respiratory systems Flashcards
which factors affect rate of diffusion?
FICKS LAW
temperature p,p gradient length of diffusion pathway size of molecule s.a. of gas exchange surface its solubility in liquid
what is important about s.a:V
as organism gets larger its SA:V ratio gets smaller so it cannot rely on simple diffussion anymore
> so require specialised gas exchange surfaces
what structural features do larger organsims have to make gas echange more efficient?
(general)
> they have evagination and invaginations (folidng of exchange surface) which increases the s.a
thin surfaces to mimimise the diffusion pathway
they often are vascular or have access to fresh supply of substances
in gas, the internal tissue is moist so the gas can adjust to the bodies internal liquid enviroment.
True or false?
the dead zone is involved with gas exchange
False! the dead zone does not take part in gas exchange but helps with ventilation
what values can you get from a spirometer?
tidal volume
vital capacity
inspiritory capacity
resdiual volume - prevent complete collapse of lung
avian birds (comparative anatomy)
they have air sacs and unidirecional airflow
so all air can be used for gas echange and not wasted on ventilation
forgs (comparative anatomy)
they have a POSITIVE pressure pump
air forced into lungs when mouth cloese
Insects (comparative anatomy)
they have spiricles and can also do abdomnal pumping
fish (comparative anatomy)
water moves across gills
counter current system for max gas exhang
when mouth closes the pressure increases and forces water out
compare tidal breathing with unidirectional flow
flow is more efficient as incoming air NEVER mixes with the expired air so all air can be used for gas exchange.
It is optimised to MINIMISE the ‘dead space’
body reaction to hypercapnia (high co2)
Hypercapnia causes increase in minute ventilation so frequency and tidal ventialtion increases
> Body more responsive to hypercapnia than hypoxia but hypoxia has the same effects
All gas movement is…
active
passive
osmosis
passive process governed by diffusion
what DOESN'T make the Bohr shift occur? (shift to right) A increase of Co2 B decrease [H+] - more acidic C increase [H+] - more alkali D increase temperature E increase 2-3 BPG
option C decreasing H+/increaed pH a
> high carbon increases acidity, high temp and 2-3 bpg all contribute to Bohr
how does 2-3 bpg infulence haemoglobin///?
changes Hb from a high affnity to low affinity oxygen state
at rest intrapleural pressure is…
negative w.r.t atmospheric pressure
Alveolar pressure/ intrapleural pressure is lower than atmospheric pressure
A during inspiration
B during expiration
in INSPIRATION
quick deinitions of the pressures x3
- atmospheric
- intrapleural
- intraalveolar
Atmospheric pressure- pressure of the air outside the body.
Intrapleuralpressure- pressure within the pleuralcavity.
Intraalveolar pressure- pressure inside thealveoliof the lungs.
These three pressures are responsible for pulmonary ventilation.
which lung has less lobes?
left lung has 2 lobes (bicuspid valves winkywink)
‘‘left lung less lobes’’
surfacant is produced from which type of alveolar cell?
type 1 pneumocyte
type 2 pneumocyte
type 3 pneomocyte
type 2 pneumocytes secrete surfacant which reduces surface tension of the alveoli!
What is external respiration?
delivery and removal of gases to and from tissues and cells
which part of the respiratory tract is part of the respiratory zone and not the conducting zone?
transitional and respiratory zones = respiratory bronchioles, alveolar ducts, alveolar sacs
How do resistive forces affect airflow?
They oppose inspiration and assist expiration.
how does gravity affect pattern of ventilation and perfusion (blood flow)?
blood flow is more affected by gravity. at the top of the lungs we have the least volume of blood and ventilation.
when ventilation mathces perfusion we get the optimum gas exchange
what are the features of the pulmonary system?
ung to heart
high flow system as cardiac output flows thrug lungs low pressures and low resistance
arterial walls are thin to allow for high flow
how can ventilation be modified to reach optimum gas exchange?
you can vasoconstrict and divert blood away from poorly ventilated areas (e.g. low ppO2/ hypoxia)
which is the most efficient gas exchange system?
fish! the countercurrent system is around 905 efficient at extracting oxygen
how is oxygen transported arounf body?
via haemoglobin
how does cooperative binding occur?
conformational change
how does ppCO2 affect Hb?
it releases oxygen so bohr shift to the right
other Hb pigments facta
myoglobin has high affinity and so does foetal
how can we we hold our breath in?
