Circulatory System
Role of the circulatory system
1. To transport marterials around ghe body
2. To protect the body against disease
Materials transported by the circulatory system
Blood cells
Waste- carbon dioxide + urea
Absorbed food molecules- glucose and amino acids
Hormones- insulin and adrenaline
Vitamins and minerals
Water
Heat
White blood cells
exist in a number of different forms that can either produce antibodies (lymphocytes) to destroy pathogens or can carry out phagocytosis (phagocytes) to enguly and digest pathogens
Platelets
Carry out the process of blood clotting at the site of the wound. Prevent entry of bacteria and excessive blood loss. They work by converting a protein called fibrinogen to fibrin which forms a scab over the wound.
Red blood cells
Biconcave disc shaped cells that are very small but have a large surface area. They have no nucleus to increase room available for oxygen. They contain haemoglobin that binds with oxygen to creat oxyhaemoglobin (rich in iron)
Plasma
The liquid part of the blood. Yellow/straw coloured substance. It is responsible for the transport of blood cells, absorbed food, wastes etc.
Artery Role
•Blood flows away from heart
•High blood pressure
•No valves
•Always carries oxygenated blood (except pulmonary)
Vein Role
•Carries blood to heart
•Low blood pressure
•Valves-to prevent blood backflow
•Carries deoxygenated blood (except pulmonary)
Capillary Role
•Carries blood from arteries to vein
•Low blood pressure
•No valves
•Permeable blood for certain things
•Carried both blood
Pulmonary vein
carried oxygenated blood from the lungs to the heart
Aorta
carries oxygenated blood from the heart to the body
Vena cava
carries deoxygenated blood from the body to the heart
Pulmonary artery
Carries deoxygenated blood from the heart to the lungs
Hepatic Artery
Carries oxygenated blood and glucose from the heart to the liver where it can b stored
Hepatic portal vein
carries digested food(glucose and amino acids) from the small intestine to the liver (deoxygenated blood)
Hepatic Vein
carries glucose and amino acids from the liver to the rest of the body. Deoxygenated blood and carries carbon dioxide from the liver cells to the heart and lungs
Renal Artery
Carries oxygenated blood and urea to the kidneys
Renal Vein
Carries purified blood (low in urea) from the kidney to the heart. It is deoxygenated and carries carbon dioxide from the cells in the kidney back to the lungs and heart
Doubke Circulatory System
The blood flows through the heart twice. The first time it leaves the heart and is pumped to the lungs and the second time it is pumped from the heart all around the body