Transport In Animals Flashcards
Why do multicellular organism need a transport system?
Low SA:V therefore simple diffusion can’t deliver sufficient nutrients or oxygen to cells deeper in the organism, which has a high metabolic rate.
What are the different types of circulatory system?
Open, closed, single, double
What is an open circulatory system?
Blood bathes tissues directly, not always contained in blood vessels.
What is a closed circulatory system?
blood confined to vessels, tissue fluid bathes tissues.
Advantages of closed circulatory system
High BP = High Blood flow
Transport independent to body movement.
Disadvantages of open circulatory system
Low BP = Low Blood flow
Body movements or lack of may affect circulation
Structure of blood vessels
Lumen, Endothelium, elastic fibre Smooth muscle Collagen fibres
What do arteries do
carry blood away from the heart
How is the artery adapted to its function?
Small lumen = maintain high pressure
Folded endothelium = lumen can expand as BP increases
Elastic fibres = allow stretching and recoil to maintain BP
Collagen and elastic tissue outermost layer = withstand high pressure.
vein function
carry blood to the heart
How is a vein adapted to its function
Large lumen = ease blood flow Thin walls ( low pressure, no need to stretch and recoil as much)
Valves - prevent backflow
Surrounding skeletal muscle can apply pressure on veins and force blood flow
function of capillaries
Allow material exchange between blood and tissue fluid.
How are capillaries adapted to their function?
Endothelium is one cell thick with pores between cells for semi-permeability.
= low diffusion distance
Arterioles function
Distribute blood from arteries to capillaries
How do arterioles perform its function?
Constriction = increased blood flow resistance
So less blood flows to some capillaries
More blood to those who need it
