L13 (respiratory) Flashcards
what is respiration
Respiration is the exchange of O2 and CO2 between the tissues and the environment
what 4 processes are involved in respiration
External - Exchange of O2 and CO2 between the atmosphere and blood flowing through the lungs
Transport of gases by the blood
Internal - Gas exchange between capillaries and tissues
-> cellular respiration
Overall regulation of respiratory function (you don’t have to think about breathing)
what is ventilation
the process of moving air into and out of the lungs
it supplies O2 and removes CO2 from the alveoli
this is bulk flow
what is gas exchange
(air to blood i.e. into body).
Exchange of O2 and CO2 across alveolar membrane
this is a process of diffusion therefore this process is all about the pressure gradient
what is gas transport
Gas transport: Deliver O2 from lungs to tissues and and transport CO2
produced by metabolism to lungs. (Cardiorespiratory)
this is bulk flow
explain gas exchange once the O2 has gotten into the blood
Exchange of O2 and CO2 between the capillaries and
the cells
this is a process of diffusion
what is cellular respiration
Cells use O2 and produce CO2
this is a process of metabilisum
what are some of the functions of the respiratory system
Provide oxygen
Eliminate carbon dioxide
Filters, warms and humidifies the air we breathe
Communication (vocal cord and larynx)
Sense of smell
Regulate the pH of the blood, in association with the kidneys (CO2 produces carbonic acid)
Defend against microbes
Temperature regulation
what is the most important function of the respiratory system
The most important function is to bring in O2 and remove CO2 but this is not the only function
it high altitules is there an increase or decrease in partial pressure
what does this mean for the respiratory system
there is a decrease in pressure which means that the respiratory system needs to be highly adaptable
what is the anatomical start of the respiratory system
the start is the nasal cavity (pharynx)
what structure does the larynx contain and what is its role
the epiglottis which stops food from getting into the lungs
what is an extra feature that the trachea has that the larynx and pharynx don’t
cartilaginous rings to keep the airways open
what does the trachea branch into
bronki and then into bronchioles
what happens to the cartilaginous rings as the trachea branches
they become smaller bits of cartilage until they are no longer there (at the alveolar sacs)
what is the site of gas exchange in the lungs
why
alveolar sacs
These structures are surrounded by many capillaries. The alveoli and the sacc have a very thin membrane separating them
is the lung directly attached to tendons or muscles
no
what happens as the diaphragm contracts
it moves down increasing the vertical diameter in the thoracic cavity causing the lung to expand
when you are exercising diaphragm contraction is not enough. what other muscles are recruited during this time for insperation
the external intercostal muscles
how do the external intercostal muscles cause the lungs to expand
These contract the chest wall rises up increasing the anterior posterior diameter giving enough space for the lungs to expand more to get more O2 into the lungs
what muscles are recruited for expiration in a healthy individual at rest
Expiration is a passive process therefore it doesn’t require any energy in a healthy individual at rest
what is the diaphragm shape at rest
dome shaped
what muscles would be required for forced expiration
The internal intercostal muscles contract to bring the ribs down during exercise and sometimes the external oblique which is in the stomach
what is the role if the steroid muscle in the neck and the Pectoralis minor
increase the anterior posterior diameter to increase inspiration
describe the process of passive breathing
Inspiration caused by diaphragm contraction
Expiration caused by lung elastic recoil pulling
thorax and relaxed diaphragm inwards. No
muscle contraction, therefore “passive”
describe the process of deeper breathing
eg walking up a steep street
Inspiration – diaphragm and external intercostal muscle contraction
Expiration – lung elastic recoil and internal intercostal muscle contraction
describe the process of very deep forceful breathing
working out
Inspiration – diaphragm and external intercostal muscle contraction plus contraction of sternocleidomastoid and pectoralis minor muscles
Expiration – lung elastic recoil and internal intercostal muscle contraction plus abdominal muscle
contraction
what nerves play a role in respiration
phrenic nerve
sympathetic and parasympathetic nerves
dont damage the medulla
what are the pleura
The Pleurae form an envelope between the lungs & chest wall
what is the parietal pleura
outer layer of the pleura - lines inside of chest wall &
diaphragm
what is the visceral pleura
directly on lung - lines outside of lungs
in between the 2 pleural layers there is a membrane. what does this create
the pleural cavity
what is found in the pleural cavity
a minimal amount of pleural fluid
what is the role of the pleural fluid
it causes the pleural cavity to stick to the chest wall and the lungs therefore as the chest wall expands so do the lungs
what is the definition of the pleural cavity
Pleural cavity – slit-like potential space filled with pleural fluid
Both the pleural surfaces slide, but separation from each
other is resisted (like film between 2 plates of glass)
Lungs cling to thoracic wall and are forced to expand and
recoil as volume of thoracic cavity changes during breathing
what is ventilation
Defined as the exchange of air between the atmosphere
and alveoli
how does air move
Air moves by bulk from the region of high pressure to low
pressure
what is bulk flow proportional (and inversely proportional) to
Bulk flow (F) is proportional to pressure difference (∆P) between two points and inversely proportional to the resistance (R).
