BLOOD SUPPLY OF CNS/ MENINGES/ VENTRICULAR SYSTEM/ CSF PRODUCTION Flashcards
How is CSF produced
- is produced by the choroid plexus- a vascular proliferation of the ependymal layer- in lateral and 3rd and 4th ventricles
- is produced by ultrafiltration of plasma and active transport
What is CSF
Cerebrospinal fluid
Has low protein and glucose levels due to ten needing t be actively transported
What is the function of CSF
- protection - separates the brain from blood
- Support- buoyancy
- Nutrition
How is CSF production regulated
- rate of CSF production depends on blood pressure
- Arachnoid villi act as one way valves to regulate pressure within the CSF
Where is CSF outside the brain
The meninges
What are the 3 layers of the meninges
- Dura mater
- Arachnoid mater
- Pia mater
Where is th dura mater found
Outer layer of the meninges
In skull= attaches to periosteum
In spinal cord= separates from periosteum by the epidural space filled with fat
Decribe the arachnoid mater
-fine layer found intbetween the dura and pina mater
Describe the pina mater
Thin layer which is adherent to undying brain and spinal cord
Describe the lateral ventricles
Found in the telencephalon
- there is variation in size between individuals and breeds
- often difference in size between the 2 sides of the brain
What is the functions of the meninges
- protection
- containment of CSF
- maintenance of blood brain barrier
- support
What is the blood brain barrier
Is the selective barrier between the circulating blood and the functional tissue of the nervous system
What are the capillaries of the brain surrounded by
- closed overlapping epithelium
- dense basement membrane
- processes of astrocytes
Which pairs of vessels supply the brain
- Rostral cerebral arteries
- Middle cerebral arteries
- Caudal cerebral arteries
- Rostral cerebellar arteries
- Caudal cerebellar arteries
What does the rostral cerebral arteries supply
Medial aspect of the cerebral hemispheres
What does the middle cerebral arteries supply
Lateral and ventrolateral aspects of the cerebral hemispheres
What does the caudal cerebral arteries supply
Occipital lobes
Why does the rostral cerebellar arteries supply
The rostral aspects of the cerebellum
What does the caudal cerebellar arteries supply
Caudal and lateral aspects of the cerebellum
Describe the structure and location of the arterial circle (circle of Willis)
Sits on base of brain around the pituitary gland with blood vessels radiating off
It is supplied by the basilar artery underneath and internal carotid artery at the top
What artery up plies the internal carotid artery
Can either be supplied by the: -common carotid artery -external carotid artery - vertebral artery Varies between species
What is the maxillary rete mirabile and what does it do
Is a network of vessels located within the cavernous sinus, it is postulated to cool the blood or reduces fluctuations from pulsatile flow
Describe the blood supply to the spinal cord
Supplied through the segmental arteries: -cervical -vertebral artery -thoracic- intercostal artery -lumbar- aorta Which then separate t supply blood to the whole spinal cord