3.1.1 Flashcards
What is the agar gel experiment?
Place cubes into varying sizes
place into NaOH for a set time
cut cubes open and
record how far the alkali has diffused into the cube
What are the findings o the agar gele xperiment?
smaller cube has diffused all the way through compared t bigger cube
What are limitations of the agar gel SA experiment?
inconsistiency with SA
subjective results
Why do we need specialised gas exchange surfaces?
smaller SA:V ratio
oxygen cannot diffuse quickly enough
to meet metabolic needs
higher metabolic activity
What does the inc SA of a root hair cell allow?
large SA to inc rate of diffusion
What are the walls of alveoli made from?
squamous epithelial cells
What is beneficial about the alveoli that allows diffusion to be fast?
thin diffusion pathway
so faster diffusion
What does a good blood supply / ventilation allow?
concentration gradient to be maintained
What lines the trachea?
cartilage
What does the trachea split into?
bronchi
What do bronchi split into?
bronchioles
What is the name of the membrane that surrounds the lungs?
pleural membrane
What is the pleural cavity?
contains fluid
What is the role of the pleural cavity?
stops lungs rubbing against rib cage during inhalation
What are goblet cells?
found inbetween ciliated epithelial cells that line trachea
What do goblet cells do?
secrete mucus
trap dust and bacteria that enter lungs
What do cilia do?
waft mucus to the back of the throat where it is swallowed or coughed up
What is the role of elastic fibres?
recoil to their original shape
expel air
prevent lungs from bursting
What is the role of smooth muscle?
constricts the airways
by reducing diameter of bronchus
What is the role of the cartilage?
provides strength and support for trachea
keeps trachea open
helps prevent collapse during inhalation
as chest volume inc, lower pressure in trachea
What tissues compose the trachea?
C shaped rings of cartilage
elastic fibres in walls
smooth muscle
ciliated epithelilal cells
What tissues compose the bronchi?
pieces of cartilage
elastic fibres
squamous epithelilal
What tissues compose alveoli?
elastic fibres
squamous epithelial
What are the features of gaseous exchange in fish?
many lamellae
What is the impact of many lamellae on gas exchange in fish?
large SA for gas exchange
presence of secondary lamella on primary lamella
inc SA for gas exchange
short distance between blood and water
maintains concentration gradient for faster diffusion
Outline gaseous exchange in fish
Water flows into fish mouth
Water forced over gill filaments
and out the operculum
What does countercurrent echange system maintain?
concentration gradient
What happens when fish mouth opens?
floor of buccal cavity lowers
What does the lowering of the buccal cavity allow?
increases volume of buccal cavity
What happens as a result of an increase in the volume of the buccal cavity?q
pressure in cavity decreases
When does the opercular valve shut?
when pressure drops in the buccal cavity
What happens as a result of the opercular cavity expanding?
pressure drops and buccal cavity floor moves up
What happens as a result of the buccal floor moving up?
inc pressure so water moves from buccal cavity over the gills
What actions increase the pressure in the opercular cavity in exhalation?
mouth closes
operculum ions and
sides of opercular cavity move inwards
What does the increase in pressure of the opercular cavity allow?
forces water over gills and out operculum
How is the flpw of water maintained over the gills?
the floor of the buccal cavity steadily moving upwards
What do spiracles allow?
allow diffusion of oxygen into the organism
allows diffusion of CO2 out of the organism
What does the trachea in insects lead to?
tracheoles
How do spiracles work?
O2 diffuses into the trachea by entering spiracles
and then moves into the tracheoles
to the muscle fibres
What happens to tracheal fluid during anaerobic respiration>
fluid moves from tracheoles into the surrounding muscle tissue by osmosis in an active tissue
fluid moves into muscle fibres
more oxygen diffuses further into the muscle fibres so more oxygen available for aerobic respiration
How does the insect jumping/moveing affect the spiracles?
helps to change the volume of the body cavity and therefore causes changes in pressure therefore helping draw air in and out through spiracles
What do you need to remove in a fish and an insect in a dissection?
fish - operculum
insect - exoskeleton
What happens in inspiration?
Diaphragm - contracts and flattens
Ribs - move up and out, internal intercostal muscles relax and external intercostal muscles contract
Volume - thoraxic volume inc
Pressure - pressure in thorax dec
Pressure gradient - air moves into the thorax along the pressure gradient
What happens in expiration?
Diaphragm - relaxes and rises
Ribs - moves down and in, external intercostal muscles relax, internal intercostal muscles contract
Volume - thoraxic volume dec
Pressure - thoraxic pressure decreases
Pressure gradient - air moves out along the pressure gradient
How is a spirometer used?
healthy volunteer with blocked nose
breathe in and out at rest
chamber goes up as person breathes out
chamber goes down as person breathes in hrough mouth piece
soda lie absorbs CO2
Spirometer reduced gradually (valuie)
What is vital capacity?
max volume of air a person can breathe in and out in 1 breath
What is residual volume?
air that cannot leave lungs
What is tidal volume?
volume of air breathed in and out in 1 single breath at rest
What is breathing rate?
number of breaths per minute
What is the oxygen upake?
volume of oxygen taken up by body / lungs
What does the soda lime do to the CO2?
air breathed into spirometer has CO2 removed by soda lime and oxygen used for areoic repsiration
