Gas Exchange, Gas Transport And Control Of Respiration Flashcards
Identify a typical disease for restrictive respiratory problems.
-fibrosis of the lung; actually respiratory disorder syndrome.
Identify a typical disease for obstructive respiratory problems.
-asthma or emphysema.
How would a restrictive respiratory disease affect a persons breathing and more particularly their dynamic lung measurements?
Decrease in lung capacity.
How would an obstructive respiratory disease affect a persons breathing and more particularly their dynamic lung measurements?
Airways narrowed or collapsing on expiration.
Explain obstructive lung disease.
Generally have difficulty in getting the air out from their lungs on expiration. Diagnosed by measuring the FEV1sec/FVC ratio (FEV1%).
-FEV1sec is low, but FVC is normal.
Explain restrictive lung disease.
Generally have difficulty in getting a full amount of air into their lungs on inspiration. On expiration there is no airway collapse. Both FEV1sec and FVC and decreased.
At vertebral level T4/T5 the trachea divides into?
Left and right primary bronchi.
Which lung are foreign objects more likely to be inhaled into?
Right lung as its primary bronchi intro is more vertical and wider than left.
How many secondary bronchi (lobar) are there in each lung?
- R lung: 3 (one to each of the three lobes).
- L lung: 2 (one for each of the two lobes).
Define the term bronchopulmonary segment.
Segment of lung tissue which is served by its own tertiary bronchus, artery/vein and lymphatics.
Approximately how many bronchopulmonary segments are there in each lung?
10 per lung (some books: 10R and 8L).
Where does the primary bronchus supply air?
The lung.
Where does the secondary bronchus supply air?
The lobe.
Where does the tertiary bronchus supply air?
The bronchopulmonary segment.
Where does the terminal bronchiole supply air?
The lung lobule.
If there is no cartilage present in the bronchioles, what holds the airway open?
Smooth muscle.
The last part of the conducting portion is known as the?
Terminal bronchiole.
What distinguishes a terminal bronchiole from a respiratory bronchiole?
The respiratory bronchiole has alveoli budding directly off it.
What is the origin of the pulmonary artery?
Right ventricle via pulmonary trunk.
What is the origin of the bronchial artery?
The aorta.
What type of blood does the bronchial artery carry?
Oxygenated.
What is the function of the bronchial artery?
To take oxygenated blood from aorta to supply all lung tissue (except alveoli).
What is the function of pneumocyte type 1/alveolar cell type 1?
Gas exchange.
What is the function of pneumocyte 2/alveolar cell type 2?
Secrets surfactant.
What is the function of surfactant?
Decrease surface tension.
How does surfactant aid expiration?
Prevents alveolar collapse.
A third type of cell wanders along alveolar surfaces removing dust, debris and bacteria. These are called?
Alveolar macrophages (dust cells).
Small alveolar pores connect adjacent alveoli. What is their function?
Equalise pressure between alveoli.
Why is only a small percentage of O2 normally carried by blood plasma?
O2 dissolves very poorly in solution.
Another O2 binding protein which is similar to haemoglobin is found in muscle called?
Myoglobin.
What is the driving force for the transport of O2 and CO2 across the respiratory membrane?
Partial pressures.
How is CO2 normally dissolved in the blood? What are the relative percentages?
- dissolved: 7%.
- bound to haemoglobin: 23%.
- as the bicarbonate ion: 70%.
When CO2 binds to haemoglobin, what compound is formed?
Carbaminohaemoglobin.
When carbon monoxide (CO) binds to haemoglobin, what compound is formed?
Carboxyhaemoglobin.
Why is CO such a poisonous substance?
It competes with, and displaces O2 from haemoglobin.
On a oxygen-Hb dissociation curve what happens to the %O2 Hb saturation at a PO2 of 40mm Hg for the right shifted curve?
Decreases.
On a oxygen-Hb dissociation curve what happens to the %O2 Hb saturation at a PO2 of 40mm Hg for the left shifted curve?
Increases.
On a oxygen-Hb dissociation curve which shift facilitates O2 delivery to the tissues?
Right shift.
On a oxygen-Hb dissociation curve which shift facilitates O2 binding to haemoglobin?
Left shift.
Would an increased tissue metabolism be associated with an increase or decrease in pH?
Decrease.
Would an increased tissue metabolism be associated with an increase or decrease in temperature?
Increase.
Would an increased tissue metabolism be associated with an increase or decrease in PCO2?
Increase.
What sensory mechanisms exist in the body to monitor blood gases?
Chemoreceptors.
Where are the peripheral chemoreceptors located?
- carotid (arotid sinus).
- aortic (aortic arch) bodies.
Where are the central chemoreceptors located?
In the medulla of the brain, close to the respiratory centres.
What specific chemicals do the peripheral chemoreceptors monitor?
H+, CO2 and O2.
What body fluid are the peripheral chemoreceptors bathed by?
Arterial blood.
What specific chemicals do the central chemoreceptors monitor?
H+ derived from blood CO2.
What body fluid are the central chemoreceptors bathed by?
CSF.
Why are central chemoreceptors so sensitive to blood PCO2 levels?
CSF contains no buffers to contain any change in pH. As soon as CO2 diffuses into the CSF, it is quickly converted to H+ and stimulates the chemoreceptors.
Why are peripheral chemoreceptors not very sensitive to PO2 levels?
They are monitoring arterial blood which normally has a PO2>98mmHg.
When do peripheral chemoreceptors respond to changing PO2 levels to stimulate respiration?
When the PO2 falls below 60mm Hg, they stimulate the respiratory centres to increase respiration rate; this is called hypoxic drive.
