What are the 5 functions of the Circulatory System?
1) Supply oxygenated blood to all areas of the body.
2) Transport nutrients to the cells of the body.
3) Remove waste materials eg. CO2.
4) Fight infection.
5) Help regulate temperature.
What are the 3 main components of the Circulatory System?
3) Blood Vessels
How much blood does an average adult have?
4 - 5 litres.
What are the 5 functions of blood?
1) Transport oxygen and nutrients.
2) Collect waste products eg. CO2
3) Fight Infection
4) Help regulate body temperature.
Blood is composed of plasma and blood cells. What percentage of blood does plasma make up?
Plasma is mainly composed of water. What else does it contain?
1) Mineral salts.
4) Hormones (produced in endocrine system).
5) Enzymes (used in food/energy production).
6) Gases (CO2, O2, Nitrogen).
Where are red blood cells, white blood cells and platelets formed?
Red bone marrow (found in cancellous (spongy) bone).
Red blood cells have ______________ which carries _________.
Red blood cells have haemoglobin which carries oxygen.
What helps to give blood its colour?
White blood cells help to protect the body from infection but are they larger or smaller than red blood cells?
Platelets are fragments of blood and play a vital role in what?
What are the two circulation paths in the human body?
1) Pulmonary Circulation - to the lungs and return to heart
2) Systemic Circulation - to the rest of the body and return to the heart.
- Blood travelling from heart to lungs (pulmonary aretery) - and return (pulmonary vein).
- Blood is reoxygenated in the lungs.
- C02 is offloaded in the lungs.
What is special about the pulmonary artery?
It is an artery that carries deoxygenated blood.
- Circulation to the body other than the lungs.
- Starts at the aorta and branches off in different directions through a series
- of arteries and arterioles.
- then capillaries.
- then a network of what returns the blood to the heart?
Veins and venules.
Arteries carry blood to the heart or away from the heart?
Arteries carry oxygenated or deoxygenated blood?
Oxygenated (except the pulmonary artery).
Why do arteries have thick walls?
1) To withstand pressure.
2) For protection.
What are arteries made up of?
Elastic and muscle tissue (smooth muscle).
Does the amount of muscle tissue in the artery increase or decrease as the distance from the heart increases? Why?
Increases in order to maintain pressure.
What is the inside space of the artery referred to as?
What is vasodilation?
Is when the smooth muscle walls relax and increase blood flow. This is turn decreases blood pressure.
What is vasoconstriction?
This is when the smooth muscle walls contract and reduce blood flow. This in turn increases blood pressure.
Capillaries are the smallest blood vessels but how many cells are their walls in thickness?
One cell thick.
Capillaries have porous walls to allow the passage and exchange of what?
Capillaries are like the distribution network for oxygen and nutrients to the body. They supply every part of the body except which 3 areas?
1) The deep brain.
3) Outer layer of skin.
Veins carry blood towards or from the heart?
Do veins have thinner or thicker walls than arteries? Why?
Thinner - not as much pressure. As such they also have a larger lumen.
What helps to push blood back to the heart?
(importance of the cool down section of a workout)
What do veins have that arteries don't?
Valves which prevent back flow when blood pressure is low.
What is a pulse?
The rate at which heart beats, caused by a wave of artery wall expansion caused by the pumping of the heart.
Where are the two main areas generally used to take a pulse?
1) Radial Artery (wrist)
2) Carotid Artery (neck)
*also the temporal, femoral, popliteal (back of knee) and brachial.