Respiratory S1 (done except sinusitis) Flashcards
What are the basic concepts of the kinetic theory of gases?
Gases are a collection of molecules moving around in a space
Pressure is generated by collision of molecules with the walls
The more frequent and harder the collisions the higher the pressure
What is Boyle’s law?
Describe the underlying physical basis
Presure is inversely proportional to volume
If a given amount of gas is compressed to a smaller volume molecules will hit the walls more often therefore raising pressure
What is Charle’s law?
Describe the underlying physical basis
Pressure is proportional to absolute temperature (Kelvin scale)
As temperature increases molecules will have more kinetic energy and will therfore impact the walls of a container more often hence rainsing pressure
What is the universal gas law?
What does it allow us to calculate?
**P **x **V **= n x R x T
Allows calculation of how volume will change with temperature and pressure changes
What is meant by ‘STP’?
Standard temperature and pressure
Temp = 273K
Pressure = 101.0kPa
Describe what is meant by ‘Partial pressure’ of a gas in a mixture of gases
In a given mixture of gases molecules of each type behave independently
Therefore each gas will contribute a portion of overall pressure
The fraction of pressure is equal to the fraction of gas each molecule type makes up in a given mix
Describe the behaviour of gas mixtures in contact with water
Relate your answers to pressure
Water vapour:
Water moecules enter the gas via evaportation and exert vapour pressure
Gas dissolution:
Gases will enter water and exert ‘tension’
When water molecules enter and leave a gas at the same rate, what has been reached?
What does this equilibrium depend on?
Saturated vapour pressure
Equilibrium is temperature dependent
What is saturated vapour pressure at 37 deg C?
6.28kPa
Describe ‘Tension’?
Hint: Not what your feeling now you’ve finally started revising
Tension is the ‘pressure’ exerted by gas molecules dissolved in water were the water not there
Describe Tension equilibrium
What is it equal to?
When there is no net movement of gas molecules in and out of a body of water
At equilibrium tension is the same as the partial pressure of a gas in gas mixture
How is tension relevant to gas exchange?
Tension in the pulmonary system drives oxygen out into tissues.
What is indicated by gas tension in a liquid?
How readily a gas will leave a liquid
NOT: How much gas is in a liquid
How is solubility relevant to gas tension?
Solubility determines how much gas will enter a liquid to establish a particular tension
**Gas content of a liquid = Solubility **x Tension
How is our calculation of gas content of a liquid modified by chemical reaction of said gas and liquid?
Reaction must complete before tension is established
Equation:
**Reacted gas **+ **Dissolved gas **= Total gas content
Per minute in the lungs what is the required minimum blood flow and O2 absorption rate?
Surface area needed for this is roughly equivalent to?
5L of blood in pulmonary circulation
12mmol of O2
Surface area:
Roughly one tennis court
How many alveoli does the averge human posess?
300 million
What are the divisions of the airway from trachea to bronchiole?
Trachea branches to form Main bronchi
Main bronchi branch to 3 right and 2 right lobar bronchi
Lobar bronchi divide into segmental bronchi
Then subsegmental
Then bronchioles
What are the layers (and hence the histological differences) between bronchi and bronchioles?
Bronchi:
Mucosa
Smooth muscle
Submucosa - contains glands
Crescent shaped cartilage (smaller than in trachea)
Bronchioles:
Epithelia Smooth muscle (more than bronchi)
What are terminal bronchioles and what do they divide into?
How many are there?
Terminal bronchioles are analogous to ‘twigs on a tree’
Not directly connected to alveoli but branch into a set of respiratory bronchioles, alveolar ducts and alveoli
~ 200,000 terminal bronchioles
Describe the blood supply of alveoli
Each alveoli surrounded by capillary supplied by branching blood vessels throughout the lungs
What are the 5 key features of the pulmonary circulation?
Low resistance (many parallel branches of short, wide vessels)
Low pressure
Recieves entire cardiac output
Forms practically no tissue fluid
Regional perfusion matched to ventilation
What are the external features of the nose?
