🫀Circulatory System 🫀 Flashcards
Name the four components of blood
Plasma
Red blood cells
White blood cells
Platelets
Explain plasma
• The liquid part of the blood.
• It is a straw yellow colour that is mostly made of water.
• Function to transport dissolved chemicals and heat around the body. Plasma also is an excellent solvent as it is 90% water.
Explain red blood cells
• Contain a protein pigment (haemoglobin).
• Haemoglobin helps carry oxygen around the body.
• RBCs are bioconcave shaped to allow for maximum surface area.
• RBCs are slightly elastic to prevent being damaged easily as they move around the body.
• RBCs do not contain a nucleus.
• RBCs are made in the bone marrow.
Explain white blood cells
• WBCs fight infection by surrounding and engulfing micro organisms.
• WBCs contain a nucleus.
• WBCs are made in the bone marrow
Explain platelets
Help form blood clots e.g. a scab is formed.
• Blood clotting has two purposes:
1. To prevent blood loss
2. To prevent the entry of micro organisms into the body.
Explain blood vessels
• Each have a similar function - transport blood.
• Each are slightly different in their function:
• Arteries carry blood away from the heart.
• Veins carry blood towards the heart.
Capillaries connect arteries and veins and it is here where the substances are exchanged between cells.
Arteries have …
Thick walls to resist pressure
Carry blood under pressure
Carry blood away from the heart
Have no valves
Narrow lumens
Blood travels in spurts
Veins have…
Thin walls because the pressure i much less
Carry blood under low pressure
Carry blood to the heart
Valves to prevent back flow of blood
Wide lumen
Blood flows evenly
Describe the heart
The size of a clenched fist 👊
• Made of cardiac muscle very tough and doesn’t tire easily - average 70 BPM every day from birth to death.
• Located in the centre of the chest
Name and explain the fur chambers of the heart
• The left & right ventricles and the left and right atriums.
• The left ventricle is thicker due to it pumping blood all around the body. Hence why we feel it more on the left hand side.
• The septum divides the two sides of the heart.
• Heart valves make sure blood moves in one direction only.
• The coronary artery provides nutrients and oxygen to the cardiac muscle of the
• heart itself.
The two blood circuits
Pulmonary (lung) circuit: heart - lungs - heart
• Systemic (body) circuit: heart - body - heart
Name and explain the major blood vessels
• Vena cava: Carries deoxygenated blood to right atria.
• Pulmonary artery: Carries deoxygenated blood to the lungs.
• Pulmonary vein: Carries oxygenated blood to left atria.
• Aorta: Carries oxygenated blood to rest of body.
Explain pulse rates
• 72 BPM at rest (average).
The pulse can be felt at the neck and wrist where the artery is closest to the skin.
When we exercise our cells require more energy as they are doing more work.
• Oxygen and nutrients need to get to the cells quickly. The heart beats faster to ensure the body gets oxygen and nutrients quickly.
A reason for heart disease…
Heart disease:
• Caused by eating too much fatty foods, not exercising and smoking.
