case 3 - neurovasculature and vesicular system Flashcards
anterior blood supply
common carotid –> internal+external carotids
posterior blood supply
vertebral arteries –> basilar artery
circle of willis
o Circle of Willis: The circle of Willis is a circular arrangement of blood vessels located at the base of the brain, where the internal carotid arteries and vertebral arteries fuse
Anterior and posterior communicating arteries are the fusion
middel cerebral arteries
The middle cerebral arteries are the largest branches of the internal carotid arteries and supply blood to the lateral (outer) aspects of the brain, including areas responsible for motor and sensory functions.
anterior cerebral arteries
The anterior cerebral arteries supply blood to the frontal lobes of the brain and are connected to the middle cerebral arteries through the anterior communicating artery within the Circle of Willis. From carotid
posterior cerebral arteries
The posterior cerebral arteries supply blood to the occipital lobes of the brain. They are connected to the basilar artery through the posterior communicating arteries within the Circle of Willis.
cerebellar blood supply
superior cerebellar from basilar
anterior inferior (aica) from basilar
posterioir inferioir (pica) branches of earlier from the vertebral before it forms the basilar
ventricular system
- lateral ventricles
- foramen of monro
- third v.
- cerebral aquaduct
- forth v.
- foramine of luschka and magendie
- subarachnoid space (brain and spinal cord)
functions ventricular system
o CSF Circulation: CSF flows through the ventricles and into the subarachnoid space, where it circulates around the brain and spinal cord. This circulation helps transport nutrients and remove waste products from the brain.
o Pressure Regulation: The ventricles help maintain intracranial pressure within a normal range by regulating the volume of CSF. Changes in CSF production or absorption can lead to conditions like hydrocephalus (increased intracranial pressure due to excessive CSF accumulation).
o Protection: The CSF-filled ventricles also act as a shock absorber, protecting the brain from injury caused by sudden movements or impacts.
BBB anatomy
- Endothelial cells with tight junctions
- Pericyte
- Astrocyte endfeet
- The pericytes and astrocytes secrete factors that make the endothelial cells produce junction proteins to form the BBB
- Microglia are in close relation with the capillaries
- Tight but not completely impermeable
* High energy demand
transport across BBB
- Passive diffusion:
- Very small molecules (gases)
- Lipophilic molecules
- Low polarity –> high charged
- Active diffusion:
- ABC transporters : drugs, xenobiotics, Abeta
- Carrier-mediated transport : specific molecule transporters (like glucose, amino acids, hormones, etc.)
- Receptor-mediated transport : molecule binds to receptor which is then endocytosed
- Ion transport
CSF resporption
CSF is eventually absorbed back into the bloodstream through structures called arachnoid granulations (also known as arachnoid villi or granular villi). These finger-like projections of the arachnoid membrane extend into the venous sinuses within the skull. CSF is absorbed into the venous blood, where its constituents are recycled and returned to the systemic circulation (vena cava).
a. Transcytosis
b. Aquaporins
c. Between cells
d. Look up table of ions at this location (osmotic pressure is the same)
glymphatic system
idk yet
veins/sinusses
- the veins of the brain do not follow the arteries (enough pressure to move the venous blood)
- the blood pools in sinuses (veins but no muscular walls at all)
- from the sinuses it collects into the jugular vein and goes to teh vena cava
1. superior sagital S.
2. confluence of sinuses
3. transverse S.
5. sigmoid S.
6. jugular V.
