Respiratory System Flashcards
What are the 3 functions of the respiratory system?
1) Provides the body with O2.
2) Excretory organ - CO2, heat, water, alcohol and ketones
3) Maintains the pH of body fluids.
Describe the gross anatomy of the right lung
It is wider and shorter than the left lung (because it sits on top of the liver)
Describe the gross anatomy of the left lung
It is taller and narrower than the right lung (because more of the heart sits behind the left lung)
What are the 3 different lobes of the right lung?
1) Superior
2) Middle
3) Inferior
What are the different fissures that separate the lobes of the right lung?
Horizontal - separates the superior and the middle
Oblique - separates the inferior from the other 2 lobes
What is the fissure called that separates the lobes of the left lung?
Oblique
How to describe the membranes surrounding the lungs?
Double plural membrane
What are the names of the plural membranes surrounding the lungs and what is contained between them?
Visceral pleura (surrounding lungs) and parietal pleura. In-between the 2 layers = plural fluid
3 important roles of the double plural membranes surrounding the lungs?
1) Resist friction between the lungs and the surrounding structures when breathing in and out
2) Creates a pressure gradient which assists ventilation.
3) Isolates the 2 lungs - so infection in one doesn’t cause infection in the other
What are the 3 components of the upper respiratory tract?
1) Nasal cavity
2) Pharynx
3) Larynx
What are the 3 components of the lower respiratory tract?
1) Trachea
2) Bronchus
3) Right and Left Lung
What is meant by the conducting zone of the respiratory tract and what are its components?
The parts of the LOWER respiratory tract that are responsible for getting air to the respiratory zones
1) Trachea
2) Left and right primary bronchus, secondary bronchus, tertiary bronchus, bronchioles, terminal bronchioles
What is meant by the respiratory zone of the respiratory tract and what are its components?
The parts of the LOWER respiratory tract that are responsible for gas exchange.
1) Respiratory bronchioles
2) Alveolar sacs
What are the 3 functions of the nasal cavity?
1) Warm and cleanse the air (nose hairs will filter and add moisture to the air)
2) To detect odours
3) Modifies the sound of our voice.
What are the names of the 2 mucus membranes in the nasal cavity?
1) Olfactory mucosa
2) Respiratory mucosa
What 3 things are beneath the respiratory mucosa?
1) Goblet cells
2) Mucus glands
3) Cirus glands (secrete a water fluid that contains lysosomes)
What are conchae and what is the importance of them?
(superior, middle and inferior conchae)
Conchae are folds of tissue in the nasal cavity.
1) Allow for the turbulent flow of air
2) The blood flowing through the conchae allow for the air to warm up
3) The mucus membranes surrounding the conchae allow for the air to be humidified.
What are meati?
(superior, middle and inferior meati)
The channels inbetween the conchae.
What are the air sinuses and what is their function?
Air sinuses are holes in the skill and they secrete mucus.
Where is the pharynx located?
Continuous with the nasal cavity and extends down to the larynx
What is the role of the pharynx?
1) Passageway for air and food
2) Mucus that moves down the pharynx warms and humidifies the air
3) Modifies the sound of your voice.
What are the 3 sections of the pharynx and what does it convey?
1) Nasopharynx (air)
2) Oropharynx (food and air)
3) Laryngopharynx (food and air)
What does the larynx connect?
The larynx connects the laryngopharynx to the trachea.
What is the larynx made of and their importance?
Rings of cartilage, in order to maintain an open airway
What are the 3 components of the larynx?
1) Epiglottis
2) Thyroid cartlidage
3) Trachea
How does the larynx help us swallow and what is the importance of this?
1) The larynx pushes up
2) The epiglottis moves down to cover the larynx
This is so food enters the oesophagus and not the trachea
How does the larynx help the cough reflex?
1) The larynx pushes down and builds up pressure behind it.
2) Air moves into the pharynx
What is the larynx also described as and why?
‘Voice box’ - because different tensions the larynx creates modifies they way we speak
What is the trachea made of and their importance?
