B5.1B5. Transport in Humans
Circulatory systems — Combined Science 0653 - Biology Revision Notes & Topical Questions
5 min read 27 parts Lesson 2 of 15 1 quiz
Lesson summary
B5.1 Circulatory systems — COMBINED SCIENCE notes: Compare the single circulation of fish with the double circulation of mammals.Definition — an organ system whose role is to transport blood around the body.Components — blood vessels, a pump and valves that ensure one-way flow.He…
- Right side
- Pressure drop
- Returning to the heart
- Separation
- Pulmonary circulation
- Systemic circulation
Part 1 of 9The circulatory system
The circulatory system
Definition
- Definition an organ system whose role is to transport blood around the body.
Components
- Components blood vessels, a pump and valves that ensure one-way flow.
Part 2 of 9Single circulation in fish
Heart
- Heart fish have a two-chambered heart.
Single circulation
- Single circulation for every circuit of the body the blood passes through the heart once.
Route
- Route heart, gills, body, heart.
Part 3 of 9Double circulation in mammals
Heart
- Heart mammals have a four-chambered heart.
Double circulation
- Double circulation for every circuit of the body the blood passes through the heart twice.
Route
- Route heart, lungs, heart, body, heart.
Part 4 of 9The two circuits
| Circuit | Pumped by | Blood goes | Blood carried |
|---|---|---|---|
| Pulmonary | Right side of the heart | To the lungs and back | Deoxygenated blood from the body goes to the lungs |
| Systemic | Left side of the heart | To the body and back | Oxygenated blood from the lungs goes to the body |
Part 5 of 9Side of the heart
Right side
- Right side receives deoxygenated blood from the body and pumps it to the lungs.
Left side
- Left side receives oxygenated blood from the lungs and pumps it to the body.
Part 6 of 9Why double circulation is an advantage
Pressure drop
- Pressure drop blood loses a lot of pressure as it passes through the small capillaries in the lungs.
Returning to the heart
- Returning to the heart the blood returns to the heart after the lungs, so its pressure is raised again before it goes to the body.
Supply
- Supply cells receive oxygen and glucose for respiration faster and more often.
Part 7 of 9Septum
- Separation
- it keeps oxygenated and deoxygenated blood from mixing.
Part 8 of 9More from the specification
More from the specification
Venous return through systemic veins
- Venous return through systemic veins internal pocket valves and skeletal muscle contraction assist the low-pressure return of blood through systemic veins.
Phagocyte
- A white blood cell that engulfs pathogens.
Ventricle
- A heart chamber that pumps blood out.
Coronary artery
- An artery that supplies the heart muscle.
Artery
- A vessel that carries blood away from the heart at high pressure.
Activity
- The rate at which the nuclei in a sample decay.
Muscle
- Tissue that contracts to cause movement.
Platelet
- A cell fragment that helps blood to clot.
Part 9 of 9More on this topic
More on this topic
Components
- Components blood vessels, a pump and valves to keep the blood flowing one way.
Circulation
- Circulation blood delivers defence cells and platelets to any damaged site.
Key terms
| Term | Meaning |
|---|---|
| Single circulation | Blood passes through the heart once per circuit, as in fish. |
| Double circulation | Blood passes through the heart twice per circuit, as in mammals. |
| Pulmonary circulation | Heart to lungs and back. |
| Systemic circulation | Heart to body and back. |
| Deoxygenated blood | Blood with little oxygen. |
| Oxygenated blood | Blood carrying a lot of oxygen. |
Avoid these mistakes
1
Saying blood passes through the heart once in a mammal's circuit — it passes twice.
2
Saying fish have a double circulation — fish have a single circulation.
3
Saying the left side receives blood from the body — it receives it from the lungs.
4
Forgetting the pressure advantage — the heart boosts the pressure after the lungs.
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