EXCHANGE AND TRANSPORT Flashcards
Exchange surface adaptations
Large surface area- root hairs
Thin- alveoli= one cell thick
O2 diffuses our and CO2 diffuses in the opposite direction
Good blood supply
Good ventilation
Alveoli surrounded by large capillary network
Fish fills contain a large network of capillaries which keeps them supplied with blood
Lungs
INSPIRATION The external intercostal muscles and diaphragm contract Rib cage moves upwards and outwards Diaphragm flattens Volume of thorax increased Lung pressure decreases Air flows out the lungs EXPIRATION External intercostals and diaphragm muscles relax Rib cage moves downwards and inwards Diaphragm curves Thorax volume decreases Air pressure increases Air forced out the lungs
Fish counter-current system
Water enters the fish through the mouth and out the gills
Each Gill is made of many thin branches called gill filaments which provide a large surface area for gaseous exchange
Gill filaments covered in many gill plates
Each gill supported by a gill arch
Gill plates have many blood capillaries and a surface layer of thin cells
Blood flows one way water the other
Maintains large conc gradient
Conc of water always higher than in the blood
Fish gills
Fish opens mouth
Lowers floor of buccal cavity
Volume of buccal cavity increases
Decreases pressure inside the cavity and water is sucked in
The bony flap called the operculum is forced open on each side of the head to allow water to leave
Insect tracheae
Microscopic air filled pipes used for gas exchange
Air moves into the tracheae through spiracles
Oxygen travels down conc gradient towards the cells
Carbon dioxide from the cells moves down its own conc gradient towards spiracles to be released into the atmosphere
The tracheae beach off into smaller tracheoles which have thin, permeable walls and go into individual cells
Tracheoles contain fluid with oxygen dissolved in
Oxygen diffuses from this fluid into body cells and CO2 diffuses in the opposite direction
Insects use rhythmic abdominal movements to change the volume of their bodies and move air in and out of the spiracles
Structures of gaseous exchange system
Goblet cells- secrete mucus which traps microorganisms and dust particles in inhaled air, stopping them reaching the alveoli
Cilia- beat the mucus, they move the mucus up away from the alveoli towards the throat where it is swallowed
Elastic fibres- walls of the trachea, bronchi, bronchioles and alveoli, they help the process of breathing out, when inhaling, the lungs inflate and elastic fibres are stretched, then these recoil to help push the air out when exhaling
Smooth muscle- allows diameter to be controlled
Rings of cartilage- walls of trachea and bronchi and provide support, strong and flexible and prevents the trachea from collapsing when the pressure drops
