Respiratory Physiology Flashcards by Oliver Taylor

There are 3 lobes in the _____ lung and 2 lobes in the _____ lung. This is so that there is room for the______

Right Lung
Left Lung
Heart

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What are the functions of the pleural membrane

Reduce Friction
Creation of a pressure gradient
Compartmentalisation

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What are the functions of the conducting regions of the lungs?

Warm and humidify air
Distribute the gas
Serve as part of the body’s defense system

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What is the function of the respiratory regions of the lungs?

Provide a site for gas exchange

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What is the value of atmospheric pressure?

760 mmHg

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The pressure in the pleural cavity is _________. This is because the visceral layer is being pulled towards the lungs due to the _______ properties of the lung and the parietal layer is being pulled towards the ___________.

Negative

Elastic property of the lungs
Chest wall

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When _____________ is less than the _________ pressure air will flow down it’s pressure gradient into the lungs

Pa (Alveolar Pressure)

Atmospheric

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What is Tidal volume (TV)?

The amount of air you ventilate normally, around 500ml

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What is inspiratory reserve volume (IRV)?

The amount of air you can force yourself to breathe in

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What is expiratory reserve volume (ERV)?

The amount of air you can force yourself to breathe out

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What is residual volume (RV)?

The amount of air that stays in your lungs at all times,

FRC - ERV

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What is vital capacity (VC)?

The amount of air you can move in and out of your lungs

IRV + TV + ERV

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What is functional residual capacity (FRC)?

The volume of air left in the lungs after passive expiration, this usually changes with disease

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What is anatomical dead space? (Vd)

Air in the respiratory passage way that doesn’t participate in respiration, usually 150mL

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How do you calculate alveolar ventilation?

(Tidal Volume - Dead Space) x breathing frequency

(TV - Vd) x freq

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Compliance is the ability of a hollow organ to ________ and ________. ______________opposes the expansion therefore the more _____ the harder it is to distend.

Distend and expand
Elastic recoil
recoil

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How do you calculate Compliance?

Change in Volume / Change in Pressure

ΔV / ΔP

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Compliance varies __________ with Lung volume. High volume = ____________. Low volume = ___________

Inversely

High V = low Compliance
Low V = High Compliance

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Obstructive lung diseases affect the ________ regions of the lung. They inhibit _________ and ________ compliance.

Conducting regions
Inhibit gas flow
Increase compliance

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Restrictive lung diseases affect the __________ by replacing it with ________ tissue. It ________ compliance.

Lung tissue
Fibrous
Decreases compliance

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Why does compliance increase in Obstructive lung disease?

Gas gets trapped in the lung which increases the residual volume. This means that the lung is expanded more so we get decreased elasticity

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Why does compliance decrease in Restrictive lung disease?

Healthy lung tissue is replace by non-elastic fibrous tissue. This means the lungs are harder to inflate.

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What factors affect lung compliance?

Elastic recoil of the chest wall
Elastic recoil of the lungs
Surface tension of the alveoli

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Surface tension is an _________ directed force and tends to ________ alveolar diameter

Inwardly directed

Reduce alveolar diameter

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____ of the work needed to inflate the lung is dedicated to overcoming the _____________________.

2/3 | Air-liquid interface surface tension

Surfactant _______ the surface tension at the liquid-air interface. This means that air will flow ______ into each alveolus

Reduces surface tension | Evenly

Surfactant is a _________ rich in phospholipids. It is also called ______. It is produces by the ______ alveolar cells.

Lipoprotein DPPC Type 2 alveolar cells

What substances cause bronchoconstriction?

Acetylcholine and Histamine

What substances cause bronchodilation?

Adrenaline and noradrenaline

The residual volume prevents ____________ and ensures _______________

Lungs from collapsing | Ensures continuous gas exchange

What is the normal value of FEV1/FVC?

80%

What disease is most likely if FEV1/FVC is around 40% ?

Obstructive Lung Disease, this is because lung volume is high but the rate at which they can exhale in 1 second is low

What disease is most likely if FEV1/FVC is around 90% ?

Restrictive Lung Disease, this is because the lung volume is low but the rate at which they can exhale in 1 second is high

How do you calculate the partial pressure of a gas?

Barometric Pressure x fraction of dry gas Pb x [fraction of dry gas] i.e. fraction of oxygen = 0.21 .'. Partial Pressure = 760 x 0.21 = 160 mmHg

What is the partial pressure of Alveolar CO2?

