Respiratory System component 14 Flashcards
What are the requirements to breathe?
- An open airway (tongue can be most common obstruction but you can’t swallow it)
- effective muscles of respiration e.g diaphragm, intercostal muscles (in between ribs)
- A non toxic atmosphere e.g of a toxic atmosphere would be carbon monoxide
- Stable chest wall
- Ability of the lungs to expand and contract
- Free passage of gas between the alveoli and blood
- Good circulation (do compressions before respiration’s in CPR)
Composition of Inspired v expired air %
Nitrogen - 78% vs 78%
Oxygen - 21% vs 16% (decreases as used for cell respiration)
Co2 - 0.04 vs 4%
Water vapour - variable (depends where you are and type of day) vs saturated (can’t hold anymore water vapour than you breathe out)
What are the functions of the respiratory system?
- Extract 02 (02 + glucose = energy and waste)
- Excrete co2
- Maintain acid base (PH of the blood). balance between how much co2 we want to keep and how much we want to get rid of. Too acidic not good and to alkali not good.
- Ventilate the lungs
How does the resp system do its functions
- Pulmonary ventilation - the movement of air in and out the lungs
- External respiration - the movement of 02 from lungs into the bloodstream and co2 from bloodstream into the lungs.
- Internal respiration - the movement of 02 from the bloodstream into the tissues and cells of the body and co2 from the cells and tissues in the bloodstream
Route of air
Air goes into the Nasal cavity > this warms the air up quickly as has lots of blood vessels. The hair filters and stops foreign bodies. The mucus moistens the air as it comes in and helps to expel particles > nasopharynx > soft palate (part of this prevents food going into nose called uvula) > oropharynx > epiglottis (leaf shaped - closes over trachea when you swallow to prevent food going in) > laryngopharynx
How many cartilages does the larynx have and what is the function of the larynx?
9 cartilages
They are: 3 single cartilage - epiglottis, thyroid and cricoid cartilage
And 3 pairs of cartilage - arytenoid, cornice late and cuneiform
larynx is a different shape in children
Larger in males than females
Functions: production of sound, speech, protection, passage for air, filtering and warming. Epiglottis stops food entering larynx.
The trachea…
Extends from the larynx to region of 5th thoracic vertebra where bifurcation takes place
10-11cm in length, 2.5cm in diameter
Cartilaginous C shaped rings, 16-20 in number. Shaped like this as we want it open all the time.
Terminating at the carina
Outer layer - fibrous, elastic tissue, encloses the cartilage
Middle layer - cartilage and bands of smooth muscle (smooth muscle can’t be controlled)
Inner layer - ciliated columnar epithelium with goblet cells.)I
What do goblets cells do?
Secrete/ produce mucus
What are the functions of the trachea
Support\patency
Mucociliary escalator (hairs on lining of trachea will push mucus up to back of throat) if above throat will push it down to swallow)
Cough reflex
Right and left primary bronchus
Right and left primary bronchus
Right is more acute in angle and shorter (2.5cm) resulting in foreign objects more likely to enter right lung.
Left bronchus is longer and narrower.
In children haven’t developed the more acute angle or bigger bronchus.
Bronchial tree
Right and left primary bronchus divide further into
Secondary bronchi
Tertiary bronchi
Bronchioles
Terminal bronchioles
Alveoli (external respiration takes place here approx 300 million covering 70m2)
The lungs
Two, coned shape lungs, with an apex, base, Costal surface and medial surface
Pleural membrane - parietal pleura. Potential space between these. Then visceral pleura. Lung has two layers so that when you breathe in it opens the lungs. But occasionally those two layers get air between and pulls away. This is called a haemothorax.
5 lobes in chest (right lung has 3 and left has 2)
Lobes subdivided into lobules and then into alveoli.
Surfactant stops the alveoli collapsing on themselves. Premature babies don’t have this and so alveoli start to collapse when breathe out and snap shut.
Elastic fibres (if they weren’t there then chest wouldn’t move as much as it should). In emphysema patients have difficulty breathing out as lost elastic fibres)
How much air does diaphragm produce
70%
Where are the lungs found
Thoracic cavity
What is the hilum?
One on each lung. An entry point for…
blood vessels - pulmonary artists and veins The bronchi Lymph vessels Nerves At a level of t5 to t7
What is the pleura?
Double layer of serous membrane which covers the lungs and the inside of the chest wall.
The layer that covers the lungs is called the visceral layer and the layer covering the inside of the chest wall is the parietal layer.
A potential space between the 2 layers is filled with serous fluid which prevents friction. This fluid also assists in the expansion of the chest wall during inspiration.
Allows chest wall to expand and drag lung with it without friction.
What does Elastic tissue do
Allows chest cavity to come back down to normal shape when you breathe in.
Pulmonary artery
We have two as go to left and right lung
Carry deoxygenated blood back to lungs to be oxygenated.
