STUDIES ON BLOOD CAPILLARIES

The pathway by which intravenously injected ferritin molecules move from the blood plasma across the capillary wall has been investigated in the muscle of the rat diaphragm. At 2 min after administration, the ferritin molecules are evenly distributed in high concentration in the blood plasma of capillaries and occur within vesicles along the blood front of the endothelium. At the 10-min time point, a small number of molecules appear in the adventitia, and by 60 min they are relatively numerous in the adventitia and in phagocytic vesicles and vacuoles of adventitial macrophages. Thereafter, the amount of ferritin in the adventitia and pericapillary regions gradually increases so that at 1 day the concentration in the extracellular spaces approaches that in the blood plasma. Macrophages and, to a lesser extent, fibroblasts contain large amounts of ferritin. 4 days after administration, ferritin appears to be cleared from the blood and from the capillary walls, but it still persists in the adventitial macrophages and fibroblasts. At all time points examined, ferritin molecules within the endothelial tunic were restricted to vesicles or to occasional multivesicular or dense bodies; they were not found in intercellular junctions or within the cytoplasmic matrix. Ferritin molecules did not accumulate within or against the basement membranes. Over the time period studied, the concentration of ferritin in the blood decreased, first rapidly, then slowly, in two apparently exponential phases. Liver and spleen removed large amounts of ferritin from the blood. Diaphragms fixed at time points from 10 min to 1 day, stained for iron by the Prussian Blue method, and prepared as cleared whole mounts, showed a progressive and even accumulation of ferritin in adventitial macrophages along the entire capillary network. These findings indicate: (1) that endothelial cell vesicles are the structural equivalent of the large pore system postulated in the pore theory of capillary permeability; (2) that the basement membrane is not a structural restraint in the movement of ferritin molecules across the capillary wall; (3) that transport of ferritin occurs uniformly along the entire length of the capillary; and (4) that the adventitial macrophages monitor the capillary filtrate and partially clear it of the tracer.

What Are Blood Vessels?

Blood vessels are intricate networks of hollow tubes that transport blood throughout the entire body.
Types of Blood Vessels

Arteries
Arteries are elastic vessels that transport blood away from the heart.

Veins
Veins are elastic vessels that transport blood to the heart.
Capillaries
Capillaries are extremely small vessels located within the tissues of the body that transport blood from the arteries to the veins.

Sinusoids
Sinusoids are extremely small vessels located within the liver, spleen and bone marrow.

Circulation
Blood vessels carry blood from the heart to all areas of the body. The blood travels from the heart via arteries to smaller arterioles, then to capillaries or sinusoids, to venules, to veins and back to the heart.

Microcirculation deals with the flow of blood from arterioles to capillaries or sinusoids to venules. As the blood moves through the capillaries, substances such as oxygen, carbon dioxide, nutrients and wastes are exchanged between the blood and the fluid that surrounds cells.

The Blood And Circulation

This page tells you about the blood and circulation. There is information on

• What the blood does
• The circulation
• What is in the blood
• White blood cells
• Red blood cells
• Platelets
• How and where blood cells are made
• Your blood and chemotherapy

What is blood for?
The blood circulates throughout the body. It carries nutrients (food) and oxygen to all the cells of the body. And carries away waste products so that they can be removed from the body. Without access to the blood, cells and body tissues die.

The blood moves around the body inside the circulatory system. This is made up of blood vessels (tubes) called arteries, veins and capillaries. The blood keeps moving through these blood vessels because it is being pumped by the heart.

Arteries carry blood that is full of oxygen from the heart to all parts of the body. As the arteries get further and further away from the heart, they get smaller and smaller.

Eventually they turn into capillaries. These are the smallest blood vessels. They go right into the tissues. Here the blood in the capillaries gives oxygen to the cells and picks up the waste gas, carbon dioxide, from the cells.

The capillaries are connected to the smallest veins in the body. The veins get bigger and bigger as they carry the blood back towards the heart.
The blood passes through the right side of the heart and goes to the lungs where it gets rid of carbon dioxide and picks up more oxygen.

