4. RESPIRATORY SYSTEM Flashcards
The parts of the respiratory system and its structure and function. Signs, symptoms, investigation procedures and some mainstream treatments of common respiratory diseases.
List four functions of the respiratory system
- Exchange of gases
- Warming/cooling and moistening of air
- Removal of inhaled particles
- Voice production and olfaction
Describe specifically the route air flows through the respiratory tract, identifying key structures
Air flows in through the nose (and mouth) and through the paranasal sinuses down into the nasopharynx, oropharynx and laryngopharynx. Then through the larynx (voice box) into the trachea which branches into the left and right bronchi. These then branch into smaller bronchioles and finally into millions of alveoli where gas exchange occurs.
Describe the difference between external and internal respiration
External respiration is the exchange of gases between the blood and lungs where the pulmonary capillaries carry blood around the alveoli.
Internal respiration is the exchange of gases between blood and cells.
What is cellular respiration?
The process whereby energy (ATP) is obtained by metabolising carbs, fats and proteins.
The mucous membrane of the respiratory tract is lined with a ________ epithelial membrane that contains mucous secreting _______ cells. Mucus traps ______ particles and acts as a surfactant. It also has _______ properties. Cilia move the particles towards the _________ where they can be coughed up and/or swallowed. This protects the lungs from inhaled ________.
ciliary goblet inhaled antimicrobial oesophagus pathogens
Describe the role of nasal concha
Nasal concha are shelves that increase surface area and trap water during exhalation. They also spin the air which filters it and encourages particles to become trapped in nasal mucous membranes.
List four functions of the nasal cavity
- Filtering air - hairs and concha
- Warming air - lots of capillaries near surface
- Humidification - air travelling over moist mucosa
- Sneezing reflex - in case of mucosal irritation
- Olfactory function - olfactory receptors
List two functions of the paranasal sinuses
- Moistening/humidifying the air
- Resonance in speech
- Lightening the cranial mass
- Nasolacrimal ducts drain tears from the eyes
Name two paranasal sinuses
Ethmoid
Frontal
Sphenoid
Maxillary
List four functions of the pharynx
- Passageway for air and food
- Warming and humidifying of air
- Taste
- Speech
- Equalising of pressure in the middle ear
- Immune protection (adenoids0
- Hearing
Which hormone thickens and lengthens the vocal chords?
Testosterone
List four functions of the larynx
- Production of sound and speech
- Warming and humidifying air
- Protection (epiglottis closes and protects airway)
- Air passageway
What are the two main components that the trachea is made up of?
C-shaped rings of hyaline cartilage with interconnecting smooth muscle (trachealis).
The larynx is also known as the ___________ and connects the _______________ with the trachea. It consists of _____ pieces of cartilage (including the thyroid cartilage and ___________ ) and _____ cords.
voice box laryngopharynx nine epiglottis vocal
List four functions of the trachea
- Air flow
- Mucociliary escalator
- Cough reflex
- Warming, humidifying and filtering air
Describe in specific detail the ‘cough reflex’
- The coughing reflex starts when the highly sensitive epithelial receptors in the respiratory tract mucus membrane becomes irritated
- Sensitive nerve endings gets stimulated in the larynx, trachea and bronchi
- Via the vagus nerve, an impulse travels to the respiratory centre in the brainstem.
- This leads to deep inhalation and closure of the glottis (and vocal chords)
- Contraction of abdominal and respiratory muscles occur to increase pressure
- Finally, there is a forced removal of irritation (at a speed of up to 600 miles/hr)
The trachea divides into the left and right ______ at the vertebral level of T5. The ______ bronchi is more ________, shorter and wider. Where the trachea divides into two bronchi, an internal ridge called the _______ is formed. The latter is a sensitive structure and triggers the _____ _______.
bronchi right vertical carina cough reflex
Why is an aspirated object more likely to enter the right lung?
Because the right bronchus is more vertical, wider and shorter.
What role does the nervous system play in air entry into the bronchi?
The sympathetic nervous system stimulates bronchodilation and thus more air can be taken in.
The parasympathetic nervous system encourages bronchoconstriction during a restful state.
Explain fully how alveoli are maximised for gaseous exchange.
The 250 million alveoli in each lung creates a large surface area (approx 80m2) and the alveolar walls are only a single cell layer thick. Each alveoli is surrounded by many blood capillaries and the alveolar surfaces are moist to enable gasses
Describe the difference between Type I and Type II alveolar cells
Type I alveolar cells are simple epithelial cells, cover 90% of alveolar surface and are very thin to support gas exchange.
Type II alveolar cells secrete alveolar fluid that contains pulmonary surfactant which reduces surface tension, preventing alveolar collapse and allows gasses to diffuse through it.
How many lobes in the
a) right lung
b) left lung
a) 3
b) 2
Describe the main role of the pleura
The pleura are serous membranes that surround the lungs and have the characteristic visceral and parietal layers with a small quantity of serous fluid inbetween. Its main role is in preventing friction and as it adheres to the lungs, it helps the expansion of the lungs.
