To make sure that the blood is full of oxygen The heart operates 2 systems:

Systemic circuit

• One is called the Systemic circuit

• The Systemic circuit goes through the body

Pulmonary circuit

• The other is called the Pulmonary circuit

• The Pulmonary Circuit goes to the lungs

1. Through the villi into the capillary

2. Along the capillary, into a venule then into a vein

3. Into a mesenteric vein then into the hepatic portal vein

4. Into the liver

5. Into a venule then into a capillary in the liver lobule

6. Into the Liver lobule central vein

7. From the liver lobule central vein, into the hepatic vein

8. From the hepatic vein into the vena cava

9. From the vena cava into the heart.

Notice that the nutrient, from the intestine to the heart has travelled only through capillaries and veins

Notice that the hepatic Portal vein is called the portal vein because it connects one capillary bed (in the intestines) to another (in the liver)

10. From the heart the blood goes through the pulmonary artery to the lungs to pick up oxygen

11. From the lungs the blood returns, full of oxygen, to the heart through the pulmonary vein

12. From the heart the blood enters the aorta

13. Aorta, to the carotid artery and then to the brain

14. From the brain, back through the jugular vein, to the vena cava and back to the heart

For both circuits the blood vessels show the same pattern:

1. Heart

2. Main Artery (aorta / pulmonary artery)

3. Artery

4. Arteriole (little artery)

5. Capillary

6. Venuole (little vein)

7. Vein

8. Main Vein (vena cava / pulmonary vein)

9. Heart

The Colour of the map of the cardiovascular system indicates how much oxygen is in those blood vessels

Red means lots of oxygen

Blue means not much oxygen

This does NOT correlate with the names; arteries and veins. Look at the color of the pulmonary arteries and pulmonary veins

As the heart pumps it pushes the blood into the two circuit simultaneously. Because of this it is sometimes called a "double pump"

Because of the different sizes of the circuits, more muscle is needed to push the blood through the body then the lungs.

You can see this when looking at the heart. The Left side of the heart has more muscle as it pumps through the body. The right side doesn't have as much muscle as it pumps just to the lungs

Right Side = Lungs

Left Side = Body

The Heart has two sides:

• Right - goes to lungs

• Left - strong - goes to body

The Heart as top and bottom

• Top - Atrium (Think Atrium on Top like, Atrium on Elliot)

• Bottom - Ventricle - these to the big pumping

Blood from the Body pours into the Right Atrium, this then pours and is pushed into the Right Ventricle

When the Right Ventricle contracts, blood is pushed upwards, this closes the valves to the atrium, and forces blood through the main pulmonary artery and into the pulmonary arteries, where they go the the lungs to get oxygen

Blood returns from the lungs full of oxygen. It moves through the pulmonary veins into the Left Atrium

The left atrium contracts a little bit helping blood to pour into the Left Ventricle

When the heart beats, the high pressured, strong Left Ventricle pushes this oxygen rich blood through into the aorta where it moves into the body

Arteries

Arteries have thick muscular walls that are wrapped in elastic tissue

This is so that they can flex each time a wave of systolic blood pressure rushes along following each heart beat

Arteries are like the motorways and main roads at night time. The courier driver drives fast along these roads.

Becuase they have both a large amount of muscle and elastic tissue, once they swell with the heart beat pressure wave (that you can feel when you take your radial pulse at your wrist) they then contract. In other words, its kind of like you on your trampoline. The wave is when you land on the trampoline, it swells outwards (downwards for the tramp) but then all that elastic tissue pushes back (upwards for the tramp) this helps to then continue to push the pressure wave on its journey around the body (flingning you back up into the air for the tramp)

Capillaries

Capillaries are so small that red blood cells change shape to fit through them

Capillaries have only one cell, called an endothelial cell, making up their wall

Nutrients like glucose diffuse out of the capillaries into the tissues where it is taken up by cells.

Wastes made by those cells move through the endothelial cells or the gaps between these cell and move into the capillary

Oxygen moves from the capillary into the cells surrounding the capillary

Carbon dioxide moves from the cells surrounding the capillary, past the endothelial cells and into the capillary.

