19. Respiratory System Practicals Flashcards

Question

Predict and explain the change (if any) in the ratio FEV1/FVC in restrictive lung disease

Answer 1

Vital capacity is reduced dramatically, but airway resistance is normal, so both values decrease and the ratio stays the same

Answer 2

It is small, inexpensive, and easy to use, which means that peak flow can be monitored at home Patients can be educated to recognise when the values change to a degree that they should seek medical advice

Answer 3

FVC, FEV1, FEV1/FVC ratio, and PEFR generally increase with increased subject size, as measured by height

Answer 4

FVC, FEV1, FEV1/FVC ratio, and PEFR generally decrease with age after peaking at 20

Answer 5

FVC, FEV1, FEV1/FVC ratio, and PEFR are generally lower in females than in males of the same age and height

Answer 6

These changes in structure and function may increase airway resistance: - Bronchoconstriction: o Smooth muscle contracts in the wall of the airways o This is frequently the case in asthmatics - Physical blockage: o An example is increased mucus secretion o This leads to more viscous mucus, which is more difficult to remove and thus forms mucus plugs in airways - Loss of radial traction (outward pull) - Change to the airway wall structure: o The lumen can narrow, which occurs frequently in asthmatics - Airway inflammation: o This leads to swelling of tissue and a reduction in luminal diameter

Answer 7

Arterial PO2 decreases Arterial PCO2 increases Consequently, oxygen saturation of the blood falls: o There is less oxygen for the haemoglobin to carry o Carbon dioxide now binds to the haemoglobin to be carried back to the lungs to be removed

Answer 8

Over-breathing of room air: - Arterial PO2 increases - Arterial PCO2 decreases - O2 saturation remains constant Normal: - Arterial PO2 increases greatly - pCO2 remains constant - O2 saturation rises slightly Over-breathing of oxygen: - Arterial PO2 increases even more greatly - pCO2 goes down - O2 saturation rises slightly

Answer 9

Increased pCO2 and decreased pO2 stimulates the central and peripheral chemoreceptors, which instigate nervous impulses from the respiratory centre that overcome voluntary suppression by the apneustic centre: o This forces the subject to stop holding his/her breath and take another breath of fresh air to bring oxygen levels back up and lower carbon dioxide levels

Answer 10

Ventilation increases linearly with pCO2, but a marked fall in pO2 must occur before there is a noticeable rise in ventilation: o This means that if the arterial pO2 falls significantly during breath-hold, the various responses will cause the ventilation rate to be increased and so the breath can no longer be held

Answer 11

If pCO2 is reduced immediately before breath hold, stimulation of the chemoreceptors will occur in the required degree at a later time, thereby allowing the breath to be held for longer There is, however, little effect if the pO2 is changed before the breath hold

Answer 12

Neural stimuli from the chest wall and lung receptors induce chest expansion and thus influence breath holding time

Answer 13

The factors that determine alveolar PO2 and PCO2 are: o Composition of inspired air o Alveolar ventilation o Metabolic rate (O2 use and CO2 production)

Answer 14

Hypoventilation: breathing at an abnormally shallow and slow rate, resulting in increased pCO2 Hyperventilation: breathing at an abnormally rapid rate (at rest) leading to a decreased pCO2 Hyperpnoea: rapid ventilation appropriate for a metabolic acidotic state, as observed in exercise

Answer 15

Alveolar PO2 and PCO2 and end-pulmonary PO2 and PCO2 should be the same respectively due to the efficiency of the diffusion process

Answer 16

A reduction of haemoglobin concentration in the blood, or anaemia, does not affect arterial pO2 or pCO2 However, anaemia drastically decreases oxygen content Hyperventilation with oxygen-rich gas will improve pO2 will improve pO2, but since the haemoglobin present is already 97% saturation, it will not cause a significant rise in oxygen content

Answer 17

Hypoventilation causes a decrease in pO2 and oxygen content, and a rise in pCO2 Breathing an oxygen-enriched gas will improve pO2 and return oxygen content to normal, but will also reduce pCO2

Answer 18

pO2: 13.3 kPa pCO2: 5.3 kPa Hb saturation: 97% Hb concentration: 15 g/dl

Answer 19

COPD can consist of three pathological conditions, bronchitis, emphysema and small airways disease, but people with COPD do not necessarily have all three conditions

Answer 20

This affects the bronchi mainly and generally not the bronchioles The bronchi here are cartilaginous as they are part of the large airway path compared to the non- cartilaginous bronchioles which are part of the small airway

Answer 21

This mainly affects the respiratory bronchioles, especially of smokers It leads to the loss of the connective tissue scaffold, basement membrane and normal cell organisation There is also a loss of surface area and elastic recoil of alveoli, which compromises gas exchange

Answer 22

This affects the bronchioles and other non-cartilaginous regions of the airways

Answer 23

Lung function tests measure FEV1, vital capacity, and so on to obtain a baseline level of measurements to measure against These tests will be repeated after the trial and a comparison of the two results will be done