‘C- shaped cartilage’ - with smooth muscle in-front of the oesophagus, in order to expand to allow food to get through
How to describe the epithelial cells lining the trachea?
Pseudo-stratified columner epithelium
Where does the cilia transport the mucus in the upper respiratory tract and lower respiratory tract (and what is the importance of this)?
Upper respiratory tract - Down towards the pharynx
Lower respiratory tract - Up towards the pharynx
This is so the mucus can be swallowed and enter the oesophagus
What are the components of the bronchial tree?
1) Trachea
2) Left and Right Primary bronchus
3) Left (2) and Right (3) Secondary bronchus
4) Tertiary bronchus
5) Bronchioles
6) Terminal Bronchioles
7) Respiratory Bronchioles
How does the cartilage change as you go down the bronchial tree?
Rings of cartlidage, starts to become platelets at the secondary bronchus and at the bronchioles and further there is no cartlidge
What is the most sensitive part of the respiratory tract?
Carina (the end of the trachea, just before it splits into the right and left primary bronchus
How do the epithelial cells change as you move down the bronchial tree?
1) Trachea - pseudostratified columner cells
2) Primary Bronchus - pseudostratified columner cells
3) Secondary Bronchus - non- pseudostratified and pseudostratified columner cells
4) Tertiary Bronchus - simple columner cells
5) Bronchioles - simple columner
6) Terminal bronchiole - simple columner
7) Respiratory bronchiole - cuboidal
8) Alveoli - squamous
Where does gas exchange take place?
The capillary network surrounding the alveoli
Describe the blood flow to and from the capillary network surrounding the alveoli?
Pulmonary arteriole - brings deoxygenated blood from the heart to the lungs
Pulmonary venule - takes oxygenated blood from the lungs to the heart
What are the 2 types of alveolar cells and their function?
Type 1 - squamous epithelial cells (O2 diffuses through, basement membrane, capillary endothelium, erythrocytes)
Type 2 - septal cells (secretes serfactant which coats the inside of the alveoli and is important for the lungs to inflate)
Def. of pulmonary ventilation:
The exchange of air between the atmosphere and the alveoli in the lungs.
What is the difference between quiet ventilation and forced ventliation?
Quiet - at rest
Forced - when exercising
What are the 2 muscles that are involved in quiet ventilation?
1) External inter-coastal muscles
2) Diaphragm
What happens during quiet inspiration?
(active process)
1) External inter-coastal muscles contract and expand outwards - pushing the ribcage up and outwards
2) Diaphragm contacts and flattens out
3) The volume in the thoracic cavity increases and intra pulmonary pressure decreases lower than atmospheric pressure
4) Air is forced into the lungs (down the pressure gradient)
What happens during quiet expiration?
(passive process)
1) External inter-coastal muscles relax and pull inwards - pulling the ribcage in and downwards
2) Diaphragm relaxes and becomes domed shaped
3) The volume in the thoracic cavity decreases and the intrapulmonary pressure increases higher than atmospheric pressure.
4) Air is forced out of the lungs (down the pressure gradient) UNTIL INTRAPULMONARY PRESSURE = 0.
What muscles assist in forced ventilation?
Accessory muscles which assist the external intercoastal muscles
Which 4 muscles assist the external inter-coastal muscles in in forced inspiration?
(active process)
1) Scalenes (3 pairs of muscles in the neck, attached to the 1st and 2nd ribs)
2) Sternocleidomastoid (attaches to the sternum and the mastoid muscle in the neck)
3) Pectoralis minor
4) Pectoralis major - fan shaped muscles
What 4 muscles assist the external inter-costal muscles in forced expiration?
(active process)
1) Internal intercostal muscles (form a cross behind the external intercostal muscles)
2) Oblique muscles (attach the 8 lower ribs to the pelvic gurdle)
3) Rectus abdominis muscles (attach the xiphisternum to the pelvic gurdle)
4) Quadratus Luborum (connects the pelvic gurdle to the spine)
Atmospheric pressure
The pressure created by the air and gases surrounding the body
What is the atmospheric pressure at sea level?
