Mass transport

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  • Created by: Hindleyc
  • Created on: 03-06-18 13:18
What do all organisms need to do?
Exchange materials between themselves and the environment
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What sort of materials?
Respiratory gases, metabolites, excretory products
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what do exchange surfaces require?
Large SA and moist surfaces, small distances and concentration gradients
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What is this simple in?
Unicellular organisms such as prokaryotes, protozoans and unicellular algae
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What does increasing size do?
Increase problems- as diffusion no longer sufficient
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What did complex multicellular organisms evolve?
more sophisticated systems- muscles, digestive systems, excretion leaves and flowers etc
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What do larger organisms have?
A higher metabolic rate
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what have evolved to make exchange more efficient?
specialist exchange surfaces
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Why has mass transport circulatory systems evolved?
to connect tissues with exchange surfaces
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When are they needed?
When SA:Vol is low, metabolic activity is high
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What are the general characteristics of a circulatory system?
Provides rapid mass flow of materials in bulk from exchange surfaces to respiring tissues and from repairing tissues to exchange surfaces
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What must be maintained? what must surfaces be?
concentration gradient. adapted to allow efficient exchange
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What are the various distinct characteristics?
Circulatory fluid such as blood or fluid in phloem. Closed system of branching vessels through which fluid can circulate eg blood/xylem vessels. Mechanism for transporting fluid relying on pressure gradients being maintained
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What else?
mechanism to ensure flow is in one direction eg valves. mechanism to control flow rate depending on metabolic requirements eg nervous system or stomatal control
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Transport in mammals direction?
Heart to arteries to arterioles to capillaries to venues to veins back to heart
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What is double circulation in mammals?
Systematic circulation- where left side of heart goes to tissues and organs of body back to right side of heart. Pulmonary circulation- right side to lungs back to left side of heart enabling lower pressure to lungs
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What else does it ensure?
Pressure is high enough for efficient exchange at tissues
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What are the circuits mostly?
Parallel to enable even distribution
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Where is the heart?
Middle of thorax above diaphragm behind sternum between 2 lungs partially overlapped by left lung- apex points towards left lung
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What is the major tissue in the heart wall
cardiac muscle
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what is cardiac muscle tissue known as?
myocardium
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What is it made of?
Branching cells which can share nuclei- cross striated. transmit electricity excitation- capable of contracting and relaxing
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Where is the blood supply from?
Coronary artery- delivering oxygenated blood to heart muscle branches from aorta and receives 5% of total cardiac output with a dense capillary network
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What returns blood to the heart directly into right atrium through coronary sinus?
Coronary veins
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What are the coronary arteries?
Branch from aortic arch delivering oxygenated blood to the cardiac muscle
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What is the aorta?
takes oxygenated blood from heart to respiring tissues
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What is the vena cava?
takes deoxygenated blood from the respiring tissues to the heart
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What is the pulmonary artery?
Takes deoxygenated blood from heart to lungs
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what is the pulmonary vein?
takes oxygenated blood from lungs to heart
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whats the hepatic artery?
takes oxygenated blood from aorta to liver
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whats the hepatic portal vein?
Takes deoxygenated nutrient rich blood from intestines to the liver
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what is the hepatic vein?
takes deoxygenated blood from liver to vena cava
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What is the left and right renal arteries?
takes oxygenated blood to kidneys
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What is the left and right renal veins?
Takes deoxygenated blood to vena cava
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Vena cava?
Deoxygenated blood from body tissues into right atrium
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Pulmonary artery?
Deoxygenated blood from right ventricles to lungs
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Pulmonary vein?
Oxygenated blood from lungs back to left atrium
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Aorta?
carries oxygenated blood from left ventricle to respiring body tissues
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what do the atria do?
relax to receive blood from veins- vena cava to right atrium, pulmonary veins to left atrium
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what are they like?
Thin walled elastic and contract to push blood into ventricles
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how do they work with regards to veins?
rings of muscle surround veins on their point of entry- contract to close off veins which prevents reflux of blood into veins
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what are the ventricles like?
Myocardium thicker than atria- distance to atria v small
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left compared to right?
Myocardium of left ventricle is 3x thicker than right ventricle
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what does this do? why?
creates higher blood pressure in systematic circulation as essential for efficient function of organs and allows tissue fluid formation
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Why is there a lower blood pressure in pulmonary circulation?
Prevents rupture of delicate pulmonary arteries
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What are the ventricles separated by? what do they do?
Septum, relax to receive blood from atria and contracts to push blood through the arteries - left ventricle into aorta and right ventricle into pulmonary artery
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What are valves?
Responsible for heart sounds and ensures unidirectional flow of blood through heart
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What do the atrioventricular valves do?
lub. Between atria and ventricles and prevent blood flowing back into atria when ventricles contract
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How do they close?
High pressure in ventricles causes them to close back towards atria
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What is the chordae tendinae?
fibrous chords that attach lose edge of valves to walls of ventricles- connect papillary muscle to valves
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what happens when ventricle contracts?
papillary muscle contracts and tightens chordae tendinae
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What is tricuspid valve?
3 flaps on right side of heart
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what is bicuspid valve?
2 flaps- left side of heart
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what is the pocket/semilunar valves?
at entrance of aorta and pulmonary artery- hence aortic and pulmonary valves
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what do they do?
Prevent back flow of blood into ventricles
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how?
When ventricles relax pressure in ventricle drops below pressure in arteries causing ventricle to fill with blood creating dub sound
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Other cards in this set

Card 2

Front

What sort of materials?

Back

Respiratory gases, metabolites, excretory products

Card 3

Front

what do exchange surfaces require?

Back

Preview of the front of card 3

Card 4

Front

What is this simple in?

Back

Preview of the front of card 4

Card 5

Front

What does increasing size do?

Back

Preview of the front of card 5
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