Answer 24

An endoscope is passed through the respiratory tract and then into the lungs, in through the bronchioles and alveoli The endoscope aspirates a sample of tissue and other material, much like in a biopsy; the sample is then analysed The material aspirated is known as a peripheral wash and contains: o Surfactant, found in the epithelia and produced by Type II cells o Macrophages o Neutrophils The number of these inflammatory cells (neutrophils and macrophages) is analysed: o In healthy lungs, there should be a ratio of 70% macrophages to 30% neutrophils o In COPD, there is a ratio of 70% neutrophils to 30% macrophages The purpose of the branchoalveolar lavage is to obtain a cell count of inflammatory cells

Answer 25

High resolution CT scans offer a far more detailed scan than regular CT, allowing things to be seen on a micro scale With bronchitis, the small airways would appear to be denser in number on the scan With emphysema, there would be many holes in the small airways of the lungs With COPD, the small airways would again seem to be denser

Answer 26

Bronchoalveolar lavage is a medical procedure in which a bronchoscope is passed through the mouth or nose into the lungs and fluid is squirted into a small part of the lung and then collected for examination It is typically performed to diagnose lung disease

Answer 27

There are many holes in the small airways of the lungs, which are the result of an endogenous immune response The macrophages and neutrophils contain proteases, which are released during the inflammatory phase of emphysema These proteases break down the host tissue in order to help cell migration and break down any particulate matter deposited in the lungs The neutrophils release many oxygen free radicals, which are very toxic: o These reactive oxygen species are secreted to kill any infecting microbes The macrophages also secrete many chemicals prior to the phagocytosis of the foreign or infecting microbe: o Lysozymes within the macrophage complete the digestion of the microbe However, if either the oxygen free radicals, lysozymes, or proteases leak out of the inflammatory cell, they cause irreversible damage to the host tissue: o It is basically protease secretion overload that causes tissue destruction in emphysema Emphysema is far more prevalent in smokers: o This is due to a deficiency in the enzyme α-1-antitrypsin, which circulates in the blood and is able to mop up all the excess proteases

Answer 28

Small airways are easily obstructed by particular matter and mucous Smokers inhale cigarette smoke, which contains many harmful particles that obstruct their airways: o This leads to the 'smoker’s cough', as coughing is the only way smokers can manage to remove some of these trapped particles

Answer 29

The airway becomes damaged in some way, either due to the endogenous immune response or by cigarette smoke As it is repaired, the airway narrows as new tissue grows to replace the old, damaged tissue The scar tissue remains and narrows the airway

Answer 30

Excess mucous is produced by the goblet cells as the number of goblet cells increases; at the same time, the number of ciliated cells decreases Consequently the trapped particles cannot be removed by the cilia, as there are not enough of them, and they tend to beat in a disordered fashion Coughing is the only way possible to attempt to clear the blocked airways, leading to the characteristic smoker’s cough As the mucous traps particles, dirt, and foreign microbes, the inflammatory cell number also increases In the peripheral lung, there are likely to be deposits of particle matter In conducting lung airways, there are likely to be deposits of foreign infecting cells and so many neutrophils will be found here

Answer 31

A protease inhibitor inhibits the action of the secreted proteases It is only given to people who stop smoking completely as inhaled cigarette smoke will tend to inhibit protease inhibitors

Answer 32

An example of an endogenous inhibitor is a tissue inhibitor of metalloproteinases (TIMP) Endogenous inhibitors do not work as there is proteolytic overload: o Too many protease enzymes have been released into the lungs, causing damage An endogenous inhibitor would not remove any of the protease already present The oxidants in cigarette smoke also prevent endogenous inhibitors from working

Answer 33

A dual inhibitor would be effective, as the protease inhibitor would inhibit the protease already present in the lungs and the endogenous inhibitor would act by preventing the release of more protease There would be a synergistic effect in limiting the protease action

Answer 34

The excess mucous present in the lungs would not allow inhaled therapy to be effective Some of it would be coughed up in order to try and remove it, but not enough would be removed The method of massaging the chest may also help to remove some of the mucous Administration of mucolytic, which breaks down mucous, would be the only effective way of removing the excess mucous

Answer 35

A bronchodilator would help, as it makes breathing easier: o The airways would be dilated However, if the airways are constricted due to reasons other than bronchoconstriction, the effectiveness of the bronchodilator would be lessened

Answer 36

The LFT should show improvement: o FEV1 should increase o VT should increase Bronchoalveolar lavage should show a drop in inflammatory cell numbers CT scan would not show a decrease in the number of holes in the lungs: o Some may appear to have been healed, but this will not be functional tissue; rather, it is scar tissue o If therapy was successful, there should not be any more holes in the lung walls than before the treatment

Answer 37

[See http://www.icsmsu.com/exec/wp-content/uploads/2011/12/ABS-Respiratory_System.pdf Page 90] [See Google Images]

Answer 38

Metaplasia: the reversible change in differentiation from one fully differentiated type to another Dysplasia: an abnormal pattern of growth in which some of the histological features of malignancy are present Hyperplasia: an increase in size of a tissue or organ resulting from an increase in the number of cell Hypertrophy: an increase in size of a tissue or organ resulting from an increase in size of individual cells