Capillaries are like through driveways, where the courier driver slows down, throws your package at you, while you throw waste at them, they then drive away

Veins

Veins have thin walls and are wide inside

With veins being wider than arteries, more blood is contained in them. Over half of your blood is in your veins (around 65%) the rest is in the arteries and capillaries.

They have thin walls because the wave of systolic blood pressure does not reach them. The wave of pressure is absorbed by the arteries, arterioles and capillaries.

Veins have valves - these valves ensure that blood in the vein only travels in one direction

These valves are called venous valves

Blood moves in veins due to the movement of the body!

When you walk, the muscle flexes, this flexing of the muscle squeezes the veins. The blood in it moves because of this squeezing, while the valves ensure that the blood can only move in one direction

The fact that the movement of your body is important for the movement of blood in veins is shown when a person like a solder or a checkout operator, stands in a spot for a very long time. Their feet will start to swell. Their feet swell because there is not enough movement in the legs for the muscles to push the blood back up to the heart. So the blood sits in the veins causing the veins to swell. It his happens too often, then the valves have too much blood sitting on them, and they can snap. This causes Veracious Veins to form.

This lack of blood movement is also a problem if you sit for a long time. You need to get up and 'stretch your legs' every now and then so that the muscle will contract and push the blood back up to the heart.

On planes that fly for hours on end, you are trapped in your seat. You should really get up and walk to the loo, even if you don't need to go, you don't have to go in, just get there then spin around and go back to your seat. However, because it is often awkward to climb past everyone, people usually wait to go to the loo when they are busting. Anyway, because people are sitting far longer than is normal for our species, the blood pools in the veins of the legs. Eventually the blood sits here for so long that clots can form, this is Deep Vein Thrombosis.

Veins have almost no pressure inside them compared

This is so that they can flex each time a wave of systolic blood pressure rushes along following each heart beat

Veins are like the motorway during heavy traffic (remember that 65% of your blood is in the veins), lots of blood cells moving rather slowly back to the depot.

Plasma is mostly water

There are few other things in the plasma.

• Albumin - this maintains the osmotic balance in the blood compared with the tissues

• Nutrients: Glucose, amino acids, fats, minerals, vitamins

• Antibodies

• Waste products like urea, bilirubin, dissolved carbon dioxide.

Platelets are the tiny mini cells that do not contain a nucleus.

Platelets do have mitochondria so they conduct both aerobic and anaerobic respiration!

These tiny mini cells are sometimes called cell fragments because they are so small

Platelets block up any cuts in the blood vessels.

They clot any cuts and start the repair.

There are a range of different White blood cells. They provide a united front against bacteria, viruses, parasites and mutated cells.

Puss is white because a huge army of white blood cells is in there to fight bacteria

White Blood Cells are also called WBC's, and they are called Leukocytes (leuko = white, cyte = cells)

White Blood Cells are easy to find on a slide of blood because they still have their nucleus, this stains purple below

Note, Red blood cells do not have a nucleus

45% of the blood is Red Blood Cells

Red Blood Cells are also called RBS's or Erythrocytes

Red Blood Cells are full to the top with hemoglobin

Red Blood Cells do not have a nucleus!

They do no protein synthesis and last for only about 3 months

Red Blood Cells do not have any mitochondria!

Red Blood Cells only do Anaerobic respiration.

This is important as it means that they don't use the oxygen that they carry.

This is the reason that they do not have any mitochondria.

So, Red Blood cells are oxygen carrying cells that make up 45% of your 6 Liters of blood

The oxygen is held next to Iron in molecule hemoglobin.

When in the lungs, where there is lots of oxygen, the hemoglobin picks up oxygen. As the hemoglobin gets to areas that have lower oxygen concentration it gives up the oxygen.

Red Blood Cells are made in the bone marrow.

Red Blood cells are flexible and bend when they are in capillaries. This is why they have that donut shape. When in a big artery of vein, they are the normal donut shape, but when they are in capillaries they become more like a hat shape or an umbrella shape.

When Red Blood Cells are old they stop being so flexible. As they go through the capillaries of the Spleen, they get caught in the capillaries, they are then recycled by the spleen, with the cell bits turned into nutrients and the heme sent to the liver to get the iron out and to get rid of the rest of it in bilirubin through the bile and into the feces (making it brown)