we can temporality overide the medulla and VOLUNTARY breathe via the cortex
name the types of specialised receptors that control ventilation/gas exchange
LUNG - stretch, J- (pressue and gas), irritant (sharp exhale) and proprioreceptors (contraction)
PERIPHERY
» they act to allow expiration to occur so we have short shallow breaths so LIMIT inspiration
where are centro chemoreceptors found and where are peripheral chemorecepotes found
near the venolatieral surface of medula
near the cartoid and aortic arteris - areas of high blood flow
what is the realtionship between hypercapnia (high co2) and hpoxia (low oxygen)
they have a synergistic effect together to increase minute ventilation
> to meet metabolic demands of body
> much greater effect than alone
diving reflex
delays the build up of c02 and can be triggered by cold water on the faxe
what trIggers breahring?
build up of co2 triggers our next breath
how does pressure move
it moves from high to low areas
in ventilation the atmospheric pressure is compared to the alveolar pressure
what casues the presuure and volume changes during ventilation?
changes in the thorax cause the pressure and volume changes
decribe the mechanical events of breathing
inspiration uses energy
external and diaphragm contract
this allows air to flow into the lungs until pressure gradient is dissipated
air moves down a pressure gradient
which forces resist airflow?
could be airway resistance, friction in pulmonary tissue or the intertia of the air and tissue
how does air move in tubes?
it moves by bulk flow - this is essentiallt tidal breathing
define airway resitance
airway resitance changes with lung volumes
there can be LAMINAR flow which allows for normal breathing or TURBULENT flow which can lead to wheezing
TRANSITIONAL FLOW where there is slowing at junction ~ eddy flows
how could surface tension affect lung compliance?
surface tension can also promote collapse of the alveoli, reducing the surface area and draw out fluid increasing the diffusion pathway
> BUT work is required to overcome the surface tension
alveoli have elastic and collegen fibres in their walls which allow for expansion and lined with fluid allowing diffusion of gas into a liquid envrioment
what is the role of surfacant in the airways?
it acts as a detergent to MINIMISE surface tension
how do pathophysiological circumstances affect airway resistance?
inflamation narrows , mucus blocks the lumen
muscle action is unaffected but as airway resistance increases, it makes it harder to breathe as muscles need to OVERCOME the airway resistance
when can bronchioconstriction/dialtion happen and how does it affect airway resistance?
increase the Raw due to irritants, changes in gas compostion or in ill health
decrease the Raw due to hormones (adrenaline) or sympathomimetic drugs e.g when treating asthma
what is the relationship between airway resitance and radius ?
resisitance is INVERSELY proportional to 1/r⁴
narrow airway has greate resistance
true or false internal respiration is the exchange of gases between the alveoli and the blood
FALSE- that is external
internal respiration is metabolism!
which of the following does not increase the rate of diffusion of gases across the respiratory interface?
A increase in partial pressure difference
B increase in thickness of exchange surface
C increase in surface area of interface
D increase in diffusion coefficient
OPTION B as the diffustion pathway is longer
> interface = sufrace that forms a boundary = basically exchange surface
which of the following best explains the term partial pressure.
A The pressure of a gas mixture in relation to its volume
B the total pressure of all of the individual gases in a gas mixture.
C the pressure of an individual gas in a gas mixture
D the pressure of an individual gas in relation to its volume
OPTION C
During normal inspiration.. which of these statements is incorrect.
A So the phrenic nerve stimulator contraction of the diaphragm
B the interpleural pressure increases above atmospheric pressure.
C The thoracic volume increases as the diaphragm contracts
D alveoli, the pressure falls below atmospheric pressure.
OPTION B IS FALSE othwrwise we would breather out
> presur emoves from high to low
The functional residual capacity of the lungs is what is it the amount of air remaining in the lungs …
A when lung collaspes
B after forced expiration
C after a normal breath out
OPTION C (option B is redidual volume)
> after a normal tidal breath
> functional residual capacity is physiologically relevant because it, it prevents the lungs from collapsing all together and it makes the next breath easier.
> lungs are already partially inflated means that it’s an easier to get the next breath of air in there
> reservoir of oxygen so blood can still flow through lungs
airway resitance is primarily affected by
A the amount of surfactant
B the amount of elastic tissue in the airways
C the diameter of the bronchioles
D the surface area for gas exchange
OPTION C (A and B affect lung funCtion)
> So airway resistance is a dynamic property of the lung, and it’s affected primarily by the radius of the airways, the diameter of the bronchioles in the bronchioles
> bonchioles is where most resitance arises
So the compliance of the lung is primarily affected by…
A the amount of surfactant
B the thickness of the cartilage in the bronchial wall
C the partial pressure of oxygen inspired air
D the diameter of the airways.