Root to Septum:
Root (Radix) at most posterior point on face between eyebrows
Bridge (Dorsum) running between tip and root
Tip
Septum forming the medial wall of the nasal cavities
Laterally:
Wings (Alars) form lateral walls of nasal cavity in the nose
Describe the Internal structure of the nasal cavities
Extends from nostrils to posterior nares
Divides in two medially by nasal septum (cartilage and bone)
Lateral wall has 3 bony projections
Lined by pseudostratified columnar ciliated epithelium
Superior, middle and inferior Turbinate bones on the lateral walls each shaped like a stretched out seashell
Superior, middle and inferior meatus sit below each turbinate
Label the back boxes
What are represented by arrows labelled 1 to 4?
Boxes, top left clockwise:
Frontal sinus
Ethmoid sinus
Orbit
Masal cavity
Orbit
Numbers:
1 - 3 = Bony projections of the lateral wall (Turbinates)
4 = Nasal septum
Label the black boxes
What are represented by Arrows labelled 1 to 3 and 1a to 3a?
Boxes, top left clockwise:
Frontal bone and frontal sinus
Body of sphenoid and sphenoid sinus
Oral cavity
Hard Palate
Numbers:
1 to 3 = Superior, middle and inferior turbinates
1a to 3a = Superior, middle and inferior meatus
What are the functions of the nose?
Respiration:
Filters air
Humidifies and warms air
Organ of smell
Recieves local secretions:
Sinuses
Nasolacrimal duct
(Fun fact: Tears travel through this duct while crying, hence the runny nose, you’re essentially crying out your nose)
What are the functions of nasal mucosa?
Pseudostratified columnar ciliated:
Hairs filter large particles
Epithelium moistened by mucus to trap particles
Cilia help transport trapped particles
Watery secretions humidify air
Apart from the epithelium what other features of the nose have a respiratory function and what are the specific functions of each feature?
Vessels beneath epithelium:
Warms air
Turbinates:
Slows airflow and helps mix air
What are the names of the paranasla sinuses and how many are there?
Frontal
Ethmoid
Maxillary
Sphenoid
8 in total (4 pairs)
Label these structures
Boxes, top to bottom:
Frontal
Ethmoid
Maxillary
Label the black box
Sphenoid Sinus
Describe the lining of the sinuses
Pseudostratified columnar ciliated epithelium with goblet cells and glands
What might be the function(s) of the paranasal sinuses?
Many theories:
Extension of nasal cavity for humidification and warming of air
Secretion of mucus that drains into the nasal cavities to moisten them
Lightening weight of the skull
Buffer for trauma (protect cranial cavity)
Insultation fo sensitive structures from temperature variation (Dental roots, eyes)
Label lines 1 to 4
1 = Frontal sinus
2 = Ethmoid sinus
3 = Maxillary sinus
4 = Sphenoid sinus
Label the black boxes
The labelled structures are collectively called what?
Boxes, top to bottom:
Nasopharynx
Oropharynx
Larynopharynx
Collectively:
Pharynx
what is the Pharynx?
Common passage for food, water and air
What are the Eustachian tubes?
Tubes connecting nasopharynx to middle ear
What are the structures of the/within the larynx with relevance to the respiratory system?
Epiglottis
Glottis and false vocal cords
Define glottis
The 2 vocal cords and the aperture between them
(Apeature technically called rima glottidis)
What is the function of the epiglottis?
Closes during swallowing and therefore protects against aspiration of food
What are the functions of the vocal cords?
Act as a valve guarding trachea
Phonation
What are the positions of the vocal cords while performing different functions?
Abducted (away from midline/open) during respiration
Adducted (towards midline/closed) during swallowing
Partially abducted during phonation
Initially adducted then rapidly abducted during cough reflex
What is the difference between the two diagrams?
Label the boxes
Left - Adducted vocal cords
Right - Abducted vocal cords
Boxes, top to bottom:
Base of tongue
Epiglottis
False vocal cord
True vocal cord
Glottis
Inner lining of trachea (accept ‘trachea’)
Corniculate cartilage
Label the boxes
Boxes, top right clockwise:
Epiglottis
Vocal cords
Cricoid cartilage
Eosophagus
Trachea
Thyroid cartilage
Hyoid bone
From where does the reccurent laryngeal nerve arise and what does it innervate?
