CIRCULATORY SYSTEM OF A MAMMAL + THE HEART
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- Created by: S14n
- Created on: 14-03-21 10:36
WHY CAN'T MAMMALS JUST USE DIFFUSION TO TRANSPORT MATERIALS?
diffusion is fast enough for transport over short distances but for the most efficient supply of materials over larger distances, requires a mass transport system.
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WHY DO LARGE ORGANISMS HAVE A TRANSPORT SYSTEM?
small organisms exchange over body surface;
with increasing size, the SA:V DECREASES to the point where the needs of an organism cannot be met by the body surface alone= specialist exchange surfaces =needed to absorb nutrients and respiratory gases + rem
with increasing size, the SA:V DECREASES to the point where the needs of an organism cannot be met by the body surface alone= specialist exchange surfaces =needed to absorb nutrients and respiratory gases + rem
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WHERE ARE THESE EXCHANGE SURFACES LOCATED?
in specific regions of the organism.
as organisms evolved into larger + complex structures, their tissues + organs become more specialised and dependent upon eachother = transport system is essential
as organisms evolved into larger + complex structures, their tissues + organs become more specialised and dependent upon eachother = transport system is essential
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WHEN IS A SPECIALISED TRANSPORT SYSTEM NEEDED? WHAT DOES IT DEPEND ON?
whether there's a specialised transport medium or whether it's circulated by a pump or not depends on:
- SA:V ratio
- how active the organism is
- SA:V ratio
- how active the organism is
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FEATURES OF TRANSPORT SYSTEMS
(1)
(1)
- a suitable medium to carry material ( e.g. blood)
- form of mass transport which the t system is moved around in bulk over large distances: quicker than diffusion
- form of mass transport which the t system is moved around in bulk over large distances: quicker than diffusion
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(2)
- a mechanism for moving t medium within the vessels- requires a pressure difference between a part of the system and another
- closed system of tubular vessels that contain transport medium + forms a branching network to distribute it to all parts of org
- closed system of tubular vessels that contain transport medium + forms a branching network to distribute it to all parts of org
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HOW IS TRANSPORT THROUGH SYSTEMS ACHIEVED?
- animals use muscular contraction ( either of the body muscles or of a specialised pumping organ= heart)
- plants rely on natural, passive processes; e.g. evaporation of water
- plants rely on natural, passive processes; e.g. evaporation of water
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WHAT DO PLANTS REQUIRE?
- a mechanism to maintain the mass flow of movement in one direction, e.g. valves
-means of controlling flow of t medium to suit needs of different parts of organism
- mechanism for mass flow of water or gases ;
( intercostal muscles & diaphragm during b
-means of controlling flow of t medium to suit needs of different parts of organism
- mechanism for mass flow of water or gases ;
( intercostal muscles & diaphragm during b
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CIRCULATORY SYSTEM IN MAMMALS
- closed, double circulatory system
- blood= confined to vessels
- passes through heart x2
- final part of journey to cells is by DIFFUSION; it's quick as it takes place over large SA across short distances + there's a steep diffusion gradient
- blood= confined to vessels
- passes through heart x2
- final part of journey to cells is by DIFFUSION; it's quick as it takes place over large SA across short distances + there's a steep diffusion gradient
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WHY DOES BLOOD CIRCIT THROUGH THE SYSTEM TWICE?
when blood is passed through the lungs, pressure = reduced
if it were to pass immediately to rest of body, low pressure would make circulation SLOW. blood is returned to heart to restore
pressure before being circulated to tissues- necessary for HIGH BO
if it were to pass immediately to rest of body, low pressure would make circulation SLOW. blood is returned to heart to restore
pressure before being circulated to tissues- necessary for HIGH BO
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THE HEART
- muscular organ
- lies in the thoracic cavity behind sternum.
- operates constantly
- lies in the thoracic cavity behind sternum.
- operates constantly
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STRUCTURE OF THE HEART
(1)
(1)
- RIGHT side pumps DEOXYGENATED blood from body to lungs
- LEFT side pumps OXYGENATED blood from the lungs to body again
- LEFT side pumps OXYGENATED blood from the lungs to body again
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THE 2 CHAMBERS OF EACH SIDE OF THE HEART
- ATRIUM = thin walled & elastic & stretches as it collects blood
- VENTRICLE = thicker muscular wall as it has to contract strongly to pump some distance, either to the lungs or the rest of the body
- VENTRICLE = thicker muscular wall as it has to contract strongly to pump some distance, either to the lungs or the rest of the body
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WHY HAVE 2 SEPARATE PUMPS?
- blood has to pass through tiny capillaries in lungs to present large SA for exchange of gases - this makes pressure drop
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RIGHT AND LEFT VENTRICLE
- RIGHT = pumps blood only to LUNGS ( deoxygenated)
- thinner wall than left
- LEFT = pumps oxygenated blood from lungs to body
- thicker walls so there's enough pressure
- thinner wall than left
- LEFT = pumps oxygenated blood from lungs to body
- thicker walls so there's enough pressure
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THE HEART'S VALVES
PREVENT BACKFLOW OF BLOOD into the atria when ventricles contract.
