Gas exchange Flashcards
what are some examples of passive transport
osmosis, diffusion, facilitated diffusion
what are some examples of active transport
active transport and co-transport because thye both require ATP to move against the conc grad
why do small organisms not have gas exchange systems
because their surface area to volume ratios are large enough to facilitate the diffusiin of substances without needing a transporter intermediary
how are exchange surfaces adapted to the function - generally
thin membranes - shorter diffusion pathway allows for rapid diffusion
large surface area to vol ratio
some may be selectivrly permeable
what is ficks law?
diffusion is proportional = surface area x difference in conc /length of diffusion pathway
what are the component of an insects gas exchange system
trachea
tracheoles
respiring tissue
spiracles
what is the trachea in the insects made of
supported by strengthened rings to prevent collapse
what do the tracheoles do
they extend therough the body of the insect - this way o2 is brought directly to the respiring tissue
what is the function of the spiracle s
open and close to prevent the loss of water like the stomata
what is the structure of the gills
just tell me little words facts
gill filaments
lamellea
what are the gill filaments
stacks of gills stacked up high
where is the gill lamelea located
at a right angle to the gill filaments
what does the gill lamellae do
increase SA of the gills.
what is the counter current flow system
where the flow of water and blood will flow in the opposite direction to one another over the lamellae
what does the gill lamellae look like
like little stacks on top of the filament to increase the surface area of the gill and so mmore o2 can get to fish
what are the organelles in a plant
stomata
- palisade mesophyll
upper epidermis
chloroplasts
vacuole
air space
guard cell
waxy cuticle
lower epidermis
what is the function of the stomata
to open and close to allow gaseous exchange. to guard cells control this via keeping them open if they are flaccid - not a lot of water or closed by being turgid
what is a xerophyte
plants specially adapted for warm, dry or windy environments where water loss is a problem -water lossss
what are some adaptations to xerophytes
stomata in sunken pits that trap moist air therefore reducing conc grad of water between air and the leaf. this reduces the amount of water diffsuing out the leaf and evaporating away
- a layer of hairs on the epidermis to trap air around the stomata
- curled leaves with the stomata inside protecting them from wind
-a reduced number of stomata
- waxy, waterproof cuticles on leaves and stems to reduce evaporation
where is the main gas exchange surface on the plant
surface of the palisade mesophyll cells - good because big SA
how do insects limit water loss
spiracles
small surface area to vol ratio
waterproof coverings
define transpiration
water loss
describe the lungs
a pair of lobed structure that are made up of highly branched tubules called bronchioles which end in tiny air sacs
describe the human trachea
supported by rings of cartilage that prevents collapse with the fall in air pressure when breathing in
what are the tracheal walls lined with
ciliated epithileum cells - wafting
goblet cells - to produce mucus
preventing infection
what are alveoli
tiny air sacs at the end of the bronchioles that are laced in a network of capillaries. between the alveoli there are elastic fibres that allow them to stretch as they fill with air and spring back when exhaling
describe the mechanism of inspiration
the ribcage moves up and out to increase the volume of the thoracic cavity. external intercostal muscles contract and diaphragm muscle contract whilst the internal intercostal muscles relax. due to the greater volume in the thoracic cavity the pressure decreases to lower than atmospheric and therefore air will be forced in via a pressure gradient
describe the mechanism of expiration
the ribcage moves down and in to increase pressure. the external intercostal muscles and diaphragm muscle relax and the internal intercostal muscles contract. the pulmonary pressure is now higher than atmospheric due to the decreased volume. air is forced out along the pressure gradient
why are rbcs slowed as they pass through the pulmonary capillary
because they are so large in compariosn to teh capillary so only one can fit in a cross section
what are four things that allow diffusion of gases between the alveoli and the rbc to be rapid
-red blood cells are slowed as they pass through the pulmonary capillaries which allows more time for diffusion
- the walls of both the alveoli and capillary are very thin so the diffusion pathway is very thin
- alveoli and capillaries have a very large total syrface area
- blood flow through the capillaries maintains a concentration grad
when does a correlation occur
when a change in one of two variables is reflected by a change in the other variable
what is emphysema
a break down in elastin in the alveolar tissue which inhibits the stretch and recoil function in inspiration and expiration.
- alveoli can fuse together but this means that there is large air sacs with a smaller surface area to volume ration which therefore decreases the rate of diffusion
what is chronic bronchitis
symptoms must persist for more than three months
- more mucus is produced as cilia are destroyed.
- tar in cigarettes which destroy the cilia and causes mucus glands to enlarge as less is able to move up the trachea
- scar tissue will form via fibrosis. the scar tissue replaces the epithelium lining and will therefore narrow the trachea
- bacteria will gather in the mucus will can lead to infection or in severe cases pneumonia
describe fibrosis
involves scarring of the lung tissue ( epithelium lining is replaced and therefore elasticity is reduced).
- FEV1 and FVC will reduce -> less o2
- also leads to thicker walls which increases the diffusion pathway distance and therefore slows diffusion
what is asthma
there is an obstruction in the airways. there is inflammation and bronchoconstricion ( constriction of bronchioles).
this is all caused by an allergic reaction.
broncocontriction disrupts normal breathing rates and leads to a reduction in normal ventilation. lower FEV1 and could be in a deprivation of O2
define FVC
forced vital capacity - the maximum amount of air possible to expel after a deep breath in
define FEV1
the maximum volume of air that can breathed out in 1 second
