Lesson 2 - The mammalian gas exchange system Flashcards
Give 5 adaptations of an effective gas exchange system
- large surface area
- thin layers
- rich blood supply to respiratory surfaces
- moist surfaces
- permeable surfaces
why does a rich blood supply allow effective gas exchange
the blood is involved in the transport of the respiratory gases to and from the site of gaseous exchange, helping to maintain a steep concentration gradient
describe the conditions inside the lungs
- high temperature due to a rich blood supply
- moist due to the moist surfaces increasing the level of water vapour
function of nasal cavity
the main route by which air enters the gas exchange system
function of mouth
air can enter the respiratory system here, but misses out on the cleaning, warming and moistening effects of the nasal route
function of epiglottis
flap of tissue that closes over the glottis in a reflex action when food is swallowed. This prevents food from entering the gas exchange system
function larynx
the voice box, which uses the flow of air across it to produce sound
function tranchea
major airway to bronchi, lined with cells including mucus-secreting cells. Cilia on the surface move the mucus and any trapped microorganisms and dust away from the lungs
function of incomplete rings of cartilage
prevent the trachea and bronchi from collapsing but allow food to be swallowed and moved down the oesophagus
function of left and right bronchus
tubed leading to the lungs via the bronchioles
function of lung
the organ where gas exchange occurs
function of bronchioles
small tubes that spread through the lungs and end in alveoli. There’s no cartilage and they are collapsed quite easily. They function as an airway and sometimes a little gas exchange occurs
function of alveoli
main site of gas exchange in the lungs
function of ribs
protective bony cage around the gas exchange system
function of intercostal muscles
found between the ribs and important in breathing
function of pleural membranes
surround the lungs and line the chest cavity
function of pleural cavity
space between the pleural membranes, usually filled with a thin layer of lubricating fluid that allows the membranes to slide easily with breathing movements
function of diaphragm
broad sheet of muscle of tissue that forms the floor of the chest cavity, also important in breathing movements
meaning lung surfactant
a special phospholipid which coats the alveoli and makes breathing easier and supports the alveoli
meaning elastic recoil
the elastic connective tissue between the alveoli and its wall helps forcing air out of the lungs, which is stretched when you breathe in
describe the gas exchange in the alveoli
gas exchange occurs by simple diffusion between the alveolar air and the deoxygenated blood in the capillaries
describe the conditions of the blood in the capillaries
have a relatively low oxygen concentration and high carbon dioxide concentration
meaning mass transport system
an arrangement of structures by which substances are transported in the flow of a fluid with a mechanism for moving it around the body
how is forced exhalation achieved
internal intercostal muscles contract, pulling the ribs down and in, and the abdominal muscles contract, forcing the diaphragm upwards. This increases the pressure in the chest cavity, causing exhalation
what type of process is inhalation
active & energy-using
describe the series of events used in exhalation
the external intercostal muscles relax, and the internal intercostal muscles contract, causing the rib cage to move down and in. The diaphragm relaxes. This causes the volume inside the thoracic cavity to decrease, increasing the pressure, causing air to move out
describe the series of events used in inhalation
the external intercostal muscles contract, and the internal intercostal muscles relax, causing the rib cage to move up and out. The diaphragm contracts and flattens. This causes the volume inside the thoracic cavity to increase, decreasing the pressure, causing air to move in.
