W1 Flashcards by Lucy Carter (2024)

What is Ventilation?

exchange of air between atmosphere and alveoli – capillary network

What is Alveolar pressure?

gas pressure in the alveoli

What is Transpulmonary (transmural) pressure

What is the dependent lung

the lowermost portion of the lung, so in an upright position this is the bases

When do the lungs start to deteriorate?

Around the age of 35, lungs start to deteriorate.
Changes include alterations in alveoli shape, stiffening of rib bones, weakening of the diaphragm, and reduced sensitivity of nerves to irritants.

At what age is peak lung function?

Lungs typically reach their peak function around 25 years of age.

What factors can accelerate age-related changes to the lungs?

Smoking, air pollution, increased central body mass index (BMI), and prolonged bed rest can accelerate age-related changes in breathing.

What controls breathing?

Where does the control of breathing originate, and what is the pathway involved?

The control of breathing originates in the brainstem (pons & medulla) in the respiratory center.
The pathway involves the ventral lateral tract, spinal cord, phrenic nerve, intercostal nerves, respiratory muscle contraction, movement of thorax & lungs, air entering alveoli, gas exchange across the alveolar-capillary membrane, and arterial blood.
Feedback mechanisms are present in the loops.

What are mechanoreceptors and where are they located?

Mechanoreceptors are sensory receptors that detect stretch and movement in the thorax and lungs.
They are located in bronchial smooth muscles, trachea, and visceral pleura.

What are chemo receptors and what do they monitor?
What are the two types?

What are the effects of low oxygen or high carbon dioxide levels on chemo receptor activity?

Low oxygen or high carbon dioxide levels increase chemo receptor activity, leading to faster and deeper breathing to compensate.

Where are peripheral chemoreceptors located?

Peripheral chemoreceptors are located in the carotid bodies (via glossopharyngeal nerve) and aortic bodies (via the vagus nerve).

What is the pathway of blood flow in the cardiorespiratory system?

Mixed venous blood enters the right atrium via superior and inferior vena cava.
It then moves to the right ventricle via the tricuspid valve.
From there, it is pumped through the pulmonary valve into the pulmonary artery, which branches into the left and right pulmonary arteries which then further subdivide into smaller arteries and arterioles as they reach the lungs.
The capillary bed lies on the wall of the alveoli, facilitating gas exchange.
Oxygenated blood returns to the left atrium via the left and right pulmonary veins.
It then enters the left ventricle via the bicuspid valve and is pumped through the aortic valve into the aorta, circulating throughout the body.

What does FRC stand for, and what does it represent?

FRC stands for Functional Residual Capacity.
It represents the volume of air remaining in the lungs after a normal expiration.
ERV + RV

What does TV stand for, and what does it represent?

TV stands for Tidal Volume.
The volume of air moved into and out of the lungs during each ventilation cycle.
t measures around 500 mL in an average healthy adult male and approximately 400 mL in a healthy female.

What does VC stand for, and what does it represent?

Vital capacity (VC) is the maximum amount of air a person can expel from the lungs after a maximum inhalation. It is about 3.5 – 4.5 litres in the human body.
It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. It is approximately equal to Forced Vital Capacity (FVC)

What does CV stand for, and what does it represent?

CV stands for Closing Volume.
It represents the volume of air at which small airways close.
For adults, it’s around 10% of VC, while for older adults (65 years), it can be up to 40% of VC, with CV equaling FRC.
Closing capacity equals CV plus residual volume.
It indicates the rate at which lungs begin to collapse or close, increasing with age and occurring with asthma or pulmonary disease.

Total lung capacity: the volume in the lungs at maximal inflation.
IRV + TV + ERV + RV

What does RV stand for, and what does it represent?

Residual volume: the volume of air remaining in the lungs after a maximal exhalation

What does ERV stand for, and what does it represent?

Expiratory Reserve Volume. It refers to the additional volume of air that can be forcibly exhaled from the lungs after a normal exhalation.

What does IRV stand for, and what does it represent?

