gas exchange in lungs Flashcards
describe the pathway of airway
mouth
trachea
bronchi
bronchioles
alveoli
capillary
explain the difference between respiration and breathing
respiration is a chemical reaction that takes place in cells that releases energy from glucose
breathing is the movement of air in and out of cells
Explain why humans require an efficient gas
exchange system
Large volumes of CO2 and O2 need to be
exchanged
Because they have a high metabolic rate
(respiration)
Because they are large organisms with
large volume of living cells
Because they maintain high body
temperature linked to high metabolic and
respiratory rate
what are alveoli
Alveoli - tiny air sacs at the end of bronchioles. made of epithelium with elastic fibres and collagen between alveoli
what is the function of the bronchioles
Bronchioles - branches from bronchi, muscular walls control air flow to alveoli
what is the function of the bronchi
produce mucus to trap air and dirt
cilia move mucus towards the throat
what is the structure of the trachea
rings to cartilage prevent trachea collapsing due to air pressure
walls are made of muscle, lined with ciliated epithelium and goblet cells
explain what happens during the process of inhalation
- external intercostal muscles contract while the internal intercostal muscles relax
- ribs are pulled upwards and outwards increasing the volume of the thoracic cavity
- diaphragm contracts and flattens which also increases the volume of the thoracic cavity
- pressure in lungs decreases
- there is less pressure in the lungs than in the atmosphere so air moves into the lungs
explain what happens during exhalation
- internal intercostal muscles contract while external intercostal muscles relax
- ribs move downwards and inwards decreasing the volume of the thoracic cavity
- pressure in the lungs increases
- pulmonary pressure is greater than atmospheric so air moves out of the lungs
define epithelium
lining layer of tissue
what is the advantage of having many alveoli and capillaries
large surface area
what is the advantage of red blood cells in the capillary being slowed
more time for diffusion
what is the advantage of red blood cells being flattened against the wall of the capillary
distance between alveolar air and red blood cells is reduced
= short diffusion pathway
what is the advantage of walls of the alveoli and capillary being thin
distance between alveolar air and red blood cells is reduced
= short diffusion pathway
what is the advantage of constant ventilation
steep concentration gradient between alveoli and capillaries is maintained
what is the advantage of constant heartbeat and constant flow of blood through pulmonary arteries
steep concentration gradient between alveoli and capillaries is maintained
State the names of the two muscles in the thorax responsible for ventilation
Intercostal muscles, diaphragm
Describe the relationship between volume and pressure in a closed container.
As volume increases pressure decreases
With reference to pressure what determines the way in which gases move from one region to another.
Gases move from a region of higher pressure to a region of lower pressure
define ventilation
movement of air in and out of the lungs
define inspiration (in terms of pressure)
pressure in the atmosphere is greater than in the lungs - air moves in
define exhalation (in terms of pressure)
pressure in the lungs greater than in the atmosphere - air moves out
describe the diaphragm
sheet of muscle separating thorax from abdomen
describe the function of the internal intercostal muscles
contraction leads to expiration
describe the function of the external intercostal muscles
contraction leads to inspiration
Explain what is meant by pulmonary ventilation and how it is calculated
Pulmonary ventilation rate is the total volume of air that is moved into the lungs during one minute.
Calculated by: tidal volume x breathing rate
when blood enter the lungs what is the concentration of oxygen within it
low concentration of oxygen
when blood exits the lungs what is the concentration of oxygen within it
high concentration of oxygen
