Transport in Animals Flashcards
Why is there a need for a specialised transport systems in animals?
- metabolic demands are high and diffusion alone is not enough to supply the needs of the animal
- SA:V small for large organisms
- hormones need to be transported
- glucose needs tot be transported across the body
- waste products from cells need to be removed
Types of circulatory system
- Open circulatory system
- Closed circulatory system
What are the features of most circulatory system.
- liquid transport medium
- vessels transport that carry the transport medium
- pumping mechanism
Open Circulatory System
- Pumped straight from the heart to the very few vessels into the body cavity where it comes into direct contact with the tissue and exchange happens there
- This is blood is then drawn straight back into the heart
- found in INSECTS usually
- insect blood is called HAEMOLYMPH
Closed circulatory systems
- Blood is enclosed in blood vessels and does not come into direct contact with the cells of the body
- Heart pumps blood around the body under pressure
- substances leave and enter the blood via diffusion through the vessel walls
What are the two types of closed circulatory system?
- Single closed circulatory system
- Double closed circulatory system
Single closed circulatory system.
- blood is pumped from the heart around the body back to the heart
- Only travels once through the heart
- Blood pressure drops low so blood returns to the heart quite slowly (tends to be inefficient)
- Fish are the opposite they have an efficient exchange system (they can be active)
Why are is the fishes single closed circulatory system effective?
- counter current gaseous exchange system
- Body weight is supported by the water
- They do not maintain their body temperature
- All of this greatly reduces the metabolic demand on the fish
Double closed Circulatory System
- Most efficient circulatory system
- Blood travels twice through the heart
- blood is pumped to the lungs to pick up oxygen
- the oxygenated blood returns back to the heart to be pumped through the entire body
- before returning to the heart again
What are the 3 components that determine the properties of the type of blood vessel?
- elastic fibres (flexibility)
- smooth muscle (Change the size of the lumen)
- collagen (structural support to maintain the shape and volume)
What is the structure and function of arteries?
- to transport oxygenated blood under high pressure (except for the pulmonary artery)
- Contain elastic fibres, collagen and smooth muscles
- elastic fibres help withstand force of blood pumped out of the heart
- smooth endothelium so blood can flow easily
Arterioles
- contain a lot of smooth muscle cells and less elastin
- helps control blood flow into the capillaries
- Vasoconstriction / Vasodilation
How are capillaries adapted for their role?
- large surface area for diffusion of substances
- large amounts of capillaries slows the blood giving more time for exchange to occur
- thin walls for easy diffusion
What are the 3 layers of a vessel?
- outer coat
- tunica media
- tunica intima
What is the structure of veins and their function?
- tough outer coat lots of collagen
- carries deoxygenated blood to the heart
- relatively little elastic fibres
- Wide lumen
- Valves preventing the backflow of blood
- Smooth endothelium (easier flow of blood)
How can the blood travel up the vein?
- muscles in the body can contract to push blood up the vein to the heart
- breathing of the chest can act as a pump
Functions of the blood
- transport O2 & CO2, hormones, digested food, immune system cells (antibodies), amino acids, platelets…
- acts as a buffer
- helps maintain a steady body temperature
What is the function of tissue fluid (interstitial fluid)?
- blood plasma contains dissolved substances needed for the body
- this can then have direct contact with body cells and exchange can happen there