exchange surfaces Flashcards
describe the sructure of the trachael system
-network of tubes called trachae
-have rings to keep airways open
-trachae divide into tracheoles
what are the adaptations of the trachael system?
- tracheoles have thin walls= short difusion pathway
2.tracheoles highly branched = larger SA many
3.tubes of air. gas exchange is quicker in a gas not a liquid
4.abdominal contracts
=moves air so maintains a conc grad
how do insects reduce water loss?
-small SA:vol ratio
-waterproof covering. chitin cuticle
-spiracles close at rest and open when active
how do gases etc travel through the trachael system?
- diffuse down a conc grad
O2 higher in trachae and lower at tissure during aerobic respiration - abdominal muscles contract= squeezes trachae so air moves in and out of spiracles creatin g a pressure gradient
3.loss of water by osmosis
what does anerobic respiration produce? problem?
lactate
insoluble so lowers water potential in respiring cells
describe the structure of the gill
-each gill is made of gill filaments=large surface area
-covered with lots of lamellae with lots of capillaries so thin surface layer
describe the counter current system
-water flows over the lamellae
-blood flows opposite towards the water
-so water with a relatively high o2 conc will always flow next to blood with a larger conc of O2 this ensures a steep concentration gradient is maintained
gwhy is diffusion slower in multicellular organisms?
1.some cells are deep within the body so long distance
2.lower SA:V so need a specialised transport exchange organs
how are plants adapted for gas exchange?
-short diffusion pathway-many smallpores so close to stoma
-many interconnecting air spaces
-large SA to v ratio
where are the stomata?
in the epidermis
how do stomata open?
water enters the guard cells making them turgid which opens the stomatal pore
where is the main gas exchange surface in a plant?
mesophyll cells
adaptations to prevent waterloss
-stomata sunk n pits=traps vapor,reduce conc grad
-hairs on epidermis=traps water vapor
-curled leaves so stomata on inside=protects from wind
-thicker waxy cuticle
-reduced stomata
describe inspiration
-external intercostal muscles contract
-diaphragm flattens ribs move up and out
-thorax volume cavity increases
-pressure in lungs is lower than atmospheric pressure
-air moves in down a pressure gradient
describe expiration
-internal intercostal muscle contacts
-diaphragm relaxes
and becomes a dome shape
-volume of thorax cavity decrease
-pressure in lungs is grater than atmospheric pressure
-air moves down a pressure gradient
explain the need for a ventilation system
-draws o2 into the lungs
-removal / excretion of co2
-mintains conc grad
describe alveoli
small air sacs at ends of bronchioles
difference between ventilation and gas exchange system?
ventilation:
-movement of air
-muscles so active process
-involves mass flow
gas exchange:
-movement pf o2 and co2
-o2 moves from lungs to alveoli to red bood cells to tissue
-passive = diffusion
-takes place across a surface
alveoli adaptations
-large total surface area = 300 million
-thin permeable walls = single layer of flattened cells
-moist linings = surfactant reduces surface tension stopping walls sticking to each other
-elastic walls
-large network of capillaries
how is the trachae adapted?
-flexible
-rings of cartillage prevents collapsing
define forced vital capacity?
max vol of air to breathe forcfully out after a deep breath
how do you obtain a vital capacity?
person needs to breath out as much as possible and in as much as possible
define pulmonary ventilation rate
total vol of air moved into the lungs in one minute
whats the formula for pulmonary ventilation rate
tidal volume x breathing rate
define residual volume
the vol of air that remains in the lungs after a deep breath out
define forced expiratory volume
max vol of air that can be breathed forcfully out of the lungs in 1 second
why does forced expiraroty volume reduce with age
loss of elasticity of internal intercostal muscles
how do you calculate breating rate of a graph/trace?
1.how many peaks
2. 60 divide seconds taken
3. x by how many peaks
define breathing rate
number of breaths taken in or out per minute
what is a degenerate disease?
symptoms get worse over time
define acute disease
symptoms last a short time
define chronic disease
symptoms last a long time-incurable
what are risk factors of lung disease?
-genetic makeup
-occupation
-frequent chest infections