Inspiratory Reserve Volume. It refers to the additional volume of air that can be inhaled into the lungs beyond a normal inhalation. In other words, after you’ve taken a normal breath, there’s still some extra air that you could inhale if needed. IRV represents the amount of air that you can breathe in forcefully beyond this normal inhalation.

What does FEV1 stand for, and what does it represent?

Volume that has been exhaled at the end of the first second of forced expiration

What does PEF stand for, and what does it represent?

Peak expiratory flow: The highest forced expiratory flow measured with a peak flow meter

What is spirometry?

Spirometry is the measurement of flow and volume in the respiratory system.
It can be an objective measure to assess or monitor disease progression and to monitor a patient’s deterioration during an acute respiratory episode or the efficiency of a drug, such as a bronchodilator.

What are the changes in lung volumes across different age groups and conditions?

Children: Increase in lung volumes up to age 20.
Older Adults: Decrease in vital capacity and tidal volume.
Conditions leading to decreased lung volumes in adults: Chest pain; Respiratory muscle weakness; Bony thorax deformity; Pleural effusions; Pneumothorax; Depressed respiratory drive; Occupational lung diseases.

What is the process of spontaneous respiration?

What is compliance?

Compliance measures the lung’s ability to stretch and expand, which is determined by lung volume, elastic recoil, surfactant, and the lung’s ability to stretch.
Low compliance is seen with oedema (ARDS), scar tissue (pulmonary fibrosis), deformity (kyphoscoliosis), muscle paralysis (polio) and restrictive lung conditions, while high compliance is seen in conditions like emphysema (COPD) initially (although hyperinflation causes decreased compliance)

What is elastic recoil?

Refers to the ability of the lungs and chest wall to return to their original shape and size after being stretched during inhalation

What is surfactant

Specialized cells in the alveoli produce a substance called surfactant. Surfactant acts like a detergent, reducing the surface tension of the fluid lining the alveoli. By lowering surface tension, surfactant prevents the alveoli from collapsing after each breath.

What factors affect elastic recoil?

Elastic recoil is affected by collagen, elastane, and surface tension/surfactant.
Age and pathology, such as emphysema or pulmonary fibrosis, can alter elastic recoil.

What is airway resistance?

Airway resistance refers to the resistance of the respiratory tract to airflow during inspiration and expiration.
It is affected by the calibre/patency of the airway, with smaller airways having greater resistance.
Conditions like asthma and bronchospasm can increase airway resistance.

What is ventilation?
Which area of the lungs is better ventilated?

Ventilation is the movement of air into and out of the lungs.
Lower regions of the lung are ventilated better than upper zones due to the weight of the lung and pleural pressure gradient.

What is perfusion?
Which area of the lungs receives better perfusion?

Perfusion refers to the blood flow reaching the lungs to pick up oxygen and release carbon dioxide.
Blood flow is greater in the gravity-dependent portion of the lung (bottom of lungs).

What is ventilation-perfusion matching?

The bases of the lungs have a greater proportion of blood flow (perfusion) relative to air flow (ventilation).
The apex of the lungs has more ventilation relative to perfusion.
Mid-lung regions provide the most efficient gas exchange due to optimal ventilation-perfusion matching.

How are the airways protected from particles?

Large particles (>10 µm) are filtered by the nose or removed by cough or sneeze reflex.
Smaller particles (2-10 µm) are deposited in conducting airways and removed by the Mucociliary Escalator.
Smallest particles (<2 µm) are deposited in alveoli and removed by macrophages.

What are the effects of smoking and dust exposure on lung function?

Smoking and exposure to silica dust and asbestos fibers can injure macrophages and alveolar walls, making the lungs more susceptible to infections and promoting pulmonary fibrosis

What are the general features of the lungs?

