The lungs Flashcards
functions of the respiratory system?
-Gas exchange (o2 in, CO2 out)
-Regulate pH (reduce acidity in blood)
-Protection from pathogens
-Allow us to talk (force air from lungs thru vocal chords)
why do humans have an internal respiratory system
allows us to keep moist internal environment allowing for gas exchange
what is external respiration
The movement of gases from the environment to the cells in the body
what are the 4 processes of external respiration?
-Exchange of air between atmosphere and lungs
-Exchange of oxygen and CO2 between lungs and blood
-Transport of O2 and CO2 in the blood
-Exchange of gases between blood and cells
describe what the external anatomy of the respiratory system consists of?
Both a muscular and bone system:
-Intercostal muscles (between ribs)
-Diaphragm (large flat muscle at bottom of rib cage)
-Scalenes & sternocleidomastoids (attach from neck to top of clavicle)
-Abdominal muscles
What is the internal respiratory system split into?
split between upper and lower respiratory system
what does the upper respiratory system consist of?
nasal cavity, larynx, vocal cords, tongue, pharynx, oesophagus
what does the lower respiratory system consist of?
trachea, lungs, bronchus, bronchiole
what occurs within the 2 pleural membranes in lungs and pleural cavity?
they fill with liquid
What are functions of liquid in pleural cavity
-Provides slippery surface (prevents lungs from being damaged by touching the ribcage
-Holds the lungs close to ribcage (ensures lungs contract and expand fully along with the ribcage via surface tension)
What happens within the airways?
-Warms air (ensures no cold air enters alveoli- could affect body temperature and damage alveoli)
-Adds water vapour (moisture) to air as it travels down respiratory system (moisture required for gas exchange later on)
-Layer of mucus filters out pathogens (pathogens stick to layer allowing mucus to be pushed out and removed)
Describe the system within the airways?
-Conducting system(larynx, trachea which splits into 2 primary bronchus which then divide 22 more times into bronchiole finishing with alveoli cluster)
Describe the function/ adaptations of alveoli in the lungs ?
-Allows gas exchange to take place
-Due to shape/ structure alveoli are able to increase SA of lungs, increasing gas exchange
-Large blood supply provided by surrounding capillaries (allows for efficiency of gas exchange)
-Thin membranes-1 cell thick-ensuring small diffusion distance, making it easier to get O2 in and CO2 out
What does Boyles law suggest?
P1xV1= P2 x V2
-Pressure is created by collision of gases within a container
(is directly proportional to size of container- smaller container, more collisions, more pressure)
-Gases always move down pressure gradient In lungs: When we breathe out, volume decreases so pressure increases, forcing gases to move out
-We breathe in, volume increases so pressure decreases
What does atmospheric pressure mean?
the sum of the pressures of the individual gases in the atmosphere (eg. Nitrogen, Oxygen, carbon dioxide and other gases)
what does partial pressure mean?
the pressure of an individual gas
-Individual gases move down a concentration (partial pressure) gradient- continues into equilibrium is reached
Describe the process of inspiration?
For air to move into alveoli pressure in lungs must be lower than atmospheric pressure:
-Diaphragm contracts and flattens, pulling bottom of lungs down increasing surface area for inspiration
-The ribs move up and out, increasing volume, reducing pressure allowing for air to be taken into lungs in order to equalise pressure gradient
describe the process of expiration?
-Diaphragm relaxes causing lungs to drop and decrease volume, pressure increases and air is forced out
2 types:Quiet expiration (natural) and Active expiration (uses more muscles which contract and force air out)
What is tidal volume?
the amount of air that goes in and out of lungs with each breath
(at rest-½ L- 1L per breath)
what is inspiratory reserve volume?
how much more air we could breathe in (at rest 2 1/2L- 3L)
what is expiratory reserve volume?
how much more air that could be exhaled (1l-1 1/2L at rest)
What is vital capacity?
the largest breath possible (the largest inspiration + largest expiration)
what is Total lung capacity compared to vital capacity?
will always be larger than vital capacity- due to always being a slight residual volume left over
what is residual volume?
(around 1l)- air that is left in the lungs (decreases with age)
what does dynamic lung volume mean?
How much air can be forced out in a certain amount of time
What can dynamic lung volume tell us?
whether we have normal lungs or problems with restriction or obstruction
what is restriction?
lower forced vital capacity(lower elasticity)
what is obstruction?
lower FEV1 (volume of air that can be exhaled in 1 second) is lower but overall forced vital capacity is the same
what is Minute ventilation and the formula for it?
-the amount of air going in and out of lungs within 1 minute
Minute ventilation = Tidal vol x breathing rate
State the general values of breathing rate, tidal vol and minute ventilation at rest
BR=12, TV=0.5, MV=6
State the general values of breathing rate, tidal vol and minute ventilation in moderate exercise
BR=30, TV=2.5, MV= 75
State the general values of breathing rate, tidal vol and minute ventilation in vigorous exercise
BR=50, TV=3, MV= 150
Why can’t minute ventilation indicate how much fresh air reaches alveoli?
Due to dead space (150ml)- is old air and can’t be used for gas exchange
formula for alveoli ventilation?
Alveoli ventilation= Ventilation Rate x (tidal volume- dead space)
Describe the journey of oxygen within gas exchange?
-Oxygen enters alveoli and moves from pulmonary capillaries into the system
-The heart then pumps it around the body and reaches the tissues (reaches muscle tissue and capillaries within it)
-Oxygen then moves into cells where cellular respiration can take place
describe the journey of CO2 within gas exchange?
-CO2 goes back into systemic capillaries and through the system and heart into the pulmonary capillaries
-its then exchanged and taken out through the alveoli and expelled with air being exhaled
what is exchange process driven by?
-partial pressure (gas moves from area of low to high partial pressure):
-Atmosphere has high partial pressure of oxygen wheare blood reaching alveoli has lower oxygen partial pressure
what are the factors influencing alveolar gas exchange
-resistance within airways, lung compliance and rate/ depth of breathing influence alveolar ventilation which affects oxygen reaching the alveoli
-Composition of inspired air
-Barrier thickness, amount of fluid can influence diffusion distance
-Diffusuion distance and SA can influence gas diffusion between alveoli and blood
Diffusion formula
Diffusion = Surface Area x Barrier permeability/ distance
what is emphysema?
destruction of alveoli means less surface area for gas exchange
what is fibrotic lung disease?
thickened alveolar membrane slows gas exchange, loss of lung compliance may decrease alveolar ventilation
what is pulmonary edema
fluid in interstitial space increases diffusion distance
what is asthma?
increased airway resistance decreasing alveolar ventilation
what is transport of oxygen within the lungs influenced by?
by solubility of oxygen within a liquid
describe the effect of haemoglobin within oxygen transport in the lungs?
-Haemoglobin is able to bind to oxygen causing it to diffuse into the blood, each red blood cell is able to take on 4 oxygen molecules
-This then allows for more room so more oxygen can move into and dissolve the blood, increasing uptake of oxygen