Name two a) primary and two b) secondary muscles of ventilation
a) Intercostal muscles; diaphragm
b) scalenes; sternocleidomastoid; trapezius
Name one pathology that could lead to over recruitment of ventilation muscles
Pulmonary fibrosis
Define tidal volume
The normal volume of air that enters the lungs during inspiration when no extra effort is applied.
Name two factors (not gender) that contribute to a larger lung volume
Living at higher altitudes
Taller individuals
Athletes
Non-smokers
Why is there no difference between inspired and expired nitrogen gas levels?
Nitrogen doesn’t bind to haemoglobin and is not used or created in the body.
What percentage of the following is oxygen
a. inspired air
b. expired air
a. 21%
b. 16%
Which blood cells transport oxygen around the body?
Red blood cells
List three ways (% highest to lowest) in which carbon dioxide is transported in the body
70% is found in plasma as bicarbonate (HCO3-)
23% is carried in RBSs (bound to haemoglobin)
7% is dissolved in blood plasma
Explain in specific detail the role of carbon dioxide and the bicarbonate buffer reaction in controlling blood pH
- CO2 diffuses down its concentration gradient from tissues into the blood
- CO2 combines with the water in the blood to produce carbonic acid (H2CO3)
- Carbonic acid is unstable and it decomposes immediately into bicarbonate (HCO3-) and hydrogen (H+)
- Hydrogen is exhaled and excreted into urine to reduce the acidity. The bicarbonate that is formed, is alkaline and ‘buffers’ the acidity of the blood to keep the pH stable.
What causes ‘respiratory acidosis’?
When higher amounts of CO2 dissolves in the blood, it causes an increase in H+ ions and thus an increase in acidity.
Complete the following formula:
Carbon dioxide + water = ________ ______ = Bicarbonate + _________
CO2 + H2O = Carbonic acid (H2CO3) = Bicarbonate (HCO3-) + Hydrogen (H+)
What is the normal range that blood pH should remain within?
pH of 7.35 -7.45
List three ways in which an increase in blood acidity can be managed
- Buffer system: Temporarily bind to H+, removing them from the solution (i.e. proteins, bicarbonate)
- Increased exhalation of CO2
- Kidney excretion of H+: This is a slow mechanism and the kidneys can also synthesise new bicarbonate and reabsorb bicarbonate, thus influencing pH
Define ‘cell respiration’
Cell respiration describes the process of energy production (ATP) within cells.
Which of the following yields more energy:
a) Aerobic respiration
b) Anaerobic respiration
a) Aerobic respiration [yields 36 (net) molecules of ATP]
Which of the following yields more energy:
a) Aerobic respiration
b) Anaerobic respiration
a) Aerobic respiration [yields 38 molecules of ATP]
How does chemical receptors in the brainstem play a role in ventilation?
The ‘respiratory centre’ is located in the medulla oblongata and pons in the brainstem. The chemical receptors here measure CO2 levels and acidity. If receptors detect high arterial CO2, this triggers hyperventilation in order to exhale excess CO2
Describe how chemical receptors in the aorta and carotid arteries play a role in ventilation control
Chemical receptors in the aorta and carotid arteries measure CO2 and O2 levels and acidity and adjusts the heart rate accordingly.
Define rhinitis
Rhinitis is inflammation of the nasal mucosa
List two signs/symptoms of rhinitis
Itchy runny nose
Sneezing
Stuffy nose
Loss of smell
Describe the difference between allergic and non-allergic rhinitis
Allergic rhinitis develops as a result of an allergic reaction to an allergen such as pollen, spores or mites and it involves IgE stimulating mast cells to release histamines which leads to inflammation.
Non-allergic rhinitis is associated with environmental and lifestyle changes such as pollution, diet, stress and drugs such as NSAIDs
List one complication of rhinitis
Nasal polyps
Ear infections
Loss of smell
List two ways in which smoking can contribute to respiratory disease.
Cigarettes contain carcinogens which compromises the immune system and can ultimately cause cancer.
Smoking damages the delicate cilia that line the respiratory tract and cause mucus and trapped particles to build up in the lungs causing smoker’s cough and increasing the risk of respiratory infections and disease.
List one respiratory pathology that can cause cyanosis
Bronchitis
List two respiratory pathologies that can cause finger clubbing
Lung cancer
COPD
Cystic fibrosis
List possible respiratory pathology for:
a. purulent sputum
b. mucoid sputum
c. serous sputum
d. blood in sputum
a. purulent sputum - infections like bronchitis, pneumonia
b. mucoid sputum - asthma, bronchitis, CF
c. serous sputum - pulmonary oedema
d. blood in sputum - TB, lung cancer, pulmonary embolism, clotting disorders
List two complications that could arise from influenza
- Secondary infections can take root while the immune system is depleted
- Post-viral syndrome (chronic fatigue syndrome) following a compromised immune system
- Morbidity / mortality
List two causes of nasal polyps
Nasal polyps are usually the end product of chronic inflammation due to:
- Chronic rhinitis
- Viral, bacterial or fungal
List two signs / symptoms of nasal polyps
Difficulty breathing, runny nose, persistant stuffiness
Chronic sinus infections, reduced sense of smell
Dull headaches, snoring, mouth breathing
Can cause sleep apnoea
List two causes of tonsillitis
Viral (rhino or influenza virus)
Bacterial (Streptococci)
List two symptoms of tonsillitis
Sore throat that becomes worse when swallowing
Fever over 38 degrees
Coughing, headache, red/inflamed tonsils
List one sign that is more characteristic of quinsy
Severe unilateral throat pain
unilateral earache
trismus (limited mouth opening)
List two key symptoms of laryngitis
Hoarseness
Weak voice / voice loss
Sore, dry, tickly throat
What are ‘leukotrienes’?
