1.2 The Respiratory System Flashcards
Put simply, what is the function of respiration?
To intake oxygen and remove carbon dioxide.
Describe the passage of air from the atmosphere into the lungs.
Nose; Larynx; Trachea; Bronchi; Bronchioles; Alveoli.
What process is responsible for the exchange of gases between the blood and the alveoli?
Diffusion.
What is diffusion?
The movement of gas molecules from an area of high partial pressure (high concentration) to an area of low partial pressure (low concentration).
How is the structure of alveoli adapted for gaseous exchange?
Very thin cell walls (one cell thick);
Dense capillary network;
Large surface area (:volume ratio).
What is gaseous exchange?
The movement of oxygen from the air to the blood and carbon dioxide from the blood into the air.
There is a space between the two lungs in diagrams, what occupies this space?
The heart.
During inhalation, what is the pressure of air in the lungs relative to the pressure of the atmosphere?
Pressure is lesser than external air, meaning air rushes into the lungs due to the concentration gradient.
During exhalation, what is the pressure of air in the lungs relative to the pressure of the atmosphere?
Pressure is greater than external air, meaning air rushes out of the lungs due to the concentration gradient.
What effect will increasing the thoracic cavity have on concentration of air in the lungs?
Decreased pressure.
What effect will decreasing the thoracic cavity have on concentration of air in the lungs?
Increased pressure.
What is tidal volume?
The volume of air breathed in or out per breath.
What is inspiratory reserve volume?
The volume of air that can be forcibly breathed in after a normal breath.
What is expiratory reserve volume?
The volume of air that can be forcibly breathed out after a normal breath.
What does ERV mean? (lung volumes)
Expiratory reserve volume.
What does IRV mean? (lung volumes)
Inspiratory reserve volume.
What is residual volume?
The amount of air that remains in the lungs after maximal expiration.
What is minute ventilation?
The volume of air inspired or expired per minute.
What is the calculation for minute ventilation?
Number of breaths per minute x tidal volume.
Approximately how many breaths are taken per minute?
Approximately 12 at rest.
When could the residual volume of the lungs be depleted?
If the lungs were punctured or had some sort of hole to let the air out of.
What would happen to the lungs if the residual volume was lost?
The lungs would collapse and stick together, which means breathing would not be possible.
What happens to the tidal volume during exercise?
Increases.
What happens to the IRV during exercise?
Decreases.
What happens to the ERV during exercise?
Slightly decreases.
What happens to the residual volume during exercise?
Stays constant.
What happens to the minute volume during exercise?
Massive increase.
What is a spirometer?
A device that is used to measure the volume of air inspired and expired by the lungs per breath.
What is a spirometer trace?
The results produced by a spirometer that has measured breathing volumes.
Why does minute ventilation increase during heavy exercise?
To meet the increased demand for oxygen.
What is the partial pressure of a gas?
The pressure exerted by an individual gas when it exists withing a mixture of gases.
What does pO2 stand for?
Partial pressure of oxygen.
What percentage of environmental air (inspired air) does oxygen make up?
21%
What percentage of environmental air (inspired air) does carbon dioxide make up?
0.03%
What percentage of environmental air (inspired air) does nitrogen make up?
79%
When will oxygen stop diffusing from the alveoli to the blood?
When the partial pressure is equal in the two.
What is the diffusion pathway of oxygen?
Alveoli;
Blood;
Muscles.
What is the diffusion pathway of carbon dioxide?
Muscles;
Blood;
Alveoli.
Before pressure is equalised, which has a higher partial pressure of carbon dioxide, the blood in the alveolar capillaries or the alveoli?
The blood in the alveolar capillaries as carbon dioxide goes from blood to the alveoli.
What happens to the percentage of oxygen in the air when it is expired compared to when it was inspired?
The concentration decreases as oxygen is diffused into the blood.
What happens to the percentage of carbon dioxide in the air when it is expired compared to when it was inspired?
The concentration
What happens to the percentage of nitrogen in the air when it is expired compared to when it was inspired?
The concentration stays pretty much constant (may increase by less than 1%).
What is the unit measurement for partial pressure?
mmHg - millimetres of mercury.
What are the three factors involved in the regulation of pulmonary ventilation during exercise?
Neural control;
Chemical control;
Hormonal control.
What is meant by the term pulmonary ventilation?
Breathing
What does pCO2 stand for?
The partial pressure of carbon dioxide.
What is neural control?
The brain and nervous system.
What is chemical control?
The acidity of the blood.
How do the neural and chemical controls work together to control pulmonary ventilation?
When blood acidity is high, the brain is informed and it sends impulses through the nervous system to increase breathing.
Which hormone increases breathing rate?
Adrenaline.
What is the passage of neural and chemical control for inspiration?
Receptors;
Medulla oblongarta;
Phrenic nerve;
Diaphragm and external intercostals.
What is the passage of neural and chemical control for expiration?
Receptors;
Medulla oblongarta;
Intercostal nerve;
Abdominals and internal intercostals.
The brain sends impulses to which gland to release adrenaline?
The renal gland.
What are stretch receptors?
They prevent over-inflation of the lungs by sending impulses to the expiratory centre.
What are cilia?
Microscopic hair-like projections that help to sweep away fluids and particles in the respiratory system.
What effects can smoking have on the respiratory system?
- Irritation of the trachea and bronchi;
- Swelling and narrowing of the lungs’ airways;
- Damages cilia, which pushes mucus out the lungs;
- Break down alveoli walls;
- Increases risk of COPD;
- Reduces haemoglobin affinity.
Smoking can lead to COPD, what is this?
Chronic Obstructive Pulmonary Disease - such as emphysema.
What affect does the sympathetic nervous system have on breathing rate?
Increases to prepare for exercise.
