The Circulatory system

(Summerize version)

1. The Circulatory System as a Transport Network

The blood system acts as a transport system, utilizing the heart (the vital pump) to circulate blood through blood vessels. It ensures every cell receives a continuous supply of "fresh blood," transporting:

Nutrients: Digested food and salts.
Gases: Oxygen and Carbon Dioxide.
Regulators & Waste: Hormones, heat, and waste materials.

2. Components of the Blood

Blood is a living fluid composed of four main parts:

Red Blood Cells (RBCs): Transport oxygen. They contain haemoglobin, which binds with oxygen in the lungs to form oxyhaemoglobin. RBCs lack a nucleus to maximize space for haemoglobin.

* Reaction: Oxygen + Haemoglobin \rightleftharpoons Oxyhaemoglobin

White Blood Cells (WBCs): The body's defense system.
Phagocytes: Have oddly shaped nuclei; they "eat" and kill germs at wound sites.
Lymphocytes: Have round nuclei; they produce antibodies to attack foreign surface proteins.
Plasma: A watery fluid (90% water) that carries the blood cells, platelets, dissolved food, CO2, hormones, and heat.
Platelets: Tiny cell fragments responsible for clotting. They form a network of protein fibers to trap cells, creating a clot (and eventually a scab) to stop bleeding and block germs.

3. The Blood Vessels

Blood travels at high pressure through three types of tubes:

|---|---|---|---|

4. Anatomy of the Heart

The heart is divided into chambers with specific roles:

Atria (Upper): Smaller, thinner walls; receiving chambers connected to veins.
Ventricles (Lower): Larger, thicker muscular walls; pumping chambers connected to arteries.

Note: The left ventricle is the largest and most muscular because it must pump blood to the entire body.

5. The Double Circulation Loop

Blood moves through two distinct circuits to ensure efficient oxygenation:

A. Pulmonary Circulation (Heart \leftrightarrow Lungs)

1. Deoxygenated blood enters the Right Atrium via the Venae Cavae.

2. It is pumped through the tricuspid valve into the Right Ventricle.

3. The Pulmonary Arteries carry it to the lungs to pick up oxygen.

4. Oxygenated blood returns via Pulmonary Veins to the Left Atrium.

B. Systemic Circulation (Heart \leftrightarrow Body)

1. Oxygenated blood moves from the Left Atrium to the Left Ventricle.

2. It exits through the Aorta (the main artery) to the rest of the body.

3. Major branches include the Carotid artery (to the brain/face) and the Subclavian artery (to the arms).

4. After the body uses the oxygen, deoxygenated blood returns to the right side of the heart to begin the cycle again.

(Full detailed version)

Blood is a red fluid or liquid that is living and travelling around the body in special tubes called blood vessels. These blood vessels supply blood to and collect blood from all cells of the body. The heart, the body’s most vital organ, pumps the blood and keeps it circulating around to ensure that every cell in the body always has a continuous supply of fresh blood. Blood carries digested food, oxygen, waste materials, heat and more around the body. This is why we call the blood system a transport system. Red Blood Cells The red blood cells transport oxygenaround the body. They contain a red pigment called haemoglobin. When there is a lot of oxygen, as in the lungs, hemoglobin readily joins up with oxygen to form oxyhemoglobin. Oxygen is carried around the body as oxyhemoglobin in the red blood cells. When the cells reach an area that is low in oxygen, as in the body’s cells, the oxyhaemoglobin releases the oxygen.

Oxygen + Haemoglobin Oxyhaemoglobin

Oxyhaemoglobin Oxygen + Haemoglobin

Red blood cells are unusual in that they do not have a nucleus. This means that they can contain hemoglobin and are therefore very efficient at carrying oxygen. White Blood Cells There are fewer white blood cells.They help to defend the body against disease-causing germs. The white blood cells with oddly shaped nuclei are called phagocytes. They attack germs by eating them. If you cut yourself, germs can get into your body. The phagocytes come to your rescue and rush to the wound. They start eating and killing the germs. The white blood cells with round nuclei are called lymphocytes. They also protect us from germs that get inside our bodies by producing special proteins called antibodies. Antibodies attack the surface proteins on the germs and this kills them. If something gets into the body that the white blood cells recognize as being ‘foreign’ to the body they go on the attack. When organs are donated from one individual to another, the body starts rejecting these organs because they are not accustomed to it. Since then doctors have tried to erase this problem by treating them with drugs or using organs from individuals with similar chemistry.

Plasma

The red and white blood cells are carried in the plasma. It is a watery fluid which contains 90% water. It also carries dissolved food, carbon dioxide, hormones, waste substances, salts, heat and platelets.

Platelets

Platelets are tiny pieces of blood cells that play a part in the clotting of blood. When we cut ourselves the cut bleeds for a while then stops. The reason for this is that a network of tiny protein fibers forms in the cut and traps the blood cells and platelets. The clot forms as a result, then it dries up to form a scab that Blood is carried at high pressure,in the blood vessels, to all the cells of the body.

There are three types of blood vessels: arteries, veins and capillaries.

Arteries

Arteries carry blood away from the heart and to the body’s organs and tissues. Arteries have thick, muscular walls so it can withstand the high pressure of the blood being pumped directly from the heart. Arteries usually carry oxygenated blood. The pulmonary arteries are exceptions because they carry deoxygenated blood from the heart to the lungs.

Veins

Veins collect blood from the capillaries in the body and carry the blood to the heart.Veins have thin, less muscular walls because there is less pressure pushing the blood along. Veins usually carry deoxygenated blood. The pulmonary veins are exceptions because they carry oxygenated blood from the lungs to the heart. They also have valves to prevent the back flow of blood. The valves are flaps that push open as the blood flows through and move back to stop the blood from flowing backwards. prevents germs from entering. After a few weeks we will no longer see where the cut was; however, if the wound is very deep then it leaves a scar. Are smaller and have thinner, less muscular walls than the ventricles. Have thicker, more muscular walls than the atria. Are receiving chambers of the heart. Are the larger, stronger pumping chambers that send blood out of the heart.Connected to the veins that carry

blood to the heart

Connected to the arteries that carry

blood away from the heart.

The Flow of Blood

Deoxygenated blood returning from the

body first enters the heart from the

venae cavae. The blood enters the right

atrium and is pumped through the

tricuspid valve into the right

ventricle. This blood is pumped through

the pulmonary arteries into the lungs

where the red blood cells pick up

oxygen.

Oxygenated blood is carried back to the

heart from the lungs in the pulmonary

veins to the left atrium. The blood

then flows into the left ventricle, the

biggest and most muscular chamber of

the heart. Oxygenated blood leaves the

left ventricle by the aorta, which

takes blood to the body via its system

of blood vessels - arteries,

arterioles, and capillaries.

The Flow of Blood

Major arteries leading from the heart

(via the aorta) include the carotid

artery which supplies blood to the

brain, neck and face, and the left

subclavian artery which supply our arms

with blood. These are just a few of the

main arteries of the body.

Pulmonary

Circulation

Deoxygenated blood

from the right side

of the heart is

pumped to the lungs

and returns to the

left side of the

heart as oxygenated

blood.

Thus, the pulmonary

loop only transports

blood between the

heart and the lungs.

Systemic

Circulation

Oxygenated blood from

the left side of the

heart is pumped to

rest of the body and

returns to the right

side of the heart as

deoxygenated blood,

after the body uses

the oxygen.

Thus, the systemic

loop transports blood

between the heart and

the rest of the body.

Can you summerize these note without stripping away the original content