Intercranial Components - Lecture 2 Flashcards
What are the 3 components of the inter cranial vault?
Brain, blood, CSF
What is the % of each
Brain
Blood
CSF
Brain 80-85%
Blood 5-10%
CSF 10-15%
What is the blood supply to the brain
BL carotid arteries
BL vertebral arteries
Where does the left carotid artery arise from?
the aortic arch
Where does the right carotid artery arise from?
the innominate artery
What the the carotid artery bifurcate into?
the external and internal carotid arteries
Where does the internal carotid artery enter?
the base of the skull
Where does the external carotid artery go?
remains superficial to the skull
What does the internal carotid artery supply blood to? (2)
Arterial supply to the Circle of Willis
Arterial supply of the eye via the ophthalmic artery
What does the internal carotid artery bifurcate into?
anterior and middle cerebral arteries
Where does the vertebral arteries arise from?
sunclavian arteries
Where does the vertebral arteries supply blood to?
The Circle of Willis
Venous blood drains in the venous sinuses which lie between the layers of the ____ and drain into the ______
dura mater
internal jugular vein
Characteristics of the venous sinuses
- Sinuses are _____
- Blood can flow _____
- Pressure within them is _____
- Little influence by the ______
valveless
back and forth
negative (air embolism)
autonomic nervous system
What do meninges cover?
covers the brain and spinal cord
What does the meninges consist of?
Dura mater
Arachnoid mater
Pia mater
How is the Pia mater anchored to the brain?
by astrocytes, this forms the blood brain barrier
What does the blood brain barrier allow passage of?
- Small molecules (H2O, O2, CO2)
- Lipophilic molecules (EtOH, heroin)
- Passive transport of glucose
- Active transport of amino acids/ NT precursors
What does the blood brain barrier prevent passage of?
- Large molecules (dopamine)
- Charged (ionized) molecules
What 2 layers does the dura mater consist of?
Outer and inner layer
What are between the outer and inner layer of the dura mater?
Dural Sinuses
What do the dural sinus drain?
CSF
Subarachnoid hemorrhage is a
neurological emergency
Subarachnoid hemorrhage is a hemorrhage in the ______ space
subarachnoid
SAH hemorrhage is less common but a important cause of a
stroke
Where is the bleeding occurring with an epidural hematoma?
Bleeding between the skull and the dura mater
In an epidural hematoma, where is the bleeding usually from?
Usual arterial in origin (meningeal arteries)
Where is the bleeding occurring with a subdural hematoma?
Bleeding between the dura and the arachnoid mater
In a subdural hematoma, where is the bleeding usually from?
Usually resulting from tear in bridging veins
Where is the bleeding occurring with a subarachnoid hemorrhage?
Bleeding between the arachnoid membrane and the Pia mater
In a subarachnoid hematoma, where is the bleeding usually from?
Usually from a ruptured cerebral aneurysm
Where is CSF produced?
by the Choroid Plexus in the cerebral ventricles
What does CSF surround?
Surrounds the brain and spinal cord
What does CSF do?
Cushions, supports and facilitates transfer of nutrients
What os the total volume of CSF?
roughly 150cc
How much CSF is produced daily?
roughly 500cc