It then passes through the left side of the heart and is pumped back around the body.
The blood always circulates through the body in the same direction. As well as oxygen and carbon dioxide, many other substances are carried in the blood. The blood circulating through the digestive system picks up digested food products and carries them to the liver to be used or stored.

The circulation can help explain why some cancers nearly always spread to the same place. Cancers of the colon (large bowel) often spread to the liver. This is because blood circulates from the bowel through the liver on its way back to the heart. If there is a cancer in the large bowel, and some cancer cells have found their way into the circulation, they may stick in the liver as the blood passes through. They can then begin to grow into secondary cancers.

The Blood

Although blood looks like a red liquid, if some is left in a test tube it separates out into a pale liquid called plasma and a solid layer of blood cells.
The blood is about 55% plasma and 45% cells. Plasma is mostly water with some proteins and other chemicals dissolved in it. There are three main types of cells in the blood

• White blood cells
• Red blood cells
• Platelets

White blood cells
There are several different types of white cells in the blood in differing amounts. They all play a part in the immune response. This is the response of the body to infection, or anything else the body recognises as 'foreign'. These blood cells can be made very quickly and generally have a short life. Some only live for a few hours, others for days.

There isn't an exact 'normal' figure for blood counts. 'Normal' for a large man wouldn't be the same as for a small woman. But generally the normal white cell count is between about 4,000 and 11,000 per cubic millimeter of blood. If you have surgery or an infection, your white blood cell counts will go up within a day or two.

The most numerous of the white blood cells are the neutrophils. There are between 2,000 and 7,500 of these per cubic millimeter of blood. They are important for fighting infection. If you have chemotherapy, particularly high dose, your doctors will probably talk about your neutrophil count.

The next most numerous are the lymphocytes. A normal lymphocyte count is between 1,300 and 4,000 per cubic millimeter of blood. Lymphocytes are involved in making antibodies as part of the immune response.

There are other white blood cells that are present in smaller numbers in the circulating blood. There are between

• 40 and 400 eosinophils
• 0 and 100 basophils
• 200 and 800 monocytes

per cubic millimeter of blood. As we've said, the range quoted as normal for blood cell counts does vary. These figures have come from the Oxford Handbook of Clinical Medicine.

Red blood cells
Red blood cells give the blood its red colour. There are more than 4 or 5 million of them in every cubic millimeter of blood. A red blood cell can live for up to 120 days.

Red blood cells are able to attach to oxygen to carry it within the circulation to the tissues. When they get to an area where the oxygen is needed, they give it up and pick up carbon dioxide which they carry back to the lungs. A shortage of red blood cells is called anaemia. The role of the red blood cell in carrying oxygen explains why very anaemic people usually feel breathless.

Platelets
Platelets are really bits of much bigger cells called megakaryocytes. A normal platelet count is between 150,000 and 440,000 per cubic millimeter of blood.

Platelets are very important in blood clotting. They clump together to form a plug if bleeding occurs. Then they release other chemicals that help the blood to clot and the blood vessel to be repaired.

How and where blood cells are made
All the different types of blood cells develop from one type of cell called a 'blood stem cell'. In adults, blood stem cells are normally found in the red bone marrow inside the bones. Blood cells are made in the bone marrow in the skull, ribs, sternum (breast bone), spine and pelvis.

The stem cells divide and multiply to make the blood cells. These cells differentiate (develop and mature) as they grow into white cells, red cells or platelets. It is now possible to collect stem cells and freeze them. Then give them back to you after high dose chemotherapy treatment. There is information about stem cell and bone marrow transplants elsewhere in this section of CancerHelp UK.

Chemotherapy And The Blood Cells

If you are having chemotherapy, you will know that it affects your blood counts. Chemotherapy often kills cells that are actively multiplying.

The developing blood cells are multiplying all the time as they mature. So they are also killed by the chemotherapy drugs. The white cell counts are affected first because many white cells in the circulation naturally die off within a few days at most. Normally these are replaced by newly developed white cells. But the developing white cells have been killed by chemotherapy. So there will be a short wait before more can be made. About a week or two in fact. Just in time for your next course of chemotherapy!

