Fluid Supply to the Nervous System Flashcards
What do Arterial Blood Vessels do?
Takes blood away from the heart
What do Venous Blood Vessels do?
Takes blood back to the heart
Where is blood reoxygenated at?
The lungs
How does the sympathetic nervous system affect blood supply?
It dilates the bronchioles to bring in more oxygen to supply more blood
What artery takes de-oxygenated blood from the heart to the lungs?
Pulmonary Artery
What vein takes newly oxygenated blood back to the heart?
Pulmonary Vein
What area does the external branch of the carotid artery feed into?
Most of the face and scalp; stays outside the cranium
The brain depends on what artery?
Internal Carotid Artery
What is bifurcation of the carotid?
A split into another branch
Where does the common carotid bifurcate?
At the base of the head
What does the bifurcation of the carotid artery do?
Forms the Internal and External Carotids
What does the Vertebral Artery System do?
Feeds the spinal cord
Where does the right and left vertebral artery merge?
Foramen Magnum
What is the merging of the left and right vertebral artery called?
The Basilar Artery
What does the Basilar Artery do?
Feeds most of the brainstem
What is the Circle of Willis?
A collection of arteries int he brain that allows blood to be delivered through either internal carotid branch or vertebral branch to any portion of the cerebrum
What are capillaries?
The smallest blood vessels
What do capillaries do?
Delivers individual red blood cells to allow for diffusion of oxygen and glucose to blood cells and diffusion of CO2 and waste products from cells into blood
What are gap junctions?
Connections between neighboring cells that allow transport of small molecules from cytoplasm of cell to cell
What are connexons?
Complex of 6 protein units that form the physical bridge across gaps
What are connexins?
The individual protein units
What happens when there is a mutation of the Connexin 26 gene?
Causes congenital or progressive hearing loss in children
Takes away the recycling of K+ from cell to cell and the backlog of K+ builds up and kills hair cells
Are people with a Connexin 26 gene mutation good CI candidates?
Yes
What passes through easily in the blood-brain barrier?
Gases and water
What does not pass easily through the blood-brain barrier?
Proteins and other large molecules, like pathogens
Why does the blood-brain barrier exist?
The brain doesn’t have an aggressive immune system response
What forms the blood-brain barrier?
Tight junctions of astrocytes with/around blood vessels
What are 3 types of vascular injuries in the brain?
1.) Occlusive Vascular Pathology
2.) Hemorrhage
3.) Arteriovenous Malformations
What is anoxia?
Loss of blood supply to tissue
What is the main issue with anoxia?
Tissue will die with prolonged anoxia; this has a direct effect on the size of the brain lesion and size of injured blood vessel
What is atherosclerosis?
A gradual narrowing and hardening of blood vessels that reduces flow to the supplied tissues
How does the heart respond to atherosclerosis?
It compensates by increasing cardiac output and increasing blood pressure; it can also be overcome with blood-thinning drugs
What is the problem with blood-thinners?
It reduces the amount of platelets in the blood
What is a thromboembolism?
The adherence of fatty material and blood platelets to a vessel wall
What is an embolism?
The breaking off of the fatty material into the bloodstream
What is a thrombosis?
A complete blockage of an artery
What is a hemorrhage?
A rupture of the arterial wall and blood leaks from the artery, so capillaries and tissues do not receive their supply and die off
What is an aneurysm?
A balloon-like dilatation of an artery that is often congenital
What is the problem with an aneurysm?
It can pre-dispose the vessel to hemorrhage
What are the four Ventricles of the brain?
1.) and 2.) Lateral Ventricles
3.) Third Ventricle
4.) Fourth Ventricle
Where are the Lateral Ventricles?
Run anterior-posterior along the temporal lobe
Where is the Third Ventricle?
Sits deep in the brain below the corpus callosum
Where is the Fourth Ventricle?
Positioned near the brainstem and continuous with the central canal of the spinal cord
What does the central canal do?
Supplies the spinal cord with CSF
What are 3 things that cerebrospinal fluid does?
1.) Removes waste products from CNS
2.) Creates the fluid medium in which the brain and SC float
3.) Helps transport hormones
What does the Choroid Plexus do?
It is a bed of capillaries and ependymal cells that filter blood to produce CSF
Where is the Choroid Plexus found?
In all 4 ventricles
Where is CSF found?
Surrounds the brain and SC in the subarachnoid space and flows from ventricles
What are Ependyma?
Glial cells that line the ventricles
What does Ependyma do?
Helps circulate CSF and secrete/absorb nutrients to/from CSF
What are the 3 layers of protective coverings in the CNS?
1.) Dura Mater
2.) Arachnoid Mater
3.) Pia Mater
Where is CSF absorbed?
Through arachnoid granulations
