Anatomy of Respiratory System Flashcards
What is the function of the respiratory system?
- Gas exchange 2. Speech 3. Smell
What are the 2 functional divisions of the respiratory system?
- Conducting portion 2. Respiratory portion
What is function of conducting portion?
- Transports air from external environment to structures where gas exchange occurs - Conditions air (warms, moistens, filters)
What does the nasal cavity open out into?
Paranasal sinuses
Where does the conducting portion start and finish?
Nasal cavity to terminal bronchi
What are the paranasal sinuses? How many of the are there?
Group of 4 paired air-filled spaces that surround the nasal cavity. Help to warm, moisten and filter the air.
What are the 4 paranasal sinuses?
- Maxillary sinuses
- Frontal sinuses
- Ethmoidal sinuses
- Sphenoidal sinuses
Where are the maxillary sinuses located?
Under the eyes (inferior)
Where are the frontal sinuses located?
Above the eyes (superior)
Where are the ethmoidal sinuses located?
Between the eyes (middle)
Where are the sphenoidal sinues located?
Behind the eyes (midline)
What is the pharnyx?
The body cavity that connects the nasal cavity and oral cavities with the larynx and oesphagus (route of inspired air)
What is the pharynx divided into?
- Nasopharynx –> superior
- Oropharynx –> middle
- Laryngopharnyx –> inferior
Projecting out of the lateral walls of the nasal cavity are curved shelves of bone. What are these called and how many are there?
Conchae. 3 - inferior, middle and superior
What is the function of the conchae?
- Project into the nasal cavity, creating 4 pathways for the air to flow –> produces turbulent flow of air allowing it to enter the sinuses for conditioning
- Increases surface area of nasal cavity which increases the amount of inspired air that comes into contact with the cavity walls
- Disrupt the fast, laminar flow of air, making it slow and turbulent –> air spends longer in nasal cavity so can be humidified
What are the pathways created by the conchae?
- Inferior meatus –> between the inferior concha and floor of the nasal cavity
- Middle meatus –> between the inferior and middle concha
- Superior meatus –> between the middle and superior concha
- Spheno-ethmoidal recess –> superiorly and posteriorly to the superior concha
Where do the paranasal sinuses drain into?
The nasal cavity
What is the nasolacrimal duct?
Drains excess tears from the eyes to the nose (why your nose runs when you cry). Opens into the inferior meatus.
Where do the intercostal muscles lie? What are the 3 types of intercostal muscles?
In the space between the ribs.
- External
- Internal
- Innermost
What is function of the external intercostals?
Move ribs up and out during inhalation and increase lateral and anterior-posterior diamteter of the thorax (expands chest cavity)
They run inferoanteriorly from rib above to rib below
What is function of internal intercostals?
Responsible for forced exhalation. Depress the ribs and decrease space in the chest cavity.
Run inferoposteriorly from rib above to rib below (opposite direction to external)
What is function of innermost intercostals?
Reduces thoracic volume by depressing ribcage.
Deepest of the intercostal muscles.
How many pairs of ribs are there? What are they divided into?
12 pairs of ribs
- Upper 7 pairs are ‘true’ ribs as attached to sternum
- Lower 5 pairs are ‘false’ ribs as don’t directly attach to sternum
The upper 3 false ribs connect to the costal cartilage of the ribs just above them.
The last 2 ribs have no ventral attachment –> ‘floating’ ribs
What is costal cartilage?
Segements of cartilage that connect the sternum to the ribs and help extend the ribs into a forward motion.
What is the costal margin?
The lower edge of the rib cage running from 7th to 10th rib
Formed by the joined costal cartilages of ribs 7-10. This forms the anterolateral boundary of the inferior throracic aperture.
How does the left and right lung differ?
Right:
- Short, broad, larger
- Has 3 lobes
- Oblique and horizonal fissure
Left:
- Tall, narrow
- Has 2 lobes (due to presence of heart)
- Oblique fissure
N.B. lobes are separated by oblique fissure
What does the trachea branch into? What does this then continue to branch into?
- Trachea branches into 2 primary bronchi (left and right)
- Primary bronchi enter the lung and divide to form lobar (secondary) bronchi (one supplying each lobe)
- Each lobar bronchus then further divides into several segmental (tertiary) bronchi (functional units of the lungs)
- These eventually lead into terminal bronchioles
What is job of pulmonary arteries/veins?
Carry deoxygenated blood from the right ventricle to the lungs for reoxygenation.
Carry oxygenated blood from the lungs to the left atrium of the heart.
What do the terminal bronchioles branch into?
To respiratory bronchioles and alveolar sacs
What is function of alveolar sacs?
Site of gas exchange - Sacs surrounded by capillary beds that receive oxygenated blood via pulmonary veins and send deoxygenated blood via pulmonary arteries. Sacs have thin walls.
What does the Upper Respiratory Tract consist of?
URT infection (e.g. common cold)
Nasal cavity to pharynx to larynx (also includes sinuses)
What does the lower respiratory tract consist of?
Trachea to bronchi to lungs
LRT infection (e.g. pneumonia)
What can the bony thorax/sternum be divided into?
- Manubrium –> superior to sternum body
- Sternum body
- Xiphoid process –> inferior to sternum body
Where/what is the sternomanubrial joint?
Between sternum and manubrium. Angle sits at rib 2.
What is function of diaphragm?
Muscular sheet that closes off thoracic outlet, separating thorax from abdomen
What happens to diaphragm during inspiration?
