Animal Transport Systems

This section of Biology is absolutely awesome. We get to learn about the blood and the big muscle that pumps it all around your body - the heart.

Oxygen and Nutrients are transported around the body in the blood within your blood vessels.

Large surface area allows transport across membranes to be very efficient, allowing nutrients to travel from the blood into organs.

Blood Cells
Blood is made up of red blood cells, white blood cells, plasma and platelets.
The role of red blood cells is to transport oxygen around your body using haemoglobin.
White blood cells work with the immune system to fight off infectious diseases and pathogens.
Plasma is the fluid of the blood that allows movement of cell such as red and white blood cells.
Platelets are in charge of clotting blood, incase there is a breach of blood vessels, such as a cut or unexpected burst of a blood vessel.

Red Blood Cells and Haemoglobin
Red blood cells are specialised cells, with a biconcave shape. They transport a haemoglobin and don’t contain a nucleus.
The biconcave shape of red blood cells provides more surface area, making these cells efficient at transporting oxygen. Not having a nucleus gives the cells more room for haemoglobin.
Haemoglobin is the protein within red blood cells that binds oxygen.
Haemoglobin allows oxygen to be transported around the body. It picks up oxygen from the lungs when you breath in and transports it all around the body.
When haemoglobin pick up oxygen from the lungs, it is called oxyhemoglobin.

White Blood Cells
White Blood cells are part of the immune system. This is the body’s defence mechanism agains bacteria and toxins.
The two main white blood cells that you need to be aware of in National 5 are Phagocytes and Lymphocytes.
Phagocytes engulf pathogens and destroy them. These cells are not specific.
Lymphocytes create antibodies which act to kill pathogens. These antibodies are specific to individual pathogens.
Antibodies are amazing proteins that kill pathogens and have limitless use in the world of medical research.

The Heart
The heart is a large muscle that pumps blood around the body. This blood transports oxygen and nutrients to all of the organs in your body.
Image the heart is like a house, with two rooms upstairs and two floors downstairs. These rooms of the heart are called chambers:
You have the left and right atria (upstairs rooms)
And the left and right ventricles (downstairs rooms)
The left and right sides of the heart are separate. The right side of the heart takes deoxygenated blood from the rest of the body through the right atrium, which then travels to the right atrium. The right atrium then pumps blood to the lungs, where the blood takes in oxygen.
The oxygenated blood then travels from the lungs to the left side of the heart into the left atrium, which then travels to the left ventricle. The left ventricle then pumps the oxygenated blood out into the rest of the body.
Valves separate the atria from the ventricles and the ventricles from the blood vessels they pump blood into. Valves stop the back flow of blood.
You also need to know the 4 large blood vessels that take blood to and from the heart.
Aorta, Vena Cava, Pulmonary Vein and Pulmonary Artery.
The coronary arteries are blood vessels that bring blood directly to the muscle of the heart to allow the heart to work. If one of these coronary arteries gets blocked, the heart muscle can become starved of oxygen and nutrients. This is called a myocardial infarction, or a heart attack.

Blood Vessels
Blood vessels are the tubes that transport blood around the body.
Arteries are blood vessels that carry blood away from the heart and towards organs. These are muscular blood vessels, with high pressure. So, in movies or TV shows when you see blood comically squirting, this is probably coming from an artery, as there is high blood pressure in these vessels.
Veins carry blood away from organs and towards the heart. These are fairly thin blood vessels with low pressure. They contain valves to stop the back flow of blood. Veins are often drawn as blue as they contain deoxygenated blood.
Capillaries are the smallest blood vessels in the body. There are large beds of capillaries within organs which allow the transfer of nutrients and oxygen from the blood to travel into the organ tissues. Waste can also transfer into and out of capillaries.
So, the journey of blood goes:
Left side of heart -> Arteries -> Capillaries -> Veins -> Right side of heart -> Lungs -> Left side of heart.
Note - The pulmonary vein contains oxygenated blood and the pulmonary artery contains deoxygenated blood. These are the only two vessels in the body where the oxygenation of the blood doesn’t match the name of the vessel. This is because the pulmonary artery is carrying blood AWAY from the heart, towards the lungs, making it an artery, and the pulmonary vein is carrying blood TOWARDS the heart, making it a vein.

Key Points!

Blood Cells

Blood is made up of red blood cells, white blood cells, plasma and platelets.
The role of red blood cells is to transport oxygen around your body using haemoglobin.
White blood cells work with the immune system to fight off infectious diseases and pathogens.
Plasma is the fluid of the blood that allows movement of cell such as red and white blood cells.
Platelets are in charge of clotting blood, incase there is a breach of blood vessels, such as a cut or unexpected burst of a blood vessel.
Red Blood Cells and Haemoglobin

Red blood cells are specialised cells, with a biconcave shape. They transport a haemoglobin and don’t contain a nucleus.
The biconcave shape of red blood cells provides more surface area, making these cells efficient at transporting oxygen. Not having a nucleus gives the cells more room for haemoglobin.
Haemoglobin is the protein within red blood cells that binds oxygen.
Haemoglobin allows oxygen to be transported around the body. It picks up oxygen from the lungs when you breath in and transports it all around the body.
When haemoglobin pick up oxygen from the lungs, it is called oxyhemoglobin.
White Blood Cells

White Blood cells are part of the immune system. This is the body’s defence mechanism agains bacteria and toxins.
Phagocytes engulf pathogens and destroy them. These cells are not specific.
Lymphocytes create antibodies which act to kill pathogens. These antibodies are specific to individual pathogens.
Antibodies are amazing proteins that kill pathogens and have limitless use in the world of medical research.
The Heart

The oxygenated blood then travels from the lungs to the left side of the heart into the left atrium, which then travels to the left ventricle. The left ventricle then pumps the oxygenated blood out into the rest of the body.
Valves separate the atria from the ventricles and the ventricles from the blood vessels they pump blood into. Valves stop the back flow of blood.
You also need to know the 4 large blood vessels that take blood to and from the heart.
Aorta, Vena Cava, Pulmonary Vein and Pulmonary Artery.
The coronary arteries are blood vessels that bring blood directly to the muscle of the heart to allow the heart to work. If one of these coronary arteries gets blocked, the heart muscle can become starved of oxygen and nutrients. This is called a myocardial infarction, or a heart attack.
Blood Vessels

Blood vessels are the tubes that transport blood around the body.
Arteries are blood vessels that carry blood away from the heart and towards organs. These are muscular blood vessels, with high pressure. So, in movies or TV shows when you see blood comically squirting, this is probably coming from an artery, as there is high blood pressure in these vessels.
Veins carry blood away from organs and towards the heart. These are fairly thin blood vessels with low pressure. They contain valves to stop the back flow of blood. Veins are often drawn as blue as they contain deoxygenated blood.
Capillaries are the smallest blood vessels in the body. There are large beds of capillaries within organs which allow the transfer of nutrients and oxygen from the blood to travel into the organ tissues. Waste can also transfer into and out of capillaries.
So, the journey of blood goes:
Left side of heart -> Arteries -> Capillaries -> Veins -> Right side of heart -> Lungs -> Left side of heart.