Lecture 4 - The respiratory system Flashcards

1
Q

List four functions of the respiratory system

A

1- Exchange of gases
2- Warming/cooling and moistening of air
3- Removal of inhaled particles
4- Voice production and olfaction

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2
Q

Describe specifically the route air flows through the respiratory tract, identifying key structures

A

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.

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3
Q

Describe the difference between external and internal respiration

A

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.

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4
Q

What is cellular respiration?

A

The process whereby energy (ATP) is obtained by metabolising carbs, fats and proteins.

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5
Q

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 ________.

A

ciliary
goblet
inhaled
antimicrobial
oesophagus
pathogens

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6
Q

Describe the role of nasal concha

A

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.

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7
Q

List four functions of the nasal cavity

A

1- Filtering air - hairs and concha
2- Warming air - lots of capillaries near the surface
3- Humidification - air travelling over moist mucosa
4- Sneezing reflex - in case of mucosal irritation
5- Olfactory function - olfactory receptors

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8
Q

List two functions of the paranasal sinuses

A

1- Moistening/humidifying the air
2- Resonance in speech
3- Lightening the cranial mass
4- Nasolacrimal ducts drain tears from the eyes

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9
Q

Name two paranasal sinuses

A

Ethmoid
Frontal
Sphenoid
Maxillary

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10
Q

List four functions of the pharynx

A

1- Passageway for air and food
2- Warming and humidifying of air
3- Taste
4- Speech
5- Equalising of pressure in the middle ear
6- Immune protection (adenoids0
7- Hearing

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11
Q

Which hormone thickens and lengthens the vocal cords?

A

Testosterone

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12
Q

List four functions of the larynx

A

1- Production of sound and speech
2- Warming and humidifying air
3- Protection (epiglottis closes and protects the airway)
4- Air passageway

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13
Q

What are the two main components that the trachea is made up of?

A

C-shaped rings of hyaline cartilage with interconnecting smooth muscle (trachealis).

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14
Q

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.

A

voice box
laryngopharynx
nine
epiglottis
vocal

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15
Q

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 _____ _______.

A

bronchi
right
vertical
carina
cough reflex

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15
Q

List four functions of the trachea

A

1- Air flow
2- Mucociliary escalator
3- Cough reflex
4- Warming, humidifying and filtering air

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16
Q

Describe in specific detail the ‘cough reflex’

A

1- The coughing reflex starts when the highly sensitive epithelial receptors in the respiratory tract mucus membrane become irritated
2- Sensitive nerve endings get stimulated in the larynx, trachea and bronchi
3- Via the vagus nerve, an impulse travels to the respiratory centre in the brainstem.
4- This leads to deep inhalation and closure of the glottis (and vocal cords)
5- Contraction of abdominal and respiratory muscles occurs to increase pressure
6- Finally, there is a forced removal of irritation (at a speed of up to 600 miles/hr)

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17
Q

Why is an aspirated object more likely to enter the right lung?

A

Because the right bronchus is more vertical, wider and shorter.

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18
Q

Explain fully how alveoli are maximised for gaseous exchange.

A

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

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19
Q

What role does the nervous system play in air entry into the bronchi?

A

The sympathetic nervous system stimulates bronchodilation and thus more air can be taken in.
The parasympathetic nervous system encourages bronchoconstriction during a restful state.

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20
Q

Describe the difference between Type I and Type II alveolar cells

A

Type I alveolar cells are simple epithelial cells, that cover 90% of the 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 allowing gasses to diffuse through it.

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21
Q

How many lobes in the

a) right lung
b) left lung

A

a) 3

b) 2

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22
Q

Describe the main role of the pleura

A

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.

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23
Q

Name two a) primary and two b) secondary muscles of ventilation

A

a) Intercostal muscles; diaphragm

b) scalenes; sternocleidomastoid; trapezius

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24
Q

Name one pathology that could lead to over-recruitment of ventilation muscles

A

Pulmonary fibrosis

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25
Q

Define tidal volume

A

The normal volume of air that enters the lungs during inspiration when no extra effort is applied.

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26
Q

Name two factors (not gender) that contribute to a larger lung volume

A

Living at higher altitudes
Taller individuals
Athletes
Non-smokers

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27
Q

Why is there no difference between inspired and expired nitrogen gas levels?

