Posted in Journeys to the brain Resources

Brain’s blood flow: Journeys to the brain-4

Intro: I extracted and cropped several visuals for this post on brain’s blood flow from a video clip produced by the University of Utah under the Creative Commons license. The presenter who appears in the original clip is Dr Suzanne S. Stensaas, PhD, Professor Emeritus in that University. I am greatly indebted to Dr Suzanne S. Stensass, and her team for making this invaluable resource. I have cited the link at the end of this post for the benefit of anyone interested in watching the full video.  

Look at the red tube that the metal pointer is directed at (Figure 1). It is the major oxygen and food supply route to the brain. This is called the common carotid artery; the one in this illustration is the left carotid artery. We have it on the right side too. As we can see, it immediately divides into two branches – external (outside) and internal (inside).

Figure 1: carotid arteries (Courtesy: University of Utah); creative commons license

The outer branch transports oxygen and food to the face and all over the skull; the inner branch transports to the inside of the brain.

The junction where the common carotid artery divides into two is a crucial place. It is the commonplace where fat deposits, a plaque develops, and then narrowing the route happens. We can hear a sound – “bruit” – using a stethoscope. They are at high risk of getting a stroke either by cutting off the blood supply or by dislodging plaque particles. The plaque particles can travel higher through blood further inside and may cut-off blood supply to a smaller area of the brain. This type of stroke, which is the commonest type, is called an ischemic stroke.

Figure 2 (below) illustrates blood supply on the skull base. The demonstrator is pressing to the red tube’s cut surface. The red tube represents the internal branch of the carotid artery to the brain’s left side. Figure 1 shows how this branch originates.

Figure 2: Carotid arteries inside the skull (Courtesy: University of Utah); creative commons license

The green-colored tube is not a supply route; it represents nerve bundles that relay information from our eyes to its assigned location in the brain – the Occipital lobe.

This internal branch divides into smaller branches again and again just like tree branches. The purpose is to supply oxygen and food to every single neuron cells, glial cells, and all other living cells.

Experts have named these branches. The naming is useful in healthcare to communicate accurately where either a stroke or any other problem occurs.

In Figure 5, the metal pointer is directed at another supply route; it travels through bones.  

Figure 5: vertebral artery (Courtesy: University of Utah); creative commons license

This supply route joins with its sibling who brings oxygen and food from the other side to form a circle; this is called the Circle of Willis (Figure 6).

Figure 6: vertebral arteries entering the brain to the Circle of Willis (Courtesy: University of Utah); creative commons license

 Visual credit: Videos drawn from the NeuroLogic Exam and PediNeuroLogic Exam websites are used by permission of Paul D. Larsen, M.D., University of Nebraska Medical Center and Suzanne S. Stensaas, Ph.D., University of Utah School of Medicine. Additional materials were drawn from resources provided by Alejandro Stern, Stern Foundation, Buenos Aires, Argentina; Kathleen Digre, M.D., University of Utah; and Daniel Jacobson, M.D., Marshfield Clinic, Wisconsin. The movies are licensed under a Creative Commons Attribution-NonCommerical-ShareAlike License.

The information source: I extracted and cropped above stills from a video presentation presented by Dr Suzanne S. Stenaas, PhD, Professor Emeritus in the Department of Neurobiology and Anatomy of the University of Utah School of Medicine in 2012. I have no formal affiliation with the University. However, I found this valuable resource which is licensed under Creative Commons Non- Commercial use. 
Since my intention of this blog is to promote understanding what happens in a stroke among stroke carers and those involved with a stroke  I am using resources available on this website.
According to the Creative Commons regulations, I am giving due prominence to the resource and its link for my readers to gain a thorough knowledge of the topics I cover in this blog since this is a very useful resource for anyone. 
The website details are as follows: 
Neuroanatomy Video Lab: Brain Dissections by Suzanne S. Stensaas, PhD, Professor Emeritus
Department of Neurobiology and Anatomy
University of Utah School of Medicine

web link: https://library.med.utah.edu/neurologicexam/html/brain-dissections.html#10