Arises from vagus
Supplies all intrinsic laryngeal muscles except cricothyroid
Describe the course of the reccurent laryngeal nerves
Right:
Branches from vagus in nech, curves under subclavian artery and back up the neck in the groove between the trachea and eosophagus to supply intrinsic muscles of larynx
Left:
Branches from vagus in neck, curves around the arch of the aorta and comes back up neck in groove between trachea and eosophagus to supply the intrinsic muscles of the larynx
What s the clinical relevance of the reccurent laryngeal nerves?
Can be involved in disorders of the chest
Lesions may cause hoarseness of voice
What nerve supplies the cricothyroid muscle?
From where does it arise?
Superior laryngeal nerve
Vagus nerve
If you were to contract an upper respiratory tract infection (URTI) then when in the body might it commonly spread?
Sinuses via openings into nasal cavities resulting in sinusitis
To the middle ear via Eustachian tubes
What disorders of the Larynx may cause repiratory difficulty?
Oedema (anaphylaxis/severe infection)
Tumour
Aspiration of foreign body
Bilateral cord paralysis (cords adducted)
What disorders of the Pharynx can cause repiratory difficulty?
Tongue falling into airway while unconscious can obstruct airway
Sleep apnoea (decrease pharyngeal uscle tone during sleep obstructs airway during sleep)
What disorders of the nose might cause significant respiratory difficulty?
Nasal polyps may lead to mouth breathing (not ideal, less humidification)
In an unconscious patient what may be obstructing the pharynx?
Vomit (may be aspirated to lung)
Tongue
Foreign body
The respiratory system contains two types of membrane, what are they and where are they found?
Mucous membranes:
Lines the conducting portion of respiratory tract, secretes mucous
Serous membranes:
Lines the pleural sacs which envelope each lung
Label this diagram
Boxes from top picture, top to bottom:
Visceral pleura
Rib
Parietal pleura
Boxes from lower picture, top center clockwise:
Left lung
Moist pleura (makes lung shiny)
Impression of heart (Cardiac notch)
Impression of aorta
What is the conducting portion of the respiratory tract?
Include each structure in descending order
Nose
Pharynx
Larynx
Trachea
Primary bronchi
Secondary bronchi (lobar)
Tertiary bronchi (segmental)
Bronchioles
Terminal bronchioles
What is the respiratory portion of the respiratory system?
Include each structure in descending order
Respiratory bronchioles
Alveolar ducts
Alveoli
What structures of the lung are intrapulmonary and which are extrapulmonary?
Intra:
Secondary bronchi to Alveoli
Extra:
Nose to Primary bronchi (enter the lung at the hilum)
Label this picture
Boxes from top right clockwise:
Trachea
Superior left lung lobe
Primary bronchus
Secondary (lobar) bronchus
Tertiary (Segmental) bronchus
Inferior lobe of left lung
Inferior lobe of right lung
Middle lobe of right lung
Superior lobe of right lung
How does diameter of passageways change from nose to alveoli?
Diameter decreases as you travel towards alveoli
Passage walls also get thinner
What epithelia are present in the conducting portion of the respiratory system?
Nasal cavity to large bronchioles:
Pseudostratified columnar ciliated epithelium w/goblet cells
Smaller bronchioles and terminal bronchioles:
Simple columnar ciliated epithelia with clara cells
What epithelia are present in the respiratory portion of the respiratory system?
Respiratory bronchioles and alveolar ducts:
Simple cuboidal with clara cells and sparse cilia
Alveoli:
Type 1 - Simple squamous epithelia
Type 2 - Cuboidal epithelia
Label the box
Olfactory Mucosa
Epithelia in the nose can be split into two broad regions, what are these regions?
Non-olfactory regions
Olfactory regions
Describe in detail the mucosa of the non-olfactory regions of the nasal cavities
Pseudostratified columnar ciliated epithelium w/mucous glands and venous sinuses in lamina propria
What is the function of the venous sinuses in the nasal cavity mucosa?