The mature red blood cells live for about three months. So you often don't get anaemic or low in red cells until further into your chemotherapy course (if at all). Your doctor may want you to have a transfusion of red cells or a drug called erythropoietin until you are producing red cells normally again.

Chemotherapy can also make you become very short of platelets. If you do, you may get nose bleeds, or notice a red rash on your skin like tiny bruises. Your doctor may then want you to have a platelet transfusion. After high dose chemotherapy it can take longer for the platelet count to get back to normal than any other blood cell count.

Taking Care Of Your Teeth

When you get your picture taken, everyone says, "Say cheese! Smile!" So you do - you open your mouth and show your teeth. When you see the picture, you see a happy person looking back at you. The healthier those teeth are, the happier you look. Why is that?

It's because your teeth are important in many ways. If you take care of them, they'll help take care of you. Strong, healthy teeth help you chew the right foods to help you grow. They help you speak clearly. And yes, they help you look your best.
Why Healthy Teeth Are Important
How does taking care of your teeth help with all those things? Taking care of your teeth helps prevent plaque (say: plak), which is a clear film that sticks to your teeth. The film itself might not sound so bad, but it's very sticky, and it acts like a magnet for bacteria (say: bak-teer-ee-uh) and sugar.

Like ants at a picnic, bacteria go crazy over the sugar on your teeth, breaking it down into acids that eat away tooth enamel, causing holes called cavities. Plaque also causes gingivitis (say: jin-juh-vi-tis), which is gum disease that can make your gums red, swollen, and sore. Your gums are those soft pink tissues in your mouth that hold your teeth in place.

If you don't take care of your teeth, it won't be long before cavities and unhealthy gums make your mouth very, very sore. Eating meals will be difficult. And you won't feel like smiling so much.
Before Toothpaste Was Invented

We're lucky that we know so much now about taking care of our teeth. Long ago, as people got older, their teeth would rot away and be very painful. To get rid of a toothache, they had their teeth pulled out. Finally people learned that cleaning their teeth was important, but they didn't have toothpaste right away. While you're swishing that minty-fresh paste around your mouth, think about what people used long ago to clean teeth:

• ground-up chalk or charcoal
• lemon juice
• ashes (you know, the stuff that's left over after a fire)
• tobacco and honey mixed together

Give Thanks For Healthy Teeth

Fall is upon us and Thanksgiving is here. As you gather with friends and family for your magnificent feast this year, it’s important to remember oral health because what you eat can reflect on your mouth and teeth.

Proper nutrition is essential to maintaining good oral health. Many times, improving your diet can help prevent tooth decay and gum disease. It's also important to brush and floss after eating those yummy Thanksgiving desserts!

Gum (Periodontal) Disease
Studies have shown that periodontal disease, also known as gum disease, is linked to heart attacks and strokes. Gum disease is an infection in the gums surrounding the teeth. Gum disease is also one of the main causes of tooth loss among adults. There are two major stages of gum disease: gingivitis and periodontitis. Regular dental check ups along with brushing at least twice a day and flossing daily play an important role in preventing gum disease.

Mouth Sores
There are several different types of mouth sores and they can be pesky and bothersome. Unless a mouth sore lasts more than two weeks, it is usually nothing to worry about and will disappear on its own. Common mouth sores are canker sores, fever blisters, cold sores, ulcers and thrush.

Gum (Periodontal) Disease

Periodontal disease (infection of the gum tissue and bones surrounding teeth) is an increasing health risk which will not go away by itself, but requires professional treatment.

Our Periodontal specialists are dedicated to saving teeth. Please call the Department of Periodontics clinic for information or for an appointment (319-335-7233).

What Is It?
Gum (periodontal) disease is an infection that is a major cause of tooth loss in adults. Because gum disease is usually painless and develops slowly, a person may not be aware that the infection exists.

Gum disease is caused by plaque, a sticky film of bacteria (germs) that constantly forms on the teeth. These bacteria create toxins that can eventually damage the gums and the bone surrounding the teeth.