Key chemical inflammatory mediators in asthma and they cause bronchoconstriction.
What is the difference between intrinsic and extrinsic asthma?
Extrinsic (Atopic) Asthma: generally affects children and is immunologically mediated, with an increase in IgE antibodies, brought on by exposure to an allergen
Intrinsic Asthma: generally adult onset and is not due to antigen-antibody stimulation. Instead, it is a reaction to triggers such as anxiety, chemicals, exercise, dust, drugs (NSAIDs etc.), etc.
Name three conditions that make up the atopic triad
Asthma
Eczema (Atopic dermatitis)
Hay Fever (Allergic Rhinitis)
Using pathophysiology, describe the difference between asthma and COPD
Asthma is a chronic inflammatory airway disease in which REVERSIBLE narrowing of the bronchi and bronchioles occur, mediated by leukotrienes.
COPD is also a chronic inflammatory condition, but it is PROGRESSIVE and not fully reversible. The airflow limitation is due to damaged airways and functional lung tissue resulting from inhaled toxins or long-term irritation and inflammation.
List three key signs / symptoms of asthma
Recurrent episodes of breathlessness and tight chest
Wheezing when exhaling
Nocturnal coughing
Describe the difference between emphysema and chronic bronchitis associated with COPD
In emphysema, the walls of the alveoli are damaged and destroyed, leading to collapse of alveoli during expiration and reduced gas exchange (breathlessness).
In bronchitis, the bronchial lining is constantly irritated and inflamed which leads to thickening of the bronchial lining and hyper-secretion of mucus, coughing and wheezing.
Name two signs common to bronchitis
Cackles on auscultation
Tachypnoea, tachycardia
Cyanosis
List three main signs of COPD
Tachypnoea
Breathlessness on exertion, pursed lips breathing
Barrel chest (hyperinflation)
Patients leaning forward, resting arms on table
Flapping tremor (when arms stretched out forward)
Using definitions, compare pneumonia to pulmonary fibrosis
Pneumonia is an infection of the alveoli and terminal bronchioles, mostly bacterial. [is associated with inflammation, oedema and an infiltration of neutrophils].
Pulmonary fibrosis is the replacement of the single layer epithelial lining in the alveoli, with fibrotic tissue.
List two signs / symptoms of pneumonia
Breathlessness Cough with purulent sputum (sometimes blood) Crepitations on auscultation Malaise Fever
List one autoimmune cause of pulmonary fibrosis
Rheumatoid Arthritis
List two signs / symptoms of pulmonary fibrosis
Progressive dyspnoea
Chronic cough
Fatigue
Discomfort in the chest
List two risk factors for sleep apnoea
Obesity Nasal obstruction (rhinitis, polyps) Smokers Male gender Alcohol, sedatives
List two signs / symptoms of sleep apnoea
Loud snoring Daytime sleepiness Nocturnal choking Morning headaches and drowsiness Reduced libido
Define pneumothorax
A medical emergency where air accumulates within the pleural cavity, causing all or part of the lung to collapse.
Describe the nature of chest pain in pleurisy
Sharp chest pain while breathing
Describe the pathophysiology of pleurisy
The pleural surfaces become coated with inflammatory materials and are hence roughened, producing a ‘friction rub’ on auscultation.
In regards to pneumothorax, identify:
a. one spontaneous cause
b. one traumatic cause
a. Rupture of a cyst, TB, cystic fibrosis, emphysema
b. Fracture, surgical complication
List two signs / symptoms of pneumothorax
Dyspnoea Cyanosis Loss of consciousness Pleuritic chest pain (sharp) Reduced breath sounds Decreased cardiac output
Explain how a pulmonary embolism develops
A pulmonary embolism results from obstruction within the pulmonary arterial tree, often as a result of a thrombosis travelling up from one of the deep veins in the legs
Why is calf pain an important sign in pulmonary embolism?
Calf pain signifies a DVT being causative
Outline the pathophysiology of Cystic Fibrosis
Cystic fibrosis is a multi-organ genetic disease (due to a mutation on gene 7) that affects chloride channels and subsequently key exocrine glands. Chloride channels help maintain the proper balance of salt and water within a cell. A genetic mutation causes a dysfunction of salt and water balance.
List two signs / symptoms of Cystic Fibrosis
Persistant cough and sputum production Recurring lung infections Wheezing Chest pain Clubbed fingers [GIT symptoms: bloating, obstruction, malnutrition, dyspepsia, bleeding]
