3A - Exchange and Transport Systems Flashcards
How does body size affect heat exchange?
- higher the SA-volume ratio, the more heat is lost
- smaller animals need high metabolic rate
How does shape of the animal affect heat exchange?
- compact shape minimises heat loss
- less compact shape increase heat loss
How do you calculate volume?
- length x width x depth
What other adaptations do animals with high SA : volume ratio have?
- lose more water
- their kidney structure produces less urine
- cold conditions, eat large amounts of food
What are the two major adaptations do gas exchange surfaces have?
- large surface area
- short diffusion pathway
What is the name of gas exchange in fish?
- counter current system
How does the counter current system in fish work?
- water passes through mouth and gills
- gill filaments are covered in lamellae, increases SA
- lamellae have lots of blood capillaries and thin surface layer of cells
- blood flows through lamellae in one direction and water flows the opposite
- concentration of oxygen in water is always higher than blood
How do insects use tracheae for gas exchange?
- air moves into tracheae through spiracles
- oxygen travels down gradient towards cells
- tracheoles have thin, permeable walls
- oxygen diffuses directly into cells, CO2 moves down gradient to spiracles and is released
How do dicotyledonous plants exchange gas?
- surface of mesophyll cells have large SA
- gases move in and out of stomata
- stomata open to allow gas exchange and close if plant is losing too much water
- guard cells control the opening and closing of stomata
What are the steps for gas exchange in the lungs?
- air enters the trachea
- trachea splits into 2 bronchi
- each bronchus branches off to bronchioles
- bronchioles have alveoli (air sacs)
- rib cage, intercostal muscles and diaphragm work together to move air in and out
What is meant by ‘inspiration’?
- breathing in
- intercostal and diaphragm muscles contract
- rib cage moves outwards and diaphragm flattens
- volume increases as lung pressure decreases
- active process so it requires energy
What is meant by ‘expiration’?
- breathing out
- intercostal and diaphragm muscles relax
- rib cage moves inwards and diaphragm is curve again
- volume of cavity decreases, air pressure increases
- air forced down pressure gradient and out of the lungs
- passive process so it doesn’t require energy
How does gaseous exchange happen in alveoli?
- loads of alveoli, big surface area
- surrounded by network of capillaries
- O2 diffuses out of alveoli and into haemoglobin in the blood
- CO2 diffuses into alveoli from the blood
How are alveoli adapted for gas exchange?
- thin exchange surface, short diffusion pathways
- large surface area
How does Pulmonary Tuberculosis affect the lungs?
- tubercles form
- infected tissues die and exchange surface is damaged
- causes fibrosis, reduces tidal volume
- less air can be inhaled
