exchange surfaces

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why do we need exchange substance
to survive - for example oxygen from the environment and nutrients and releasing carbon dioxide
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what are way in which substances can be exchanged
osmosis, diffusion, active transport
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what is the difference of active transport and diffusion
it goes against the concentration gradient and it requires ATP
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what factors affect weather an organism needs an exchange surface
size - large organisms have cells that are too far from their body, surface area to volume ratio, the metabolic activity
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how to you calculate the surface area to volume ratio
first calculate the volume which is length x width x height, then the surface area - work out the area of one side then time by the number of sides then simplify the ratio
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how does the ratio change with an organism and why does this matter
as the organism gets larger the ratio gets smaller- an organism with a smaller ratio will have a greater need for a specialised exchange surface - smaller organisms have a larger ratio and do not need an exchange surface
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how does the metabolic activity affect weather an organism needs an exchange surface
organisms with a lowe metalboic rate require fewer nutrients and produce less waste - if an organisms has a high metabolic rate then it will require a specialised exchange surface
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how do exchange surface maximize the efficiency of exchange
a large surface area - provides more space and contact for substances to pass through they can fold or add hairs - thin barriers - shorter diffusion distance allows quick exchange
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how are trachea and bronchi specialised
trachea has c-shapes rings of cartilage to provide support and also allow flexibility - smooth muscle allows them to constrict to reduce air flow - the walls are lined with epithelial tissue containing goblet cells -secret mucus that trap pathogens
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brochioles
the bronchioles consists mainly of smooth muscle and epithelial cells
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what is the alveoli mainly consist of
alveoli consists of squamous epithelial tissues and elastic fibres
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adaptations of the alveoli
large surface area and good blood supply, grape like structure and lots of blood vessels - short diffusion distance - constant blood supple helps to keep a favorable gradient
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how do elastic fibres in bronchi aid ventilation
smooth muscle in bronchi may contract in presence of harmful substances in the air, this deforms the elastic fibres. The smooth muscle cannot once relaxed return to its original length to open the airways again by itself. instead as the muscle relax
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how do elastic fibres in bronchi aid ventilation (2)
the elastic fibres recoil to their original size and shape, dilating the lumen of the airway, reducing obstructing of airflow
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what cells secrete mucus
goblet cells
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explain how antiseptic enzymes present mus aid it in its role
the mucus traps pathogens. Antiseptic enzymes reduces the chances of the host becoming infected by these pathogens by preventing their growth
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suggest why mucus does not line the cells of the alveoli
it would increase the diffusion distant of the gases it also would not be cleared, as there are not cilia on the squamous epithelial cells
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what is ventilation
it is the process of moving in (inspiration) and breathing out (expiration)
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what structures are required for ventilation
intercostal muscles, external and internal - diaphragm, separates the thorax from the abdomen
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what is inspiration
an acrive prcess that requires ATP
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what happens during inspiration
the external intercostal muscles contract and internal intercostal relax - diaphragm contracts and flattens , volume of thorax increased, atmospheric pressure is greater than pulmonary pressure as the volume has increased - air is forced into lungs
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what is expiration
is exhaling it is a passive process and does not require as much ATP than inhaling
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what happens during expiration
external intercostal muscles relax and internal intercostal muscles relax - diaphragm relaxes and i pushed up by the contents of the abdomen - the volume of thorax is decreased - pulmonary pressure is greater than atmospheric pressure -air is out
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how can the volume of the lungs be measured
spirometer
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how does the spirometer work
oxygen is inhales causes lid to drop down - exhaling back into the spirometer the air is replaced causes lid to rise
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why is there soda lime
records the movement of the lid and indicates the volume of air ventilated - CO2 exhaled by the patient is absorbed by soda lime
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what is tidal volume
it is the volume of air moved in and out of the lungs with a normal breath
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what is vital capacity
the maximum amount of air that can be moved by the lungs in one breath
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what is the residual volume
residual volume is the volume of air left in the lungs after a forced expiration
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explain why a collapsed lung can cause difficulty breathing
in a collapsed lung the intercostal muscles cannot help to change the volume of the lung. To breath this must be increased or decreased as this changes the direction of the air pressure gradient which is what cause air to move.
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structure of the gills
set or series of bony gill arches each with two stack of gill filaments - very thin lamellae, disc shapes - each lamella consits of a network of capillaries - gills are delicate protected by opeculum
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why is it important to ventilate their gills
fish also need to ventilate their gills to maintain a strong diffusion gradient to provide efficient gas exchange
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what is contercurrent flow
is a term that describes two liquids in close proximity to each other flowing in opposite directions
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why is countercurrent flow important to gas exchange in fish
ensures maximum efficiency of gas exchange, as water flows past the capillary it loses oxygen to the blood down a diffusion gradient - clood that has very little oxygen flows past water with some oxygen and diffusion occurs
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what exchange system do insects have
tracheal system - delivers oxygen directly to every tissue in the body
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where does gas exchange happen in insects
in the tracheal fluid at the ends of the tracheoles
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how does the tracheal exchange occurs
when resting the liquid seeps into the tracheoles from the surrounding cells - when the insect is active the muscles draw up the tracheal fluid, provides them with oxygen containing fluid for respiration - lowers the pressure in the tracheoles which
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how does the tracheal exchange occurs (2)
draws more air in through the spiricals - increases the surface area available for oxygen to diffuse through tracheal walls directly
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state and explain how the direction of fluid flow in the fills of bony fish is specialised to achieve gas exchange
fluid in the gills moves by countercurrent flow exchange i.e water moves in the opposite direction to blodd flow, so well oxygenated blood meets fully oxygenated water. Deoxygenated blood meets less well oxygenated water. at all time an o2 gradient
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what are way in which substances can be exchanged

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osmosis, diffusion, active transport

Card 3

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what is the difference of active transport and diffusion

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Card 4

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what factors affect weather an organism needs an exchange surface

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Card 5

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how to you calculate the surface area to volume ratio

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