Circulation
Structure & Function of the Heart
To produce a rapid of material from one part of the body to another over distances where
diffusion would be too slow
o Nutrient + waste transport
o Carbon dioxide and oxygen transport
o Delivery of nutrients from food and of oxygen from the lungs
o Excretion: removal of waste produced from metabolism (does not include
defaecation)
o Thermoregulation
o Hormone transport
o Body defences (white blood cells and antibodies)
o Structural in species without skeletons
Types of Systems
1. No circulatory system -> bacterium/flatform transport metabolites and wastes by diffusion
2. Unspecialised system -> roundworm’s body fluid can move through body cavity and
functions as hydrostatic skeleton
3. Specialised open system -> insects/molluscs have a tube heart that pumps haemolymph,
which bathes cells in sinuses, through vessels that are open ended through peristalsis
(pseudoheart)
4. Specialised closed, one cycle system -> fish’s blood confined to blood vessels, high pressure
that requires more effective pumping, efficient
5. Specialised closed, two cycle system -> mammals/birds pumps for two circuits combined into
one
Constituents of System
1. Circulatory fluid (haemolymph/blood)
2. Interconnecting vessels (arteries, capillaries, veins)
3. Muscular pump (heart)
Benefits of a Closed System
1. Controllable -> able to support high activity and meet high energy demands (aerobic
metabolism)
2. High pressure
3. Ultra filtration -> kidney and capillary beds
The Heart
Epicardium: epithelial + connective tissue
Myocardium: cardiac muscle
Endocardium: epithelial
Pericardium: double-layered sac that surrounds the heart that has lubricating fluid which
reduces friction
, Circulation
Oxygenated blood to body
Deoxygenated blood from body Deoxygenated blood to lungs
Oxygenated blood from lungs to
heart
Deoxygenated blood from body
Cardiac Cycle
Cardiac diastole: all chambers relaxed and blood flows IN the heart
Atrial systole, Ventricular diastole: atria contact, blood INTO ventricles
Atrial diastole, Ventricular systole: atria relax, ventricles contract, blood OUT of heart
Structure & Function of the Heart
To produce a rapid of material from one part of the body to another over distances where
diffusion would be too slow
o Nutrient + waste transport
o Carbon dioxide and oxygen transport
o Delivery of nutrients from food and of oxygen from the lungs
o Excretion: removal of waste produced from metabolism (does not include
defaecation)
o Thermoregulation
o Hormone transport
o Body defences (white blood cells and antibodies)
o Structural in species without skeletons
Types of Systems
1. No circulatory system -> bacterium/flatform transport metabolites and wastes by diffusion
2. Unspecialised system -> roundworm’s body fluid can move through body cavity and
functions as hydrostatic skeleton
3. Specialised open system -> insects/molluscs have a tube heart that pumps haemolymph,
which bathes cells in sinuses, through vessels that are open ended through peristalsis
(pseudoheart)
4. Specialised closed, one cycle system -> fish’s blood confined to blood vessels, high pressure
that requires more effective pumping, efficient
5. Specialised closed, two cycle system -> mammals/birds pumps for two circuits combined into
one
Constituents of System
1. Circulatory fluid (haemolymph/blood)
2. Interconnecting vessels (arteries, capillaries, veins)
3. Muscular pump (heart)
Benefits of a Closed System
1. Controllable -> able to support high activity and meet high energy demands (aerobic
metabolism)
2. High pressure
3. Ultra filtration -> kidney and capillary beds
The Heart
Epicardium: epithelial + connective tissue
Myocardium: cardiac muscle
Endocardium: epithelial
Pericardium: double-layered sac that surrounds the heart that has lubricating fluid which
reduces friction
, Circulation
Oxygenated blood to body
Deoxygenated blood from body Deoxygenated blood to lungs
Oxygenated blood from lungs to
heart
Deoxygenated blood from body
Cardiac Cycle
Cardiac diastole: all chambers relaxed and blood flows IN the heart
Atrial systole, Ventricular diastole: atria contact, blood INTO ventricles
Atrial diastole, Ventricular systole: atria relax, ventricles contract, blood OUT of heart
