Intro To Respiration W1 Flashcards
Neural control of respiration involves 3 components. What are they?
- Generation of alternating inspiration/expiration rhythm
- Regulation of the magnitude of ventilation
- Modified respiratory movements (voluntary and involuntary)
What is Regulation of the magnitude of ventilation?
How much we breath in and out
ie hold breath or slow down breathing. If not getting enough oxygen the brain will take back control and wont be voluntary
What does breathing depend on?
Cyclical respiratory muscle contraction
What is the pre-botzinger complex?
In the brain and sets respiratory rhythm
What is inspiration indicated by ?
Burst of action potentials in spinal motor nerves :
- phrenic nerve innervates the diaphragm
- intercostal nerves innervate the external intercostal
When these motor neurons are activated, what do they stimulate?
They stimulate muscle contraction leading to inspiration and when action potentials in these neurons cease the muscles relax leading to expiration
What determines how deep and quickly we breathe
This is determined by the oxygen and carbon dioxide in our system. More carbon dioxide needs more deeper breathing and more rapidly.
Our respiratory rate and tidal volume isn’t ……
Fixed
The Mac sheet of ventilation is adjusted in response to …..
Three chemical factors:
- PO2
- PCO2
- H+`
What do the three chemical factors respond to?
Changes in blood pH and gas content
Changes in blood pH and gas content detected by?
Peripheral chemo receptors in carotid and aortic bodies
Central chemo receptors stimulated by increased hydrogen in brain extra cell cellular fluid
Which part of the spiritually anatomy of medicines used to treat asthma/COPD?
The bronchi
What does bronchial smooth muscle depend on?
The balance between the parasympathetic input, circulating adrenaline/non-noradrenergic and non-cholinergic nerves
Cartilage and smooth muscle as you move from bronchi to bronchioles
There is less cartilage and more smooth muscle
Is bronchodilation agonist or antagonist?
Agonist
Relaxation/sympathetic
Is bronchoconstriction agonist or antagonist?
Antagonist
Contraction
Which types of muscarinic receptors and adrenergic receptors are most prominent in airway smooth muscles?
Muscarinic subtype = m1 and m3 (antagonist)
Adrenergic subtype = a1, a1 and b2 (agonists)
Both are GPCR’s
Where do we use agonists?
At adrenergic to encourage broncho dilation
Where do we use antagonists?
At muscarinic to encourage bronchoconstriction
What do bronchodilators do and what are the different types?
They open up the airways
Type one = beta adrenergic agonist
- SABA - salbutamol
- LABA - serovent
Type two = muscarinic antagonist
- SAMA - atrovent
- LAMA - incruse
Type three = xanthines
What do anti-inflammatories do and what are the different types?
They target the causes of bronchi dilation
One = corticosteroids
Two = leukotriene modifiers (LTRA) - motelukast
Three = anti IgE antibody
Four = biologics
What is asthma?
An inflammatory disease of the airway categorised by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. The airway obstruction is mostly reversible with treatment or spontaneously.
Classification of asthma
Extrinsic
- atopic
- Indoor triggers and outdoor triggers
Intrinsic
- non-atopic
- Obesity, stress, food additives, exercise, infections, occupation, exposure, cold air, drugs
Asthma aetiology
Environmental
- allergens
- pollutants
- Tobacco smoke
- infections
- Diet
- Drugs
- Object
Host
- Genetic predisposition
- Age
- atrophy
- Airway hypersensitivity
- Biological sex
- ethnicity
Asthma signs and symptoms
Shortness of breath, difficulty breathing, dry cough, cough, wheezing, chest pain
What is COPD?
A disease characterised by airflow obstruction which is usually progressive, not fully reversible and does not change over several months. Airflow obstruction is due to airway and parenchymal damage on the result of chronic inflammation that differs from asthma.
