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A pulmonary and critical care physician explained how COVID-19 affects the lungs of severely sick patients and showed how breathing is restricted with an actual computerized tomography scan (CAT scan) of COVID-19 infected lungs.

"The virus will enter through your trachea into your lung and it binds to a certain receptor," said Dr. Cedric “Jamie” Rutland in Fox Nation's latest episode of "COVID Diaries."

"Once it binds to that receptor," he continued, "your immune system gets alarmed... so now you get all these cells that are going to rush to your lung. And when these cells rush to your lung, they start to fill your lung up with cells and fluid."

The new Fox Nation series brings viewers behind the scenes in hospitals across the country, using videos and testimonials collected by health care workers on the frontlines of the pandemic.

The virus triggers an "overexaggerated" immune system response in some severely ill patients, according to Rutland, and that results in lungs that are too full of cells and fluid to effectively supply the body with oxygen.

"You don't get oxygen in your bloodstream and you become extremely short of breath," he said, "That's what's so dangerous about this disease."

Using CAT scans, Rutland showed how the disease evolved in one patient over the course of two weeks.

"The first thing you're going to see is this increased whiteness -- this light grey material -- that we call ground-glass opacity (GGO)," he explained. "The lungs are supposed to be black.

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"We know that the infiltration of cells into the [lungs] causes a reduction of your gas exchange, so you get really short of breath," said Rutland. "You can't absorb that oxygen."

CAT scan of COVID-19 infected lung

CAT scan of COVID-19 infected lung

"But in this case," he went on, "you can see these white areas of the lung, first starting out with ground-glass opacity -- very light gray area -- and then as the density becomes more thick and as the cell infiltration becomes increased, you get more whiteness."

To watch all of the series "COVID Diaries," and hear physicians growing concerns about patients putting off routine testing during this pandemic, go to Fox Nation and sign up today.

And for more information on the coronavirus pandemic, watch "America Vs Virus" with Dr. Mehmet Oz, "Pandemics and Epidemics 101," with Dr. Nicole Saphier, a full-time practicing physician at Memorial Sloan Kettering Cancer Center and "Fox Nation 101: Making Vaccines," with Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security.

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