Answer 39

Lobectomy: removal of a lung lobe Pneumonectomy: removal of a complete lung

Answer 40

Emphysema: destruction of the walls of the alveoli, producing abnormally large air spaces Pleural effusion: accumulation of fluid in the pleural space, possible causing pleurisy Atelectasis: incomplete expansion of the lung or portion of the lung due to airway obstruction, lung compression or inadequate pulmonary surfactant Haemoptysis: coughing up of blood

Answer 41

A: Normal lung B: Emphysema D: Normal lung E: Emphysema

Answer 42

Signs: - Finger clubbing: increased nail bed sponginess, which leads to a loss of angle between the nail and the nail bed - Hyperinflation: increased volume and hyper-expansion of the thorax due to expiratory airflow limitation - Central cyanosis: a bluish tongue that indicates a low pO2 of around 7-8 kPa - Tachypnoea: an increase in respiratory rate to maintain pCO2 and pO2 within normal range

Answer 43

Symptoms: - Dyspnoea: shortness of breath or an unpleasant awareness of breathing - Cough: a rapid expiratory manoeuvre due to stimulation of irritant receptors in the respiratory tract membrane - Haemoptysis: the coughing up of blood from the nose, nasopharynx, vocal cords or lower respiratory tract - Chest pain: pain in the thorax, attributable to various causes: o Pleural pain is due to infection, infarction, and connective tissue disease o Mediastinal pain is due to a large pulmonary embolism or mediastinal lymphadenopathy o Chest wall pain is due to rib fracture, nerve root pain, or costonchondritis, which is the inflammation of the junction between the bone and cartilage

Answer 44

Lymphadenopathy or adenopathy is disease of the lymph nodes, in which they are abnormal in size, number, or consistency Lymphadenopathy of an inflammatory type (the most common type) is lymphadenitis, producing swollen or enlarged lymph nodes

Answer 45

Breathlessness can be tested during a shuttle walking test Signs include tachypnoea: o Tachypnoea is an appropriate involuntary response in which the respiratory rate is increased to maintain PO2 and PCO2 o Hyperventilation is instead a voluntary increase in the minute ventilation that results in a fall in arterial PCO2 Other signs include a sense of doom, wheezing, chest pain, cold, clammy skin and central cyanosis

Answer 46

Peripheral cyanosis: - Peripheral cyanosis can be indicated by a bluish colour of the hands - However, a bluish colour of the hands could also indicate poor peripheral circulation Central cyanosis: - Central cyanosis is often due to a circulatory or ventilatory problem that leads to poor oxygenation of blood in the lungs - Assessment of the tongue colour is preferred - A bluish tongue indicates a low arterial PO2 of 7-8kPa

Answer 47

Hyperinflation commonly accompanies COPD, as the predominant problem in COPD is expiratory flow limitation Expiratory flow is limited, resulting in air trapping and therefore an increased volume of air in the lungs at the end of expiration Signs present upon examination include: ``` o Prolonged expiratory phase o Expanded, barrel-shaped chest o Reduced overall movement of ribcage o Apex beat of the heart not palpable o Increased activity of the sternocleidomastoid ``` Results of the lung tests include increased TLC, RV, and FRC, as it is harder to breathe out

Answer 48

Palpitation: - Reduced overall movement of the chest wall: Hyperinflation - Reduced local chest wall movement: Consolidation - Deviation of the trachea to: Collapse - Deviation of the trachea away: Tension pneumothorax Percussion: - Note reduced: Lung collapse, effusion, or consolidation - Note increased: Pneumothorax

Answer 49

Wheeze: - Wheeze is a musical sound that reflects the airways narrowing - It can be caused by a generalised disease such as asthma, COPD, or pulmonary oedema, or by a localised factor such as a tumour or foreign bod Crackle: - Crackle is the equalisation of the intra-luminal pressure of the collapsed small airways during inspiration - This occurs in Acute Respiratory Distress Syndrome (ARDS), pulmonary fibrosis, and bronchiectasis.

Answer 50

Pitting oedema is the accumulation of fluid within the connective tissue of the skin in a gravitational distribution An indentation remains after gentle pressure is applied over a bony prominence It may arise in conditions like COPD or pulmonary hypertension

Answer 51

Colour Consistency Volume Smell

Answer 52

Clear/White: COPD Green: Chest infection Blood-stained red: Pulmonary embolism Blood-stained rusty red: Pneumonia Blood-stained pink: Pulmonary oedema

Answer 53

Mucoid: COPD Thick: Cystic fibrosis High volume of clear sputum: Asthma

Answer 54

Over 20ml per day: Bronchiectasis or Cystic fibrosis

Answer 55

Foul smelling: Anaerobic chest infection

Answer 56

Bronchiectasis is a disease in which there is permanent enlargement of parts of the airways of the lung Symptoms typically include a chronic cough with mucus production Other symptoms include shortness of breath, coughing up blood, and chest pain