40 mmHg

What is the partial pressure of Alveolar O2?

104 mmHg

What factors affect diffusion of gases?

Surface Area Partial Pressure gradient Thickness of membrane Diffusion Coefficient (Takes into account solubility)

What is the partial pressure of CO2 in the capillaries?

45mmHg

What is the partial pressure of O2 in the capillaries?

40mmHg

What is the thickness of the alveolar membrane?

0.2 - 0.6 um

When oxygen binds to haemoglobin a _______________ occurs which makes subsequent oxygen molecules ________ to bind

Conformational change | Easier

At high temperatures, ________ of oxygen is promoted

Offloading of O2 is promoted

At low temperature, _________ of oxygen is promoted

Retention of O2 is promoted

At low blood pH, there is __________ affinity of haemoglobin for oxygen. This ________ offloading

Reduced affinity | Increases offloading

At high blood pH, there is ___________ affinity of haemoglobin for oxygen. This _______ offloading

Increased affinity | Decreases offloading

At high partial pressures of CO2, there is ___________ affinity of haemoglobin for oxygen. This _______ offloading

Reduced affinity | Increases offloading

At low partial pressures of CO2, there is _________ affinity of haemoglobin for oxygen. This ________ offloading.

Increased affinity | Decreases offloading

CO2 binds to the _________ on the haemoglobin therefore it __________ with oxygen

Amino group | Doesn't compete

What is the Alveolar Gas Equation?

Alveolar Partial Pressure of O2 = Inspirired Partial Pessure of O2 - (Alveolar Partial Pressure of CO2 / Respiratory Quotient) PaO2 = PiO2 - (PaCO2/RQ) PiO2 = (760 - 47) x [fraction of gas]

At rest consumption of oxygen is approximately what?

250ml/min

At rest the production of carbon dioxide is approximately what?

200ml/min

The main respiratory centers, the ___________________ and the ___________________, are found in the _________

Dorsal respiratory group and the Ventral respiratory group | Medulla

The Pre-Botzinger complex is located ________________

Above the ventral respiratory group

There are 2 respiratory centers in the pons, they are the ________________ and the __________ centers

Pneumotaxic and Apneustic

Cells in the pre-botzinger complex _______ spontaneously and stimulate the __________________. The neurons in this group will fire for about __ seconds and cause the diaphragm to contract

Depolarise Dorsal Respiratory Group 2 seconds

As more neurons in the DRG are stimulated the contraction of the ___________, increases. This results in ________ and ________ breathing

Diaphragm | Smooth and controlled

The ____________ in the __________ area controls the rate and depth of breathing and prevents over stretching of the lungs by sending ________ signals to the DRG

Nucleus Parabrachialis in the Pneumotaxic area | Inhibitory

The Apneustic Area coordinates the transition from __________ to __________ by sending simulatory signals to the ____ to prolong inspiration

The transition from inspiration to expiration | DRG

When the pneumotaxic area is active the _________ area is inactive

Apneustic area

The ________ respiratory group is ________ during normal inspiration. It gives extra ________ drive

Ventral Respiratory Group Inactive Extra respiratory drive

During laboured breathing the signals from the ___________ spill over to the ____. This group then sends signals to the intercostals and ________ muscles to contract

Pre-botzinger complex Ventral Respiratory Group (VRG) Abdominal muscles

The central chemoreceptors are a pair of ________ groups of cells located below the __________________. The detect changes in the ___ (in the CSF)

Bilateral Ventral medulla surface pH

Peripheral chemoreceptors are located in the ______ and _____ bodies. The detect changes in ____ (mainly), ___ and __.

``` Carotid or Aortic P O2 (Partial Pressure of O2), PCO2 and pH ```

A large ________ in P O2 is required before the _______ chemo-receptors start to fire

Decrease | Peripheral

A steady state period is when ________ has increased but leveled

Ventilation

What is the Hering-Breuer Inflation reflex?

A protective mechanism that prevents over inflation of the lungs. Stretch receptors in the smooth muscle of the conducting regions relay information about the volume inside the airways

What is the Irritant receptor reflex?

Response to touch or noxious substances by pressure and chemo-receptors. Causes coughing, gasping and prolonged inspiration.

What volumes/capacities can't be measured using spirometry?

Residual Volume Functional Residual Capacity Total Lung Volume

What is the secondary function of the Pneumotaxic area?

Increasing breathing frequency, inhibitory signals stop the ramp signal sort which means more can occur in a shorter period of time .'. Faster breathing rate