will not have symptoms
- rupture will lead to stroke; Middle Cerebral A. most common artery involved in stroke in brain
1) Sacular
- berry like
- where arteries branch
- very likely to rupture
2) Fusiform
- bulging spindle shaped
- tend to not be a problem
- unlikely to rupture
3) Pseudoaneurysm
- does not involve all 3 layers of artery
- due to trauma causes separation between media and adventitia
- can be very painful
- usually do not rupture
Tentorial Incisure
-oval opening in the tentorium cerebelli at anterior end that allows passage of brainstem into posterior cranial fossa