All arteries except this one carry oxygenated blood. This is one exception
pulmonary veins then return the blood To the heart (left atrium) with oxygenated blood.
Bronchial artery
Feeding lung tissue itself
Branch from the aorta
Oxygenated blood to the lungs
Perfuses walls of the bronchi and bronchioles
Returns to right atrium via the pulmonary veins or bronchial veins via the superior vena cava
What is your larynx?
Allows you to talk when air moves in and out
What is tidal volume?
Normal breath - the amount of air that passes in and out the lungs during quiet breathing.
0.5L
What is minute volume?
Can be altered
What are the muscles used in respiration?
Normal breathing - diaphragm and intercostal muscles
Increase times of breathing the accessory muscles are used - scalanes and sternocleidomastoid
Nervous control in respiration
Phrenic nerve C3,4,5 controls diaphragm
The C stands for cervical
Intercostal nerve to control intercostal (T2-T12)
Inspiration
Active, uses energy
Simaltaneous contraction of the intercostal (external) muscles pull the rib cage upwards and outwards.
The diaphragm flattens when contracted and moved down. and both of these increase the size of the thoracic cavity.
As the cavity increases in size, the pressure inside the cavity will drop causing negative pressure and once the pressure in the cavity drops below that of the atmospheric pressure, air is drawn in.
Lasts approx 2 seconds
Physiological variables affecting respiration
Elasticity - loss of elasticity of the connective tissue in the lungs, will bring about an increase in effort to inspire and will necessitate forced expiration
Lung compliancy
High compliancy - means that the lungs and thoracic wall expand easily
Low compliancy - resistant to expansion
What is airway resistance?
Resistance offered to airflow by the respiratory passages especially the bronchi and bronchioles
Any condition/ environment that obstructs the air passageways increases resistance
Breathing rate when you have a fever
Normal rate is increased as trying to increase body temp to fight temp the bug can cope with
Normal breathing rate is increased when
Exercise
Fever
Shock
Some conditions e.g pneumonia
Breathing rate is decreased in…
From certain drugs
Some Conditions that affect the brain e.g head injury
Other Factors that can affect breathing rate…
Body temp Sudden cold stimuli Severe pain Irritation of pharynx or larynx Hering Breuer reflex - stretch receptors (stop you bursting lung from intake of too much breath - send impulse to brain to say breathe out)
What is anatomical dead air space?
The residual volume which remains in the air passages but isn’t involved in alveolar exchange
What is Partial pressure
Each gas will exert is own pressure as a % to the total pressure being provided.
E.g would be written as Po2
Nervous control of respiration… where is your respiratory control centre?
Involuntary.
Happens in In the medulla oblongata in the brain
Inside the MO is the medulla Rhythmicity centre. This tells the body to inspire and breathe in.
Above the medulla oblongata is the pons. This has two parts to it. The pneumotaxic area and the apneustic area. These assist the MRC.
The pneumotaxic area tells you to breathe out or stop breathing in (you then naturally breathe out).
MRA and pneumotaxic set the rhythm.
Voluntary control is exerted during activities such as speaking and singing.
Muscles involved in breathing are…
Diaphragm and intercostal muscles.
Timing of inspiration and expiration
2 seconds breathe in 3 seconds breathe out
Hyperventilation
If we keep inflating the lungs without stopping, like a balloon, the lungs eventually burst, so to prevent this happening the pneumotaxic area will step in to stop inspiration and bring about expiration.
The increase in respiration will occur until normal PC02 and O2 levels are returned to normal
PH of blood
7.4 ph. Slightly alkali. Needs to stay within 0.1 really.
Where are chemoreceptors found and what do they do?
Found centrally in the medulla and in the peripheries within the carotid and aortic bodies. The chemoreceptors are responsible for sending impulses to the brain so corrective action can be taken following changes to the partial pressure of c02 and 02.
What is hypercapnia and hypocapnia?
Hypercapnia - Increases in PC02 levels
Hypocapnia - decreases
What is the bohr effect
Increasing PC02 and H+ decreases oxyhemoglobin saturation.
A decrease in blood PH from 7.4 to 7.3 reduces oxygen saturation by 6%.
The heldane effect - decreasing PC02 and H+ increases oxyhemoglobin saturation
How is oxygen transported in the blood?
Oxygen attaches to haemoglobin as can’t travel in blood as it is.
1.5% of oxygen transported in the blood is dissolved in plasma. The rest 98.5% is carried on the haem portion of the haemoglobin (which consists of 4 atoms of Fe).
Oxygen and haemoglobin combine in an easily reversible reaction to form oxyhemoglobin.
The greater the P02 the more oxygen will combine with haemoglobin until the available haemoglobin molecules are saturated.
How is carbon dioxide transported in the blood?
