W25 The Respiratory System Flashcards

Question

End of Expiration

Answer 1

* Alveolar/intra-pulmonary pressure = atmospheric pressure * No air movement

Answer 2

* Alveolar/intra-pulmonary pressure = atmospheric pressure * No air movement

Answer 3

* Pleural Pressure ( the pressure in the pleural cavity) * Normally lower than alveolar pressure. * Suction effect - fluid removal by the lymphatic system * Negative pressure difference (lower pleural pressure than alveolar pressure) keeps the alveoli expanded * Pulls the pleura away from the outside of the alveoli * Pressure on the alveoli is lower * Expansion is opposed by the tendency of the lungs to recoil

Answer 4

* Air introduced * Pleural pressure is not low enough to overcome lung recoil * Alveoli collapse

Answer 5

End of Expiration * Alveolar/ intra pulmonary pressure = atmospheric pressure * No air movement * Inspiration * Increased thoracic volume → * Increased alveolar volume * Decreased alveolar pressure * Atmospheric pressure > alveolar pressure * Air moves into lungs End of Inspiration * Alveolar pressure = atmospheric pressure * No air movement Expiration * Decreased thoracic volume * Decreased alveolar volume * Increased alveolar/intrapulmonary pressure * Alveolar pressure > atmospheric pressure * Air moves out of the lungs

Answer 6

* A passive event due to elastic recoil of the lungs * Relaxation of diaphragm and external intercostal muscles * During forced expiration, ONLY there is contraction of abdominal, internal intercostal (accessory muscles)

Answer 7

* No inherent rhythm * Generate tension due to rhythmic pattern of neuron-induced action potentials activating them * Muscles attempt to overcome the resistance to airflow within the airways * When at rest, the thorax assumes the FRC (Functional Residual capacity) position

Answer 8

* Spirometry is the process of measuring volumes of air that move into and out of the respiratory system * Measurements of the respiratory volumes can provide information about the health of the lungs * Peak Flow * Many more * Static Lung Volumes * Volumes/capacities * Dynamic Lung Volumes * How quickly air can be inspired/expired

Answer 9

* Respiratory volumes: * Measures of the amount of air movement during different portions of ventilation, * Respiratory capacities * Sums of two or more respiratory volumes. * The total volume of air contained in the respiratory system ranges from 4 to 6 L

Answer 10

* The volume of gas expired/inspired in one breathing cycle * Also known as ‘resting’ or ‘quiet’ breathing * Around 500ml (info)

Answer 11

* Inspiratory reserve volume is the amount of air that can be inspired forcefully beyond the resting tidal volume

Answer 12

* Expiratory reserve volume is the amount of air that can be expired forcefully BEYOND the resting tidal volume.

Answer 13

* Residual volume is the volume of air still remaining in the respiratory passages and lungs after maximum expiration (you cant breathe it out) * Without a residual volume, the lungs would completely collapse and the pressure required to generate inflation would be high

Answer 14

* The volume of gas in the lungs and airways at a position of full inspiration –therefore we are measuring how much air the lungs can actually hold * Lung expansion is limited at a point which defines TLC * Consists of IRV + TV + ERV + RV

Answer 15

* The total volume of gas that can be expired from the lungs from a position of full inspiration/ the total volume of gas that can be inspired from a position of residual volume * This is similar to an FVC manoeuver except it is not forced * Consists of IRV + TV + ERV

Answer 16

* The tidal volume plus the inspiratory reserve volume * The amount of air a person can inspire maximally after a normal expiration * Consists of IRV + TV

Answer 17

* The volume of gas in the lungs and airways at the end of a tidal breath * This is the point at which the inward pull of the lungs and the outward pull of the chest wall are in equilibrium * Consists of ERV and RV

Answer 18

A condition that makes it hard to exhale all the air in the lungs. Dec (small) ERV, TV and IRV Inc (big) residual volume

Answer 19

A condition that makes it hard to inhale all the air in the lungs. Dec in IRV TV ERV and RV

Answer 20

Cannot measure Total lung capacity (TLC), Forced Residual Capacity (FRC) and Residual Volume (RV)

