Biology
Circulatory System Notes
Introduction:
- Circulatory fluid is blood.
- Simple animals the body is small and thin so substances can diffuse from cell to cell.
- Larger multicellular animals the body is thick so it requires the circulatory system to carry
out the task of collecting substances and transporting them around the body.
- What are the characteristics of the circulatory system?
= Blood, it transports dissolved gases, nutrients and waste products around body.
= Blood vessels, the blood flows around the body.
= Heart, to pump the blood around the body.
= Valves, to ensure blood flows only in one direction.
Types of circulatory systems:
- There are two basic designs.
- Open and Closed.
What is an Open Circulatory System:
- No veins, arteries or capillaries.
- Found in most invertebrates.
- Eg; Snail, insects and crustaceans.
- Blood from the heart is pumped at a relatively low pressure into the main body cavity, the
haemocoel.
- The blood bathes all internal organs directly and only moves slowly through the tissues
returning to the heart by a system of collecting vessels.
- This is rather inefficient. (only for small organisms)
What is a Closed Circulatory System:
- For larger animals.
- Eg; Humans, sea urchins, segmented worms and all vertebrates.
- The blood remains encolsed and circulates in a continuos network of tubes called blood
vessels.
- There is a seperate fluid, called tissue fluid, which is found between the blood vessels
and cells.
- It is a very effective transport system as it allows the blood to travel rapidly under high
pressure to within a few microns of where it is needed.
, The Human Circulatory System:
- Have a closed circulatory system.
- Called cardiovascular system. (heart and blood vessels)
- It is a double system.
- The heart is made up of two pumps located side-by-side.
= Right side pumps blood to the lungs whihc returns to the left side of the heart.
= Left side blood pumps to the rest of the body which returns to the right side of heart.
- The two distinct circulstions.
= The pulmonary and the systemic.
- This is what give the name a double circulatory system.
Pulmonary Circulatory System:
- Blood that is deoxygenated and high in carbon dioxide flows from the right side of the
heart to the lungs.
- In capillaries of the lungs, blood takes in oxygen and gives off carbon dioxide.
- Oxygenated blood the flows from the lungs to the left side of the heart.
Systemic Circulatory System:
- Carries oxygenated blood from the left side of the heart to all cells of the body.
- In capillaies of body tissues nutrients, gases and wastes are exchanged between blood
and cells.
- Deoxygenated blood then flows form the body tissues to the right side of the heart.
- This is the major part of the circulatory system.
Advantages of a double circulatory system:
- Pulmonary system, blood is pumped to the lungs for gaseous exchange.
- Systemic system, blood is pumped under pressure to all parts of the body to supply
oxygen and nutrients and take up carbon dioxide and other wastes.
Circulatory System Notes
Introduction:
- Circulatory fluid is blood.
- Simple animals the body is small and thin so substances can diffuse from cell to cell.
- Larger multicellular animals the body is thick so it requires the circulatory system to carry
out the task of collecting substances and transporting them around the body.
- What are the characteristics of the circulatory system?
= Blood, it transports dissolved gases, nutrients and waste products around body.
= Blood vessels, the blood flows around the body.
= Heart, to pump the blood around the body.
= Valves, to ensure blood flows only in one direction.
Types of circulatory systems:
- There are two basic designs.
- Open and Closed.
What is an Open Circulatory System:
- No veins, arteries or capillaries.
- Found in most invertebrates.
- Eg; Snail, insects and crustaceans.
- Blood from the heart is pumped at a relatively low pressure into the main body cavity, the
haemocoel.
- The blood bathes all internal organs directly and only moves slowly through the tissues
returning to the heart by a system of collecting vessels.
- This is rather inefficient. (only for small organisms)
What is a Closed Circulatory System:
- For larger animals.
- Eg; Humans, sea urchins, segmented worms and all vertebrates.
- The blood remains encolsed and circulates in a continuos network of tubes called blood
vessels.
- There is a seperate fluid, called tissue fluid, which is found between the blood vessels
and cells.
- It is a very effective transport system as it allows the blood to travel rapidly under high
pressure to within a few microns of where it is needed.
, The Human Circulatory System:
- Have a closed circulatory system.
- Called cardiovascular system. (heart and blood vessels)
- It is a double system.
- The heart is made up of two pumps located side-by-side.
= Right side pumps blood to the lungs whihc returns to the left side of the heart.
= Left side blood pumps to the rest of the body which returns to the right side of heart.
- The two distinct circulstions.
= The pulmonary and the systemic.
- This is what give the name a double circulatory system.
Pulmonary Circulatory System:
- Blood that is deoxygenated and high in carbon dioxide flows from the right side of the
heart to the lungs.
- In capillaries of the lungs, blood takes in oxygen and gives off carbon dioxide.
- Oxygenated blood the flows from the lungs to the left side of the heart.
Systemic Circulatory System:
- Carries oxygenated blood from the left side of the heart to all cells of the body.
- In capillaies of body tissues nutrients, gases and wastes are exchanged between blood
and cells.
- Deoxygenated blood then flows form the body tissues to the right side of the heart.
- This is the major part of the circulatory system.
Advantages of a double circulatory system:
- Pulmonary system, blood is pumped to the lungs for gaseous exchange.
- Systemic system, blood is pumped under pressure to all parts of the body to supply
oxygen and nutrients and take up carbon dioxide and other wastes.
