1. Animal Circulatory Systems
Miss Rayner ATAR YR 11 BIOLOGY

2. Outcomes The purpose of a circulatory system
Animals have different circulatory systems because they have different metabolic requirements & live in different environments
Animals either have a closed or open circulatory system

3. Purpose
Living cells need to absorb nutrients & oxygen & release waste products, single celled organisms are small enough to do this by diffusion (amoeba). Larger multicellular animals need a circulatory system to transport substances to & from their cells
Transportation of nutrients, oxygen and carbon dioxide
Distribution and removal of wastes
Maintain body temperature (endothermic organisms)
Circulation of hormones
Achieved using an open or closed circulatory system
Animals have either an open or closed circulatory system due to differences in the metabolic requirements or environmental conditions

4. Circulatory system Watch the video and answer the questions
What are the two types of circulatory systems found in animals
Give examples of animals that have each type of circulatory systems
What are the main differences between these systems
Or Click view video – Transportation Systems in Animals

5. Animal circulatory systems
Animals have either an open (insects) or closed circulatory system (annelids, mammals, fish, reptiles - vertebrates)

6. Open Circulatory system
Has a tubular heart to pump haemolymph but not all vessels are connected to each other
Referred to as an open circulatory system because there are gaps or openings between different vessels
Blood flows out of vessels, surrounds tissues for exchange of nutrients then passively returns to the heart to be moved to a different part of the body
Common in smaller organisms such as arthropods, insects & crustaceans

7. Open circulatory system (insects)
Don’t have true blood as it is mixed with other fluids, have ‘haemolymph’ (mixture of blood & interstitial fluid)
haemolymph flows freely through the body cavity, carrying nutrients to their cells which is only sometimes contained in vessels
Flows through open spaces called lacunae & sinuses
Flows at a very slow velocity
Does not carry oxygen. Oxygen is delivered directly to the insect’s tissues through tracheoles that open to the outside (spiracles)

8. Open Circulatory system
Do not have a true heart, they have a tubular heart consisting of blood vessels that pump blood away from the heart
The vessels that take blood away from the heart open into the body cavity/sinuses
The blood re-enters the blood vessels from the body cavity/sinuses to return to the heart
Body cavity (Haemocoel) is filled with blood & internal organs are bathed by blood, they have no capillaries

9. Open circulatory system

10. Open circulatory systems
Advantages
Oxygen system and circulatory system are separated so have less energetic demands on their bodies
Does not use as much energy to operate & maintain
Don’t have blood pressure (which is due the pumping of the heart) so external pressure is not a problem
Exchange of materials is direct between the haemolymph and tissues. There is no diffusion barrier
Disadvantages
Little control over distribution of the haemolymph to body regions. No mechanism for reducing flow to a specific part of an organ
BIOZONE ACT 115 &117

11. Closed Circulatory System
Referred to as closed because the blood in the system flows within a complex network of vessels or tubes that are all connected to each other
Blood pumped by a heart throughout the body in a continuous circuit of different types of vessel
Organisms able to grow larger because it creates higher pressure in the blood vessels so they are able to push the blood further around the body
Blood & other fluids do not mix

12. Closed circulatory system (vertebrates & earthworms)
Blood is always contained in vessels (internal organs are not in direct contact with blood)
Blood flows at high velocity
Have a muscular heart

13. Closed Circulatory system
Blood vessels
Arteries
carry blood away from the heart & connect to other blood vessels , capillaries and then veins
Have thick muscular walls
Veins
collect the blood from capillaries and then take the blood back to the heart
Have valves to keep blood flowing to the heart
Capillaries
surround the organs.
They have very thin walls & are very narrow. Walls are 1 cell thick, allowing the diffusion of all nutrients that the cells needs, such as glucose & oxygen and the removal of wastes such as carbon dioxide and urea to occur

14. Closed circulatory system

15. Closed circulatory system

16. closed circulatory system
Advantages
More efficient
The blood can reach further distances (larger body sizes)
Allows for more control over oxygen delivery
Higher metabolic rate
Disadvantages
Higher energy costs
BIOZONE ACT 118 & 119