Swell every 20-30 minutes alternating airflow from nostril to nostril to prevent overdrying
Describe the location and structure of the olfactory mucosa
Posterior, superior region of each nasal fossa
Thick pseudostratified columnar epithelium without goblet cells and with non-motile cilia
Contain olfactory cells (bipolar neurons)
Serous glands in the lamina propria (Bowman’s glands) flush odourants from epithelial surface
Label the boxes
Boxes from top left clockwise:
Duct
Olfactory epithelium
Duct
Olfactory glands (Bowman’s glands)
Olfactory nerves
Label the boxes
Boxes from center top clockwise:
Junctional complex
Cilia
Pseudostratified columnar ciliated epithelia
Axon
Basal cell
Olfactory (Bowman’s) Gland
Olfactory cell
Basal lamina
Microvilli
Olfactory vesicle
Label the boxes
Boxes left to right, top to bottom:
Mucous glands
Vestibule of larynx
Ventricular folds of the false vocal cords (x2)
Ventricles
Vocal fold (x2)
Vocalis muscle (x2)
Intraglottic cavity
What is the function of the ventricles and ventricular folds?
What lines the ventricular folds?
Ventricles along with ventricular folds contribute to resonance of the voice
Ventricular folds lined by pseudostratified epithelium and contains mucous glands and numerous lymph nodes
Describe the structure of the true vocal cords
Lined by stratified squamous epithelium
Contains a vocal ligament (large bundle of elastic fibres running anteroposterior)
Also a vocalis muscle (bundle of skeletal muscle under somatic control)
What is the clinical relevance of the paths of the primary bronchi?
Path of right bronchi more vertical than left therefore foreign objects more likely to lodge in right bronchus
What structure(s) are shown?
Use this image to estimate age of specimen, what features are important to your evalutation?
Label the boxes
Trachea and Oesophagus
Age:
Elderly, as indicated by calcified bone tissue present in cartilage
Boxes from top left clockwise:
Cartilage (C-shaped)
Bone tissue
Fibroelastic membrane containing trachealis muscle
Trachea
Bone tissue
Cartilage
Oesophagus
What strucutre is shown?
Label the boxes
Wall of trachea
Boxes left to right:
C shaped cartilage
Submucosa with seromucous glands
Lamina propria
Epithelium
What is shown?
Label boxes
A section throught the mucosa of the trachea or bronchi
Boxes, top 2:
Epithelium
Boxes, bottom 6:
Seromucous glands
What is secreted by submucosal seromucous glands in the trachea and larger bronchi?
Mucins
Water
Serum proteins
Lysozyme
Antiprotease
Lymphocytes contribute Immunoglobulins (Especially IgA)
Identify the salient histological features the tracheal mucosa
Ciliated
Thick basement membrane
Lamina Propria rich in immune cells
Lamina propria includes a layer of elastic fibres
Label the boxes and identify the cell type/location
Boxes from top to bottom
Goblet cells
Ciliated epithelial cells
Basal cells
Connective tissue
Epithelium type:
Tracheal pseudostratified ciliated eipthelium/respiratory epithelium
Describe the effect of cystic fibrosis on epithelia and the respiratory tract
Sufferers lack the cystic fibrosis transmembrane regulator (CFTR) ion channel on the apical membranes of epithelial cells
Chloride ion transport across the membrane compromised
In the respiratory tract water does not adequately leave the epithelium and hydrate the secreted mucous
Viscous mucus is less readily moved by the oropharynx for swallowing
Serious pulmonary infection can occur
What is the blood capacity of the pulmonary vasculature
500ml of blood
Label the boxes and identify the tissue
Box at the very top:
Cresent shaped cartilage
Remaining boxes from bottom clockwise:
Submucosal glands
Artery
Epithelium
Smooth muscle
Vein
Tissue:
Secondary or tertiary bronchi
Label the boxes and identify the tissue
Boxes from top to bottom:
Pulmonary artery
Bronchial artery
Island of cartilage
Same as above
Bronchus
Island of cartilage
Pulmonary artery
Bronchial artery
Glands in submucosa
Bronchiole
Pulmonary artery
What differentiates a bronchiole from a bronchus?
Less than 1mm diameter
No cartilage
Epithelium is pseudostratified at first however progresses to simple ciliated columnar then simple cuboidal as diameter decreases
Describe how asthma affects bronchioles
Excessive constriction can occur due to lack of cartilage
During expiration bronchioles can collapse/severely constrict
(During inspiration bronchioles held patent by alveoli)
Where are clara cells found?
What are the functions of a clara cell?
Location:
Small bronchioles between ciliated cuboidal cells
Function 1:
Secrete surface lipoprotein to prevent walls of bronchioles sticking together during expiration
Function 2:
Secrete Clara cell protein (CC16)
A marker of alveolar damage (if lowered)
A marker in serum (if present then leakage across air/blood barrier)
What are terminal bronchioles and how do their structures differ from othe bronchioles? Why is this important?
