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