T/F - expiration is a passive process.
True.
During inspiration, what happens to the diaphragm and intercostal muscles?
They contract and the diaphragm flattens.
During inspiration, what happens to the ribs?
They are pulled upwards and outwards.
During inspiration, what happens to the volume of the thoracic cavity?
The volume increases.
During inspiration, what happens to the pressure of air within the lungs?
Pressure decreases.
During expiration, what happens to the diaphragm and intercostal muscles?
They relax.
During expiration, what happens to the volume of the thoracic cavity?
The volume decreases.
During expiration, what happens to the ribs?
They are pulled inwards and down.
During expiration, what happens to the pressure of air within the lungs?
The pressure increases.
During inspiration, what happens as a result of air pressure changing?
Air is sucked in.
During expiration, what happens as a result of air pressure changing?
Air is breathed out.
During exercise what happens to the depth and rate of breathing?
Breathing rate and depth increases.
What does the sternocleidomastoid do during inspiration?
It raises the sternum to increase the thoracic cavity.
What do the scalenes and pectoralis minor do during inspiration?
Lift the ribs further to increase the thoracic cavity further.
What is the function of the abdominals in expiration?
They contract, pushing the diaphragm up reducing the thoracic cavity further to push air out.
What do the external intercostals do during expiration?
They pull the ribcage inwards and downwards which reduces the size of the thoracic cavity.
When is expiration a passive process and when is it an active process?
Passive at rest and active during exercise.
Which lung volume is represented by the equation:
IRV + TV + ERV?
Vital capacity.
What is the vital capacity?
The maximal volume of air that can be forcibly expired after maximal inspiration.
Calculation for vital capacity?
(VC =) IRV + TV + ERV
What is total lung capacity?
The volume of air in the lungs following a maximal inspiration.
State the calculation for minute ventilation?
(VE =) Tidal Volume x breathing rate
TV x f
Why does minute ventilation increase dramatically when exercise begins?
To meet the oxygen demand of the working muscles and the need to remove carbon dioxide.
Define oxyhaemoglobin.
A combination of oxygen binded haemoglobin.
What is excess post-exercise oxygen consumption?
The increased volume of oxygen consumed following exercise.
When during breathing does the diaphragm contract and when does it relax?
The diaphragm contracts during inhalation and relaxes during exhalation.
What shape is formed when the diaphragm contracts?
It changes from a dome shape to a flatter shape.
What is the name for the windpipe?
Trachea.
After going through the trachea, where does air go?
Into one of the bronchi and then bronchioles after.
What is nicotine?
An addictive stimulant found in cigarettes.
What is the main proctetor of the lungs?
The rib cage.
A pleura surrounds each lung, what is this and what is the function of it?
It is a double layer membrane containing lubricating pleural fluid in order to reduce friction.
Which muscle seperates the lungs from the abdominals?
The diaphragm.
Which lung is the largest?
The right lung is slightly larger, it has 3 ‘lobes’ as opposed to 2 on the left.
How is O2 carried in the blood?
- 97% within the haemoglobin of red blood cells.
- 3% in the blood plasma.
How is CO2 carried in the blood?
- 70% as carbonic acid.
- 20% as carbaminohaemoglobin.
- 7% in the blood plasma.
What long term effect does long-term training have on lung volume?
Training has a very slight effect on volumes.
What will long-term training increase the strength of?
Strengthens the intercostals and diaphragm due to increased respiratory muscle performance.
What effect can aerobic training have on alveoli?
Training can increase the surface area of the alveoli thus increasing gaseous exchange.
What is nicotine?
Nicotine is an addictive substance found in cigarettes.
Nicotine can cause bronchoconstriction, what is this?
The narrowing of the bronchi and airways in the lungs due to the tightening of the surrounding smooth muscle tissue.
How does nicotine effect gaseous exchange?
Nicotine can cause bronchoconstriction, this means that less air can reach the alveoli, thus reducing gaseous exchange.
Cigarette smoke contains carbon monoxide, what effect does this have on gaseous exchange?
CO binds irreversibly with haemoglobin in RBC’s more readily than oxygen does, this stops the formation of oxyhaemoglobin, reducing the O2 carrying capacity of the blood.
What is CO and where is it found commonly?
Carbon Monoxide found commonly in cigarette smoke.
If a molecule of haemoglobin has two carbon monoxide molecules binded to it, what has happened to the carrying capacity of oxygen?
It has halved as 2 of the 4 carrying sites of the haemoglobin have been taken by carbon monoxide.
What effect does cigarette smoke have on alveoli walls?
The toxins in the smoke break down the thin alveoli walls which means they cannot ‘inflate’ fully as they have lost their elasticity.
What can cause alveoli to fuse together?
Cigarette smoke.
Cigarette smoke can cause irritation of the trachea and bronchi, what can this lead to?
Breathlessness and emphysema / COPD.
Where are cilia found and what is their function?
Cilia line the airways in the lungs, their function is to ‘filter’ the air entering the lungs by removing dirt and dust and excreting mucus from hte lungs.
What causes smoker’s cough?
When the cilia become damaged and cannot remove mucus effectively so it has to be coughed out.
Smoking can lead to the killing of cilia cells, what does this lead the lungs more exposed to?
Lung infections caused by bacteria in the air.
Tar a toxin found in cigarettes, what effect does tar have on the body?
Tar destroys cilia.
What is haemoglobin?
Haemoglobin is the red pigment that is present in red blood cells, it has a very high affinity for oxygen as it acts as the carrier in the body.
What is formed when Oxygen combines with Haemoglobin?
Oxygen + Haemoglobin = Oxyhaemoglobin.
What forms when Carbon Dioxide combines with Haemoglobin?
Carbon Dioxide + Haemoglobin= Carbaminohaemoglobin.