- BISCUSPID VALVE ( LEFT)
- TRICUSPID VALVE (RIGHT)
- BISCUSPID VALVE ( LEFT)
- TRICUSPID VALVE (RIGHT)
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VESSELS CONNECTING HEART TO THE LUNGS = PULMONARY VESSELS:
(1)
(1)
AORTA= connected to L Ventricle & carries oxygenated blood to the body - not the lungs
VENA CAVA= connected to right atrium and brings deoxygenated
blood back from tissues to body -not the lungs
VENA CAVA= connected to right atrium and brings deoxygenated
blood back from tissues to body -not the lungs
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(2)
PULMONARY ARTERY= connected to right ventricle, carries deoxygenated blood to lungs;
where its O2 is replenished & CO2 is removed
where its O2 is replenished & CO2 is removed
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(3)
PULMONARY VEIN= connected to left atrium and brings oxygenated blood back from lungs
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SUPPLYING THE HEART WITH OXYGEN
oxygenated blood passes through left side of the heart but heart doesn't use this O2 for it's own needs. heart muscle supplied by its own blood vessels - CORONARY ARTERIES
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CORONARY ARTERIES
&
MYOCARDIAL INFARCTION
&
MYOCARDIAL INFARCTION
coronary arteries branch off aorta, shortly after it leaves the heart.
BLOCKAGE of these arteries causes a heart attack as an area of heart muscle is deprived of blood and therefore O2 too.
muscle cells in this region cannot aerobically respire and so die
BLOCKAGE of these arteries causes a heart attack as an area of heart muscle is deprived of blood and therefore O2 too.
muscle cells in this region cannot aerobically respire and so die
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RISK FACTORS ASSOCIATED WITH CARDIOVASCUALAR DISEASE
(1)
(1)
SMOKING:
- giving up = most effective to increase life expectancy.
- in tobacco ;
carbon monoxide= binds with the haemoglobin and not easily reversed, forms carboxyhaemoglobin, reduces O2 capacity + heart works harder= high blood pressure
- giving up = most effective to increase life expectancy.
- in tobacco ;
carbon monoxide= binds with the haemoglobin and not easily reversed, forms carboxyhaemoglobin, reduces O2 capacity + heart works harder= high blood pressure
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(2)
HIGH BLOOD PRESSURE:
- excessive stress, lack of exercise, diet;
as there's already higher pressure in the arteries the heart must work harder- therefore more prone to failure. high blood p in arteries = prone to aneurysm and burst causing a haemorrhage
- excessive stress, lack of exercise, diet;
as there's already higher pressure in the arteries the heart must work harder- therefore more prone to failure. high blood p in arteries = prone to aneurysm and burst causing a haemorrhage
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(2.1)
- to resist high pressure within them the walls of the arteries tend to become thickened and may harden, restricting the flow of blood.
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(3)
BLOOD CHOLESTROL=
- essential component of membrane
- carried in the plasma as tiny spheres of lipoproteins ; there's 2 main types HDLs and LDLs
- essential component of membrane
- carried in the plasma as tiny spheres of lipoproteins ; there's 2 main types HDLs and LDLs
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LIPOPROTEINS (1)
high-density lipoproteins
(HDLs) :
which remove cholesterol from tissues and transport it to liver for excretion. they help protect arteries against heart disease
(HDLs) :
which remove cholesterol from tissues and transport it to liver for excretion. they help protect arteries against heart disease
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(2)
low-density lipoproteins (LDLs)
:
which transport cholesterol from the liver to the tissues, including the artery walls, which they infiltrate, leading to the development of atheroma, may lead to heart disease
:
which transport cholesterol from the liver to the tissues, including the artery walls, which they infiltrate, leading to the development of atheroma, may lead to heart disease
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(3)
DIET:
- high levels of salt, raise blood pressure
- high levels of saturated fat increase low-density lipoprotein levels hence blood concentration conc.
ANTIOXIDANTS; vitamin C and non-starch polysaccharide ( dietary fibre) reduce risk of heart disease
- high levels of salt, raise blood pressure
- high levels of saturated fat increase low-density lipoprotein levels hence blood concentration conc.
ANTIOXIDANTS; vitamin C and non-starch polysaccharide ( dietary fibre) reduce risk of heart disease
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Other cards in this set
Card 2
Front
WHY DO LARGE ORGANISMS HAVE A TRANSPORT SYSTEM?
Back
small organisms exchange over body surface;
with increasing size, the SA:V DECREASES to the point where the needs of an organism cannot be met by the body surface alone= specialist exchange surfaces =needed to absorb nutrients and respiratory gases + rem
with increasing size, the SA:V DECREASES to the point where the needs of an organism cannot be met by the body surface alone= specialist exchange surfaces =needed to absorb nutrients and respiratory gases + rem
Card 3
Front
WHERE ARE THESE EXCHANGE SURFACES LOCATED?
Back
Card 4
Front
WHEN IS A SPECIALISED TRANSPORT SYSTEM NEEDED? WHAT DOES IT DEPEND ON?
Back
Card 5
Front
FEATURES OF TRANSPORT SYSTEMS
(1)
(1)
Back
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