(Recap/chemoreceptors/Anatomy) Flashcards
What does the FEF 25-75 measure?
What is another term for the FEF 25-75?
- Looking at the rate of airflow when the middle half of the VC is being expired
Forced Mid expiratory Flow
What would the FEF test show if there was an airway obstruction?
Prolonged 25-75 = lower number which signifies a worse test result
Acceptable FEF 25-75 reading for an asthma patient?
500-1000 mls/sec
Whats the purpose using the FEF test compared to the FEV1/FVC Ratio test?
- Thought to be a more sensitive test than FEV1/FVC for medium and small airway obstruction inside the chest
- Not as sensitive as the Closing volume/capacity tests which are the most sensitive
If there was less inward recoil by the lungs, the chest wall could…?
the chest wall could pull out further than normal = leads to higher lung volumes and a more positive Pleural pressure
When laying supine, do we have higher/lower lung volumes and higher/lower chest recoil?
Why?
We have lower lung volumes and lower chest recoil. The tissue above the chest wall is pushing down, opposing chest recoil outwards.
Higher BMI = Less chest recoil
Which set of muscles resting tone contribute to outward chest recoil?
Adding paralytics will cause what to happen?
Intercostal Muscles
Adding paralytics decreases their tone = decreases lung volume
Where does the majority of the control in rate and depth of breathing take place?
Brain Stem/Medulla
What is the physiology behind SIDS per lecture?
-Parts of the brainstem haven’t fully developed yet = run into Blood gas problems
If brainstem takes longer to develop and they don’t have as good of a sleeping respiratory control system they may not be able to adjust and counteract the problem
The Brain stem is looking at these 3 compounds in the CSF:
Which ones does the brain stem primarily look at?
What is the name of these receptors?
High Protons > High CO2 > Low O2
Central chemoreceptors
Where exactly are the central chemoreceptors located?
When stimulated, what do they do?
Anterolateral medulla
Increase Respiratory drive
What is the main thing that is able to cross the BBB?
CO2
Normal pH, PCO2, Protein levels in the CSF
pH = 7.32 (or 7.31)
PCO2 = 50 mmHg
Low levels of protein buffers
As far as the chemoreceptors go, how much of the blood gas sensing and feedback do the central chemoreceptors take care of?
What about the peripheral chemoreceptors?
Central: 85%
Peripheral: 15%
Why is the PCO2 higher in the CSF compared to the blood?
It is being produced in the CSF
What is one thing that is unique/interesting about the control of these respiratory centers per lecture?
This is one system where we can alternate between having voluntary or automated control. Awake vs. asleep
Central Chemosensitivity
Where is the true location in which the vast majority of blood gas management is taken care of?
Why?
Front of the frontal lobe
The body doesn’t rely on the chemoreceptors much for blood gas management because the brain is anticipating the changes already
Where are the peripheral chemoreceptors located?
2 pairs of carotid bodies located superior of bifurcation of the internal and external carotid arteries.
3-5 Aortic Bodies
How do the peripheral chemoreceptors (“bodies”) relay their information back to the brainstem?
Carotid bodies = CN IX (Glossopharyngeal Nerve)
Aortic Bodies = CN X (Vagus Nerve)
What do the peripheral chemoreceptors look at?
Which one primarily?
Also protons, CO2 and PRIMARILY O2
At what measure are the peripheral chemoreceptors able to vary their output/impulses?
What happens at higher or lower levels?
When do we really see a sharp increase in impulses?
They are able to measure their output at 80 mmHg of PaO2 +.
> 80mmHg = impulses slow down
< 80mmHg = impulses speed up
See a sharp upstroke at 60 mmHg
Do we utilize the peripheral chemoreceptors often?
NO! Only unless there is a major problem.
How does the body manage changes in ventilation?
Why?
By first changing Tidal volume, if that isn’t enough then the RR changes second
VT = Easier to manage than RR changes
When there is a large increase in CO2 and protons, the Oxygen levels drop: what is the next response by the body?
Increase C.O.
Recruits the heart to help out to increase gas exchange
Can we lower BP by only changing settings on the ventilator?
How?
YES!
Increase ventilation (blow off CO2)
Why do we have to be cautious when changing the ventilation to lower BP?
We could severely deplete our ionized Calcium levels.
Why does increasing ventilatory rate decrease ionized Ca levels?
What does this do to our C.O.?
When we blow off more CO2/Protons, the negatively charged areas inside proteins (albumin) are left vacant = therefore Calcium will move into the proteins and hang around the negatively charged areas which decreases their ionized levels
Decreases C.O.
What are the 2 layers of connective tissue surrounding the lungs?
Visceral = connected to the lung itself
Parietal = connected to the inside of the ribcage
Where are the intercostal muscles located?
How are they described in terms of their relationship to one another?
In between each of the first 10 Ribs
They are a paired set (Internal = Deep) (External = more superficial)
What happens when the internal intercostals contract?
