Respiritory: Physiology Flashcards
Which parts of the brain are responsible for voluntary/ involuntary breathing?
Voluntary: Cortex
Involuntary: Pons, Medulla and Spinal Chord aka brain stem
What are the names of the three respiritory groups
- Pontine Respiritory Group
- Ventral Respiritory Group
- Dorsal Respiritory Group
Describe the positioning of the three main respiritory groups from a dorsal view
What are more passive, the inspiritory neurons or the expiritory neurons?
Expiritory neurons, in normal breathing the only thing they do is inhibit the inspirtory neurons
Describe the process of neuron activation during normal breathing?
By activating the inspiratory neurons this causes contraction of the inspiritory muscles. It also causes activation of the expiritory neurons which in turn inhibit the inspiritory muscles thus relaxing the muscles of inspiration allowing expiration to take place.
Normal muscles of inspiration
Diaphragm and Intercostals
Describe the prrocess of neuron activation during large respiration
In order to have a large expiration you must first take a large inpiration. This large activation of inspiration neurons has a large activation on the expiritory nuerons. When this happens the activate muscles of expiration as well as inhibiting muscles of inspiration
5 receptors which effect respiration
Which nerve carries the lung receptors
Vagus Nerve
How do the vagal nerves effect your breathing pattern?
Cutting the vagus nerve produces a reflec of slow deep breaths
Why does a normal breathing pattern look like this?
Inspiration is steep because it is active while expiration is slower because it is passive
Which of this receptors is rapidly/slowly adapting?
Slowly adapting receptors keep firing in response to a stimuus whereas rapidly adpating receptors slettle down quickly.
What are the slowly adapting receptors responsible for?
These are stretch receptors and are responsible for sensing when the airways are streched therefore activating expiration. The take a bit of time to settle down after stimulating because you want expiration to continue fully even when the airways aren’t fully stretched anymore
What are the rapidly adapting receptors responsible for?
These are irritant receptors and are responsible for sensing obnoxious substances in the airways and triggering things like the cough mechanism. Because these reactions are extreme you want them to settle quickly after the stimulus is dealth with.
What are c-fibre ending responsible for?
Stimulated by interstitial fluid and inflammatory mediators
Peripheral vs Central chemoreceptors
Peripherals sense changes in PCO2, PO2 and H+ and have a fast response. These signals are carried by the vagus nerve.
Central detects shifts in PCO2 once it has diffused over the blood brain barrier hence has a slower response.
Vagus nerve vs Phrenic nerve
Both and for breathing. Vagus is afferent, Phrenic is efferent
What are the terms for the different ammounts of oxygen and CO2 in the blood?
Why is it dangerous to give COPD patients high O2 therepy.
After chronic hypoxia and hypercapnia the central chemoreceptors become desenitised.
The drive to breath then comes from hypoxia rather than hypercapnia.
If they are given high O2 then they loose the drive to breath completely leading to further hypercapnia, CO2 narcosis and acidosis and evnetually death
Drugs that inhibit respiration
- Anaesthetics
- Opioids
- Sedatives e.g. benzos
Drugs that stimulate respiration
- Primary: these actually drive the respiritory drive e.g. doxapram. However these aren’t used due to nasty side effects
- Secondaries: these are things like bronchodialators that make breathing easier such as B2 agonists
What happen’s if control of your respiritory function is too common for example surpressing a tickly cough? And what is the name of the dissorder?
If you overide your autonomic respiritory system too often it gives up and then you rely on the cortex for breathing. This is called breathing pattern dissorder.
What is Obstructive Sleep Apnoea?
This occurs because of a loss of the tonic neural drive to maintain the upper the airways during sleep.
If you have a condition which already means your upper airways are impaired such as obesity, alcohol or anatomical abnormalities when you sleep then can get completely obstructed resulting in you waking up in order to breath therefore disrupting sleep. However you might not always fully wake up so might not know why you are so tired.
What is the tonic drive?
This is the continuous background drive that maintains our upper airways and keeps then clear.
What is tidal volume?
Tidal volume is your standard breath volume without forced respiration
What is dynamic hyperinflation in COPD?
Due to damage of lung structure the lung loses it’s elastic property and the patient loses the ability to passively deflate their lungs. Therfore without force expiration breaths stack
Quick refresher on oxygen haemoglobin dissociation curve: What is on the axis and what 4 things cause a right shift?
What does V and Q mean in a V/Q missmatch?
V = Ventilation (oxygen)
Q = Perfusion (blood flow)