760 mm/Hg
What is intraplural pressure (Pip)?
The pressure inside the 2 plural membranes surrounding the lungs (visceral pleura and parietal pleura)
What causes negative intraplural pressure?
1) When the parietal pleura is pulled outwards during inspiration when the lungs expand outwards
2) When the visceral pleura is pulled inwards during expiration when the lungs recoil
What is the importance of intraplural pressure?
Important so the lungs do not collapse
What is intrapulmonary pressure?
Pressure inside the lungs
How much lower in intraplural pressure than intrapulmonary pressure?
4 mm/Hg lower.
Boyle’s law:
The pressure of a gas will vary due to it’s volume (as long as the temperature remains constant)
What is lung compliance?
A measure of how easily the lungs can expand due to intrapulmonary pressure differences.
What 4 things reduce lung compliance?
1) Scar tissue (as elastic fibres are replaced with collagen fibres that are less able to expand)
2) If individuals have muscle issues
3) Blockages in the airways
4) Low level of surfactant (secreted by the type 2 (septal) alveolar cells - that is important for the lungs being able to inflate)
Who may have low levels of surfactant?
Premature babies - because serfactant is produced in late pregnancy. Premature babies lungs may collapse
What happens to the alveoli during pneumonia?
The alveolar walls thicken causing gas exchange to reduce
What happens to the alveoli during emphysema?
The networks in the alveoli are destroyed causing:
1) A reduction to the surface area
2) Air filled spaces - which can retain air but able less able to get rid of the air during expiration
What does the lung surfactant contain?
1) Phospholipids
2) Lipids
3) Proteins
What is the main phospholipid in serfactant?
DPPC
Why does serfactant contain a high amount of phospholipids instead of water?
Water would create surface tension and encourage the alveoli to collapse whereas the phospholipids dispell the surface tension, enabling the alveoli to inflate.
What causes the restriction of airflow during an asthma attack?
The smooth muscles of the bronchioles contract, causing the bronchioles diameter to decrease and airflow in and out is restricted
What 3 instruments can you use to access lung function?
1) Stephoscope
2) Peak Flow Meter
3) Spirometer
What does the stephoscope measure?
Chest sounds
What 2 chest sounds show that there is a problem and what is the problem?
1) Bubble wrap popping - shows there is fluid in the lungs
2) No chest sounds - the lungs have collapsed
What does a peak flow meter measure?
1) Measures the speed in which an individual is able to breath out
2) Measures the amount of litres of air breathed out per MINUTE.
What is the average amount of litres a person should be able to breath out per minute?
400-500L per minute
What kind of patients will use a peak flow meter?
Asthma patients will use it everyday to see if their treatment is effective
What instructions are given to patients in order to use a peak flow meter or a spirometer?
Breath out as fast and as hard as possible
What is a spirogram recorded with?
Spirmometer
What is the inspiratory reserve volume?
How much extra air can be breathed in (per 1 breath)
What is expiratory reserve volume?
How much extra air can be breathed out (per 1 breath)
What is the tidal volume?
How much air can be breathed in and out (per 1 breath) at rest
What is residual volume?
Any air that is left in the lungs after breathing out
What is the vital capacity and how to find it out?
(Inspiratory reserve volume + expiratory reserve volume) Measure the MAXIMUM amount of air that can be breathed in and out per 1 breath
How to find out the inspiratory capacity?
Inspiratory reserve volume + tidal volume
How to find out the functional residual capacity?
Expiratory reserve volume + residual volume
What is the equation for working out the Forced Expiratory Volume per 1 second (FEV1) as a percentage of the FVC?
FEV1 / FVC x 100
What is a healthy and unhealthy percentage for FEV1 (out of the FVC)?
Healthy = above 70% Unhealthy = below 70%
What are the 2 classes of respiratory disorders and examples?
1) Destructive disorders = preventing airflow in and out of lungs (e.g. asthma)
2) Restrictive disorders = preventing the lungs from inflating (e.g neuromuscular problems)
What is Partial Pressure (pp)?
