features of a transport system Flashcards
what are the essential features of a transport system
- suitable medium in which to carry materials
- a pump for moving blood
- valves to maintain one directional flow
- respiratory pigment which increase volume of oxygen
- a system of vessels to distribute transport medium to all parts of the body
what is the difference between an open and closed circulatory system
open- the blood does not move around the body in blood vessels but bathes tissues directly
closed- the blood moves in blood vessels; either in single circulation or double circulation
what is the difference between a single and double circulatory system
single- only passes through the heart once in its journey around the body
double- passes through the heart twice on its journey around the body
where is blood moved to in open circulatory systems
- The haemocoel where materials are exchanged between blood and body cells
what is the advantage of a double circulatory system
it is more efficient has material exchange between blood and body cells is faster and can be pumped at a higher pressure
what are the components of a double circulatory system
1) pulmonary ciruclation= the right side of the heart pumps deoxygenated blood to the lungs and oxygenated blood returns to the heart at the left side= heart to lungs
2) systemic circulation= left side of the heart pumps oxygenated blood to tissues and deoxygenated blood from the body returns to the right side of the heart= heart to the body)
what are the different types of blood vessel
1) vein
2) artery
3) capillary
outline the structure of the artery
consists of three layers
1) the endothelium= the innermost layer which is one cell thick and surrounded by the tunica intima- smooth lining reduces friction
2) The Tunica media= is the thick middle layer containing elastic fibers and smooth muscle. Elastic fibers allow stretching to accommodate high pressure, recoils to push blood through the artery
3) Tunica externa= outmost layer containing collagen fibers that resist overstretching
outline the structure of the vein
1) thinner layer of tunica interna
2) thinner layer of tunica media
3) thinner layer of tunica externa
what is the role of the artery, vein and capillary
1) carry blood away from the heart under high pressures- thick walls to withstand this
2) carries blood towards the heart at lower pressures- contain semilunar valves to prevent backflow from gravity
3) a vast network which penetrates all tissues and organs for material exchange
how is the structure of a capillary adapted for its function
- thin walls for short diffusion distance - only one cell thick
- pore between cells to make them permeable to water and solutes such as glucose
- small diameter to slow rate of blood flow for material exchange
define myogeneic contraction
the heartbeat is initiated within the muscles cells themselves and no dependant on nervous of hormonal stimulation
