L1 - 1.1 - Transport in substance - ms Boyle
SA to volume ratio - Why do we need an Exchan'ge system?
• Human or mammals have a large size, increase in size of organism : surface area to
volume ratio decreases - the diffusion distance increasing hence metabolic rate
increase.
• Diffusion become insufficient. As result large organism have mass transport -
consisting of heart and circulation - move substance around the body and allows
gas change.
3 cubes X 3 cubes
2 cubesacubes
SA =
6 x 32 = 54
SA =
6x 28 = 24
r
V =
33 =
27
V = 23 =
8
SA: V =
SAIV =
54 : 27 =
54/27 2
=
SA : V =
SAIV =
24:8 = 2418:3
a cubes x4 cubes
SA = 6x42 =
96
V = 43 =
64
SA V
. -
SAIV =
96 64
. =
96/64 =
1 5
.
The bigger the Sa to volume ratio the faster the rate of diffusion
Human Earthworm m = am-
surface = 180 dm2 Surface = 0.36 dm2
volume = 68 dm2 M Volume = 0.0048 dm2·
180/68= 2.5
15 don't 0.36/0.0048 = 75 dm-
The earthworm has a higher SA to volume ratio which suggest that it has a smaller
diffusion distance and doesn’t need mass transport .
-we Have a specialized organs for gas ' exchange.
-Earthworm is moist better diffusion.
·
, L1 - 1.1 - The heart - ms Boyle 11. 9. 23
• four chambers - RL atrium and ventricle
• four main blood vessels -vena cave, aorta,
plumery vine plumery artery
• Atrioventricular valve - Tricuspid bicuspid -
separate atria from ventricle
• Semilunar valve - separate atria from ventricle
• Tendinous chords - prevent atrioventricular
from turning in and out due to pressure
• Septum - prevent oxygenated and deoxygenated
blood from mixing
• Cardiac muscle - thicker on LHS - pumps blood septumY
at high pressure. cardiac
muscle
Double circularly system - Passes through the heart twice
Why - respiration release energy - want to get blood around - get energy.
• The deoxygenated blood from the body Enters the vena cava and then travels to
Right atrium then into through the t-valveInto the right ventricle and pumps out
of the Pulmonary artery (way from the heart)
• The oxygenated blood from the lungs enter the Pulmonary vein (towards the
heart)into the left atrium and Through the b-valve it enters the left ventricle And
blood pump to the rest of the body throughAorta. N
Irregular beating of the heart is called - arrhythmia