what is the equation for bulk flow
F = dP/R
(R= resistance)
dP = alveolar pressure - atmospheric pressure
what is Atmospheric pressure (Patm) or barometric pressure (Pb)
partial pressure outside the lungs
what is alveolar pressure (Palv or PA)
pressure inside the alveoli
what is intra pleural pressure (Pip or Ppl)
Pressure between the 2 layers of pleura
what is transpulmonary pressure (Ptp) or Lung pressure (PL)
The difference between the pressure inside and outside of the lung
this is the pressure that needs to overcome the elastic recoil of the lungs to stop them from collapsing
All pressures in the respiratory system, as in CVS, are given relative to what
All pressures in the respiratory system, as in CVS, are given relative to atmospheric pressure – 760mmHg
what is the pressure at the end of each breath
0 because there is no air flow therefore there is no difference in pressures
during ventilation why do we need a pressure graident
because air flows from high to low therefore to move air we need a pressure graident
how do you change the pressure greident in the lungs
by changing lung volumes
As you reduce the volume then the gas moves faster creating more pressure
When you take a breath in the lung volume increases therefore the pressure drops. This is the opposite when you breath out
what is boyle’s law
At constant temperature, the volume of a gas varies inversely with absolute pressure.
what are the 2 determinants for lung volume
Difference in the pressure between the inside and outside
of the lung (transpulmonary pressure (Ptp or PL ))
Stretchability of the lungs (compliance) – how much the
lungs expand for a given change in Ptp
what governs that static property of the lungs
Transmural pressure
how do you calculate the transmural pressure
Pressure inside the lung = pressure inside the alveoli (Palv)
Pressure outside the lung = pressure of the intrapleural fluid
surrounding the lung (Pip)
threfore
Ptp = Palv - Pip
what does the lung require to expand its volume
+ive transpulmonary pressure
when the lung is at its smallest size what is transpulmonary pressure = to
0
what is capacity
the total amount of air we can shift in and out of the lungs
what is fibrosis
Fibrosis is when the lung become thick therefore the lung has to work harder to expand
what is emphysema
emphysema is when lung becomes flaccid so easy to expand but hard to collapse
what pressures are = when there is no airflow
alveolar and atmospheric pressure
Lung has the tendency to recoil
inwards and chest wall tends to expand outwards (they pull away each other)
how do these things stay in ballance
the pleural cavity ballantines these by creating a vacuum
this means that the intrapleural pressure (Pip) is always -ive (vacuum) so that transpulmonary pressure is always positive
Lung has the tendency to recoil
inwards and chest wall tends to expand outwards (they pull away each other)
how do these things stay in ballance
the pleural cavity ballantines these by creating a vacuum
this means that the intrapleural pressure (Pip) is always -ive (vacuum) so that transpulmonary pressure is always positive
what happens if the balance in transpulmonary pressure is losted
Any damage to the visceral pleura or parietal pleura when it changes the balance between the pleural cavity
When this balance is lost then the lung starts to collabs (pneumothorax)
what is pneumothorax
a collapsed lung meaning that there is air in the pleural cavity
what is a pleural effusion
when you have fluid in the pleural cavity
Which ONE of the following is the key for achieving stable
balance between the breaths?
A. Transpulmonary pressure should always be positive
B. Intrapleural pressure should become positive at the end of inspiration
C. Intrapleural pressure should become positive at the end of expiration
D. Alveoli should expand in size to its maximum during
inspiration
E. Chest wall should maintain its elastic recoiling in between the breath
A