Bleeding Gums Are Not Normal!
In the early stage of gum disease, called gingivitis, the gums become red, swell, and bleed easily. The disease is still reversible at this stage, and can usually be eliminated by careful daily brushing and flossing. In the more advanced stages of gum disease, called periodontitis, the gums and bone that support the teeth become seriously damaged. If the disease is left untreated, it can eventually lead to loss of teeth.

What are the signs of gum disease? Any of the following conditions may indicate the presence of gum disease, and a dentist or dental specialist called a periodontist should be consulted. If the gums:

• bleed when brushing teeth
• are red, swollen or tender

• have pulled away from the teeth

Or if one of the following conditions is present:

• bad breath that doesn't go away
• pus between teeth and gums
• loose teeth
• a change in the way the teeth fit together when biting
• a change in the fit of partial dentures

Remember that pain usually is not present in the early stages of gum disease.

Fighting Gum Disease: How to Keep Your Teeth

More than 75 percent of Americans over 35 have some form of gum disease. In its earliest stage, your gums might swell and bleed easily. At its worst, you might lose your teeth. The bottom line? If you want to keep your teeth, you must take care of your gums.

The mouth is a busy place, with millions of bacteria constantly on the move. While some bacteria are harmless, others can attack the teeth and gums. Harmful bacteria are contained in a colorless sticky film called plaque, the cause of gum disease. If not removed, plaque builds up on the teeth and ultimately irritates the gums and causes bleeding. Left unchecked, bone and connective tissue are destroyed, and teeth often become loose and may have to be removed.

A recent poll of 1,000 people over 35 done by Harris Interactive Inc. found that 60 percent of adults surveyed knew little, if anything, about gum disease, the symptoms, available treatments, and--most importantly--the consequences. And 39 percent do not visit a dentist regularly. Yet, gum disease is the leading cause of adult tooth loss. Moreover, a Surgeon General's report issued in May 2000 labeled Americans' bad oral health a "silent epidemic" and called for a national effort to improve oral health among all Americans.

The good news is that in most people gum disease is preventable. Attention to everyday oral hygiene (brushing and flossing), coupled with professional cleanings twice a year, could be all that's needed to prevent gum disease--and actually reverse the early stage--and help you keep your teeth for a lifetime.

In addition, several products have been approved by the Food and Drug Administration specifically to diagnose and treat gum disease, and even regenerate lost bone. These products may help improve the effectiveness of the professional care you receive. (See "FDA-Approved Products for Gum Disease".)
What Is Gum Disease?

In the broadest sense, the term gum disease--or periodontal disease--describes bacterial growth and production of factors that gradually destroy the tissue surrounding and supporting the teeth. "Periodontal" means "around the tooth."

Signs And Symptoms

Periodontal disease may progress painlessly, producing few obvious signs, even in the late stages of the disease. Then one day, on a visit to your dentist, you might be told that you have chronic gum disease and that you may be at increased risk of losing your teeth.

Although the symptoms of periodontal disease often are subtle, the condition is not entirely without warning signs. Certain symptoms may point to some form of the disease. They include:

• gums that bleed during and after toothbrushing
• red, swollen or tender gums
• persistent bad breath or bad taste in the mouth

• receding gums
• formation of deep pockets between teeth and gums
• loose or shifting teeth
• changes in the way teeth fit together on biting, or in the fit of partial dentures.

Even if you don't notice any symptoms, you may still have some degree of gum disease. Some people have gum disease only around certain teeth, such as those in the back of the mouth, which they cannot see. Only a dentist or a periodontist--a dentist who specializes in gum disease--can recognize and determine the progression of gum disease.

The American Academy of Periodontology (AAP) says that up to 30 percent of the U.S. population may be genetically susceptible to gum disease. And, despite aggressive oral care habits, people who are genetically predisposed may be up to six times more likely to develop some form of gum disease. Genetic testing to identify these people can help by encouraging early treatment that may help them keep their teeth for a lifetime.