What is the Main Function of Blood?

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iStock

What is the main function of blood?

Ray Schilling:

Blood has many functions.

1. Most of all, blood transports oxygen from the lungs to all the tissues by way of hemoglobin that is embedded in the red blood cells. On the way back to the heart and lungs it transports CO2, which is exhaled by the lungs.

2. Nutrients are taken up in the capillaries of the gut, transported via the portal vein into the liver. Here many metabolic pathways are followed and the nutrients are further transported through the blood to all of the body cells.

3. Clotting factors in the plasma of the blood together with platelets contained in the blood see to it that any tiny tears or holes are immediately plugged. Blood has a certain blood pressure, so any defect cannot be tolerated or this could lead to a major bleed. It is interesting that coagulation from clotting factors/platelets and fibrinolysis are constantly balancing each other automatically.

4. Infection is being contained by white blood cells (lymphocytes for viruses, neutrophils for bacteria) on the one hand and antibodies from plasma cells on the other hand. This is quite an effective system to fight infection. Occasionally antibiotics are needed when our immune system is overwhelmed.

5. Hormones and other signaling molecules (e.g. nitric oxide) integrate the function of various organs. As long as all hormones are present and balanced we have energy and all our organs function perfectly. But when hormones are missing, we feel miserable. As we age, some hormones are not produced sufficiently. Having reviewed the literature, bioidentical hormone replacement will allow our system to get rebalanced.

6. Heat distribution and blood redistribution are other aspect of perfusion of our limbs with blood, our abdominal organs, the head and skin. After a meal the blood is rushing to the gut and the liver as we start to digest our meal. We may get tired, because some of the blood from the brain gets pulled away to the stomach, small intestine and the liver. On a hot day our skin veins open up wide, we sweat and lose some of our body heat through our skin. It’s the body’s way to keep us cool inside.

7. There is one aspect that seems to be out of our control. When we get excited or a person is extremely shy, the head, neck, and the ears will turn red. This is out of our control. Some people have this more than others and some don't have it at all. It comes from dilated skin blood vessels. When they dilate, blood rushes into that region giving your skin a reddened appearance.

This post originally appeared on Quora. Click here to view.

What Happened to the Physical Copy of Martin Luther King's 'I Have a Dream' Speech?

AFP, Getty Images
AFP, Getty Images

On August 28, 1963, Martin Luther King Jr. stood on the steps of the Lincoln Memorial and gave a speech for the ages, delivering the oratorical masterpiece "I Have a Dream" to nearly 250,000 people.

When he was done, King stepped away from the podium, folded his speech, and found himself standing in front of George Raveling, a former Villanova basketball player who, along with his friend Warren Wilson, had been asked to provide extra security around Dr. King while he was speaking. "We were both tall, gangly guys," Raveling told TIME in 2003. "We didn't know what we were doing but we certainly made for a good appearance."

Moved by the speech, Raveling saw the folded papers in King’s hands and asked if he could have them. King gave the young volunteer the speech without hesitation, and that was that.

“At no time do I remember thinking, ‘Wow, we got this historic document,’” Raveling told Sports Illustrated in 2015. Not realizing he was holding what would become an important piece of history in his hands, Raveling went home and stuck the three sheets of paper into a Harry Truman biography for safekeeping. They sat there for nearly two decades while Raveling developed an impressive career coaching NCAA men’s basketball.

In 1984, he had recently taken over as the head coach at the University of Iowa and was chatting with Bob Denney of the Cedar Rapids Gazette when Denney brought up the March on Washington. That's when Raveling dropped the bomb: “You know, I’ve got a copy of that speech," he said, and dug it out of the Truman book. After writing an article about Raveling's connection, the reporter had the speech professionally framed for the coach.

Though he displayed the framed speech in his house for a few years, Raveling began to realize the value of the piece and moved it to a bank vault in Los Angeles. Though he has received offers for King’s speech—one collector wanted to purchase the speech for $3 million in 2014—Raveling has turned them all down. He has been in talks with various museums and universities and hopes to put the speech on display in the future, but for now, he cherishes having it in his possession.

“That to me is something I’ll always be able to look back and say I was there,” Raveling said in the original Cedar Rapids Gazette article. “And not only out there in that arena of people, but to be within touching distance of him. That’s like when you’re 80 or 90 years old you can look back and say ‘I was in touching distance of Abraham Lincoln when he made the Gettysburg Address.’"

“I have no idea why I even asked him for the speech,” Raveling, now CEO of Coaching for Success, has said. “But I’m sure glad that I did.”

What is a Polar Vortex?

Edward Stojakovic, Flickr // CC BY 2.0
Edward Stojakovic, Flickr // CC BY 2.0

If you’ve turned on the news or stepped outside lately, you're familiar with the record-breaking cold that is blanketing a lot of North America. According to The Washington Post, a mass of bone-chilling air over Canada—a polar vortex—split into three parts at the beginning of 2019, and one is making its way to the eastern U.S. Polar vortexes can push frigid air straight from the arctic tundra into more temperate regions. But just what is this weather phenomenon?

How does a polar vortex form?

Polar vortexes are basically arctic hurricanes or cyclones. NASA defines them as “a whirling and persistent large area of low pressure, found typically over both North and South poles.” A winter phenomenon, vortexes develop as the sun sets over the pole and temperatures cool, and occur in the middle and upper troposphere and the stratosphere (roughly, between six and 31 miles above the Earth’s surface).

Where will a polar vortex hit?

In the Northern Hemisphere, the vortexes move in a counterclockwise direction. Typically, they dip down over Canada, but according to NBC News, polar vortexes can move into the contiguous U.S. due to warm weather over Greenland or Alaska—which forces denser cold air south—or other weather patterns.

Polar vortexes aren't rare—in fact, arctic winds do sometimes dip down into the eastern U.S.—but sometimes the sheer size of the area affected is much greater than normal.

How cold is a polar vortex?

So cold that frozen sharks have been known to wash up on Cape Cod beaches. So cold that animal keepers at the Calgary Zoo in Alberta, Canada once decided to bring its group of king penguins indoors for warmth (the species lives on islands north of Antarctica and the birds aren't used to extreme cold.) Even parts of Alabama and other regions in the Deep South have seen single-digit temperatures and wind chills below zero.

But thankfully, this type of arctic freeze doesn't stick around forever: Temperatures will gradually warm up.

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