Exchange and transport systems Flashcards
What are the microscopic air-filled pipes used in gas exchange in insects?
tracheae
What are the pores on the surface of an insect called?
spiracles
Does oxygen travel down or against the concentration gradient in insects?
down
What are tracheoles?
tracheae branches off into tracheoles, they have thin and permeable walls and go to individual cells
What are the adaptations of most gas exchange surfaces?
-Large surface area
-Thin->short diffusion pathway
What are the adaptations in fish gills for more efficient gas exchange?
-Made of thin plates called gill filaments->increase the surface area
-Gill filaments are covered in lamellae->increase surface area
-Lots of blood capillaries
-Thin surface layer of cells
What is the counter-current system?
-Blood flows through lamellae in one direction and water flows over them in another direction
-Water with a relatively high oxygen concentration always flows next to the blood with a lower concentration of oxygen
-Steep concentration gradient is maintained
How does gas exchange occur in dicotyledonous plants?
-Gases move in and out through stomata in the epidermis
-Stomata can open to allow gas exchange and close when the plant loses too much water
What cells control the opening and closing of stomata?
-Guard cells
How are dicotyledonous plants adapted for efficient gas exchange?
-Mesophyll cells->large surface area
How are xerophytes adapted to live in warm and dry conditions?
-Stomata are sunk in pits->trap water vapour
-Layer of ‘hairs’ on the epidermis->trap water vapour
-Curled leaves with the stomata inside->protects them from wind
-Reduced number of stomata->fewer places for water to escape
-Thick, waxy and waterproof cuticles on leaves and stems->reduces evaporation
Describe the structure of the gas exchange system in humans
-Trachea
-Splits into two bronchi (one bronchus leading to each lung)
-Each bronchus branches into smaller tubes called bronchioles
-Bronchioles end in alveoli
Where are the intercostal muscles found and what are the two types of intercostal muscles?
-Found in the rib cage
-External intercostal muscles
-Internal intercostal muscles
What are the two processes that occur during ventilation?
-Expiration and inspiration
What occurs during the process of inspiration?
-External intercostal muscles and diaphragm muscles contract
-Ribcage moves upwards and outwards and the diaphragm flattens
-Volume of thoracic cavity increases
-Lung pressure decreases
-Air flows down trachea and into the lungs
Is inspiration an active or passive process?
-Active->requires ATP
What occurs during the process of expiration?
-External intercostal muscles and diaphragm muscles relax
-Ribcage moves downwards and inwards and the diaphragm curves upwards
-Volume of the thoracic cavity decreases
-Lung air pressure increases
-Air is forced down the pressure gradient and out of the lungs
Is expiration passive or active?
-Normally passive, however if you force expiration to happen then it is active
What are the adaptations of the alveoli?
-Surrounded by a network of capillaries
-Walls are one cell thick, made from alveolar epithelium
-Alveoli walls contain a protein called elastin->allows alveoli to return to normal shape after inhalation/exhalation of air
What processes does lung disease affect?
-Ventilation
-Gas exchange
What is tidal volume?
-Volume of air in each breath
What is the ventilation rate?
-The number of breaths per minute
What is the forced expiratory volume (FEV)?
-The maximum volume of air that can be breathed out in one second
What is the forced vital capacity (FVC)?
-The maximum volume of air it is possible to breathe forcefully out of the lungs after a really deep breath in