OPTION A
> lack of surfactant = lung is much less elastic (surfacatn lowers usrfce tnesion in alveoli
> compliance is how easy it is to stretch and expand lungs (distends)
when hemoglobin is fully saturated, this means that
A the red blood cells contain as many hemoglobin molecules as possible
B oxygen is attached to both the haem and the globin molecule.
C the hemoglobin molecule is carrying both oxygen and carbon dioxide
D there is an oxygen molecule attached to each of the 4 haem groups.
OPTION D
> easy one give yuorself a pat in the back!
what reduces the oxygen saturation of Hb / the affinity of Hb
increase in ppCo2
increase in temp -> increase metabolism -> more c02
low pH / acidic
2-3 BPG - produced by RBC when hypoxic
If the resistance of the pulmonary circulation increased then..
A the pulmonary blood flow would decrease
B the pulmonary blood pressure would decrease
C the pulmonary blood volume would increase.
OPTION A
> an increase in the resistance means that the heart has to work harder against that resistance to push the same amount of blood flow through it.
where does the basic rhythm and pattern of breathing arise in the.. A pons B diaphragm C medulla oblongata D spinal cord.
OPTION C
The medallia olongata and pons is in the brainstem,
- medulla fires AP in osscialting rhythm
- PONS finetunes the rhythm
Which of these is NOT a role of the conducting space/dead space?
A To exchange gases from the blood. Deliverly of O2 to the blood and CO2 transfer from the blood.
B To transfer gases to and from the alveoli.
C To filtrate and remove foreign material.
D To warm and humidify inspired air.
OPTION A
bronchioles, terminal bronchiole, bronchi conduct
repiratory brocnhi, alveoli ducts and sacs respire
What is the primary role of a respiratory system?
Meet the metabolic needs of the organism
which best describes avian unidirectional airflow?
A two breath cycle where air is drawn into posterior air sacs where gas exchange can begin to occur, then is passed over the lungs and into the anterior air sacs before being exhaled. There is no mixing of air.
A one breath cycle where air is drawn into posterior air sacs, then passed over the lungs where gas exchange occurs, and then into the anterior air sacs before being exhaled. There is no mixing of air.
A two breath cycle where air is drawn into posterior air sacs, then passed over the lungs where gas exchange occurs, and then into the anterior air sacs before being exhaled. There is no mixing of air.
OPTION C
2 breath cycle
? gas exchange in LUNGS, the sacs act as air reservoirs
Which best describes laminar flow in tidal breathing?
Slow flow rate, parallel stream lines. It is slow and efficient due to little to no resistance.
High flow rate, disorganised streamlines; often seen in narrow airways with higher resistance.
Intermediate flow rate; eddy currents are caused due to airways splitting in different directions.
OPTION A
b- turbulant flow
c- transitional flow
brochioconstriction affects airways how?
it INCREASES airway resistance
what happens when we exercise?
the tidal volume increased and the frequency of respiration increases
> deeper and frequent breaths
the heart rate increases and so does the stroke volume (C.O)
>faster and more powerful breaths
what do you see if Va:Q (ventilation:perfusion) is 0?
blood does not come in contact with air (0/Q)
what do you see if Va:Q (ventilation:perfusion) is INFINITY?
there is no blood flow - dead space (Va/0)
where does the pattern of breathing arise?
in the MEDULLA!
> poons can modify this as well as tempersture and emothion input form hypothalsms
why is the control of breathin needed in the brain
repisratory muscles have NO INTRINSIC RHYTHM so are dependent on the brainstem
how do chemoreceptors work - generally
detect c02, o2 and pH and alster tidal volume + frequecny of breathing
why do centrochemoreceptors have a slow response time?
as C02 accumualtes, it creaes carbonic acid in the CSF increasing acidity
» this stimulates centrochemoreceptors but the C02 has to accumulate in the blood first before it reaches the CSF!
the diving reflex (holding our breathe) can be triggered by splash of cold water to face. what are its characgtersitics
vasoconstrict - blood goes to essential organs
reduced heart rate
lactate accumulates in muscle
» all to DELAY build up of C02 which triggers our next breath!!