The total pressure exerted by a mixture of gases = the sum of pressure exerted by each gas within the mixture (this pressure will be directly proportional to the percentage that the gas takes up out of the whole mixture)
What is the atmospheric pressure at sea level and at 10,000 ft?
Sea level - 760 mm/Hg
10,000 ft - 523 mm/Hg
How do you work out the pp of each gas in the mixture of gases?
Divide the percentage of that gas by 100 and then multiply it by the pp of the mixture of gases
What is the percentage of nitrogen in atmospheric pressure (sea level) and in alveoli?
Atmospheric - 78.6
Alveoli - 74.9
What is the percentage of oxygen in atmospheric pressure (sea level) and in alveoli?
Atmospheric - 20.9
Alveoli - 13.7
What is the percentage of carbon dioxide in atmospheric pressure (sea level) and in alveoli?
Atmospheric - 0.04
Alveoli - 5.2
What is the percentage of water in atmospheric pressure (sea level) and in alveoli?
Atmospheric - 0.46
Alveoli - 6.2
Which 2 gases will increase in percentage from atmospheric pressure (sea level) to alveoli?
1) Carbon dioxide
2) Water
Describe the components of the respiratory membrane?
1) Type 1 alveoli cells (squamous epithelium)
2) 2 fused basement membranes
3) Capillary endothelium
How does the solubility of gases and the partial pressure of each gas aid diffusion across the respiratory membrane?
The more the gas is able to dissolve in the surfactant (fluid surrounding the alveoli) and the higher its % in atmospheric partial pressure - the more of the gas will be able to be diffused across the respiratory membrane and into the blood.
Describe the solubility of each gas in water (most soluble to least soluble)?
CO2, O2, N2
Why are equal amounts of Co2 and O2 exchanged across the respiratory membrane?
So even though CO2 is more soluble in water, O2 takes up a higher of the atmospheric pp than CO2 does.
What are the steps of pulmonary circulation?
1) Deoxygenated blood is bought to the lungs via the pulmonary artery from the right side of the heart.
2) Gases will diffuse across the pulmonary membrane across their pressure/concentration gradients.
3) Oxygenated blood is transported via the pulmonary vein to the left side of the heart.
How is O2 transported in the blood and what is the benefit of this?
98.5% - haemoglobin
1.5% - plasma
(benefit - O2 is poorly soluble in plasma)
What instrument is used to measure how saturated the haemoglobin are with O2?
Pulseoximeter (on finger)
Out of the total percentage of oxygen bound to haemoglobin, how much unloads to systemic tissue and how much is left to be returned to the heart?
Unloaded to systemic tissues = 25%
Left bound to haemoglobin to be returned to the heart = 75%
What 2 factors cause the oxygen dissociation curve to be sigmoidal shaped?
1) Co-operative binding = as one molecule of O2 bings to haemoglobin, causes other molecules to bind until 4 molecules have binded.
2) The higher the partial pressure of oxygen, the higher the affinity for oxygen, the more easily it binds to haemoglobin
What factors cause the oxygen dissociation curve to shift to the left?
left = LOW factors but HIGH AFFINITY
1) low temperature
2) low H+ (more acidic e.g. when exercising)
3) low 2-3 DPG
4) low CO2
What factors cause the oxygen dissociation curve to shift to the right?
left = HIGH factors but LOW AFFINITY
1) high temperature
2) high H+ (more alkaline)
3) high 2-3 DPG
4) high CO2
What is 2-3 DPG?
Produced by the erythrocytes during glycolysis
Describe the foetal oxygen dissociation curve?
Shifted to the left as the structure of the haemoglobin causes it to have a higher affinity for oxygen.
How is Co2 transported in the blood?
1) 7% dissolves in plasma
2) 93% diffuses into red blood cells =
3) 23% binds to haemoglobin (carbamino-haemoglobin)
4) 70% is converted to carbonic acid by carbonic anhydrase by adding water.
