Case 8 Flashcards
What are features of a diseased airway?
Airway narrowed
Mucus accumulation
Muscular layer thickens
Inflammatory cells infiltrate area
Examples of external causes of a diseased airway?
Smoke
Environmental pollution
Infection
Chemicals
Dust
Examples of internal causes of a diseased airway?
Heredity
Airway hypersensitivity
Maldevelopment
Nature and function of type 1 alveolar cells?
Simple squamous epithelium, non ciliated and the main site of gas exchange
Covers 90% of alveolus
Nature and function of type 2 alveolar cells?
Produce surfactant
This reduces surfaces tension, preventing alveoli collapse and renewing type 1 cells
What is meant by immune tolerance of respiratory system?
Tolerance of respiratory system to inhaled allergens to prevent unnecessary immune response.
What happens if the immune tolerance of respiratory system is too high?
Decreased immune responsiveness
Body becomes more susceptible to infections
What happens if the immune tolerance of the respiratory system is too low?
Immune system overreacts
This can cause allergies and autoimmune conditions (eg asthma)
What is in the brown/preventer inhaler (for asthmatics)?
Inhaled corticosteroids to reduce inflammation
Used daily even when no symptoms
What is in the blue/reliever inhaler (for asthmatics)?
Bronchodilators
Causes smooth muscle to relax, opening up airway
Used when symptoms are experienced
What is the autonomic nervous system?
Subconscious nervous system
What are the 2 branches of the Autonomic nervous system?
Parasympathetic and Sympathetic
What are afferent nerves?
Transmit signals from tissues and organs to the CNS
What are efferent nerves?
Transmit signals from CNS to tissues and organs
What does CNS (central nervous system) consist of?
Brain and spinal cord
What are ganglia?
Clusters of nerve cell bodies located outside the CNS.
What are dorsal root ganglia?
Found along dorsal roots of spinal nerves
Transmit sensory information from peripheral tissues to the spinal cord
What are autonomic ganglia?
Involved in regulating involuntary body functions (eg heart rate, digestion and respiratory rate)
What is parasympathetic nervous system?
Rest and digest nervous system
Promotes relaxation and recovery
EG. Slows heart rate, stimulates digestion
What is sympathetic nervous system?
Fight or flight system
Prepares body for quick vigorous action
Increases heart rate, redirects blood flow to muscles, releases energy stores
Which neurotransmitters are used for sympathetic pathways?
Acetylcholine and noradrenaline
Which neurotransmitters are used for parasympathetic pathways?
Acetylcholine
How are nervous system signals ‘turned off’?
Enzyme destroys transmitter
OR
Transmitter is re-captured by pre-synaptic never terminals
What are cholinesterases?
Widely distributed enzymes which are the targets of drugs and inhibitors.
They break down acetylcholine neurotransmitters
What is dysautonomia?
Dysfunction of autonomic nervous system
How do drugs impact autonomic nervous system?
Induce over/under activation of Parasympathetic and/or Sympathetic nervous system
Purpose of surfactant in alveolus?
Reduces surface tension, holding them open
What is the pleural space?
Area between the 2 layers of the pleura, a double layered membrane surrounding the lungs.
What are the 2 pleura?
Visceral and Parietal pleura
Function of visceral pleura?
Inner layer which adheres to surface of lungs
Function of parietal pleura?
Outer layer which lines chest cavity
What is contained in pleura?
Pleural fluid
Function of pleural fluid?
Lubricates the lung
What is pressure grad required between atmosphere and alveolar in order for inspiration to occur?
Patm>Palv
Muscles used in ‘normal’ breathing?
Diaphragm and intercostal muscles
What is tidal volume?
Normal volume of lungs used in normal breathing
What is inspiratory reserve volume?
Amount beyond tidal volume the lungs can increase too
What is inspiratory capacity?
Max capacity of lungs
What group of muscles are used to reach inspiratory capacity?
Accessory muscles
What is expiratory reserve volume?
Additional volume beyond tidal volume the lungs can expire to.
What is residual volume?
Volume of air within lung that cannot be expired
What is vital capacity?
Total functional capacity of lungs including inspiratory and expiratory reserve volumes
What is functional residual capacity?