A

Nitrogen doesn’t bind to haemoglobin and is not used or created in the body.

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28
Q

What percentage of the following is oxygen

a. inspired air
b. expired air

A

a. 21%

b. 16%

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29
Q

Which blood cells transport oxygen around the body?

A

Red blood cells

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30
Q

List three ways (% highest to lowest) in which carbon dioxide is transported in the body

A

70% is found in plasma as bicarbonate (HCO3-)
23% is carried in RBSs (bound to haemoglobin)
7% is dissolved in blood plasma

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31
Q

Explain in specific detail the role of carbon dioxide and the bicarbonate buffer reaction in controlling blood pH

A

1- CO2 diffuses down its concentration gradient from tissues into the blood
2- CO2 combines with the water in the blood to produce carbonic acid (H2CO3)
3- Carbonic acid is unstable and it decomposes immediately into bicarbonate (HCO3-) and hydrogen (H+)
4- 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.

32
Q

What causes ‘respiratory acidosis’?

A

When higher amounts of CO2 dissolve in the blood, it causes an increase in H+ ions and thus an increase in acidity.

33
Q

Complete the following formula:

Carbon dioxide + water = ________ ______ = Bicarbonate + _________

A

CO2 + H2O = Carbonic acid (H2CO3) = Bicarbonate (HCO3-) + Hydrogen (H+)

34
Q

What is the normal range that blood pH should remain within?

A

pH of 7.35 -7.45

35
Q

List three ways in which an increase in blood acidity can be managed

A

1- Buffer system: Temporarily bind to H+, removing them from the solution (i.e. proteins, bicarbonate)
2- Increased exhalation of CO2
3- Kidney excretion of H+: This is a slow mechanism and the kidneys can also synthesise new bicarbonate and reabsorb bicarbonate, thus influencing pH

36
Q

Define ‘cell respiration’

A

Cell respiration describes the process of energy production (ATP) within cells.

37
Q

Which of the following yields more energy:

a) Aerobic respiration
b) Anaerobic respiration

A

a) Aerobic respiration [yields 36 (net) molecules of ATP]

38
Q

Which of the following yields more energy:

a) Aerobic respiration
b) Anaerobic respiration

A

a) Aerobic respiration [yields 38 molecules of ATP]

39
Q

Describe how chemical receptors in the aorta and carotid arteries play a role in ventilation control

A

Chemical receptors in the aorta and carotid arteries measure CO2 and O2 levels and acidity and adjusts the heart rate accordingly.

39
Q

How do chemical receptors in the brainstem play a role in ventilation?

A

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

40
Q

Define rhinitis

A

Rhinitis is inflammation of the nasal mucosa

41
Q

List two signs/symptoms of rhinitis

A

Itchy runny nose
Sneezing
Stuffy nose
Loss of smell

42
Q

Describe the difference between allergic and non-allergic rhinitis

A

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

43
Q

List one complication of rhinitis

A

Nasal polyps
Ear infections
Loss of smell

44
Q

List two ways in which smoking can contribute to respiratory disease.

A

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.

45
Q

List one respiratory pathology that can cause cyanosis

A

Bronchitis

46
Q

List two respiratory pathologies that can cause finger clubbing

A

Lung cancer
COPD
Cystic fibrosis

47
Q

List possible respiratory pathology for:

a. purulent sputum
b. mucoid sputum
c. serous sputum
d. blood in sputum

A

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

48
Q

List two complications that could arise from influenza

A
  • Secondary infections can take root while the immune system is depleted
  • Post-viral syndrome (chronic fatigue syndrome) following a compromised immune system
  • Morbidity/mortality
49
Q

List two causes of nasal polyps

A

Nasal polyps are usually the end product of chronic inflammation due to:

  • Chronic rhinitis
  • Viral, bacterial or fungal
50
Q

List two signs/symptoms of nasal polyps

A

Difficulty breathing, runny nose, persistent stuffiness
Chronic sinus infections, reduced sense of smell
Dull headaches, snoring, mouth breathing
Can cause sleep apnoea

51
Q

List two causes of tonsillitis

A

Viral (rhino or influenza virus)

Bacterial (Streptococci)

52
Q

List two symptoms of tonsillitis

A

Sore throat that becomes worse when swallowing
Fever over 38 degrees
Coughing, headache, red/inflamed tonsils

53
Q

List one sign that is more characteristic of quinsy

A

Severe unilateral throat pain
unilateral earache
trismus (limited mouth opening)

54
Q

List two key symptoms of laryngitis

A

Hoarseness
Weak voice/voice loss
Sore, dry, tickly throat

55
Q

What are ‘leukotrienes’?