7% dissolved in the plasma
23% is combined with the globin portion of haemoglobin as carbaminohaemoglobin
70% is carried as bicarbonate ion
Basic assessment
Rate Rhythm - either regular or irregular Volume - if shallow breathing not taking in as much 02 Effort - Efficiency - Effect -
Breathing patterns
Eupnoea - normal breathing
Apnoea - no breathing at all
Vesicular - normal breath sounds
Hypoxia - lack of oxygen in tissues
Tachypnoea - abnormally rapid rate of breathing normally above 20BPM
bradypnoea - abnormally slow rate of breathing (normally resp rate lower than 10 need to intervene)
Cheyne stokes - abnormal pattern of respiration, characterised by alternating periods of apnoea and deep rapid breathing. E.g end of life patients
Kussmauls - abnormally deep and very rapid sighing respiration’s, characterised by diabetic ketoacidosis.
Abnormal (adventitious) breath sounds
Rales - small clicking, bubbling or rattling sounds. Heard on inhalation and are believed to occur when air opens closed air sacs.
Rhonci- snoring sounds. Indicates air is blocked or flow becomes rough through the large airways.
Stridor - wheeze like sound heard when a person breathes. It is usually due to a blockage of air flow in the trachea or back of the throat.
Wheezing - high pitched sounds produced by narrowed airways. Most often heard upon exhalation
Rubs - pleural rubs are discontinuous or continuous, creaking or grafting sounds. Similar to walking on fresh snow. Produced because two inflamed surfaces are sliding by one another, such as in pleurisy.
Just because a person is breathing, doesn’t mean…
There is adequate ventilation
What are the functions of the nasal cavity?
Smell
Warm the air breathed in, filter it and moisten it.
How long is the pharynx and where is it found?
12-14cm long
Found posterior to the nasal cavity
Lies immediately in front of the cervical vertebrae
Divided into - nasopharynx, oropharynx and laryngopharynx
How long is the trachea and what is its diameter?
10-11cm in length
2.5cm in diameter
Larynx and trachea order of cartilage…
- Hyoid bone
- Thyroid cartilage
- Cricoid cartilage
- Tracheal cartilages
What is the top of the lung called and where does it lie?
Apex and lies 1” above the claricle
What happens in expiration?
Relaxation of the intercostal muscles allows the rib cage to move down and in. relaxation of the diaphragm and it moves up makes the size of the thoracic cavity smaller.
As the cavity decreases in size, the pressure within the cavity increases resulting in positive pressure and once the pressure increases beyond atmospheric pressure, air is forced out.
What is anatomical dead air space?
The residual volume, which remains in the air passages but isn’t involved in alveolar exchange. 150mls
What is inspiration reserve volume?
The extra amount of air that can be inhaled into the lungs during maximal inspiration. 3100mls
What is inspiration capacity?
The maximum amount of air that can be inspired, this is tidal volume + respiratory reserve volume. 3600mls
What is functional residual volume?
The amount of air remaining in the air passages and alveoli at the end of quiet respiration.
The functional residual volume helps prevent the alveoli collapsing upon expiration.
2400mls
What is the expiratory reserve volume?
The largest amount of air that can be
expired during maximal expiration = 1200mls
What is residual volume?
Amount of air left in the lungs following forced
expiration = 1200mls
What is the vital capacity?
Maximum volume of air which can be moved into and
out of the lungs = 4800mls
Nervous control of respiration…
The Respiratory centre is located within the
Medulla Oblongata, which lies in the brain
stem.
• The respiratory centre in the medulla sets the
basic timing of inspiration and expiration.
• Motor impulses leave the respiratory centre
via the Phrenic nerves (diaphragm) and intercostal nerves (intercostal muscles).
- When changes to the timings of inspiration and expiration are required the apneustic and pneumotaxic areas within the Pons (also found within the
brain stem) are activated and they will influence the
respiratory centre in the medulla.
What does the apneustic area do?
The apneustic area (in the pons) will become stimulated when levels of PCO2 increase or PO2 levels decrease. This occurs because the body identifies an increase in acidity within the blood and therefore attempts to reverse this by increasing the depth of respiration. The inspiration time is therefore prolonged beyond the 2 seconds we normally associate with quiet normal breathing.
Respiratory buffer system:
Increase CO2 causes increased Hydrogen Ion concentration
• Decrease CO2 causes decreased Hydrogen Ion concentration.
What is the cerbral cortex and what does it do?
connects to the respiratory centre and allows
voluntary alteration of breathing patterns. e.g. the ability to stop breathing until CO2 (hydrogen ion) builds up in blood.
Impulses from the hypothalamus and limbic system stimulates the
respiratory centre and permits emotional stimuli to alter breathingwhich includes crying, laughing and sobbing
What is daltons law?
Each gas in a mixture of gases exerts it’s own
pressure as if the others were not present”
What is boyles law?
The pressure of a gas in a closed container is inversely
proportional to the volume of the container.
What are the respiratory rates?
Adult - 12-20 5 - 11years : 20-25 2-5years: 25-30 1-2years: 25-35 0-12months:30-40
