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