Arterial Circulatory system Flashcards
Label the image from top to bottom
- Endothelial lining
- Intima
- Media
- Adventitia
What are the three layers of vessel walls?
- Tunica Intima
- Tunica media
- Tunica adventicia
Which is the thickest layer of the Vessel walls?
Tunica media
Which layer of the vessel wall is in contact with blood?
Tunica Intima
Which layer of the vessel walls consists of tissue, nerve fibers and small vessel capillaries?
Tunica adventicia
How are arteries classified?
According to size
What is the classifications of the arteries?
- Arterioles
- Small and medium sized arteries
- Large elastic arteries
What are arterioles?
They are the main providers of resistance to blood flow within the vascular system.
What controls the extent of contraction of arterioles?
Circular smooth muscle
What are small and medium sized arteries?
All arteries except the aorta and its major branches. Contains well- developed smooth muscle layers and more elastic tissue than arterioles
What are large elastic arteries ?
Aorta and its largest branches. Contains a large amount of elastic fibers within their walls and less smooth muscle cells
The brain is directly supplied by what?
Four vessels
1. Two internal carotid arteries
2. Two vertebral arteries
Blood supply to the central nervous system is delivered by what?
The great vessels coming off the aortic arch
What is included in the aortic arch?
- Brachiocephalic
- Left common carotid
- Left subclavian
The Brachiocephalic (innominate) arteries travel how? What do they join?
Upward and slightly posterior from the arch to the right side of the neck.
At the upper boarder of the right sternoclavicular junction what does the Innominate/ Brachioscephlic do?
It divides into the right common carotid artery and the right subclavian artery
Label the black areas
The left CCA ascends from the arch and passes beneath what?
Left sternoclavicular joint
The CCAs do not have branches, but they divide into what?
They divide into the internal and external carotid arteries at the upper boarder of the thyroid cartilage
What is the carotid bulb?
The part of the vessel that becomes enlarged at the level of the carotid bifurcation
Label the image
The ICA start where?
At the carotid bifurcation and travels upwards as a single vessel until they enter the cranium and bifurcate
What supplies most of the anterior circulation of the cerebrum (Brain)?
The ICAs
The cervical (neck) ICA contains no __________ until it enters the cranium?
branches
What is the pathway of the cervical ICA?
Relatively straight or may take a tortuous path as they travel to the base of the cranium
What is the first branch of the ICA?
Ophthalmic artery
What does the ICA arise from?
Arises at the level of the carotid siphon
Within the cranium the ICA bifurcates into what?
the Middle cerebral artery (MCA) and anterior cerebral artery (ACA)
Label the image
The ophthalmic artery arises at the level of what? and travels how?
Arises at the level of the carotid siphon and travels anterior through the optic canal to the orbit
If the ICA becomes occluded the ophthalmic artery can anastomose with what?
The follow branches of the ECA to create collateral flow
1. Supraorbital artery
2. Frontal artery
3. Nasal artery
What is the supraorbital artery?
Lies over the top of the eyeball and passes through the supraorbital foramen
What is the frontal artery?
Lies towards the inner aspect of the eye along the top
What is the nasal artery?
Most medial branch and terminates close to the bridge of the nose, as the angular artery. The facial artery terminates in the same area
The ECAs normally do not supply blood to the brain, however, in the event of what does it supply the brain?
Occlusion
In the event of an occlusion several of the branches of the ECA does what?
Anastamose with the ICA or vertebrals to provide collateral flow
The ECA gives off the what branches?
- Ascending pharyngeal
- Superior thyroid (1st branch)
- Lingual
- Occipital
- Facial
- Posterior auricular
- Internal maxillary
- Transverse facial
- Superficial temporal arteries
Fast is lop
The ECA branches most vital to collateral circulation are those that are what?
In communication with the ophthalmic artery as well as those that interconnect between the muscular branches of the occipital and vertebral arteries
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What does the vertebral arteries supply?
The posterior circulation of the brain
What does the vertebral arteries lie within?
The transverse foramina of the upper cervical vertebrae
How does the vertebral arteries course?
They course anteriorly into the subarachnoid space at the side of the medulla oblongata at the level of the atlanto- occipital interspace
The vertebral arteries travel how? and Join where?
The vertebral arteries travel cephalad and anteriorly until they join at the pontomedullary level to create the basilar artery
The basilar artery contains how many branches?
4
The basilar arteries feed what?
- The pons
- Anterior and posterior cerebellum
Label the image
How/where does the circle of willis form?
At the base of the brain the cerebral branches of the ICA and vertebral arteries join to form the circle of willis
What provides the most important collateral circulation intracranially?
The circle of willis
As a collateral for circulation how does the circle of willis connects vessels?
It connects the anterior and posterior circulation when needed.
What is a frequent site of aneurysm intracranially is what?
The circle of willis
What supplies the majority of the brain?
The ACA
There are many _______ _______ with absence or hypoplasia of one or more of the communication arteries being what?
- Congenital variations
- Most common
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