Gas Exchange 🪲🐻🫁 Flashcards
Surface area to volume ratio…
Decreases as an organism gets larger
Oxygen is required to produce ___ during aerobic respiration
ATP
Carbon Dioxide is produced as a waste product during aerobic respiration. What does that do?
Generates a concentration gradient of CO2 and O2 in opposite directions
Why do single celled organisms not need gas exchange systems?
they have a large SA:V ratio to meet their gas exchange needs by diffusion across their cell membranes.
Why do larger organisms need gas exchange systems?
They have a relatively small (in comparison to single celled organisms) SA:V ratio and they can not rely on diffusion alone to meet the oxygen demands to all of their cells
What is Fick’s Law:
Rate of Diffusion=
SA x Conc gradient
—————————-
Diffusion pathway
Insects need gas exchange what else do they need?
the need to conserve water
What is the most effective surface for gas exchange? And what else are these features favourable for?
Most effective surface: large, thin and permeable area
They are also favourable for evaporation leading to potentially fatal dehydration
To limit water loss, what adaptations to insects have?
Waterproof covering over their body surfaces. Rigid exoskeleton covered with waterproof cuticles.
Relatively small SA:V to minimise the area over which water is lost
The order of gas exchange in insects
Spiracles , tracheae, tracheoles, respiring tissue
What is the primary function of spiracles in insects?
Oxygen enters the insect through spiracles and into the tracheae
Spiracles are small openings that allow gas exchange.
What are tracheae?
The tubes that transport oxygen from spiracles to tracheoles
Tracheae are part of the insect respiratory system.
What are tracheoles?
The smallest branches of the tracheal system that deliver oxygen directly to tissues
Tracheoles are crucial for efficient gas exchange.
What happens when spiracles close?
Oxygen diffusion through the tracheae into the tracheoles occurs
This process is driven by concentration gradients.
Describe the movement of oxygen through the insect.
- Oxygen enters through spiracles
- Moves into tracheae
- Diffuses into tracheoles
- Delivered to respiring tissues
This process is essential for cellular respiration.
True or False: Carbon dioxide produced by respiring tissues exits the insect when spiracles are closed.
False
Carbon dioxide exits when spiracles are open.
Fill in the blank: Oxygen diffuses through the tracheae into the _______.
[tracheoles]
What is the role of air sacs in the insect respiratory system?
Air sacs help in the storage and movement of air within the tracheal system
They enhance the efficiency of respiration.
How does carbon dioxide move in relation to oxygen in the insect respiratory system?
Carbon dioxide moves in the opposite direction to oxygen
It exits the insect when spiracles are open.
What is the significance of concentration gradients in the insect respiratory system?
They drive the diffusion of oxygen into tracheoles
Concentration gradients facilitate gas exchange.
List the components involved in the insect respiratory system.
- Spiracles
- Tracheae
- Tracheoles
- Air sacs
These components work together for efficient gas exchange.
What are spiracles?
Tiny pores through which gas enters and exits the insect
They are opened and closed to control water loss by evaporation.
When do spiracles open?
When CO2 levels increase
This helps in regulating gas exchange.
What is the significance of the distance between insect cells and tracheae?
Every cell of an insect is only a very short distance from one of the tracheae or tracheoles
This ensures that the diffusion pathway is always short.
What are tracheoles?
Small tubes with thin walls that extend throughout the body tissues
They reduce diffusion distance and are highly branched to increase surface area.
What is the function of tracheae?
A network of tubes supported by strengthened rings
Provides tubes full of air for fast diffusion.
Why does diffusion occur in the gas exchange systems of insects?
Oxygen diffuses from areas of higher concentration to areas of lower concentration
This is necessary for respiration as tissues consume oxygen.
What happens to oxygen concentration in the tissue during respiration?
It reduces as tissues respire using oxygen
This creates a concentration gradient that facilitates diffusion.
How does oxygen move from the tracheae to the tissue?
Moves from an area of higher concentration in the tracheae to lower concentration in the tissue
This process is driven by diffusion.
What is the process for carbon dioxide movement in insects?
CO2 moves from high concentration at the tissue to low concentration in the tracheae
It then exits the insect through the spiracles.
What increases the concentration of carbon dioxide at the tissue?
Respiration produces CO2
This leads to a gradient that drives diffusion out of the insect.
What is the primary mechanism of ventilation in insects?
Movement of the insect’s muscles creates a mass movement of air in and out of the trachea
How do insects increase the rate of gaseous exchange?
By using abdominal pumping and having small air sacs in their trachea
Muscles around the trachea contract to pump air deeper into the tracheoles.
What happens to water in the tracheoles during rest?
Water can build up in the tracheoles
This occurs when the insect is not in flight.
What type of respiration may occur during flight in insects?
Anaerobic respiration
This can lead to the production of lactate (lactic acid).
What effect does lactate accumulation have on muscle cells?
It lowers the water potential of the muscle cells
This causes water to pass from the tracheoles into the muscle cells via osmosis.
What adaptation helps draw air into the tracheoles during flight?
The accumulation of lactate in muscle cells
This reduces the diffusion distance for oxygen when needed.
Fill in the blank: During flight, water is drawn into the _______.
muscle cell
What occurs at the narrow ends of the tracheoles when an insect is at rest?
Water fills the narrow ends of the tracheoles
This is a key feature of the insect’s respiratory system.
