Transport In Animals Flashcards
(35 cards)
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
Compare the distribution of the different tissues in artery and vein’s walls.
Artery has thicker Elastic fibre, smooth muscle and collagen layers than vein
Artery has smaller lumen than vein
What forces are involved in tissue fluid formation?
Hydrostatic pressure and Oncotic pressure
How does tissue fluid form?
High hydrostatic pressure at arterial end and low oncotic pressure
Net movement of substance is out of capillary
What are the two end regions (near each of the two types major larger blood vessels) called in capillaries?
Near Artery end - Arterial
Near Vein end - venous
How are wastes in tissue fluid removed?
Venous end has low hydrostatic pressure and high oncotic pressure
Net movement of waste fluid is into the capillary.
What is oncotic pressure?
Pressure from dissolved substances.
What happens to excess tissue fluid?
Drained into lymphatic system
What is Lymph?
fluid in the lymphatic system
What cells are found in Blood plasma?
RBC
Neutrophils
Lymphocyte
