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Transport in Animals

OCR AS-level BiologyTopic 8 of 1232 lessons

Revision notes for Transport in Animals in OCR Biology A (H020). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.

  1. Specialised Transport SystemsLarge multicellular organisms need a specialised transport system because simple diffusion is not fast enough to meet their metabolic needs.
  2. Features of a Transport SystemTransport systems of large animals have the following features: A fluid medium which could be liquid or gas to carry substances around.
  3. Types of Circulatory SystemBlood must be brought close to the cells since nutrient and metabolic waste exchange takes place by passive diffusion.
  4. Open Circulatory SystemsIn open circulatory systems the transport medium is pumped from the heart and into an open body cavity called the haemocoel.
  5. Closed Circulatory SystemsIn a closed circulatory system, blood is the transport medium and is confined in blood vessels and does not come directly in contact with tissues…
  6. Single Closed Circulatory SystemsSingle closed circulatory Systems are a single loop system, where blood passes through two sets of capillaries before it returns to the heart.
  7. Double Closed Circulatory SystemsIn a double circulatory system, blood flows through the heart twice for each circulation of the body.
  8. Blood VesselsBlood vessels are a closed system of tubular vessels that contain blood and forms a branching network to distribute blood to all parts of the…
  9. ArteriesThe function of arteries is to transport blood rapidly under high pressure from the heart to the tissues.
  10. ArteriolesOxygenated blood is distributed throughout the body by arteries branching into sequentially smaller arteries, arterioles, and capillaries.
  11. Veins and VenulesVenules connect capillaries to larger veins.
  12. CapillariesCapillaries exchange metabolic materials such as oxygen, carbon dioxide and glucose between the blood and cells of the body.
  13. Tissue FluidTissue fluid is a watery liquid that contains glucose, amino acids, fatty acids, ions in a solution and oxygen.
  14. Return of Tissue Fluid to BloodThe loss of tissue fluid from the capillaries reduces the hydrostatic pressure inside them.
  15. Chloride ShiftWhen carbon dioxide diffuses out of respiring tissue, 5% of the CO2 dissolves in the plasma and about 10-20% binds to the amino group of the…
  16. Human HeartThe human heart consists of two pumps side by side and joined together by a dividing wall called the septum.
  17. Structure and Function of the HeartThe human heart is made of left and right pumps.
  18. Cardiac CycleThe events that take place in the heart during a single heartbeat is called the cardiac cycle.
  19. Heart SoundsThe sounds of the heartbeat heard through a stethoscope are made by the valves closing due to blood pressure.
  20. Basic Rhythm of the HeartCardiac muscle is myogenic - it has its own intrinsic rhythm of around 60 beats per minute.
  21. ElectrocardiogramsThe spread of electrical excitation across the heart can be measured using an electrocardiogram.
  22. Aortic AneurysmsAn aneurysm is a bulge or weakness in a blood vessel.
  23. Red Blood CellsRed blood cells (erythrocytes) transport oxygen from the lungs to respiring tissues.
  24. HaemoglobinHaemoglobin (Hb) is the protein in red blood cells that carries oxygen.
  25. Oxygen Loading and UnloadingHaemoglobin picks up oxygen in one place and releases it in another.
  26. The Oxygen Dissociation CurveAn oxygen dissociation curve shows the percentage saturation of haemoglobin with oxygen (y-axis) against the partial pressure of oxygen, pO2, in kPa…
  27. Partial Pressure of OxygenThe partial pressure of a gas is the pressure that the gas would exert if it alone occupied the whole volume of a mixture.
  28. The Bohr EffectThe Bohr effect is the decrease in the affinity of haemoglobin for oxygen when the partial pressure of carbon dioxide (pCO2) is high.
  29. Fetal HaemoglobinA fetus cannot breathe air; it obtains oxygen from its mother's blood at the placenta.
  30. Transport of Carbon DioxideCarbon dioxide is produced by respiring tissues and must be carried in the blood to the lungs, where it diffuses into the alveoli and is exhaled.
  31. Carbonic AnhydraseCarbonic anhydrase is an enzyme found in high concentration in the cytoplasm of red blood cells.
  32. Haemoglobinic AcidWhen carbonic acid dissociates inside a red blood cell, it releases hydrogen ions (H+).

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