1.1: What is cardiovascular disease?
Cardiovascular disease:
CVDs are diseases of the heart and circulation
Main cause of death in the UK
Roughly 1/3 die from CVD
The main forms of CVDs= CHDs and strokes
1/5 men and 1/10 women die from CHDs
Why have a heart and circulation?
Heart and circulation have one primary purpose- move substances around the body
i) In small organisms (i.e. unicellular creatures) where distances are short,
substances such as oxygen, co2 and digestive products move around by diffusion.
ii) Diffusion= movement of molecules from area of high concentration to area of
low concentration {relatively slow random movement of molecules}
iii) In unicellular organisms- diffusion = usually fast enough to meet its requirements
iv) Most complex multicellular organisms = too large for diffusion to move
substances around body quickly enough
v) They rely on a mass transport system to move substances (long distance) by mass
flow
vi) All particles move in one direction though tubes due to difference in pressure
vii) Animals have blood to transport vital substances and a heart to pump it (instead
of diffusion) = circulatory system
Open circulatory systems
i) Blood circulates in large open areas WATE
ii) Simple heart pumps blood out into cavities surrounding animal’s organs R
iii) Substances diffuse between blood and cells FLEA
iv) When heart muscle relaxes, blood= drawn from the cavity back into the
heart through small valved openings
v) Animal has low metabolic rate, large surface area to volume ratio=small and
less active
vi) Diffusion rate between blood + cells = sufficient
Closed circulatory
i) Generates higher pressure blood travels faster more efficient at delivering
substances
ii) Overcomes the limitations of relying on diffusion of substances
iii) Animal has high metabolic rate, small surface area to volume ratio, very large
and more active FISH
iv) Blood leaves heart under pressure and flows along arteries arterioles
capillaries (lots of capillaries, they come in close contact with most cells where
substances=exchanged between blood and cells) blood then returns to heart
by venules veins [valves ensure blood only flows in one direction]
Single circulatory systems
i) Animals (i.e. fish) with closed systems have either= single or double circulation
ii) Heart pumps deoxygenated blood to gills gaseous exchange occurs in the gills,
diffusion of co2 from blood into the water surrounding the gills and of oxygen
from the water into the blood in the gills blood leaving the gills the flows
around rest of body before returning to heart (blood flows through heart once)
, Double circulatory systems BIRDS
i) Birds and mammals have them AND
ii) Right ventricle of heart pumps deoxygenated blood to lungs and receives MAMMA
oxygen oxygenated blood then returns to heart to be pumped again by LS
left ventricle to the rest of the body (blood flows through heart twice) (HUMAN
iii) Heart gives blood returning to the heart an extra ‘boost’ (reduces the time S)
it takes for the blood to circulate around the whole body allows animals
to have a high metabolic rate
iv) PUMP 1: low blood pressure in lungs to protect capillaries, the resistance
from the capillaries in the lungs reduce blood pressure further
v) PUMP 2: ‘boosts’ blood pressure for rapid and effective delivery of
oxygen/glucose
How does the circulation work?
The transport medium
i) A liquid and all the particles within are transported in one direction due to a
difference in pressure in process called mass flow
ii) In animals, medium= blood
iii) Fluid (plasma)= mainly water and dissolved substances like digested food
molecules, oxygen and co2
iv) Cells are also carried by blood as well as waste products and hormones
v) Blood plays an important role in regulation of body temp- transferring energy
around the body
Water
i) Liquid at room temp
ii) It is a polar molecule- so has an unevenly distributed electrical charge
iii) 2 hydrogens are pushed together forming V shaped molecule
iv) Hydrogen end= slightly positive and the oxygen end = slightly negative (because
electrons are more concentrated at that end)
v) Water= a dipole
vi) Slightly positive end is attracted to slightly negative ends of surrounding water
molecules (the hydrogen bonding holds the water molecules together and
results in many water properties)
Solvent properties
i) Many chemicals dissolve easily in water due to dipole nature allowing chemical
reactions to occur in the cytoplasm
Cardiovascular disease:
CVDs are diseases of the heart and circulation
Main cause of death in the UK
Roughly 1/3 die from CVD
The main forms of CVDs= CHDs and strokes
1/5 men and 1/10 women die from CHDs
Why have a heart and circulation?
