Unit 3 - Transport In Animals Flashcards
What are features of an EFFECTIVE transport system?
- Fluid or medium to carry nutrients
- A pump to create pressure
- Exchange surfaces
What are features of an EFFICIENT transport system?
- Tubes or vessels to carry the blood via mass flow
- 2 circuits
Which animals have a double circulatory system?
Mammals
What are the advantages of a double circulatory system?
- Delivers oxygen and nutrients after
- The blood can flow quicker increasing pressure to the heart
What are the disadvantages to a single circulatory system?
The rate at which Oxygen and Nutrients are delivered to the tissues and waste products removed is limited
What’s the BP like in a single circulatory system of a fish? 🐠
- Drops as the blood passes through the capillaries in the gills
- Low pressure and speed as it flows towards the body
Why are fish not as metabolically active as mammals?
They are cold blooded so there is no need to maintain energy
Why do mammals need a double pump system?
They have to maintain their body temperature
Arteriolar
Small blood vessels that distribute blood from an artery to the capillaries
Venules
Small blood vessels that collect blood from the capillaries and lead into the veins
What are the DISADVANTAGES to an open circulatory system?
- Blood pressure and speed is slow
- Circulation can be affected by body movement
What are the advantages of a closed circulatory system?
- Higher pressure, faster blood flow
- Quicker delivery of Oxygen and Nutrients
- Quicker removal of Carbon Dioxide and other wastes
- Transport is independent of body movement
What layer do all blood vessels have?
Endothelium- Inner lining made of a single layer of cells.
Smooth to reduce friction with the blood
What layers do capillaries have?
- Endothelial
- Lumen
What layers do Arteries and Veins have?
- Collagen fibres
- Smooth muscle
- Elastic fibres
- Endothelium
- Lumen
What are the features of Arteries?
- Small lumen to maintain high BP
- Folded inner layer to allow lumen to expand as blood flow increases
Features of Arterioles?
- Contains a layer of smooth muscle which can contract to reduce blood flow
- Can be used to divert the blood flow to parts of the body requiring more Oxygen
What are the features of capillaries?
- Very thin walls to allow the exchange of nutrients and waste products
- Lumen around 7um (about the diameter of a erythrocyte)
- This squeeze the erythrocytes against the walls reducing diffusion distance
- Reduces rate of flow
- Leaky walls
What are the features of veins?
- Large lumen to ease blood flow
- Thin walls as they don’t need to constrict lumen
- Valves because of low pressure
- Think walls can be flattened by skeletal muscles which applies pressure to blood
Hydrostatic Pressure
The pressure that a fluid exerts when pushing against the sides of a vessel
What is the lymphatic system?
A system of tubes that returns excess tissue fluid to the blood system
Oncotic pressure
The pressure created by external fluid pushing on the blood vessels
How is tissue fluid different to blood plasma?
- Doesn’t contain many of the cells found in blood
- Doesn’t contain plasma proteins
What kind of movement is the flow of blood plasma into tissue fluid?
Mass Movement