Volume of air present in lung at the end of tidal (normal) breathing
What is total lung capacity?
Total volume of lungs
(Including all reserve capacities and residual volume)
Relationship between intrathoracic and intrapleural pressure?
Increase together and decrease together
Relationship between pressure and volume?
Increase in volume, decrease in pressure
Describe process of inspiration?
Diaphragm contracts and moves down
External intercostals contract (raising rib cage)
Thoracic volume increases (decreasing pressure)
Air flows along pressure gradient into lungs
Describe process of expiration?
Diaphragm relaxes and moves upwards
External intercostal muscles relax and rib cage descends
Thoracic volume decreases (increasing pressure)
Air flows along pressure gradient out of lungs
When does forced ventilation occur?
When there is an increased demand for oxygen or airflow (eg exercise or blowing out candles)
What is the difference between forced ventilation and normal ventilation?
Increased muscle engagement
Internal intercostal uncles contract for expiration ( in normal ventilation there is no contraction)
Higher respiratory rate
Enhanced thoracic movement
Abdominal muscles contribute to air expulsion in expiration
How is respiration controlled?
Mainly by respiratory centre in brain stem.
This regulates rate and depth of breathing
What 3 ‘levels’ are monitored by receptors and can lead to a change in breathing rate?
Oxygen
Carbon dioxide
Ph (Hydrogen ion conc)
What detects oxygen levels?
Peripheral chemoreceptors in carotid bodies and aortic arch
What detects CO2 and pH levels in blood?
Central chemoreceptors
What are the physiological changes when low oxygen levels in body?
Increased heart rate (tachycardia)
Increased respiratory rate (Tachypnea)
Peripheral vasoconstriction - directing blood flow to vital organs
What is asphyxia?
Body deprived of oxygen due to injury or obstruction of airway
What is hypoxia?
Insufficient delivery, uptake or utilisation of oxygen by body tissues.
What is hypercarbia?
Increase in CO2 in blood stream
What is stress?
A physiological and psychological response to a perceived threat/challenge or demand.
Activates sympathetic nervous system (Fight or flight response)
Describe physiological symptoms due to response to trauma or stress?
Increased heart rate (Tachycardia)
Dilation of airways (Bronchodilation)
Dilated pupils (Mydriasis)
Release of glucose (Glycogenolysis)
Increased blood pressure
Vasoconstricton in non essential areas
Enhanced blood clotting (prepare for injury)
Sweating
Suppression of non-essential functions
…. These prepare the body for action
What is meant by the integrated psychosocial stress model?
The concept that stress is a complex mixture of psychological, physiological and behavioural elements, which also varies between individuals.
Describe CBT?
Improve thoughts so feelings and behaviours are improved (there is a link between the three)
CBT includes:
-Challenging negative thoughts
-Engaging in positive activities
-Facing fears gradually
-Relaxation and Mindfullness
-Problem solving skills
What is pneumothorax?
A medical condition when there is air in the pleural space
How can we detect presence of pneumothorax on physical examination?
Deviated trachea
What is a primary spontaneous pneumothorax?
Air spontaneously enters pleural space of an individual with no pre-existing lung condition
What is a secondary spontaneous pneumothorax?
Air spontaneously enters pleural space of individuals with a pre-existing lung condition (eg COPD, cystic fibrosis, TB…)
What is a traumatic pneumothorax?
Results from chest trauma (eg rib fracture or penetrating injury
Trauma causes air to enter pleural space
What is a tension pneumothorax?
Air enters pleural space and a one way valve traps the air causing increased pressure.
It is life threatening as it can cause obstruction to venous return to heart
Methods of treating pneumothoraces?
Observation - small ones may resolve themselves
Chest tube placement into triangle of safety
Needle decompression
….. To release trapped air
Where is triangle of safety
Armpit
How do local anaesthetics work (simple terms)?
They block nerve impulses, preventing pain sensation in area
Explain the mechanism of action of local anaesthetics?
1)Enter nerve cell membrane and become hydrophilic
2)They bind to sodium ion channels
3)The binding prevents influx of sodium into nerve cell, preventing formation of an action potential.
4)This means ‘nerve signals’ can’t be transmitted, so pain is relieved