Answer 21

Peak expiratory flow (PEF): a measure of how quickly you can blow air out of your lungs. * Measured in litres/minute (l/min) * “Normal” will depend on age, height and gender * Record in a peak flow diary and compare against “best” * Can be used for diagnosis of asthma or to predict oncoming asthma attack For diagnosis of asthma: Measure for 2-4 weeks More than 20% variability regarded as positive test

Answer 22

* Rate at which lung volume changes during direct measurement of the vital capacity. * FEV1 forced expiratory volume amount of air you can force from your lungs in one second * It is a simple and clinically important pulmonary test. * The individual inspires maximally and then exhales maximally as rapidly as possible into a spirometer. * The spirometer records the volume of air expired per second. * help identify conditions where vital capacity might not be affected but the expiratory flow rate is reduced * Asthma - contraction of the smooth muscle in the bronchioles increases the resistance to airflow * Emphysema - changes in the lung tissue result in the destruction of the alveolar walls, the collapse of the bronchioles, and decreased elasticity of the lung tissue. * increase the resistance to airflow

Answer 23

Forced Exhaled Volume in 1 Second ✓Amount of air exhaled in 1 second ✓Affected by airway diameter ✓Predict ‘healthy’ values by age, gender and height

Answer 24

Forced Vital Capacity ✓The total amount of air that can be exhaled (after a maximal inhalation) ✓FVC + Residual Volume = Lung Capacity ✓Predict ‘healthy’ values by age, gender and height

Answer 25

✓Does not require tables, FEV1 values adjusted to FVC ✓Ratio <0.7 indicates airway obstruction

Answer 26

1. Ventilation –we need to be able to get air to the alveoli for gases to exchange 2. Perfusion –the circulatory system needs to ensure blood gets to the alveolar

Answer 27

* Between air and blood occurs at the respiratory membranes * Alveoli * Some in the respiratory bronchioles and alveolar ducts * Not in conducting zone - the bronchioles, bronchi, and trachea. * The volume of these = anatomical dead space * Pathology such as emphysema can increase this

Answer 28

* 1. Thickness of the membrane * O2 exchange affected before CO2 * O2 diffuses through the respiratory membrane less easily than does CO2 * 2. Total surface area of the respiratory membrane * Reducing reduces gas exchange * 3. Partial pressure of gases across the membrane * Pressure exerted by a specific gas in a mixture of gases * PO2, PCO2 * Gases in the air dissolve in the liquid * Until partial pressure in liquid = to the partial pressure in air * Gases in liquid and air diffuse from areas of higher partial pressure toward areas of lower partial pressure until equal

Answer 29

Law of diffusion. V gas = kA/t x (P1-P2) Diffusion is proportional to difference between the conc of gas on both sides Inversely proportional to the thickness of the respiratory membrane

Answer 30

1. Blood from tissues has a lower Po2 and a higher Pco2 compared to alveolar air * O2 diffuses from the alveoli into the pulmonary capillaries * Po2 in the alveoli > in the pulmonary capillaries * CO2 diffuses from pulmonary capillaries into the alveoli * Pco2 pulmonary capillaries > alveoli 2. Venous ends of the capillaries: * Pressures equal because of diffusion * The blood carries O2 away by bulk flow to the tissues where O2 is required 3. Mixing with deoxygenated blood = lower PO2 than in capillaries 4. Oxygen diffuses out of the blood and into the interstitial fluid then into cells * Po2 in interstitial fluid < capillary * Po2 in cells < than interstitial fluid * Carbon dioxide diffuses from cells into the interstitial fluid and from the interstitial fluid into the blood * 5. Equilibrium

Answer 31

* As a gas in the lungs * Dissolved in tissue fluids * As oxyhaemoglobin in blood * As oxymyoglobin in muscle

Answer 32

* Consists of 4 myoglobin units joined together- Each has one polypeptide chain and one haem group * Haem contains central Iron (Fe2+ )atom * Iron atom binds to one oxygen as blood travels between lungs and tissues * one Hb molecule can bind 4 O2 molecules

