Respiratory Flashcards
Major functions of Respiratory System: Supplies body with --- and disposes of --- Respiration: pulmonary ventilation which is... external respiration which is... transport which is... internal respiration which is...
Oxygen, C02 moving air into and out of lungs gas exchange between lungs and blood Of O2 + CO2 between lungs + tissues gas exchange between systemic blood vessels + tissues
Pulmonary ventilation:
The lungs are a — system, so they need to be ventilated in a — manner. Any cycle is defined in terms of (2)
For lungs this equates to how much can be moved and how fast. I.e volumes + rates
The pathologies of volumes is a — disorder
The pathologies of rates is a — disorder
closed cyclical Amplitude + depth restrictive obstructive
Pulmonary ventilation: the work of breathing.
Two requirements of overall lung function: (2)
Two requirements to optimise flow: (2)
To optimise diffusion, as many — as possible required.
Move gas to and from alveoli (flow) provide large SA for gas exchange (diffusion) Keep airway resistance as low as poss Wide airways required alveoli
Work Of breathing:
Alveolar ventilation is proportional to — x —
Low frequency/deep breaths have —/— load
but have increased work to counter high —/—
High frequency/shallow breaths have —/— load
but with low —/—
frequency x depth low resistive elastic 'stretch' high resistive elastic stretch
Work of breathing: Resistance + Compliance:
Compliance is the — with which the lungs can be —.
Specifically, it is the change in —/— that occurs with a given change in —/—
It is determined by which 2 factors? (2)
ease, expanded lung volume transpulmonary pressure Distensibility of lungs/thoracic cage surface tension of alveoli
Law of LaPlace: P= 2T/R P= --- T= --- r= ---
Pressure is greater in the smaller/larger alveolus?
— reduces —/— so the — is equalised in the large and small alveoli.
Surfactant is a — like complex which reduces —/—
It helps to keep the — from collapsing.
Pressure
Surface tension
radius
smaller
Surfactant, surface tension, pressure
detergent, surface tension
alveoli
Are alveoli really ventilated?
Air moves at high — through the —
As the airways divide, each gets —, but the cross-sectional area gets —, so velocity of same volume of air gets — the further down the respiratory tree.
Bulk flow is near to — at the alveoli. They do expand slightly, but much alveolar resp bronchiole is by —
This helps keep alveolar — fairly constant and exchange with the — fairly constant in face of — breathing.
velocity, trachea smaller greater smaller zero diffusion composition blood intermittent
External respiration:
The exchange zone is defined by presence of —
Terminal bronchioles –> — bronchioles –> — ducts —>
clusters of —
there are approximately (number) alveoli
diameter of –mm
they have a single — cell layer
they account for most of the —/—
Provides very large —/— for —/— of about –m^2
Bronchioles are wrapped in —/—/—
The blood vessel supplying the cluster of alveoli is called the —/—, the vessel leaving the cluster is called the —/—
Aveoli Respiratory, Alveolar Alveoli 300 mill 0.3mm epithelial lung volume surface area, gas exchange, 75 smooth muscle fibres pulmonary arteriole pulmonary venule
Gaseous exchange: Flow = K x (Delta)P / R K= --- (Delta)P= --- R= ---
For gas exchange across the resp membrane;
P is the…
R is related to…
K is related to…
Constant
Pressure gradient
Resistance
Partial pressure gradient
cross-sectional area and thickness
the gas under consideration (its MW and solubility)
Daltons Law of Partial Pressure:
DEFINITION
The PP of each gas is proportional to its – in the mixture.
Gases — differently down their own partial pressure —
This also applies at —/— interfaces.
Gradients do not reflect — due to differences in —
Total pressure exerted by a mixture of gases is equal to the sum of pressures exerted independently by each gas in the mixture (its partial pressure).
Percentage
diffuse, gradients
air/water
concentration, solubility
Henry’s law and the solubility of gases:
DEFINITION
The amount of gas dissolved depends on its —
— is the most soluble
O2 is about 1/–th as soluble as CO2
— is practically insoluble in plasma
When a liquid is exposed to a mixture of gases, each gas dissolves in the liquid in proportion to its own partial pressure.
solubility
CO2
20
N
For gaseous exchange, F x (Delta)P / R becomes... D = (s / (Root)MW) x (Delta)P x (A / d) D = --- s = --- MW = --- (Delta)P = ---/---/--- A = --- d = ---
Diffusion Rate Solubility Molecular Weight Partial Pressure Difference Diffusion Area Diffusion Distance
Gaseous Exchange:
PP gradient for CO2 is only – mm hg
Its 45 mm hg in the —/— vs 40 mm hg in the —
CO2 is v.soluble in the —
the gradient is sufficient to — CO2
PP of O2 in venous blood is 40 mm hg, the partial pressure in alveoli is 104 mm hg.
The steeper gradient is required because 02 is about –x less soluble than CO2 and so a greater — is required to shift the same amount.
The diffusion capacity can be increased by:
increase — of under—- parts of the lungs
increasing the —/—, blood normally equilibrates partly along —/—
5 venous blood alveoli plasma dump 20 push perfusion, perfused cardiac output pulmonary caps
Ventilation-Perfusion Coupling:
Ventilation is…
Perfusion is…
These two must be tightly regulated to ensure efficient…
If theres low CO2 in the alveoli, there is — of the —
If there’s low O2 in the alveoli, there is — of the —
The normal ventilation/perfusion ratio is…
When there’s reduced ventilation and increased perfusion, the pressure of O2 in alveoli is — and the pressure of CO2 is —, this causes the PA serving the alveoli to — which results in reduced —/— and —.
When there’s enhanced alveolar ventilation but inadequate perfusion the conc of 02 in the alveoli —
whereas the conc of CO2 —, this makes the PA serving the alveoli —, leading to enhanced —/— and —
Getting air to the alveoli getting blood to the alveoli Gas exchange constriction, bronchioles constriction, arterioles 0.85 decreased increased constrict alveoli ventlation perfusion increases decreases dialate alveolar ventilation perfusion
Transport + exchange of CO2:
All exchange of both gases occur via the —
Moments driven by differences in —/—
These differences arise via — and —
A — shift allows — to enter the red blood cell from the — where it combines with — to make —. Then the enzyme —/— splits it into — and — then CO2 leaves the cell and enters the — ready for expulsion. Alternatively, carbamino haemoglobin can dissociate to — and — then CO2 leaves the red blood cell and enters alveolus.
CO2 dissolved in plasma can enter the alveolus directly.
The carbonic acid process can also occur outside the — and in the plasma, but as there is no enzyme involved, this process happens —
plasma partial pressure sources + sinks chloride, HCO3- plasma H+, H2CO3, carbonic anhydrase H20 + CO2 alveoli Hb + C02 cell slowly---