(Co2 + water - carbonic acid - hydrogen + bicarbonate ions)
5) Carbonic acid is an unstable compound and will readily dissociate into hydrogen and bicarbonate ions.
6) The hydrogen ions are removed by buffers (especially haemoglobin)
7) The bicarbonate ions are removed from the red blood cell in exchange for chloride ions (chloride shift)
How does the carbonic acid equation maintain the acid base balance?
If the pH is low (high amount of hydrogen ions) the equation can move to the left = Carbonic acid can convert to water and co2.
If the pH is high (low amount of hydrogen ions) the equation can shift to the right = Carbonic acid can dissociate into H+ and bicarbonate ions.
What is respiratory acidosis?
A condition whereby the lungs can’t remove all of the CO2 produced by the body tissues, the more CO2 remains in the blood, more H+ ions can be produced, lower pH, more acidic.
What is respiratory alkalosis?
A condition whereby the lungs expell too much CO2, less CO2 in the blood, less H+ ions, high pH, more alkaline.
When does respiratory alkalosis occur?
During hyperventilation - as the exchange of CO2 occurs too fast and too much is lost
How does the body ensure that our breathing is controlled smoothly?
The respiratory control centres (in the pons and medulla). They is no specific area - rather a collection of neurones.
What are the 2 respiratory control centres?
1) Pontine respiratory centre
2) Medulla respiratory centre
Describe how the 2 respiratory control centres work to ensure breathing is smooth?
1) The pontine respiratory centre sends information to the medulla respiratory centre.
2) This will modify the information output from the medulla respiratory centre.
3) Medulla respiratory centres:
VRG (ventral respiratory group) = control the accessory muscles which assist the external intercostal muscles during forced ventilation
DRG (Dorsal respiratory group) = activate the diaphragm
Why is the maintenance of the acid-base balance so important?
Large fluctuations in Co2 will result in large fluctuations in the pH. Enzymes will function best at a certain pH. So, fluctuations in pH will result in the fluctuation of enzyme activity.
Peripheral chemo-receptors location, role and % of mediating the body’s response to changes in blood CO2 level?
Location: Aortic arch and carotid sinus
Role: To detect changes in O2, CO2 and H+ in the blood and send information to the medulla respiratory centre
% = 20%
Central chemo-receptors location, role and % of mediating the body’s response to changes in blood CO2 level?
Location: Surface of medulla
Role: To detect the pH in the CSF (cerebalspinal fluid) and send information to the medulla respiratory centre
% = 70%
What happens when the chemo-receptors detect high CO2 (more H+) and send it to the respiratory centres in the medulla?
1) Peripheral receptors detect high H+ in the blood and send signals to medulla RC.
2) Central receptors detect low pH and send signals to medulla RC.
3) Medulla RC:
VRC = send signals to the accessory muscles in order for forced expiration (so CO2 can be removed)
DRC = sends signals to the diaphragm to relax (domed shaped and decreases the thoracic cavity volume so CO2 is forced out)
What is the name given to when CO2 is found in excessive amounts in the blood?
Hypercapnia
What is the name given to when O2 is found in low amounts in the blood?
Hypoxia
What is the stimulus for the chemoreceptors, in COPD patients, to send info to the medulla respiratory centres when CO2 levels in the blood is high?
Their chemoreceptors will have adapted to a high amount of CO2 in the blood and CSF. Therefore, high CO2 will no longer be the stimulus that causes the chemoreceptors to send information to the medulla respiratory centre. Instead, the hypoxic drive (low amount of O2 detected by the chemoreceptors) is the stimulus.
What do nurses have to take caution with when giving patients with COPD oxygen masks?
Not too give too much O2 for the hypoxia to disappear, otherwise there is no hypoxic drive that stimulates the chemoreceptors to send information to the medulla respiratory centre. Then, the MRC would not be able to stimulate forced expiration in order to remove the CO2.
What is the problem with having too much oxygen in the blood (i.e from breathing in highly O2 concentrated air)?
Too much O2 can generate free radicals (highly toxic O2 molecules) which can lead to death or coma