Answer 33

*Ability of haemoglobin to bind to O2 depends on the Po2 *oxy-Hb dissociation curve *High Po2, haemoglobin binds to O2 *Low Po2, hemoglobin releases O2 *Lungs, Po2 normally high * haemoglobin holds as much O2 as it can *In the tissues, Po2 is lower * haemoglobin releases O2

Answer 34

*low Po2, *high Pco2 *low pH *high temperature *Physical Exercise

Answer 35

1. 7% is transported as CO2 dissolved in the plasma 2. 23% is transported bound to blood proteins, primarily haemoglobin 3. 70% as bicarbonate ions (carbonic acid= CO2 dissolved in H2O)

Answer 36

CO2 diffuses into plasma and RBC * Forms carbonic acid catalysed by carbonic anhydrase found inside RBC and on the capillary epithelium * Carbonic anhydrase increases the rate at which carbonic acid generated in tissue capillaries * promotes the uptake of CO2 by red blood cells. CO2 + H2O = H2CO3 = H+ + HCO3

Answer 37

Capillaries of the lungs * the process is reversed * CO2 diffuses from RBC to alveoli * HCO3−dissociates to produce H2CO3 * Carbonic anhydrase catalyses formation of CO2 and H20 from H2CO3 * The CO2 diffuses into the alveoli and is expired

Answer 38

* Carbon dioxide has an important effect on the pH of the blood * As CO2 levels increase, the blood pH decreases (becomes more acidic) because CO2 reacts with H2O to form H2CO3 (carbonic acid) * The H+ that results from the dissociation of H2CO3 is responsible for the decrease in pH. * Conversely, as blood levels of CO2 decline, the blood pH increases (becomes less acidic, or more basic)

Answer 39

Conducting zone

Answer 40

* Normal rate of breathing in adults * Between 12 and 20 breaths per minute * rate of breathing determined by the number of times respiratory muscles are stimulated * Breathing is spontaneously initiated within the central nervous system (CNS) * Medulla oblongata (brainstem) * An increased depth of breathing results from * stronger contractions of the respiratory muscles caused by recruitment of muscle fibres * increased frequency of stimulation of muscle fibres

Answer 41

The integration of stimuli that start and stop inspiration 1. Starting inspiration. * Neurons in the medullary respiratory center that promote inspiration - continuously active * stimulation from * blood gas levels, movements of muscles and joints, voluntary respiratory movements * When the inputs reach a threshold level * somatic nervous system neurons stimulate respiratory muscles ( via action potentials) * inspiration starts 2. Increasing inspiration. * Once inspiration begins, more and more neurons are activated * Progressively stronger stimulation of the respiratory muscles, lasts for approximately 2 seconds 3. Stopping inspiration. * Neurons stimulating muscles of inspiratory muscles also stimulate medullary neurons that stop inspiration * These also receive input from the pontine respiratory neurons * Stretch receptors in the lungs * When the inputs to these neurons exceed a threshold level, * they cause the neurons stimulating respiratory muscles to be inhibited. * Relaxation of respiratory muscles leads to in expiration (3 s). * Next inspiration step 1

Answer 42

1. Maintain, through involuntary controls, a regular rhythmic breathing pattern 2. Adjust the tidal volume (VT) and breathing frequency (fb) such that alveolar ventilation is sufficient to meet the demands for gas exchange at cellular level 3. Adjust the breathing pattern to be consistent with other activities using the same muscles, such as speech * Some conscious control

Answer 43

Sensors- Chemoreceptors, lungs and other receptors (input to CCS) Central Control System- Pons, medulla, and other parts of the brain (Output to effectors) Effectors- Respiratory muscles

Answer 44

The major groups of neurons in respiratory centre which control respiration: Pons * Pontine respiratory group * Controls switches between inspiration and expiration Medulla * Dorsal respiratory group (DRG) * Diaphragm (inspiratory) * Ventral respiratory group (VRG) * Intercostals * Abdominals * Inspiratory and expiratory

