Heart, Blood and blood vessels

What is blood?

Blood is **tissue** consisting of plasma, in which the red cells, white blood cells and platelets are suspended.

What are the 3 different types of blood vessel?

* Arteries
* veins
* capillaries

Label x (the top) and y (the bottom)

x= trachea

y= bronchi

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How is the alveolus adapted for diffusion?

* many alveoli provides a larger surface area to volume ratio- maximizing oxygen absorption

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* Moist surface- allows oxygen to readily dissolve

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* capillaries are thin (one cell thick)- minimizes diffusion distance/short diffusion pathway

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* large capillary network (provides good blood supply)- for efficient gas exchange with red blood cells/ to maintain a concentration gradient/ to remove oxygenated blood and bring carbon dioxide to lungs quickly

Which one is the artery? and what is its function?

**x**

The wall of arteries is very thick compared to the size of the hole (lumen). Their walls are thicker than walls of veins to withstand high blood pressure.

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* They have elastic fibres, allowing them to stretch and spring back.

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Arteries transport blood away from the heart. (usually at a high pressure)

Which one is the vein? and what is its function?

**Z** They have a large lumen and doesn’t need thick walls because the blood is at low pressure. \ Veins transport blood to the heart (usually at a low pressure)

Which one is the capillary? and what is its function?

**Y**

Capillaries are very small with walls that are usually only one cell thick.

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Capillaries have thin walls which allows substances to leave the blood to reach the body’s tissue.

How is blood prevented from flowing backwards in the vein?

Veins contains valves

which can close/shut

which prevents the black-flow of blood

Which ventricle is thicker and why?

The left ventricle is thicker because it has to transport blood to the whole body

Name the organs and journey of the blood around the whole body

Body tissues ➔ vena cava ➔ __right atrium__ ➔ right ventricle ➔ __pulmonary artery__ ➔ lungs ➔ __pulmonary vein__ ➔ left atrium ➔ __left ventricle__ ➔ aorta ➔ body tissues

What is the function of coronary arteries?

They provide the heart/cardiac muscle with oxygenated blood

How are red cells adapted for their function

* Biconcave shape

\-gives a large surface area

\-allows the cell to bend/squeeze against the capillary walls

* No nucleus to allow more space for carrying oxygen
* Contains hemoglobin which binds oxygen

Name the part of the blood that carries out clotting and its function.

Platelets

* they stop blood loss
* prevents bacteria from entering
* stops bleeding

How does white blood cells defend againts infection

Some engulf pathogens by **phagocytosis.**

some produce **antibodies** to fight pathogens

some produce **antitoxins** to neutrilise any toxin produced by the pathogen

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How is the human circulatory system adapted to carry out its function of supplying oxygen to the body and removing waste products?

* double circulatory system meaning tit has a high blood pressure and greater flow of blood to the tissues
* The oxygenated and deoxygenated blood is separated so its more efficient
* Oxygen is carried by RBCs which contain haemoglobin to bind oxygen and have no nucleus so there is more space available to carry oxygen.
* thin walls allow for easy diffusion to cells
* large surface area of capi

what are the processes in the heart which allows it carry out its function of supplying oxygen to the body and removing waste products?

* The heart pumps blood to the lungs via the pulmonary artery so that oxygen can diffuse into the blood from the air in the alveoli

* blood returns to the heart via pulmonary vein where muscles pump blood to the body via aorta

* arteries carry oxygenated blood to tissues where capillaries deliver oxygen to cells for respiration and energy release.

What happens in capillaries

1. Arteries branch into much smaller vessels, called capillaries. Capillaries have thin walls and pass very close to the body cells.
2. In capillaries, food and oxygen move out of the blood and into the cells.
3. In capillaries, waste products, such as carbon dioxide, move out of the cells and into the blood.

What is the aorta and its function.

The main artery that carries oxygenated blood away from the heart to the rest of the body.

The heart pumps out oxygenated blood to the body through the aorta.

The role of vena cava

The heart receives deoxygenated blood from the body through a vein called the vena cava.

The role of Pulmonary artery

it carries deoxygenated blood to the lungs.

The blood becomes oxygenated in the lungs. 

The role of pulmonary vein

Oxygeneted blood from the lungs to the heart

The role of coronary arteries

* The coronary arteries supply the heart muscle with oxygenated blood.

Why are artificial pace makes used?

* If someone has an irregular heart beat, it can be corrected using electrical devices, known as artificial pacemakers.

What is the function of pace makers

The natural resting heart rate is controlled by a group of cells in the right ventricle called the pace makers.

Lable the heart and the pathway of blood flow (oxygenated and deoxygenated)

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