Exchange and transport Flashcards
Why is diffusion fast in single celled organisms?
has to travel short distance
have high SA:V ratio
How does having a large surface area help root hair cells
-increases rate of absorption of water and mineral ions
How does being thin help the alveoli
There is a shorter diffusion pathway
How does having a good blood supply help the alveoli
- surrounded by dense capillary network
- which creates a steep concentration gradient
How does having a good blood supply help the gills
gills contain dense network of capillaries
also they are well ventilated due to water
-maintains steep concentration gradient
What is the structure of the gaseous exchange system
trachea splits into bronchi
bronchus leads to bronchioles
which leads to alveoli
What is the function of a goblet cell
- secretes mucus to trap microorganisams and dust particles
- stops them from reaching alveoli
What is the structure and function of cillia
structure
- made from microtuberoules 9+2
- have hair like structure
functions
-waft/beat the mucus up the air way towards the throat (helps prevent lung infections)
What is the structure and function of cartilage
-c shaped rings
function
- provide support
- stops trachea from collapsing
- rings provide flexablity
What is the function of smooth muscle
- allows diameter to be controlled (I think mark schemes like to say constrict)
- can make air tubes wider to decrease resistence to air flow
What is the function of elastic fibres
they streach and recoil when breathing in and out
prevent alveoli from bursting
where is cartilage found
trachea
small amounts on bronchi
Where is smooth muscle found
trachea, bronchi, broncheloles
but not in small broncheloles or the alveoli
Where are elastic fibres found
EVERYWHERE
Where are goblet cells
trachea, bronchi, large broncheoules
not found in smaller broncheoles, or the alveoli
Where are epithelium cells found
Cillaited
trachea, bronchi, large bronchi
squamous
alveoli
What happens during forced expiration
internal intercostal muscles contract, which pull ribcage down and in
What happens during inspiration
- intercoastal muscles and diagraphm contract
- causes ribcage to move upwards and outwards
- volume of throax increases so lung pressure decreases below atmospheric pressure
- so air comes into lungs
What happens during expiration
-intercostal muscles and diaphragm relax
-causes ribcage to move downwards and inwards
-volume of throax decreaes
-air pressure increses (above atmospheric pressure)
air is expelled from lungs
State the meaning of tidal volume
volume of air in each breath
usually 0.4 dm3
State the meaning of vital capacity
max volume of air that can be breathed in or out
State the meaning of breathing rate
how many breaths taken per minute (any unit of time really)
State the meaning of oxygen uptake
rate at which a person uses up oxygen
How do we use a spirometre
- breathe into a tube
- then a pen records the movement which is attached to the lid of the chamber
- this creates a spirometre trace
- can also use a data logger
Why does the total volume of gas in a spirometre decrease
- air breathed out is a mix of CO2 and O2
- co2 absorbed by soda lime
- as oxygen is used up in respiration so total volume decreases
Why must the person wear a nose clip when using a spirometre
- ensures they can only breathe in and out through their mouth
- gives a valid reading
(btw the machine must be airtight)
What is the structure of gills
-Gill made out of gill fillaments (primary lamelle)
these have thin walls and lots of capilaries
- these are covered by gill plates (secondary lamelle) which further increases surface area
-each gill is supported by a gill arch
Explain the countercurrent system
- blood flows through gills in one direction and water in the opposite
- this means water with high o2 flows next blood with low o2
- so a steep concentartion gradient can be mainatined
- this makes sure as much o2 can diffuse into blood
How are fish gills ventilated
- fish mouth opens, lowers floor of buccal cavity
- vol of buccal cavity and pressure decreases
- so water rushes in
- fish closes its mouth and the buccal cavity is raised
- volume decreases and pressure increases
- water is forced out of cavity into the gills
- operculmn feels increased pressure so it forces head to open
- water leaves fish
How are insects ventilated
- Air enters spiricales (which can be open or closed to prevent water loss
- travels to trachea then tracheoles
- o2 diffuses into tracheal fluid, which diffuses into cells
- co2 diffuses out of cells into trachea and out of spircales
How can insects ventilate themselves during exercise
- Tracheal fluid moves into cells via osmosis
- this occurs when lactic acid builds up in cells
- which decreases water potential so more gas exchange happens
How can an insect change its body to move air in and out
-Can use rhythmic abdominal movements to change volume of body
How do flying insects ventilate themselves and when do they do this
- use movements to pump throax
- in large insects air sacs help mechanically pump air through system
- this happens when their is a higher energy demand