Each lung has an apex, base, mediastinal surface, and costal surface.
Lungs are divided into lobes by fissures.
Hilum of lung: area on the medial surface where structures enter and leave. It’s the area where the lung is attached to the mediastinum
Root of lung: = structures themselves that enter/exit the hilum
Attached the lung to the mediastinum
Icludes a primary bronchus; delivers air to the lung
Pulmonary artery; delivers deoxygenated blood from the right ventricle of the heart
Pulmonary veins; delivers oxygenated blood back to left atrium of the heart
Bronchial arteries; deliveries oxygenated blood to supply the lung tissue itself
Lymphatic vessels
Branches of pulmonary nerve plexus to innervate the lungs

What structures make up the thorax?

Bony thorax: ribs, vertebral column, sternum
Joints: intervertebral, costovertebral, costochondral, manubrium sternum, sternocostal
Muscles: innervated by phrenic and intercostal nerves
Pleura: parietal and visceral pleura line the lungs

What is pleural linkage?

The thoracic rib cage acts as a mechanical pump for the lungs.
Pleural linkage refers to the lungs sticking to the walls of the thoracic cavity to be pumped.
Muscles of respiration drive this pump.

Visceral pleura

Covers the surface of the lungs

Parietal pleura

Lines the inner surface of the thoracic cavity

Pleural fluid

In between visceral and parietal pleura
Acts as a lubricant and allows smooth movement between the lungs and chest wall during breathing
Also assists in surface tension and pleural linkage

What is pleural linkage?

Which muscles are involved in respiration?

What dimensions does the thorax change during breathing?

Antero-posterior (forwards & backwards): “Pump Handle” movement
Transverse: “Bucket Handle” movement
Vertical: Mainly by the diaphragm

What defines the conducting zone of the respiratory system?
Function?
Structure?
Lining?

No gas exchange occours
Function = filter, warm and humidity air and conduct it into the lungs
Contains goblet cells that secrete mucus.
Features the mucociliary escalator, driven by cilia, which clears mucus and foreign particles.
Structures involved = Extends from trachea to terminal bronchioles.
Lining = simple columnar epithelium, pseudostratified ciliated epithelial cells

What characterizes the respiratory zone?
Function?
Structure?
Lining?

What are the types of dead space in the respiratory system?

Anatomical dead space: air in conducting zones (~150ml).
Alveolar dead space: air in alveoli with little or no blood supply. - Enters & leaves lungs but does not participate in gas exchange
Physiological dead space = anatomical + alveolar.
Increases with age and lung disease.

What is minute ventilation?

Total volume of gas entering the lungs each minute.
Calculated as Tidal Volume (TV) × Respiratory Rate (RR).

What is alveolar ventilation?

Total volume of fresh air entering the alveoli per minute.
Calculated as (TV - Anatomical dead space) × RR.

What are alveoli and how are they stabilized?

300-500 million hollow sacs in the lungs.
Stabilized (reduces risk of collapse) by pulmonary surfactant secreted by type II alveolar cells.
Surfactant reduces surface tension, improving stability and compliance.

What is pulmonary surfactant?
What is it secreted by?

What does the velocity of gas flow in the respiratory system depend on?

Volume of gas flow in/out of alveoli is
Directly proportional to pressure difference between atmosphere and alveoli
Inversely proportional to airway resistance

Describe the processes of inhalation

Describe the processes of exhalation

What are the types of respiration and their characteristics?

Quiet respiration: Active inspiration, passive expiration
Forced respiration: Active inspitation and expiration, involving accessory muscles.

What is the patient position for a Postero-Anterior (PA) view, and what are the effects on the film?

Patient Position: Standing, arms abducted.
Effect on Film: Accurate proportions.
Advantage: More accurate heart size on film.
Disadvantage: Unable to use this position if the patient is unable to stand.

What is the patient position for an Antero-Posterior (AP) view, and what are the effects on the film?

Patient Position: Supine, sitting up in bed.
Effect on Film: Enlarged heart. May be able to see more of the medial border of the scapula.
Advantage: Easy position to get into.
Disadvantage: Tends to magnify the mediastinum, harder to get full inspiration film.

What is the patient position for a Lateral view, and what are the effects on the film?

Patient Position: Standing lateral with arms outstretched in front.
Effect on Film: Views of fissures. Can be difficult to decipher changes at the height of the hemidiaphragm.
Advantage: Middle lobe pathology clearer.
Disadvantage: Unable to use this position if the patient is unable to stand or lift arms up.