Answer 45

* Some voluntary control * Most autonomic * Several reflexes, such as sneeze and cough reflexes, can modify breathing * The Hering- Breuer reflex * limits the extent of inspiration * As the muscles of inspiration contract the lungs fill with air * Sensory stretch receptors located in the lungs are stimulated * Action potentials sent to the medulla oblongata * Here they inhibit the respiratory centre neurons and cause expiration * In infants important role in regulating the basic rhythm of breathing and over inflation * In adults when the tidal volume is large - during heavy exercise

Answer 46

* Level of CO2 (not O2), in the blood is the major driving force * Even a small increase in the CO2 level (hypercapnia) results in a powerful urge to breathe * Breathing is controlled so finely that the PaO2 and PaCO2 are kept within normal limits * To achieve this, the system has three control pathways – * The PCO2 is the principle pathway, controlling the rate and depth of breathing on a breath-by-breath basis * Under certain circumstances, such as acclimatization to altitude, the PO2 pathway (the second pathway) can override the PCO2 pathway. * A third pathway is required to allow all other actions such as talking, swallowing and coughing to break through the normal pattern of breathing and try to match breathing to the expected voluntary or behavioural activity

Answer 47

An increase CO2 causes an inc in H+ ions which increases ventilation and vice versa as follows: 1. PaCO2 rises causing a rapid increase in H+ ions 2. This causes pH to fall (increase acidity) 3. This causes the central chemoreceptors to transmit a signal to increase ventilation 4. In doing so, PaCO2 and CO2 decrease and when balance is restored, ventilation will decrease

Answer 48

Centrally * Medulla oblongata Peripherally * Carotid bodies * Aortic bodies

Answer 49

* pH that accompanies an increase in CO2 levels * Chemoreceptors * Medulla oblongata * chemoreceptors H+ concentration * pH CO2 * If blood CO2 levels decrease, pH increase →medullary chemoreceptors signal a decreased breathing rate →retains CO2 in the blood * More CO2 in the blood causes H+ levels to increase, →blood pH to decrease to normal levels * Carotid and Aortic bodies: * pH, Co2, O2 * Increased breathing

Answer 50

Parasympathetic NS is dominant in the lungs Airways * Innervated by the vagus nerve –Parasympathetic * Dominant * Bronchoconstriction * Innervated by the Sympathetic nerve chain Respiratory Muscles * Innervated by the intercostal (motor) nerves * Phrenic nerve innervates the diaphragm

Answer 51

Neurotransmitter (effector) –Acetylcholine (Ach) * Receptors –muscarinic / cholinergic receptors * M1 to M5 * Airways: M1 M2 M3 present. M3 most important * Muscarinic receptors * Stimulation causes the contraction of bronchial smooth muscle * Muscarinic receptors located in many glands help to stimulate secretion e.g. mucus and saliva

Answer 52

Neurotransmitter (effector) –Noradrenaline (NA) * Receptors –adrenergic receptors * alpha, beta1 and beta2 * Beta1 receptors –heart * Stimulation increases rate and force e.g. adrenaline/epinephrine * Beta2 receptors –smooth muscle of bronchioles * Stimulation (Agonist) causes relaxation e.g. salbutamol

Answer 53

Static- not forced Dynamic- forced and measured over time

Answer 54

* Chronic Obstructive Pulmonary Disease (COPD) * Asthma (obstructive) * Congenital and genetic lung conditions e.g. Cystic Fibrosis (obstructive) * Obstructive sleep apnoea * Restrictive lung disease e.g. occupational lung disease * Lung cancer (restrictive) * Respiratory muscle disorders e.g. ALS (Restrictive)

Answer 55

-How much air can be inhaled -Reduced by RESTRICTIVE airway disease

Answer 56

-How quickly air can be moved out or into the lung -Air flow reduced by OBSTRUCTIVE airway disease

Answer 57

More difficult for air to flow out of the lungs due to increased airway resistance, causing a decreased flow of air in and out of the lungs This may be due to: * Partial occlusion of the lumen due to excessive secretions (e.g. chronic bronchitis) * Contraction of smooth muscle of the bronchi (e.g. asthma) * Hypertrophy of mucous glands (e.g. chronic bronchitis) * Inflammation and oedema of airway wall (e.g. bronchitis and asthma) * Loss of radial traction (e.g. emphysema)

