Transport In Animals Flashcards
Need for a transport system
High metabolic demands, and a lot of waste is produced so diffusion over the long distances is not enough to supply quantities needed.
-SA:V ratio is too small
-molecules made in one place but needed in another
- food will be digested in one organ system but needed across the whole body
Waste products have to be removed
Types of circulatory system
Open system - blood isn’t enclosed in blood vessels at all times , flows freely through the body cavity
Closed system - blood is enclosed inside blood vessels at all times
Open circulatory systems
Very few vessels that contain the transport medium
Pumped straight from the heart to the rest of the body
Insects have an open system
In insects their blood, haemolymph, doesn’t carry oxygen or co2
Closed circulatory system
Enclosed in blood vessels and blood does not directly come into contact with the cells
Blood travels at high speed and pressure
Substances leave by diffusion
Amount of blood flowing to particular tissue can be adjusted by widening or narrowing blood vessels
Single closed circulatory system
Fish
Blood flows through the heart and is pumped to the rest of the body before returning to the heart
Blood passes through 2 sets of capillaries before returning to the heart
In the first o2 and co2 is exchanged
In the second substances are exchanged to organs
Fish have a very efficient system
Doubled closed circulatory system
Most efficient system for transporting substances
- blood is pumped from the heart to the lungs to pick up oxygen and unload co2, then returns to the heart
- blood flows through the heart and is pumped to the rest of the body
Where are the valves located in the heart
Tricuspid, between right atrium and right ventricle
Bicuspid valve between left atrium and left ventricle
Semilunar valve between the right ventricle and the pulmonary artery
