3.1.1 Exchange Surfaces Flashcards
why do larger organisms require more specialised gas exchange?
- smaller SA:V ratio
- oxygen cannot diffuse in quick enough due to large diffusion distance
- higher metabolic activity
what are adaptations of root hair cells?
large surface area —> increases rate of diffusion
what are the adaptations of alveoli?
squamous epithelial cells —> thin diffusion distance
what are the features of gills?
good blood supply/ventilation —> maintains concentration gradient
what’s the role of goblet cells?
- secret mucus which traps dust/bacteria which enters the lungs
- has cilia attached to it
what’s the role of the cilia?
wafts the mucus to the back of the mouth where it is swallowed or coughed up
what’s the role of elastic fibres?
- recoil to their original shape
- expel air
- prevents lungs from bursting
- return lungs to original size
what’s the role of a smooth muscle?
- constricts the airways
what’s the role of cartilage?
- provides strength and support for trachea and bronchi
- helps prevent collapse during breathing in
- as chest volume increases there will be a lower pressure in trachea
what structures does the trachea have?
- cartilage
- ciliated epithelial cells
- smooth muscle
what structures do bronchi have?
- pieces of cartilage
- smooth muscle
- elastic fibres
- ciliated epithelial
what structures does the bronchiole have?
- smooth muscle
- elastic fibres
- squamous epithelial
what structures do the alveoli have?
- elastic fibres
- squamous epithelial
what happens during inspiration?
- diaphragm contracts and flattens
- ribs move up and out
- external intercostal muscles contract
- internal intercostal muscles relax
- volume in thorax increases
- pressure in thorax decreases
- air moves into thorax along pressure gradient
what happens during expiration?
- diaphragm relaxes and rises
- ribs move down and in
- external intercostal muscles relaxes
- internal intercostal muscles contracts
- volume in thorax decreases
- pressure in thorax increases
- air moves out along pressure gradient
how do you calculate pulmonary ventilation?
tidal volume ✖️ breathing rate
what’s the tidal volume?
volume of air breathed in and out at rest
what’s the breathing rate?
number of breaths per minute
what’s the oxygen uptake?
- air breathed into the spirometer once the carbon dioxide has been removed by the soda lime
- oxygen is used for aerobic respiration
how are fish adapted for gas exchange?
- many lamella
—> large SA - secondary lamella on primary lamella
-
short diffusion distance between blood and water
—> maintains conc gradient
—> faster diffusion
why do fish use a counter current system?
maintains a large concentration gradient between water and blood
how do the fish’s counter current system work?
- blood flows through secondary lamella in one direction and water flows over in the other direction
- conc of oxygen in water is always higher than blood so a lot of oxygen diffuses into blood
how are bony fish ventilated?
- fish opens its mouth which lowers floor of buccal cavity
- volume of buccal cavity increases, decreasing pressure of cavity
- when fish closes its mouth the floor of buccal cavity is raised
- pressure increases and volume decreases
how do insects exchange gases?
- air moves into tracheae through spiracles
- oxygen travels down conc gradient towards cells
- co2 from cells moves down its own conc gradient towards diffuse out the spiracles
- trachea branch off into smaller tracheoles which have thin, permeable walls for oxygen to diffuse into fluids
