Cerebral circulation

Therapeutic hyperventilation may treat acute cerebral edema unresponsive to other interventions. Which changes during hyperventilation enhance cerebral perfusion pressure (CPP)?

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Cerebral perfusion p. 512

Cerebral perfusion pressure (CPP) p. 513

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Jerry Ferro,Victoria Cumberbatch,Elizabeth Nixon-Shapiro, MSMI, CMI

With cerebral circulation, cerebral stands for "brain," and circulation, refers to “blood flow.”

So, cerebral circulation is the movement of blood through the vessels that supply the brain and surrounding structures.

Our brain is responsible for complex functions such as thinking, feeling, memory, movement, vision, and speech.

Therefore, some of the devastating effects of oxygen deprivation to the brain include strokes, seizures, coma, and even death.

As a result, the brain requires a very efficient cerebral circulation to provide oxygen and nutrients, and remove carbon dioxide and wastes.

Now, like any other organ in the body, the blood supply to the brain, originates from the aorta.

Arising from the heart’s left ventricle, it goes on to form the aortic arch. Here, the brachiocephalic artery, originates first.

This branch gives off the right subclavian artery and the right common carotid artery.

Then a bit further along the aortic arch, the left common carotid artery arises, followed by the left subclavian artery.

The subclavian arteries give off right and left vertebral arteries, which ascend through the intervertebral feramina up to the brain.

Because the consequences of hypoxia to the brain are so devastating, the brain is safeguarded by having a dual circulation, an anterior circulation, originating from the carotids, and a posterior circulation, originating from the vertebral arteries.

The two circulations eventually meet up, creating what’s known as the circle of Willis.

Alright, the anterior circulation starts in the neck, where the common carotid splits into the external and internal branches, the internal carotid arteries, passes through the carotid canal of the temporal bone of the skull and into the cranial cavity to supply the brain.

Once, it enters the cranial cavity, the internal carotid artery gives off branches. First are the middle cerebral arteries that supply blood to the temporal and parietal lobes.

Second are the anterior cerebral arteries, which provide to the midline portions of the frontal lobes and superior medial parietal lobes of the brain.

Both anterior cerebral arteries are connected through the anterior communicating artery, forming the anterior portion of the circle of willis.

The posterior circulation starts with the vertebral arteries,which head up towards the cranium through the transverse foramina of the cervical vertebrae and then through the foramen magnum into the cranial cavity.

Summary

The cerebral circulation is responsible for delivering oxygen and nutrients to the brain and removing carbon dioxide and other waste products. To ensure an uninterrupted blood supply to the brain, cerebral circulation consists of anterior and posterior parts. These two circulations, together, form a network of vessels known as the arterial circle of Willis. The anterior circulation consists of the internal carotid arteries and branches, which are the middle and anterior cerebral arteries. The anterior communicating artery connects the two anterior cerebral arteries.

The posterior circulation comes from the two vertebral arteries, which merge into the basilar artery and split into posterior cerebral arteries. Posterior cerebral arteries give off the left and right posterior communicating arteries, which then merge with the internal carotid arteries. Venous blood drains into the dural sinuses, which empty into the jugular veins and return to the heart through the superior vena cava.

Cerebral circulation

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