Heart and circulation have one primary purpose- move substances around the body
i) In small organisms (i.e. unicellular creatures) where distances are short,
substances such as oxygen, co2 and digestive products move around by diffusion.
ii) Diffusion= movement of molecules from area of high concentration to area of
low concentration {relatively slow random movement of molecules}
iii) In unicellular organisms- diffusion = usually fast enough to meet its requirements
iv) Most complex multicellular organisms = too large for diffusion to move
substances around body quickly enough
v) They rely on a mass transport system to move substances (long distance) by mass
flow
vi) All particles move in one direction though tubes due to difference in pressure
vii) Animals have blood to transport vital substances and a heart to pump it (instead
of diffusion) = circulatory system
Open circulatory systems
i) Blood circulates in large open areas WATE
ii) Simple heart pumps blood out into cavities surrounding animal’s organs R
iii) Substances diffuse between blood and cells FLEA
iv) When heart muscle relaxes, blood= drawn from the cavity back into the
heart through small valved openings
v) Animal has low metabolic rate, large surface area to volume ratio=small and
less active
vi) Diffusion rate between blood + cells = sufficient
Closed circulatory
i) Generates higher pressure blood travels faster more efficient at delivering
substances
ii) Overcomes the limitations of relying on diffusion of substances
iii) Animal has high metabolic rate, small surface area to volume ratio, very large
and more active FISH
iv) Blood leaves heart under pressure and flows along arteries arterioles
capillaries (lots of capillaries, they come in close contact with most cells where
substances=exchanged between blood and cells) blood then returns to heart
by venules veins [valves ensure blood only flows in one direction]
Single circulatory systems
i) Animals (i.e. fish) with closed systems have either= single or double circulation
ii) Heart pumps deoxygenated blood to gills gaseous exchange occurs in the gills,
diffusion of co2 from blood into the water surrounding the gills and of oxygen
from the water into the blood in the gills blood leaving the gills the flows
around rest of body before returning to heart (blood flows through heart once)
, Double circulatory systems BIRDS
i) Birds and mammals have them AND
ii) Right ventricle of heart pumps deoxygenated blood to lungs and receives MAMMA
oxygen oxygenated blood then returns to heart to be pumped again by LS
left ventricle to the rest of the body (blood flows through heart twice) (HUMAN
iii) Heart gives blood returning to the heart an extra ‘boost’ (reduces the time S)
it takes for the blood to circulate around the whole body allows animals
to have a high metabolic rate
iv) PUMP 1: low blood pressure in lungs to protect capillaries, the resistance
from the capillaries in the lungs reduce blood pressure further
v) PUMP 2: ‘boosts’ blood pressure for rapid and effective delivery of
oxygen/glucose
How does the circulation work?
The transport medium
i) A liquid and all the particles within are transported in one direction due to a
difference in pressure in process called mass flow
ii) In animals, medium= blood
iii) Fluid (plasma)= mainly water and dissolved substances like digested food
molecules, oxygen and co2
iv) Cells are also carried by blood as well as waste products and hormones
v) Blood plays an important role in regulation of body temp- transferring energy
around the body
Water
i) Liquid at room temp
ii) It is a polar molecule- so has an unevenly distributed electrical charge
iii) 2 hydrogens are pushed together forming V shaped molecule
iv) Hydrogen end= slightly positive and the oxygen end = slightly negative (because
electrons are more concentrated at that end)
v) Water= a dipole
vi) Slightly positive end is attracted to slightly negative ends of surrounding water
molecules (the hydrogen bonding holds the water molecules together and
results in many water properties)
Solvent properties
i) Many chemicals dissolve easily in water due to dipole nature allowing chemical
reactions to occur in the cytoplasm
