3A- gas exchange in humans Flashcards
label diagram of lungs
pg146
types of intercostal muscles
internal intercostal muscles and external intercostal muscles
two types of ventilation
inspiration- breathing in
expiration-breathing out
process of inspiration
external intercostal muscles and diaphragm contract causing ribcage to move upwards and outwards and diaphragm flattens
what does inspiration do to the volume of thoracic cavity and how does it effect pressure
volume of thoracic cavity increases lung pressure decreases, air flows from area of high pressure to area of lower pressure.
does inspiration require energy or not
yes its an active process
process of expiration
external intercostal and diaphragm relax. ribcage moves downwards and diaphragm curves upwards
what does expiration do to the volume of thoracic cavity and how does it effect pressure
decreases volume of thoracic cavity causing air pressure to increase, air forces down pressure gradient and out of the lungs
what happens during forced expiration
internal intercostal muscles contract and external intercostal muscles relax- called antagonistic
how are alveoli adapted to their function
single layer of thin flat cells, surrounded by network of capillaries
structure of an alveoli
wall made of single layer of thin flat cells called alveolar epithelium, walls of capillaries made of capillary endothelium
what is the alveolar epithelium made of
elastin to help alveoli return to normal shape after inhaling or exhaling
what is the process of movement of oxygen in alveoli
diffuses out of the alveolar, across the alveoli epithelium and capillary endothelium into the haemoglobin
what is the process of movement of CO2 in alveoli
diffuses into the alveoli form the blood
factors in the alveoli speeding up the rate of diffusion
thin exchange surface- alveolar epithelium one cell thick providing short diffusion pathway
large surface area- millions of alveoli
steep concentration gradient of oxygen and carbon dioxide between alveoli and capillaries