What is the patient position for an Oblique view, and what are the effects on the film?

Patient Position: Standing/sitting, PA/AP, rotated 45° away from the film. One arm on hip and one at shoulder level resting on.
Effect on Film: Clear picture of mediastinum.
Advantage: Mostly used for looking at heart and mediastinum. Lung fields, apices, oblique and horizontal fissures more discernible.
Disadvantage: Must stand or sit independently in a difficult position.

What does the Rotation check involve in chest X-rays?

Ensure the length of the clavicles is equal on both sides.
This check ensures that the patient was not rotated during the imaging process, which can affect the anatomical accuracy.

What does the Inspiration check involve in chest X-rays?

Confirm the visibility of 5-6 anterior ribs above the diaphragm.
Check visibility of costophrenic angles and lung apices.
Indicates the X-ray was taken at full inspiration, essential for optimal lung and pleural space visualization.

What does the Exposure check involve in chest X-rays?

Ideal exposure shows vertebrae just visible behind the heart.
Underexposed X-rays appear too white, obscuring details.
Overexposed X-rays appear too black, losing finer details like lung markings.

What should you look for in soft tissues and bones in chest X-rays?

Check ribs, sternum, spine, clavicle, and glenohumeral joint for abnormalities.
Note on ribs: Posterior ribs are calcified and more visible; anterior ribs contain more cartilage and are less visible.
Rib angles should descend from the chest; deviation may indicate a barrel chest.

What are key features to assess in the airways on a chest X-ray?

Trachea should be central; check for deviations.
Carina is the bifurcation point of the trachea.
Right main bronchus: wider, shorter, more vertical.
Left main bronchus: longer, about twice the size of the right.

What should you examine in the breathing category of a chest X-ray?

Follow an ‘infinity figure’ pattern to inspect lungs and pleura.
Look for increased or reduced lung markings, opacities, and asymmetry.
Ensure lung markings extend to the borders of the chest.

What are key circulation-related features to assess on a chest X-ray?

Heart should be centrally located with slight left extension.
Heart size should not exceed half the thoracic width.
Check for visible cardiophrenic angles and congestion around pulmonary vessels.

What should you look for in the diaphragm on a chest X-ray?

Shape should be dome-shaped; look for tenting or flattening.
Right side typically higher than the left due to liver position.
Check for sharply defined cardiophrenic and costophrenic angles.
Look for the presence of a gastric bubble indicating air in the stomach.

What does atelectasis look like on an X-ray?

Increased Density: The collapsed area appears denser due to the lack of air.
Volume Loss: Key feature, leading to shifting of the mediastinum towards the affected side, elevation of the corresponding hemidiaphragm, and rib crowding.
Displacement of Internal Structures: The trachea, heart, and nearby lung tissue may shift towards the affected area.

What does consolidation look like in an X-ray?

Increased Opacity: The affected area becomes opacified with relatively hom*ogenous density.
Air Bronchograms: These are often visible within the consolidation because the bronchi remain air-filled while surrounded by fluid-filled alveoli.
Well-defined Borders: The opacity may respect anatomical boundaries such as fissures, particularly in lobar pneumonia.
No Significant Volume Loss: Unlike atelectasis, consolidation does not typically cause a significant shift in mediastinal structures or diaphragm position.
Silhouette Sign: Adjacent structures may be obscured if they share a border with the consolidated area.

At what rib levels should be the right and left hemi-diaphragms sit on a P.A. chest X-ray?

The right hemi-diaphragm usually sits at a slightly higher level than the left due to the liver’s position beneath it. 5 th rib level on the right and 7th rib level on the left

What do elevated WBC counts indicate in pathology results?

High WBC indicates potential infection or inflammation; low counts could suggest immunosuppression

What does an elevated CRP level indicate?

High CRP levels are markers of inflammation and can indicate infection, autoimmune disorders, or other inflammatory conditions.

What does the level of haemoglobin indicate in a patient’s pathology results?