Terminal bronchioles are <0.5mm
Absence of goblet cells to prevent individuals drowning in their own mucus
Label the boxes and identify the location
Boxes from top to bottom:
Terminal pronchiole
Respiratory bronchiole
Alveolar duct
Alveolar sacs
Individual alveoli can open into what structures?
An alveolar sac
An alveolar duct
A respiratory bronchiole
Another alveolus (via alveolar pore)
What are the functions of cells in the alveoli?
Type 1 (90%):
Simple squamous cells permit gas exchange
Type 2 (10%):
Produce surfactant
Macrophages:
Line alveolar surface and phagoctose particles
Label the boxes
Top to bottom left to right:
Basal lamina
Type 2 alveolar cell
Surfactant
Fibroblast
Alveolar lumen
O2
CO2
Macrophage
Endothelial cells
Erythrocyte
Capillary lumen
What is the cause of emphysema?
What are the structural changes to lung tissue?
Cause:
Alpha-1-antitrypsin deficiency
Smoking
Structural changes:
Destruction of alveolar walls and permanent enlargement of air spaces
How does emphysema affect lung function and what is the hallmark sign?
Function changes:
Damage to alveolar walls cause bronchioles to collapse on expiration making it difficult to empty the lungs
Hallmark:
Pursed lip breathing
What condition would this be?
What allows you to form your answer?
Emphysema
Enlarged alveolar spaces
What is seen here?
What disease might this be?
What are the common causes?
Seen:
Lung tissue, alveolar spaces filled with inflammatory cells
Disease:
Pneumonia
Common causes:
Streptococus pneumoniae
Haemophilus influenzae
Staphylococcus aureus
Legionella pneumophilia
Mycoplasma pneumoniae
What structures are lined by the pleura?
Visceral:
Lungs
Parietal:
Throacic cage
Diaphragm
Mediastinal surface
What are pleural reflections?
Sharp angles in the pleura where it changes direction from the costal surface to the mediastinal or diaphramatic surfaces
Where is the apex of the lung/pleural cavity found?
3cm above the medial 1/3 of the clavicle
Describe the route of the pleaural reflections/surface markings of the pleura starting at the apex and travelling anteriorly
Describe the entire course, all the way back to the apex
Course inferiorly and medially behing the sternoclavicular joints to meet at the midline behind the sternal angle (2nd rib)
Course down to the 4th rib
At 4th rib/costal cartilage the left pleura deviates laterally and continues inferio-laterally
At 6th rib/costal cartilage the right pleura deviates laterally and continues infero-laterally
Each pleural reflection meet the 8th rib at the mid clavicular line
Meet the 10th rib at the mid axillary line
Meet the 12th rib at the scapular line
The medial border of the pleural cavity ascends vertically long the lateral border of the paravertebral muscles up to the apex
Describe the surface markings of the lungs starting at the apex and travelling anteriorly
Feel free to relate this to the pleural markings to save time
Lungs fill the pleura except at lower margins, therefore they follow the pleural markings at apex, 2nd, 4th and 6th ribs (except cardiac notch, which is more pronounced in the lung compared to pleura
The lower margins of the lung cross the:
- 6th rib at the mid clavicular line
- 8th rib at the mid axillary line
- 10th rib at the scapular line
Thereafter medial border of the lung ascends along with the pleura vertically along the paravertebral muscles up to the apex
Why are surface markings of the lungs and pleura clinically important?
Procedures such as:
Cannulation of subclavian
Liver biopsy
Exposure of the kidney
May produce a pneumothorax (possibly unnoticed) which will causing rapid deterioration
What are the fissures of the lungs?
Oblique fissure:
Separates the upper and lower lobe of the left lung
Separates the upper and middle lobe of the right lung
Horizontal fissure:
Separates the middle and lower lobe of the right lung
Describe the courses of the lung fissures
Oblique fissures:
Extends from spinous process of T2 posteriorly to the 6th costal cartilage anteriorly
Horizontal fissure:
Extends from Oblique fissure of the right lung at the mid axillary line aalong the 4th rib to the anterior edge of the lung (follows the 4th rib all the way)
