Respiratory System Flashcards
What are the features of the upper and lower respiratory tracts?
Upper respiratory tract:
Nose
Paranasal sinuses
Nasopharynx
The upper respiratory tract filters, humidifies and adjusts the temperature of the inspired air.
Lower respiratory tract: Larynx Trachea Bronchi/bronchioles Alveoli
The lower respiratory tract conducts the air to the sites of gaseous exchange.
What lines the respiratory tract?
Respiratory mucosa, composed of epithelium (‘respiratory epithelium’) and supporting connective tissue (‘lamina propria’).
What feature of the immune system is present in the lamina propria?
Lymphoid aggregates
What type of respiratory epithelium lines the upper tract?
The upper tract, larynx and trachea are lined by tall, pseudostratified columnar ciliated epithelium with many goblet cells
What is the role of cilia in the upper respiratory tract?
cilia are small finger-like processes on the luminal surfaces of the cells
the cilia move synchronously to waft particles entrapped in mucus towards the pharynx.
the goblet cells produce mucus
What respiratory epithelium lines the vocal cords?
Stratified squamous epithelium
What supports the trachea and bronchi from collapse?
Rings of hyaline cartilage >1mm diameter
Do both bronchi and bronchioles have rings of cartilage?
No, bronchioles lack cartilaginous support
What comprises the terminal portion of the respiratory tree?
Terminal bronchiole Respiratory bronchiole Alveolar duct Alveolar sacs Alveoli
What are alveoli composed of?
- Epithelium:
The alveoli are lined by 2 types of epithelial cells:
Type I pneumocytes: large, flat cells across which gas exchange occurs
Type II pneumocytes: cuboidal cells which produce surfactant and which proliferate following injury to the lung
- Capillaries
- Connective tissue
- Alveolar macrophages
Describe the nose and nasal cavity
The nose looks fairly solid but in fact contains large air-filled cavities, the paranasal sinuses (black areas on the X-ray)
Where are the paranasal sinuses located?
Frontal, maxillary, ethmoid and sphenoid sinuses
The nasal passages extend laterally into the paranasal sinuses (cavities within the frontal, ethmoid sphenoid bones and the maxillae that are lined by respiratory epithelium)
What is the pharynx and where is it located?
The throat (pharynx and larynx) is a ring-like muscular tube that acts as the passageway for air, food and liquid.
The pharynx joins the skull to the alimentary and respiratory tracts. It has three divisions (nasopharynx, oropharynx and laryngopharynx)
What are the functions of the larynx?
Allow the crossing over of the digestive and respiratory passageways
Prevent food from entering the trachea
Contribute to voice production
Permit coughing by ‘fixing’ the thorax
Where do the hyoid and cricoid bones lie?
The hyoid bone lies at the CIII to CIV level
The cricoid at the CV to CVI level
Where does the trachea bifurcate?
At the carina T4
How does the heart affect the structure of the main bronchi?
The position of the heart means that the left bronchus branches off at an angle so that inhaled foreign bodies (eg Lego) tend to go down the right bronchus.
Foreign objects are more likely to get stuck in the R bronchus as it is shorter, wider and more vertical
Identify the muscles of the thorax
Pectoralis major Pectoralis minor Subclavius Serratus anterior (Latissimus dorsi) Diaphragm External intercostals Internal intercostals Innermost intercostals Scalenes
What type of expansion is:
Pump handle
Bucket handle?
Pump handle: Anterior-posterior expansion
Bucket handle: Lateral expansion
The dome of the diaphragm moves down to allow Supero-inferior expansion
What is alongside the ciliated respiratory epithelium lining the trachea?
Goblet cells secreting mucus
What obstructs airways in asthma?
Spasm of bronchial musculature
Describe the overall structure of the lungs
cone-shaped -> apex + base + 3 surfaces + 3 borders
apex: above 1st rib, base: diaphragm, surfaces: costal, mediastinal, and diaphragmatic, borders: anterior (sharp), inferior (sharp), and posterior (smooth)
What are the lobes and fissures of both lungs?
right lung has 3 lobes, left lung has 2 lobes
formed by:
oblique fissure – separates inferior from superior + middle lobes; begins T3(L)/T(R); around thorax to level of 6th rib
horizontal fissure – separate superior from middle lobe; follows 4th rib, from inferior border to posterior border
What is the blood supply of the lungs?
pulmonary artery brings deoxygenated blood from R ventricle
pulmonary vein brings oxygenated blood to L atrium
What is the lung root?
suspends lungs from mediastinum.
covered by mediastinum pleura
phrenic nerves pass anterior to lung root
vagus nerves pass posterior to lung root
Which nerves pass too lung root and what is posterior/anterior?
