Transport In Animals
Multicellular Organisms need a transport system :
Large
Small SA:VR
Long diffusion distance
High metabolic rates-active so large number of cells respiring very
quicky so a constant ,rapid supply of glucose and oxygen needed
- Therefore, they need a transport system – circulatory system
Types of circulatory systems
If asked , mention both
- Single (fish)
Blood only passes through the heart once for each complete circuit
of the body
Heart pumps DOB to gills to become OB and then through the rest
of the body to deliver oxygen in a single circuit
- Double Circulatory System
Blood passes through heart twice for each complete circuit of the
body
Mammals have a double CS where the heart is divided down the
middle
Pulmonary System – blood to the lungs
Systemic System – blood sent to body
- Advantage of mammalian double circulatory system is the heart
gives the blood an extra push b/w lungs and rest of body making
blood travel faster so oxygen is delivered to tissues more quickly
- Closed(All vertebrates – fish and mammals)
Blood is enclosed inside the blood vessels
In fish heart pumps blood into arteries which branch out into
millions of capillaries so substances like oxygen and glucose diffuse
from blood in capillaries into body cells but as it circulates, blood
stays inside blood vessels and veins take blood back to heart
- Open (Invertebrates like insects)
This system supplies insects cells with nutrients and transports
things like hormones around body but doesn’t supply insects cells
with oxygen (tracheal system)
Blood isn’t enclosed within blood vessels all the time and instead
flows freely through body cells
Insect heart is segmented and contracts in a wave from the back
and pumps blood into a single main artery which opens up into the
body cavity
, Blood flows around the insects organs and gradually makes its way
back to the heart segments through a series of valves
1- Segmented heart pumps blood forwards
2- Blood pumped into single main artery
3- Main artery opens up into body cavity
4- Blood flows back through body cavity
5- Blood returns to heart through valves
Blood Vessels
- Arteries
Carry blood from heart to rest of body
Thick muscular walls
Elastic tissue to stretch and recoil as heat beats to maintain high
pressure
Inner lining /endothelium is folded allowing artery to expand which
also maintains the high pressure
All arteries carry oxygenated blood except for pulmonary artery
which take deoxygenated blood to lungs
Thicker layer of smooth muscle and narrow / smaller diameter
lumen
- Arterioles
Layer of smooth muscle to expand and contract and control amount
of blood flow to tissues
Less elastic tissue
Why arterioles with more smooth muscle would be better adapted
than arteries in allowing blood flow to an individual organ
1 relaxation of smooth muscle (in arteriole) causes vasodilation (of
the lumen) ✓ 2 (this) regulates / controls, blood flow to capillaries (in
the organ) ✓
3 pressure of blood in artery is higher ✓
4 as blood flows from the artery to the arteriole, the pressure falls ✓
5 (so) capillary (walls) will not rupture ✓
- Capillaries
Substances like glucose and oxygen exchanged b/w cells and
capillaries
Walls only 1 cell thick
Millions of alveoli- large SA:VR
- Venules
Thin walls containing some muscle cells
- Veins
Blood away from heart under low pressure
Large lumen /wider
Multicellular Organisms need a transport system :
Large
Small SA:VR
Long diffusion distance
High metabolic rates-active so large number of cells respiring very
quicky so a constant ,rapid supply of glucose and oxygen needed
- Therefore, they need a transport system – circulatory system
Types of circulatory systems
If asked , mention both
- Single (fish)
Blood only passes through the heart once for each complete circuit
of the body
Heart pumps DOB to gills to become OB and then through the rest
of the body to deliver oxygen in a single circuit
- Double Circulatory System
Blood passes through heart twice for each complete circuit of the
body
Mammals have a double CS where the heart is divided down the
middle
Pulmonary System – blood to the lungs
Systemic System – blood sent to body
- Advantage of mammalian double circulatory system is the heart
gives the blood an extra push b/w lungs and rest of body making
blood travel faster so oxygen is delivered to tissues more quickly
- Closed(All vertebrates – fish and mammals)
Blood is enclosed inside the blood vessels
In fish heart pumps blood into arteries which branch out into
millions of capillaries so substances like oxygen and glucose diffuse
from blood in capillaries into body cells but as it circulates, blood
stays inside blood vessels and veins take blood back to heart
- Open (Invertebrates like insects)
This system supplies insects cells with nutrients and transports
things like hormones around body but doesn’t supply insects cells
with oxygen (tracheal system)
Blood isn’t enclosed within blood vessels all the time and instead
flows freely through body cells
Insect heart is segmented and contracts in a wave from the back
and pumps blood into a single main artery which opens up into the
body cavity
, Blood flows around the insects organs and gradually makes its way
back to the heart segments through a series of valves
1- Segmented heart pumps blood forwards
2- Blood pumped into single main artery
3- Main artery opens up into body cavity
4- Blood flows back through body cavity
5- Blood returns to heart through valves
Blood Vessels
- Arteries
Carry blood from heart to rest of body
Thick muscular walls
Elastic tissue to stretch and recoil as heat beats to maintain high
pressure
Inner lining /endothelium is folded allowing artery to expand which
also maintains the high pressure
All arteries carry oxygenated blood except for pulmonary artery
which take deoxygenated blood to lungs
Thicker layer of smooth muscle and narrow / smaller diameter
lumen
- Arterioles
Layer of smooth muscle to expand and contract and control amount
of blood flow to tissues
Less elastic tissue
Why arterioles with more smooth muscle would be better adapted
than arteries in allowing blood flow to an individual organ
1 relaxation of smooth muscle (in arteriole) causes vasodilation (of
the lumen) ✓ 2 (this) regulates / controls, blood flow to capillaries (in
the organ) ✓
3 pressure of blood in artery is higher ✓
4 as blood flows from the artery to the arteriole, the pressure falls ✓
5 (so) capillary (walls) will not rupture ✓
- Capillaries
Substances like glucose and oxygen exchanged b/w cells and
capillaries
Walls only 1 cell thick
Millions of alveoli- large SA:VR
- Venules
Thin walls containing some muscle cells
- Veins
Blood away from heart under low pressure
Large lumen /wider