Answer 58

* A chronic inflammatory disorder of the airways with reversible airway obstruction and increased airway responsiveness to a variety of stimuli * Variable airflow limitation that normalises with treatment or spontaneously

Answer 59

* Shortness of breath * Chest tightness or pain * Wheezing during exhalation * Coughing or wheezing attacks that are worsened by a respiratory virus * Chronic cough * Significantly variable breathlessness * Night-time wakening with breathlessness and/or wheezing * Significant diurnal or day-to-day variability of symptoms

Answer 60

Low-velocity and narrow tubes High velocity & Irregular walls The pressure difference required to maintain airflow need to be increase Respiratory muscles need to work harder to expand and contract the lungs

Answer 61

Genetic factors: Cytokine response profiles Environment: Allergens, Pollutants, Infection, Stress Age

Answer 62

Allergens * House dust mite * Pets * Fungal spores * Pollens Infections * E.g. LRTI Others * Smoking * Pollution * Occupational hazards (e.g. flour, chemicals) * Stress * Exercise * Cold air

Answer 63

* Induced by airway inflammation * Bronchoconstriction * AHR – exaggerated bronchoconstricting response to stimuli * Airway oedema – as disease becomes more persistent and progressive AHR= Airway Hyper responsiveness

Answer 64

Bronchial smooth muscle contraction that narrows the airways in response to stimuli Narrowing the airway makes it harder to breath- increased resistance * Increased mucous decreases airway diameter * Smooth muscle contraction narrows airway = Causes asthma attack

Answer 65

Turbulent airflow around blockage causes characteristic wheezing

Answer 66

* Asthma exacerbation * Airways already narrowed -mucosal inflammation -smooth muscle hypertrophy * Airways further constricted due to increased smooth muscle tone * Decrease the diameter of the airways * Causing resistance to airflow to become very high * Combined with hyperinflation * Patient must work harder to overcome the increased resistance * This can lead to turbulent flow * Causes characteristic wheeze of an asthma attack

Answer 67

* All patients to receive a preventer inhaler in addition to their reliever. * Choice of device based on patient preference and technique. * Where possible, use an inhaler with low global warming potential. * If more than one inhaler given, give the same type

Answer 68

(P)MDI- Pressured metred dose inhaler e.g. Saprobec, Clenil Modulate Dry powder inhaler e.g. Budesonide, Salbutamol, Terbutaline

Answer 69

A measure of how quickly you can blow air out of your lungs. * Measured in litres/minute (l/min) * “Normal” will depend on age, height and gender * Record in a peak flow diary and compare against “best” * Can be used for diagnosis of asthma or to predict oncoming asthma attack

Answer 70

* Pull the counter (the red arrow) back as far as it will go to the top near the mouthpiece. * Stand or sit upright – choose what’s most comfortable for you and always do it that way. * Take the deepest breath you can. * Make sure your mouth makes a tight seal around the mouthpiece. * Blow as hard and as fast as you possibly can into the meter. * Write down your score (the number next to the pointer). * Do this three times in a row so you get three scores (all three scores should be roughly the same). * Use the highest of these scores to fill in your peak flow diary.

Answer 71

* Measure for 2-4 weeks * More than 20% variability regarded as positive test * Up to 20% lower than best is considered normal * 20-50% lower than normal means action needs to be taken * Medical help * Action plan

Answer 72

Residual volume-the volume of air remaining in the lungs after maximum forceful expiration.

Answer 73

Epiglottis which is part of the larynx Protects the airway when swallowing

Answer 74

Obstructive

Answer 75

A decrease in the total volume of air that the lungs arr able to hold

Answer 76

A decrease in the total volume of air that the lungs arr able to hold

Answer 77

Bronchioles are constricted and the airway passages become narrow (lined with mucus). You cannot breathe the full amount of air in one breath, so your breathing is short and low volume

W25 The Respiratory System Flashcards

(104 cards)