P comes before V so phrenic nerve is anterior + vagus nerve is posterior
What is the hilum?
the hilum is the entry/exit point between the root and the lungs
each root and hilum has:
1 pulmonary artery (superior) 2 pulmonary veins (inferior) main bronchus bronchial vessels nerves + lymphatics
What is the carina and where is it?
Carina is a full ring circle (cough reflex)
composed of: pseudostratified ciliated columnar epithelium + goblet cells -> mucociliary escalator
innervation: recurrent laryngeal
inferior thyroid artery
At what levels does the trachea begin and end?
C6-T4
How many segment bronchi are there in each lung with only smooth muscle?
10
What supplies each bronchopulmonary segment?
Its own pulmonary artery
What is the main secretory cell in the bronchioles?
Clara cell, secretes component of surfactant
no goblet cells
Type 1 vs Type 2 alveolar cells
Type 1 alveolar cells = alveoli, wall, large, flat, very big surface area, fewer in number
Type 2 alveolar cells = surfactant, proliferate in injury, take up less space but many more in number
What muscles are used in inspiration and what do they do
Diaphragm: Costal fibres attach to ribs, crura fibres attach around oesophagus and tether. contraction downward and raises chest wall
External Intercostals: Forced inspiration. connect adjacent rib and are angled forward so that contraction causes the chest to rise. There are 11 pairs that run inferoanteriorly (from rib above to below)
Accessory Muscles: Forced inspiration and exercise.
Scalene – elevates first 2 ribs
Sternomastoid – lift sternum
What are bronchopulmonary segments?
- An area of lung supplied by a segmental (tertiary) bronchus and accompanying pulmonary artery branch
- Each is shaped like an irregular cone with an apex facing the lung root and a base at the pleural surface
• Smallest, functionally
independent unit of a lung and smallest area that can be isolated and removed without affecting adjacent regions
• 10 in each lung (8-10 in left) as some of them fuse in the left lung
Trachea structure
The trachea consists of 4 layers • Mucosa - Goblet cells (mucin) • Submucosa • Fibrocartilage • Adventitia - Binds trachea to adjacent structures in the next and mediastinum
Secretions of mucous and serous glands
moisten the air, which protects the alveoli
from desiccation
Mobile cartilaginous and
membranous tube
• Divides into left and right
principle (main) bronchi at the level of the sternal angle (T4-T5)
• 11cm long, 2.5cm diameter
• Fibroelastic tube kept patent by U-shaped bars (rings) of hyaline cartilage
• Posterior free ends connected by smooth muscle: trachealis
Bronchial tree
Bifurcation of the trachea behind the arch
of the aorta into left and right principle
bronchi
• Bronchi divide dichotomously, giving rise
to several million terminal bronchioles
that terminate in one or more respiratory
bronchioles
• Each respiratory bronchiole divides into 2-
11 alveolar ducts that enter alveolar sacs
How does pleura develop?
Laryngotracheal tube with lung buds and coelomic cavity
Then parietal and visceral pleura
Then pleural cavity between them with fully formed lungs
What is occupied by the lungs during inspiration?
Costodiaphragmatic recess (between costal and diaphragmatic parietal pleura)
What is occupied by the anterior border of the lungs during inspiration?
Costomediastinal recess: Between costal and
mediastinal parietal pleura
Pleural effusion
Pneumothorax
Blood supply to pleura
• Blood supply via the anterior and posterior
intercostal arteries
• Originate from the internal thoracic artery
(branch of the subclavian) and descending
thoracic aorta respectively
• Form a basket-like pattern of vascular
supply around the thoracic wall
• Each intercostal artery gives off branches
to the muscles, skin and parietal pleura and
in the region of the breast in the female
the branches to the superficial structures
are particularly large
Bronchial arteries
Bronchial veins
Lymphatic drainage of the lungs: name the lymph nodes and their locations
• Pre-tracheal and paratracheal nodes are located anterior
to, and along the sides of the trachea (respectively);
• Superior tracheobronchial nodes, are seen at the superior
border of the bifurcation of the trachea;
• Bronchopulmonary or hilar nodes, are located in the hilum
of the lungs where the main-stem bronchi enter the lungs,
• Pulmonary or intrapulmonary nodes, are just deep to the
hilum and surround the bronchi;
• Inferior tracheobronchial or subcarinal nodes are inferior to
the carina of the trachea.
Pericardium
