Exchange Flashcards
Explain one advantage of concaved red blood cell compared to spherical one.
Greater surface area for oxygen diffusion
Describe two features of specialised exchange surfaces
- Large surface area to volume ratio
- Thin so shorter diffusion pathway
- Movement of environmental medium to maintain concentration gradient.
How do you calculate the SA of a cube?
Area of one side (length X length) X sides
How do you calculate the volume of a cube?
Length X width X height
How do you calculate the ratio of surface area to volume of a cube?
Surface area/ volume
How do you calculate the surface area of a sphere?
4 (pi) r^2
How do you calculate the volume of a sphere?
4/3 (pi) r^3
What is the equation for diffusion?
Diffusion= (surface area X difference in concentration) /length of diffusion path
How does mass transport of oxygen occur in insects?
Contraction of muscles through abdominal pumping enabling mass movements of air in and out
How does oxygen reach the working muscles in an insect?
Through the tracheoles
What is the advantage of having water at the end of tracheoles?
In periods of high activity, anaerobic respiration will create lactate which will reduce water potential of respiring cells causing them to take up water via osmosis. This loss of water from the tracheoles means gas is further inside them.
What are the tiny pores that gases enter and leave the insect via?
Spiracles
What are three ways gases move in and out of the tracheal system?
- Along the diffusion gradient
- Mass transport
- Movement of water at the end of the tracheoles
What are the main structure of gills?
Gill filaments
What increases the surface area of the gills?
Gill lamellae
Describe how counter current flow allows for effective gaseous exchange
Blood flows in the opposite direction to water, ensuring a concentration gradient allowing a maximum uptake of oxygen
Explain how parallel flow decreases gaseous exchange
Oxygen can only be absorbed by diffusion from higher in water to lower concentration in the blood. Equilibrium is quickly reached
How is a leaf adapted for gas exchange?
- Many stomata for short diffusion pathway
- Lots of air space in the mesophyl layer for movement of gases
- Large surface area of mesophyl cells.
How are the gas exchange systems of plants similar to insects?
- The cells using the gases are close to external air
- Diffusion occurs in the gas phase, not water
- Pores for air to enter and leave
What cell controls the opening and closing of stomata?
Guard cells
What is the name of the plants that are well adapted to dry environments?
Xerophytes
What is the process known as when a plant loses water?
Transpiration
How does a thick cuticle reduce transpiration?
Longer diffusion distance
How does rolled up leaves reduce transpiration?
Stomata end up on the inside of the leaf so the water vapour becomes trapped and the air is saturated with water. High water potential removing the potential gradient between inside and outside of the leaf
How does having hairy leaves reduce transpiration?
Trap moisture near to the leaf, increasing water potential in the air and reducing the gradient. Less water evaporated
Suggest why humans must have a high rate of gaseous exchange?
Large volume of cells and have to maintain high body temperature due to high metabolic rate
Why is the trachea supported by cartilage?
Prevent it collapsing when air pressure inside is low
What are the bronchi?
Two divisions of the trachea, each leads to a lung
What are bronchioles?
Branching divisions of the bronchi, getting smaller, leading to alveoli
What are bronchioles made of. Why?
Muscle, lines with epithelial cells. Controls the flow of air
What is the role of goblet cells and ciliated cells in the bronchi?
Goblet cells produce mucus to trap pathogens. Ciliated cells waft the mucus back up the throat to be swallowed.