Unit 3.2- Transport in animals Flashcards
(111 cards)
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 by mass flow
- Two circuits
What animals have a double circulatory system?
Mammals
What are the advantages of a double circulatory system?
- Delivers oxygen and nutrients more quickly
- The blood can flow more quickly by increasing pressure to the heart
What are the disadvantages of a single circulatory system?
The rate at which oxygen and nutrients are delivered to the tissues and waste products are removed is limited
What is the blood pressure like in the 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 do not need to maintain body temperature so do not need as much energy. The single circuit is sufficient for their needs
Why do mammals need a double pump system?
They need more energy so they can maintain their body temperature.
Arterioles definition:
Small blood vessels that distribute blood from an artery to the capillaries
Venules definition:
Small blood vessels that collect blood from capillaries an lead into the veins
What are the disadvantages of an open circulatory system?
- Blood pressure and speed of flow is low
- Circulation of blood may be affected by body movements
What are the advantages of a closed circularity system?
- Higher pressure so the blood flows more quickly
- More rapid delivery of oxygen and nutrients
- More rapid removal of carbon dioxide and other wastes
- Transport is independent of body movement
What layer do all types of blood vessels have?
Inner layer of lining made of a single layer of cells called endothelium. This is particularly smooth to reduce friction with the blood
What layers do capillaries have?
- Endothelium
- 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 blood pressure
- Folded inner wall in order to allow the lumen to expand as the blood flow increases
What are features of arterioles?
- Contain a layer of smooth muscle which can contract to constrict the diameter to reduce blood flow
- This can be used to divert the flow of blood to regions of the body that are demanding more oxygen
What are features of capillaries?
-Very thin walls to allow the exchange of nutrients and waste products
- lumen about the diameter of an erythrocyte (7um)
-This squeezes the erythrocytes against the walls to reduce diffusion distance
-Also reduces rate if flow
Walls consist of flattened epithelial cells to reduce diffusion distance
-Leaky walls
What are features of veins?
- Large lumen to ease flow of blood
- Thin walls as they do not need to constrict the lumen
- Valves because of low pressure
- Walls are thin so can be flattened by skeletal muscles which applies pressure to the blood
Hydrostatic pressure definition:
The pressure that a fluid exerts when pushing against the sides of a vessel
Lymph definition:
The fluid held in the lymphatic system, which is a system of tubes that returns excess tissue fluid to the blood system
Oncotic pressure definition:
The pressure created by the fluid outside the blood vessels pushing against them
How is tissue fluid different to blood plasma?
It does not contain most of the cells found in blood and does not contain plasma proteins
What kind of movement is the flow of blood plasma into tissue fluid? (diffusion, active transport etc)
Mass movement