Transports substances and blood cells around the body
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What is the function of white blood cells?
Part of the immune system to defend the body against pathogens
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What is the function of platelets?
Form blood clots to create barriers to infections
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What is the function of a vein?
Carries blood to the heart
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What is the function of an artery?
Carries blood away from the heart
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What is the function of a capillary?
\-Carries blood to tissues and cells
\-Connects arteries and veins
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What is the structure of an artery?
\-Thick muscular and elastic walls
\-The walls can stretch and withstand high pressure
\-Small lumen
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What are the three types of blood vessel?
\-Artery
\-Vein
\-Capillary
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What is the structure of a capillary?
\-One cell thick wall- short diffusion distance for substances to move between the blood and tissues
\-Very narrow lumen
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What is the structure of a vein?
\-Have valves to stop blood flowing the wrong way
\-Thin walls
\-Large lumen
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What happens when you breathe in?
1. Air moves into the body through the mouth and nose 2. Air moves down the trachea 3. Moves into the bronchi 4. Through the bronchioles 5. Into the alveoli
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What is coronary heart disease?
A build up of fatty material in the coronary arteries
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What types of heart valves can a faulty valve be replaced with?
\-Biological valves (pig or cow)
\-Mechanical valves (Titanium and polymers)
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What are the function and structure of the spongy mesophyll?
Function:-
To allow gas diffusion
Structure:-
\-Spherical shapes
\-Lots of air spaces for quick has diffusion
\-Large surface area to increase has exchange
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What is the function and structure of the upper epidermis?
Function:-
To protect against water loss
Structure:-
\-Single layer of cells
\-Transparent to allow light to pass through
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What is the function of the stomata?
Small opening to allow gases to diffuse in and out of the leaf
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What is the function of the guard cells?
Control the opening and closing of the stomata
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What is the structure of a guard cell?
\-Thick inner wall
\-Thin outer wall
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What is the function of the waxy cuticle?
To make the leaf water proof
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Name the layers of a leaf.
\-Waxy cuticle
\-Upper epidermis
\-Palisade mesophyll
\-Spongy mesophyll
\-Lower epidermis
\-Stomata
\-Guard cells
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What is transpiration?
Water is lost through the stomata by evaporation. This pulls water up from the roots through the xylem.
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What is the importance of translocation?
\-Moves dissolved sugars made in the leaves during photosynthesis
\-Allows for respiration, growth and glucose storage to happen
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What is the importance of transpiration?
\-Provides water to cells to keep them turgid
\-Provides water to cells for photosynthesis
\-Transports mineral ions to leaves
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What is the transpiration stream?
The constant movement of water up the xylem
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What is translocation?
The movement of dissolved sugars from the leaves to the rest of the plant through the phloem
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What is the function and structure of the palisade mesophyll?
Function:-
Photosynthesis
Structure:-
\-Tightly packed cells
\-Lots of chloroplasts to absorb light
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What are the structures of the phloem?
\-Moves water and dissolved sugars
\-Cells have end walls with small holes to allow substances to flow through
\-Substances transported in both directions
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What are the structures of the xylem vessel?
\-One way transport of water and mineral ions
\-Made of dead cells joined together
\-Thick wall stiffened with lighin
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Name the 4 factors affecting the rate of transpiration.
\-Temperature
\-Humidity
\-Wind speed
\-Light intensity
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How does temperature effect transpiration?
High temperatures increase the rate of transpiration
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Why does temperature effect transpiration?
Water evaporates faster in higher temperatures
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How does humidity effect transpiration?
Lower humidity increases the rates of transpiration
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Why does humidity effect transpiration?
The drier the air, the steeper the concentration gradient of water molecules between the air and leaf
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How does wind speed effect transpiration?
More wind increases the rate of transpiration
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Why does wind speed effect transpiration?
Wind removes the water vapour quickly, maintaining a steep concentration gradient
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How does light intensity effect transpiration?
Higher light intensity increases the rate of transpiration
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Why does light intensity effect transpiration?
Stomata open wider to let more carbon dioxide into the leaf for photosynthesis