High Hb could suggest polycythemia, often seen in chronic hypoxic conditions; low levels might indicate anemia, affecting patient energy and healing.
Low haemoglobin may limit exercise tolerance due to decreased oxygen delivery to tissues, requiring adjusted activity levels during therapy.

What do changes in platelet counts indicate in medical tests?

What does an abnormal INR value signify?

INR is a measure of blood clotting; deviations can indicate coagulation issues.
High INR suggests blood thinning which is excessive, increasing bleeding risk; a low INR indicates quicker clotting times.

What does an elevated CK level indicate in a pathology report?

High CK levels often suggest muscle damage, which can occur from myocardial infarction, muscle diseases, or physical trauma.

What is the significance of elevated troponin levels?

Troponin is highly specific to cardiac muscle injury and is a critical marker in diagnosing myocardial infarctions.

What does Pneumothorax look like on a X-ray?

Visible visceral pleural edge, absence of vascular markings.
May appear as area of translucency in supine position

What does DRSABCDE stand for in reading X-rays

Details: Correct patient and correct X-ray, no previous X-rays
RIPE
Rotation: clavicles are equal distance from the midline, minimal rotation
Inspiration: Inspiratory effort is goof, 5-6 anterior ribs, costophrenic angles visible on both sides
Projection: PA
Exposure: Good, Able to see the vertebral bodies behind the heart
Soft tissues and bones
- No rib fractures, no clavicle fractures
- Erosion of 2-3 right ribs behind the mass in apical right lung
Airways
- Trachea is deviated towards the right side
- Bronchi are obscured and difficult to visualise
Breathing
- Left lung looks normal; no obvious consolidation or opacities
- Right lung; large and well defined opacity in apical zone of right lung
- Pleura; Normal, no evidence of thickening
Circulation
- Cardiac shadow is well defined and of a normal size
- Easily visualise the arch of aorta, left ventricle and right atrium
Diaphragm
- Small bulge in diaphragm on the right side - could be normal for the patient, difficult to know with no previous X-rays
- No Costophrenic blunting or evidence of fluid
- Fundus of stomach is visible on left hand side
Extra

What do normal breath sounds indicate?

Cause: Normal breathing.
Mechanism: Air flows smoothly through the tracheobronchial tree without obstruction, sounding like a light breeze. Indicates healthy lung function and airway patency.

What causes reduced breath sounds?

Cause: Small Tidal Volumes - less air flow.
Mechanism: Inflated lung mutes sounds because minimal air enters the lung, often heard in conditions like hyperinflation in chronic obstructive pulmonary disease (COPD).

What are the causes and mechanisms behind absent breath sounds?

What causes bronchial breath sounds and how do they sound?

Causes: Consolidated lung or large pleural effusion.
Mechanism:
Consolidation: Solid lung tissue transmits air movement more clearly, producing harsh sounds on both inspiration and expiration.
Pleural Effusion: Fluid mutes normal lung sounds but may cause harsh bronchial breathing if it compresses lung tissue.

What are fine crackles and what causes them?

Cause: Acute pulmonary oedema.
Mechanism: Crackles are heard late in inspiration, typically basally and gravity-dependent as air moves through fluid-filled alveoli. Not altered by coughing, indicating fluid within the lung tissues.

What are coarse crackles and when are they heard?

Cause: Sputum in the airways.
Mechanism: Coarse crackles occur throughout the breathing cycle as air bubbles through or opens sputum-blocked airways, indicating increased secretions or mucus in the airways.

What causes a wheeze and what does it sound like?

Cause: Airway narrowing due to bronchoconstriction, foreign bodies, tumors, or airway collapse.
Mechanism: Wheezing is a musical sound, high or low-pitched, heard during expiration and/or inspiration as the air vibrates in the narrowed airways.

What is a pleural rub and what causes it?

Cause: Inflammation, infection, or tumors of the pleural surfaces.
Mechanism: Friction between inflamed or roughened pleural surfaces creates creaking or grating sounds during both inspiration and expiration, indicating pleural pathology.