Gas Exchange - Animals Flashcards
Operculum function
protects fish gills from damage
gas exchange surface in fish
gill plates
5 advantages of counter current flow
- O2 concentration always higher in water than blood
- equilibrium never reached
- concentration gradient maintained across entire gill plate
- gas exchange occurs across entire gill plate
- max. saturation of blood is higher
why do fish have to force water over their gills?
water is more dense than air so have to expend energy to push water over gas exchange surface (gill plates)
what type of ventilation do fish have?
unidirectional
are fish large or small organisms?
large
why are fish less metabolically active?
- they are bouyant in water so less energy required for support
- don’t regulate their own body temperature as take on temperature of environment, which requires less energy
how many gill pairs does a fish have on each side?
4
3 features of gas exchnage in samall organsims
- high SA:vol
- obtain O2 by diffusion across gas exchange surface of membrane or body surface
- low metabolic rate so low O2 demand
3 features for efficient gas exchange in an amoeba
- cell surface membrane thin and have a large SA:vol
- cell respires, converting O2 to ATP so O2 levels in cytoplasm lower than external levels
- membrane moist
3 features for efficient gas exchange in a flatworm
- flattened shape increasesSA:vol and very thin
- blood flow maintains diffusion gradient by constantly removing O2, taking it to cells while bringing back CO2
- skin is moist
3 features for efficient gas exchange in an earthworm
- tubular shape increases SA:vol
- skin thin and moist
- blood flow maintains diffusion gradient by constantly removing O2 and taking it to cells by bringing CO2 back
relationship between and SA:vol
as size or organism increases, SA:vol decreases
5 properties of all gas echange surfaces
- moist
- thin
- large SA
- permeable to gas
- mechanism for maintatining a diffusion gradient
fuction of an insect’s waxy exoskeleton
waterproof to prevent dessication
2 functions of valves in spiracles
- open/close to control movement of air in and out of insect
- close to reduce water loss
what does SA relate to?
rate of of O2 supply to respiring cells
what does volume relate to?
demand for oxygen by respiring cells
what substance lines the tracheae?
chitin
site of gas exchange in insects
tracheoles
4 adaptations of the tracheal system in insects that allows efficient gas exchange
- tracheal system branched, increasing SA available for gas exchange
- fluid moves into muscle cell during activity so larger SA for gas exchange
- tracheoles have thin walls so short diffusion distance to cells
- large number of tracheoles so large SA for gas exchange
why do insects have an internal gas exchange system?
reduce water loss and prevent dessication
why don’t insects need a respiratory pigment?
every tissue in contact with at least 1 tracheole so very short diffusion distance
how does water move into cells in insects?
when active, insect respires, partly anaerobically so produce lactate
this lowers the WP of the muscle cells, so water passes into muscles from tracheoles by osmosis
benefit of fluid moving into muscles
- draw air closer to muscle cells
- increases SA for O2 to diffuse
- diffusion is faster in air than in water
when does mechanical ventilation occur in insects?
when active
explain the two parts of mechanical ventilation in insects
- thoracic spiracles open, abdominal spiracles close, abdominal muscles contract, abdomen expands, lowering pressure below atmospheric pressure
2.thoracic spiracles close, abdominal spiracles open. abdominal muscles contract, pulling skeletal plates together and squeezing tracheal system, pumping air into sacs deeper in tracheoles
2 ways insect gas exchange occurs
- diffusion of oxygen down a concentration gradient gcreated by the insect respiring oxygen
- mechanical ventilation of body muscles
type of ventilation of insects
unidiretional
why is air warmed and moistened in the nasal cavity?
- warmed - increase kinetic energy of air particles and get it to body temperature
- moistened - so O2 can dissolve which is better for diffusion
why is the cartilage in the trachea C-shaped?
to accomodate the oesophagus and prevent pain when a bolus of food goes down`
function of tracheal cartilage rings
keep trachea open during inhalation
what cells secrete mucus in the trachea?
goblet cells
function of ciliated epithelium in trachea
beat mucus back towards mouth to prevent bacteria and dust entering lungs
function of mucus in trachea
catch bacteria and dust so they dn’t enter the lungs
gas echange surface of humans?
alveoli
which tubules have cartilage connected by muscle and elastic fibres?
larger brochioles
what do smaller bronchioles have in their walls? why?
only elastic fivbres and muscle, so they can expand and contract during ventilation
what increases the SA in the human gas exchange system?
- large number of alveoli
- dense network of capillaires over each alveolus
- branching network of bronchioles
how ins a concentration gradient maintained in the alveoli?
- oxygenated blood carries O2 away from alveolus
- deoxygenated blood flows towards alveolus
- inhalation brings in more O2 keepig concentration of O2 in alveolus above that in blood
what maintains a short diffusion pathwy in alveoli?
- capillary wall a single layer of squamous endothelium
- alveoli wall single layer of squamous epithelium
- capillary very close to alveolus
function of surfactant
- keeps alveoli open and prevents them sticking together
- allows O2 to dissolve so it can diffuse into blood
function of elastic fibres in wall of alveoli
allow alveoli to recoil to aid exhalation
why is ventilation important?
to move respiratory medium across/over gas exchange surface and help maintain an oxygen concentration gradient
9 steps of inhalation
- diaphragm and ex. intercostals contract
- diaphragm flattenes and rib cage moves up and out
- thorax volume increases
- outer pleural membrane pulled outwards
- pressure in pleural cavity decreases
- inner pleural membrane pulls outwards pulling on lung surface
- alveoli expand
- pressure in alveoli decrease below atmosheric pressure
- air pulled into alveoli down pressure gradient
9 steps of exhalation
- diaphragm and ex. intercostals relax
- diaphragm returns to dome shape and rib cage moves down and in
- thorax volume decreases
- no pull applied to outer pleural membrane
- pressure in pleural cavity increases
- no pull on inner pleural membrane so no pull on lung surface
- alveoli compress
- pressure in alveoli increases above atmosheric pressure
- air forced out alveoli down pressure gradient