Are they primarily involved in inspiration or expiration?
Tightens the chest
Decreases Lung volumes
More positive Ppl
Primarily involved with expiration
What happens when the external intercostals contract?
Are they primarily involved in inspiration or expiration?
Ribcage is pulled out
Increase in lung volume
More negative Ppl
Primarily involved with inspiration
If we were to be asked a second muscle that helps out with resting breathing (besides the diaphragm), which one would you pick?
External Intercostal muscles
Where does the sternocleidomastoid muscle connect?
What is its primary role?
Top of the sternum to the mastoid process (behind the ear)
Helps with stabilization of the ribcage when diaphragm contracts
Contraction of the sternocleidomastoid muscle during inspiration will…
oppose the ribcage from getting pulled down
Contraction of the Serratus Anterior muscle on inspiration will cause what to happen?
Ribcage will be pulled outward & the lung volume will increase
The pec minor is connected to the ___ & ___.
Is it an inspiratory/expiratory accessory muscle?
Scapula & front of the ribcage
Inspiratory
When might we visibly see contraction of the pec minor?
When someone is VERY worn out.
What is the significance of utilizing a stable base (resting on something) when worn out and contracting the pec minor?
If we are resting our arms on a stable base, when the pec minor is contracted = the shoulders won’t move down. The stable base prevents the pec minors from pulling the ribcage down and allows more air into the chest better than if we weren’t leaning/using a stable surface.
4 Abdominal muscles discussed in lecture?
Rectus Abdominus
Internal Oblique
External Oblique
Transverse Abdominus
Complete list of the accessory muscles to remember for this class:
Serratus Anterior
Pec Minor
Sternocleidomastoid
Scalene Muscles
Internal/external Intercostal muscles
4 Abd. muscles
What 3 components per lecture make up the “upper airway”?
Nasopharynx
Oropharynx
Laryngo-pharynx
2 names for the opening that allows for drainage of the middle ear on each side of the skull and helps middle ear pressure equilibrate to atmospheric pressure
Pharyngeal Tympanic Tube or Eustacian Canal
Roles of the nose for the upper airway:
Filtration
Mucous production
Humidification
Warming of the air
Vascularity of the nose is primarily sourced by the ___.
Why do we bleed so much from injury here?
External carotid artery.
This is a protected circulation = body will always ensure blood keeps pumping to the carotids no matter what.
Which is a more protected circulation?
Internal or External carotid branches:
Internal
How would we describe the bones in the nose?
Pros and Cons of this?
Porous
Pros: Allows for vessels to snake through, more surface area, more warming/humidification can occur
Cons: bones are way weaker and are easier to break off
The function of the bones in the nose are similar to a ___.
Turbine
3 sets of ___ in the nose that are used for spinning the air/water that enter the nose.
Concha/turbinates (inferior, middle and superior)
What are the names of the bones that house the concha?
Inferior = maxillary bone
Middle & Superior = Ethmoid bone
Describe the location and relevance of the crista galli?
Superior projection of the ethmoid bone where the falx cerebri anchors into it.
If we are doing a nasal airway, which concha would we try to stay close to?
Inferior Concha: stay midline and on the lower part of the nose
The trigeminal nerve (CN V) provides afferent innervation to which locations?
Majority of the mouth
Superficial areas of the nose
The Vagus nerve (CN X) provides afferent innervation to which locations?
Back of the throat (behind tongue)
Larynx and further down into the trachea.
What nerve takes care of the afferent innervation in the lower part of the nasopharynx?
Glossopharyngeal Nerve (CN IX)
Would a difficult intubation be described as more or less hard palate?
More or less compliant soft palate?
Less Hard Palate
More Compliant soft palate
Which tonsils are usually the culprits if we need a tonsillectomy?
Palatine tonsils
Which tonsil, when enlarged, will push on soft palate and make the uvula hang down a lot further?
Pharyngeal Tonsils
If you were involved in a slapping competition and got smacked along the side of the face, which gland would be affected?
Parotid Gland
What is the source of the fluid that we use to make saliva?
Blood, thats why there are a lot of blood vessels in the glands like the parotid.
Describe the 3 divisions of the Trigeminal Nerve:
- V1: Topmost split point, ophthalmic branch = eyes and forehead sensory
- V2: Maxillary division = top of the mouth, nose sensory
- V3: Mandibular division = majority of mandible sensory
Which CN primarily takes care of somatic sensation of the tongue?
What about the secondary nerve?
CN V (V3 branch)
- Front 2/3rds of the tongue
CN IX (Glossopharyngeal)
- Back 1/3rd of the tongue
What nerve primarily takes care of the sensory innervation to the epiglottis?
Vagus Nerve
Nerves taking care of taste sensation?
Front 2/3rds = Facial Nerve (CN VII)
Back 1/3rd = Glossopharyngeal (CN IX)
