Gas Exchange Flashcards
What are the holes in an insects body
Spiracles
What is an insects exoskeleton made of
Chitin
What is the trachea of the insect made from and why
Chitin
To prevent it from collapsing
Adaptations of the tracheoles
Extremely thin so short diffusion distance
Large number to increase surface area
Plus end filled with fluid but that’s on separate flash card
What is the fluid in tracheoles called
Tracheal fluid
What is the function of the water in the tracheoles
Anaerobic respiration produces lactic acid
This lowers the water potential of the cells
Water moves into cells by osmosis
Reduces volume in tubes and air is down down + SA is increased
What is the muscle surrounding the spiracle called
Sphincter
How do insects reduce water loss
Closing there spiracles like when the oxygen need is low
How do insects get air in and out of their bodies
Rhythmic abdominal pumping
Why do larger organisms have a specialised gas exchange systems
Larger organisms have a smaller surface area to volume ratio
Specialised system for faster DIFFUSION
Why do fish have gills on the outside rather than humans who have it on the inside Hint: this is as a result of environmental condition
Water has a lower concentration of oxygen than air
So system gives larger surface area in contact with water
Why is counter current flow efficient
Blood and water travel in opposite direction
Concentration gradient of oxygen maintained along Lamellae
Exam Technique
When talking about oxygen and needing more always use word
RESPIRATION
Explain how a reduced tidal volume affects the exchange of carbon dioxide between the blood and alveoli
Less carbon dioxide exhaled
This reduces the concentration gradient of carbon dioxide between alveoli and blood
Less diffusion of carbon dioxide out of the blood stream
If alveolar epithelium cells die inside the human body they are replaced by non-specialised, thickened tissue.
Explain why death of alveolar epithelium cells reduces gas exchange in human lungs.
[3 marks]
REDUCED SURFACE AREA
increased distance for diffusion
Reduced rate of gas exchange
Describe and explain the mechanism that causes lungs to fill with air
Diaphragm contracts and external intercoastal muscles contract and internal intercostal muscles relax
This cause volume to increase and pressure to decrease
Air moves in down pressure gradient
What is the tidal volume
Air breathed in and out at rest
What is inspiratory resume volume
Largest volume of a breath in
Expiratory reserve volume i
The maximum amount of additional air that can be force out of the lungs after a normal breath.
What is the vital capacity
The largest lung capacity from the biggest inhale and the biggest exhale (excluding residual volume)
What is the residual volume and why is it important
Air that cannot be breathed out (unless winded)
It is too prevent the lung linings sticking together
Describe what happens during expiration
External intercostal muscles relaxes and the diagram relaxes.
This cause the volume in the lungs to decrease and the pressure to increase
Air moves down its pressure gradient out of the lungs
Why would fish have a higher ratio of gill surface area to body mass
Supplies enough oxygen for respiration
Describe the pathway taken by an oxygen molecule from an alveolus to the blood.
Across alveolar epithelium
Endothelium of capillary
Abdominal Pumping increases the efficiency of gas exchange between the tracheoles and the muscle tissue of the insect. Explain why
MORE oxygen enters
Maintains concentration gradient
Explain the movement of oxygen into the gas exchange system of an insect when it is at rest x3
Oxygen moves down its diffusion gradient (2)
Oxygen is used in aerobic respiration
How does abdominal pumping help gas exchange w CO2
Abdominal pumping in tubes is linked to carbon dioxide release
Pumping raises pressure in body
Carbon dioxide moves down pressure gradient to atmosphere
EXAM TECHNIQUE When presented which a graph and then an evaluate question about a conclusion reached what show you always say
Explain the trend
However CORRELATION DOES NOT PROVE CAUSATION E.g. other facts may be at play here
% change equasion
Final-original / original
Structure of fish gills
Gills - filaments - Lamellae
Why is counter current flow beneficial
Maintains concentration gradient ACROSS WHOLE LENGTH OF GILL FILAMENT
Order of the human gas exchange system
Trachea - Bronchi - bronchioles - alveoli
Exam technique what must you mention when talking about pressure in the lungs during inhalation and exhalation
LUNG VOLUME then go on to explain
Equation for pulmonary ventilation
Tidal volume x breathing rate
What is pulmonary ventilation
Total volume of air moved into the lungs in one minute
Adaptations of trachea x2
Cartilage prevents the lungs from collapsing when we inhale
Lined with ciliated epithelial and goblet cells which secret mucus and trap pathogens
What do alveoli have that helps the contact and recoil
Contain protein elastin
Exam technique when explain relationships on graphs
Correlation does not prove causation
Other factors may cause ….. etc
Name 3 ways insects get air in
Diffusion
Abdominal pumping
Water thingy
How do insects reduce water loss x3
Small SA:V ratio less area for water to evaporate off
Waterproof exoskeleton
Spiracles can close
What is a xerophytic plant
Plants that are adapted to survive in environments with limited water
Adaptations of xerophytic plants x4
Stomata pits to trap water. Reduce water concentration gradient so less evaporation
Hairs to trap water, water concentration gradient reduced …
Curled to protect wind from removing water this means water concentration gradient …
Thick waxy cuticle to reduce evaporation
How does asthma attack effect air flow x4
Muscle walls of bronchioles contract
Walls of bronchioles secrete more mucus
Diameter of airways reduced
Therefore flow of air reduced
