13.5 Circulatory System of a Mammal. 13.5 Circulatory System of a Mammal Learning Objectives: Over...
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13.5 Circulatory System of a Mammal. 13.5 Circulatory System of a Mammal Learning Objectives: Over large distances, efficient supply of materials is provided
13.5 Circulatory System of a Mammal Learning Objectives: Over
large distances, efficient supply of materials is provided by mass
transport. The general pattern of blood circulation in a mammal.
(Names are required only of the coronary arteries and of blood
vessels entering and leaving the heart, liver and kidneys).
Slide 3
Mass Transport Why is it needed? Diffusion is adequate for
transport over small distances. Efficient supply of materials over
larger distances requires a mass transport system. With increasing
size, and decreasing surface area to volume ratio, the needs of the
organism cannot be met by use of the body surface alone.
Specialised exchange surfaces are located in specific regions of
the body to allow absorption of nutrients and respiratory gases and
the excretion of waste substances. Materials need to then be
transported from the exchange sites to other areas of the body, and
to the external environment.
Slide 4
Factors determining the presence of mass transport The surface
area to volume ratio The activity of the organism Obviously, the
greater the activity and smaller the ratio, the greater the need
for mass transport and a pump.
Slide 5
Features of Transport Systems Internal Medium to carry
substances (must be able to dissolve some substances) A closed
system of tubular vessels with a branched network allowing supply
to all areas of organism A mechanism for moving the internal medium
within the vessels: a pressure difference between different part of
the system. This is achieved by either : a pumping mechanism
muscles or organ such as heart A passive process, eg evaporation of
water A mechanism to maintain mass flow in one direction eg ? A
means of controlling the flow to suit the needs of the
organism
Slide 6
The Heart Aorta Left atrium Left ventricle Pulmonary vein Right
atrium Vena cava Right ventricle Pulmonary artery Tricuspid valve
Semi-lunar valve Bicuspid valve 1 2 3 4 5 11 10 9 8 7 6
Slide 7
Slide 8
Mammalian Double Circulatory System
Slide 9
Slide 10
Questions What does a double circulatory system mean? Blood
passes twice through the heart for each circuit of the body. Why is
it advantageous/necessary? When blood passes through the lungs, the
pressure lowers. If it didnt go back to the heart before going off
to the body, then circulation would be very slow. Having a double
circulation boosts pressure and helps to deliver substances to the
rest of the body quickly (which is needed due to mammals having a
high body temperature and a high metabolism)
Slide 11
Task Complete Summary Questions on page 185.
Slide 12
13.5 Circulatory System of a Mammal Learning Objectives: Over
large distances, efficient supply of materials is provided by mass
transport. The general pattern of blood circulation in a mammal.
(Names are required only of the coronary arteries and of blood
vessels entering and leaving the heart, liver and kidneys).