It is an umbrella term for what used to be diagnosed as emphysema and bronchitis
COPD aetiology
Smoking
- Occupational dust exposure and biomass in cooking an air pollution
- More than 90% associated with smoking but only 10% of smokers developed the disease
Alpha antitrypsin deficiency
- Autosomal recessive condition
- Auntie Alphatrypsin is an anti-protease enzyme which inhibits neutrophile elastase
- elastase breakdown extra cellular matrix leading to lung damage and Alviola collapse
Symptoms of COPD depend on whether it is…
Bronchitis or emphysema is predominant
In reality, the underlying pathophysiology may be a mixture between the two extremes
Bronchitis symptoms
• Patients often have a productive cough, are overweight, dyspnea on physical exertion.
• Retain CO2 and lose ability to increase the rate and depth of ventilation.
• Bronchospasm
• Wheeze and dyspnoea
• Hypoxia and hypercapnia
• Blue tinge on skin, lips and palms
emphysema symptoms
• Patients tend to hyperventilate to compensate for hypoxia, appearing pink with little CO2 retention.
• They are often thin with pursed lips in an effort to compensate for lack of elastic recoil.
• Breathe more but not getting enough oxygen
• Increasing dyspnea even at rest
• Bronchial infection less common
• Minimal cough
It could be hard to distinguish between COPD and asthma based on the symptoms alone.
Clinical features of COPD :
• Smoker or ex-smoker
• Symptoms under age of 35
• Chronic productive cough
• Breathlessness
• Night time waking with breathlessness and/or wheeze
• Significant diurnal or day to day variability of symptoms
• Smoker or ex-smoker - nearly all
• Symptoms under age of 35 - rare
• Chronic productive cough - Common
• Breathlessness - persistent and progressive
• Night time waking with breathlessness and/or wheeze - uncommon
• Significant diurnal or day to day variability of symptoms - uncommon
It could be hard to distinguish between COPD and asthma based on the symptoms alone.
Clinical features of asthma
• Smoker or ex-smoker
• Symptoms under age of 35
• Chronic productive cough
• Breathlessness
• Night time waking with breathlessness and/or wheeze
• Significant diurnal or day to day variability of symptoms
• Smoker or ex-smoker - possibly
• Symptoms under age of 35 - often
• Chronic productive cough - uncommon
• Breathlessness - variable
• Night time waking with breathlessness and/or wheeze - common
• Significant diurnal or day to day variability of symptoms - common
What is the pre-botzinger complex?
small but crucial group of neurons in the brain stem specifically in the Medella that is critical for generating the rhythmic breathing pattern. It is considered the main pacemaker a breathing.
What is the phrenic nerve ?
originates from the cervical spinal cord and controls the diaphragm contraction leading to inhalation
What is the intercostal nerves?
group of nerves from the spinal cord that run between the ribs and are responsible for innovating intercostal muscles which expand and contract the rib cage
Carotid
refers to the carotid arteries which are major blood vessels in the neck. There are two main carotid arteries the internal and external.
Spirometry
test to help diagnose/monitor lung conditions.measures how much air you can breathe in and out.
Atopic
refers to a genetic tendency to develop allergic conditions
Non-atopic
refers to conditions that reserve but allergic responses but are not caused by allergens or an overreactive immune system. There is no genetic predisposition.
Extrinsic
something that originates from or is due to external factors
Intrinsic
refers to something that originates from or is caused by internal factors
Tidal volume
quantity of air in millilitres that we breath in an out in a normal breath
Tidal volume
quantity of air in millilitres that we breath in an out in a normal breath
Respiratory rate
rate at which we reach in breaths per minute
Hypocapnia
below normal CO2 in arterial blood
Dyspnea
difficulty breathing/shortness in breath
Exacerbations
a sustained worsening of the patient’s symptoms from their usual stable state that is beyond normal day-to-day variations, and is acut in onset.
Cyanosis
blueness of skin
Hypercapnia
excess CO2 in arterial blood
Hypoxia
insufficient O2 at cellular level
