8.1.1
Double Circulation
Types of Circulatory Systems
Types of Circulatory Systems
All animals have circulatory systems to transport substances around their bodies. These systems are made of blood vessels, a pump (the heart) and valves to stop blood moving in the wrong direction.


Open circulatory systems
Open circulatory systems
- In open circulatory systems, the organism's blood is free to flow throughout the body cavity.
- Open circulatory systems are found in insects.


Closed circulatory systems
Closed circulatory systems
- In closed circulatory systems, blood is restricted to flowing through blood vessels and a pump (the heart) is required to get blood to all parts of the body.
- Closed circulatory systems are found in fish and mammals.
- Fish have single closed circulatory systems.
- Mammals have double closed circulatory systems.


Single closed circulatory systems
Single closed circulatory systems
- Fish have what is known as a single circulatory system because blood only travels through the heart once in every circuit around the body.
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Double closed circulatory systems
Double closed circulatory systems
- Mammals have a double circulatory system, where blood travels through the heart twice per circuit.
- Double circulatory systems get oxygenated blood to tissues (like muscles) that need it faster than single circulatory systems.
- The concentration gradient between the blood and cells is also better maintained in double circulatory systems, so substances are exchanged between the blood and body cells faster.
The Double Circulatory System
The Double Circulatory System
Complex multicellular organisms require a specialised system for transporting nutrients throughout their bodies and removing waste products.


Heart
Heart
- The heart is the centre of the circulatory system.
- Mammals have a double circulatory system. This means blood flows through the heart twice in one circuit.
- Deoxygenated blood is pumped to the lungs.
- Oxygenated blood is pumped around the body.


Coronary arteries
Coronary arteries
- The heart is a muscle that is constantly contracting and relaxing.
- The heart muscle needs a constant supply of oxygen for respiration.
- The coronary arteries supply blood to the heart.


Pulmonary artery and vein
Pulmonary artery and vein
- Deoxygenated blood is pumped out of the heart to the lungs via the pulmonary artery.
- Oxygen diffuses into the deoxygenated blood in the lungs and the blood becomes oxygenated.
- Oxygenated blood flows into the heart from the lungs via the pulmonary vein.


Aorta and vena cava
Aorta and vena cava
- Oxygenated blood is pumped out of the heart around the body via the aorta.
- Blood in the aorta is very high pressure to ensure the blood can be pumped to all the tissues in the body.
- Oxygen dissociates from the blood at respiring cells in the body and the blood becomes deoxygenated.
- Deoxygenated blood flows into the heart from the body via the vena cava.


Renal artery and vein
Renal artery and vein
- Oxygenated blood flows out of the aorta to the kidneys.
- Oxygenated blood enters the kidneys through the renal artery.
- Oxygen diffuses out of the blood to be used in the kidney cells and the blood becomes deoxygenated.
- Deoxygenated blood flows out of the kidneys via the renal vein.
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes
1.1.2Introduction to Eukaryotic & Prokaryotic Cells
1.1.3Ultrastructure of Eukaryotic Cells
1.1.4Ultrastructure of Eukaryotic Cells 2
1.1.5Ultrastructure of Eukaryotic Cells 3
1.1.6Prokaryotic Cells
1.1.7Viruses
1.1.8End of Topic Test - Cell Structure
1.1.9Exam-Style Question - Microscopes
1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones
15.1.2Receptors
15.1.3Taste
15.1.4Reflexes
15.1.5Action Potentials
15.1.6Saltatory Conduction
15.1.7Synapses
15.1.8Cholinergic Synnapses
15.1.9Neuromuscular Junction
15.1.10Skeletal Muscle
15.1.11Sliding Filament Theory Contraction
15.1.12Sliding Filament Theory Contraction 2
15.1.13Menstruation
15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
Jump to other topics
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes
1.1.2Introduction to Eukaryotic & Prokaryotic Cells
1.1.3Ultrastructure of Eukaryotic Cells
1.1.4Ultrastructure of Eukaryotic Cells 2
1.1.5Ultrastructure of Eukaryotic Cells 3
1.1.6Prokaryotic Cells
1.1.7Viruses
1.1.8End of Topic Test - Cell Structure
1.1.9Exam-Style Question - Microscopes
1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones
15.1.2Receptors
15.1.3Taste
15.1.4Reflexes
15.1.5Action Potentials
15.1.6Saltatory Conduction
15.1.7Synapses
15.1.8Cholinergic Synnapses
15.1.9Neuromuscular Junction
15.1.10Skeletal Muscle
15.1.11Sliding Filament Theory Contraction
15.1.12Sliding Filament Theory Contraction 2
15.1.13Menstruation
15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
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