A

Key chemical inflammatory mediators in asthma and they cause bronchoconstriction.

56
Q

What is the difference between intrinsic and extrinsic asthma?

A

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.

57
Q

Name three conditions that make up the atopic triad

A

Asthma
Eczema (Atopic dermatitis)
Hay Fever (Allergic Rhinitis)

58
Q

Using pathophysiology, describe the difference between asthma and COPD

A

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.

59
Q

List three key signs/symptoms of asthma

A

Recurrent episodes of breathlessness and tight chest
Wheezing when exhaling
Nocturnal coughing

60
Q

Describe the difference between emphysema and chronic bronchitis associated with COPD

A

In emphysema, the walls of the alveoli are damaged and destroyed, leading to the collapse of the 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.

61
Q

Name two signs common to bronchitis

A

Cackles on auscultation
Tachypnoea, tachycardia
Cyanosis

62
Q

List three main signs of COPD

A

Tachypnoea
Breathlessness on exertion, pursed lips breathing
Barrel chest (hyperinflation)
Patients leaning forward, resting arms on the table
Flapping tremor (when arms stretched out forward)

63
Q

Using definitions, compare pneumonia to pulmonary fibrosis

A

Pneumonia is an infection of the alveoli and terminal bronchioles, mostly bacterial. [is associated with inflammation, oedema and infiltration of neutrophils].

Pulmonary fibrosis is the replacement of the single-layer epithelial lining in the alveoli, with fibrotic tissue.

64
Q

List two signs/symptoms of pneumonia

A

Breathlessness
Cough with purulent sputum (sometimes blood)
Crepitations on auscultation
Malaise
Fever

65
Q

List one autoimmune cause of pulmonary fibrosis

A

Rheumatoid Arthritis

66
Q

List two signs/symptoms of pulmonary fibrosis

A

Progressive dyspnoea
Chronic cough
Fatigue
Discomfort in the chest

67
Q

List two risk factors for sleep apnoea

A

Obesity
Nasal obstruction (rhinitis, polyps)
Smokers
Male gender
Alcohol, sedatives

68
Q

List two signs/symptoms of sleep apnoea

A

Loud snoring
Daytime sleepiness
Nocturnal choking
Morning headaches and drowsiness
Reduced libido

69
Q

Define pneumothorax

A

A medical emergency where air accumulates within the pleural cavity, causing all or part of the lung to collapse.

70
Q

Describe the pathophysiology of pleurisy

A

The pleural surfaces become coated with inflammatory materials and are hence roughened, producing a ‘friction rub’ on auscultation.

71
Q

Describe the nature of chest pain in pleurisy

A

Sharp chest pain while breathing

72
Q

In regards to pneumothorax, identify:

a. one spontaneous cause
b. one traumatic cause

A

a. Rupture of a cyst, TB, cystic fibrosis, emphysema

b. Fracture, surgical complication

73
Q

List two signs/symptoms of pneumothorax

A

Dyspnoea
Cyanosis
Loss of consciousness
Pleuritic chest pain (sharp)
Reduced breath sounds
Decreased cardiac output

74
Q

Explain how a pulmonary embolism develops

A

A pulmonary embolism results from an obstruction within the pulmonary arterial tree, often as a result of a thrombosis travelling up from one of the deep veins in the legs

75
Q

Why is calf pain an important sign in pulmonary embolism?

A

Calf pain signifies a DVT being causative

76
Q

Outline the pathophysiology of Cystic Fibrosis

A

Cystic fibrosis is a multi-organ genetic disease (due to a mutation in 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.

77
Q

List two signs/symptoms of Cystic Fibrosis

A

Persistent cough and sputum production
Recurring lung infections
Wheezing
Chest pain
Clubbed fingers
[GIT symptoms: bloating, obstruction, malnutrition, dyspepsia, bleeding]