Topic 1 Heart and circulatory system Flashcards
State the different types of circulatory system an organism can have
None (rely on diffusion),
Open circulatory,
Closed circulatory,
Closed Double circulatory.
Explain the reasons why there are different types of circulatory system
Differing metabolic rates between species means different circulatory requirements (animals with a lower metabolic rate require a less efficient circulatory system)
Explain the advantages of an organism having a double circulatory system
Differential pressure
Blood pumped at high pressure to body
- blood can reach extremities of the body
Blood pumped at low pressure to the lungs
- wont damage the lungs
- allows more time for gas exchange via diffusion
Describe the difference between mass flow and diffusion
Mass flow is the movement of a liquid down a pressure gradient, whereas diffusion is movement of a substance down the concentration gradient
Why do certain organisms need a mass flow system
Because they need to bring substances quickly from one exchange site to another to maintain a high metabolic rate
What is the arterial pulse
Waves of blood travelling at high pressure in the arteries
Describe the structure of a capillary
Narrow lumen
One layer thick walls
Porous.
High surface area to volume ratio.
Explain how the structure of a capillary enables them to carry out their functions
High surface area to volume ratio maintains high rate of diffusion for gas exchange with surrounding tissues.
Porous walls allow for constant movement of liquids from the bloodstreams into tissues and vice versa.
Narrow lumen keeps blood pressure low to allow for more time for gas exchange
Describe the structure of an artery
Narrow lumen,
Thick elastic fibres
Thick collagen layer
Smooth endothelium layer inside.
Explain how the structure of an artery enables them to carry out their functions
Narrow lumen maintains high blood pressure,
Thick elastic fibres expand with pressure, and contract to keep the artery’s shape,
Thick collagen layer provides strength to the artery and prevents it from bursting, allowing it to maintain a higher pressure,
Smooth endothelium layer provides less resistance for blood to travel faster.
Describe the structure of a vein
Wide lumen,
Thin collagen layer,
Thin layer of smooth muscle,
Smooth endothelium layer,
Valves.
Explain how the structure of a vein enables them to carry out their functions
Wide lumen allows more blood to flow under lower pressure,
Thin collagen layer allows vein to have pressure applied from outside sources,
Smooth endothelium layer provides less resistance for blood,
Valves prevent the backflow of blood inside of the vein
Explain what is meant by the dipole nature of water molecules
The Hydrogen atoms have a partial positive charge, whereas the oxygens have a partial negative charge. This is due to Electronegativity.
Explain why water is a good solvent
Water can create hydrogen bonds through intermolecular forces, which means water can attract polar solutes and form hydrogen bonds with them, which causes them to dissolve into the water
Explain how the properties of water are essential for organisms
Water can create hydrogen bonds, which gives it properties such as being a good solvent (allows dissolved substances to be transported), being adhesive (sticking to cell walls and other substances with extra hydrogen atoms sticking out), having a high specific heat capacity (allows water to maintain a consistent temperature as extreme levels of energy are required to change its temperature)