Contracts and flattens –> increases vertical diameter of thoracic cavity –> lung expansion –> decreased pressure –> air sucked in
What happens to diaphragm during expiration?
Relaxes and returns to dome shape –> reduces volume of thoracic cavity –> increases pressure –> air blown out
What is the diaphragm innervated by?
Phrenic nerves - C3, 4, 5
How do upper/lower ribs increase diameter?
Upper ribs increase anterior/posterior diameter through superior and anterior movement of sternum
Lower ribs increase transverse diameter through elevation of lateral shaft of rib
What are the pleurae?
Serous membranes that line the lungs and thoracic cavity.
What/where are the 2 pleurae in the body? What can they be divided into?
One covering each lung. Each pleura can be divided into 2 parts:
- Visceral pleura - covering the lung
- Parietal pleura - covering the internal surface of the thoracic cavity
What is the pleural cavity?
A potential space between the visceral and parietal pleura - there are 2 pleural cavities either side of the heart in the thorax.
The pleural cavity contains a thin film of fluid. What is function of this?
- Lubricates surface of pleurae allowing them to slide over each other
- Creates surface tension –> pulling the parietal and visceral pleura together –> ensures that when the thorax expands it pulls the lungs out with it, so they expand and fill with air
What is pneumothorax?
When air enters the pleural cavity and surface tension is lost
What can the parietal pleura be divided into?
Divided depending on their location within the thoracic cavity.
- Cervical - Covers superior aspect of the thoracic cage towrads the neck
- Costal - Covers the inner aspect of the ribs, costal cartilages, and intercostal muscles
- Diagphragmatic - Covers the thoracic (superior) surface of the diaphragm
- Mediastinal - Covers the lateral aspect of the mediastinum
IMPORTANT –> different parts of the parietal pleura receive sensory information from different nerves
What is the clavicle and what does it articulate with?
Collar bones - articulates with the manubrium
What is pectus carinatum? What is it normally associated with?
An anterior protrusion of the sternum caused by overgrowth of the costal cartilages so xiphoid process is affected. Also called ‘pigeon chest’.
Normally assoicated with childhood asthma.
What are consequences of pectus carinatum?
Usually no functional consequences but in severe cases, the rigid portion of the chest can limit respiratory movements. This leads to breathlessness and fatigue, particularly during exertion.
Can have psychological effects –> decreased self confidence and avoidance of activities such as swimming
What is pectus excavatum?
A posterior depression of the sternum caused by congenital malformation. Also called ‘funnel chest’.
What are consequences of pectus excavatum?
Most cases don’t cause physical problems. In severe cases, the depressed sternum can displace the heart which may impair function of heart and lungs.
Psychological issues.
What is pleural effusion?
‘Water on the lungs’ –> build up of excess fluid between the layers of the pleura outside the lungs
Where does the diaphragm have a motor nerve supply from? Where is the sensory supply?
Motor - From cervical segments C3-C5 via the left and right phrenic nerves
Sensory - Sensory supply is also through the phrenic nerve centrally and branches of the intercostal nerves peripherally
In spinal cord injuries, where must the break be to cause apnoea and death?
Above C3-C4 will affect the phrenic nerve
What is the phrenic nerve?
Nerve that originates in the neck from the cervical spinal roots C3, C4 and C5. It passes down between the lungs to reach the diaphragm. It is important for breathing as passes motor information to the diaphragm and receives sensory information from it.
What are the nasal cavities?
Two air-filled chambers at entrance to the respiratory tract which are separated by the bony and cartilaginous nasal septum
What can the nasal cavity be divided into?
Respiratory and olfactory region
What is the respiratory region of the nasal cavity lined by?
Respiratory mucosa
What is the olfactory region of the nasal cavity lined by?
Olfactory mucosa
Where is the olfactory portion of the nasal cavity?
Upper 1/3rd (apex) of the nasal cavity
Where is the respiratory portion of the nasal cavity?
Lower 2/3rds of the nasal cavity
What type of epithelium is the nasopharynx lined by?
Psuedostratified columnar epithelium
What are the oropharynx and laryngopharynx lined by?
Non-keratinised stratified squamous epithelium
What are the oropharynx and laryngopharynx shared pathways for?
Air, food and liquid
How is the oropharnyx and laryngopharynx adapted to cope with abrasian caused by passage of air, food and liquid?
Squamous epithelium –> By having multiple layers of flat cells, the epithelium is able to withstand the loss of the superficial layer without damage to the integrity of the epithelial layer
In contrast to the oro and laryngopharynx, what is the nasopharynx a passage for?
Only inspired air
How is nasopharynx adapted for its function?
Pseudostratified columnar instead of squamous –> doesn’t need to be able to withstand abrasive materials
What is the larynx?
The passage which connects the laryngopharynx to the trachea and incudes the vocal apparatus.
What is the larynx lined by?
2 types of epithelium:
- Stratified squamous epithelium
- Psuedostratified ciliated columnar epithelium
Where is the pseudostratified ciliar ciluman epithelium located in the larynx?
In the region above the vocal folds –> this portion of the larynx is conducting air so doesn’t have to cope with attrition of its surface.
Where is the stratified squamous epithelium found in the larynx?
Overlying the vocal fold and within the laryngeal ventricles –> area subject to extremes of vibration caused by the passage of air at speed during phonation so surface must be adapted to cope with attrition of its surface
Stratified squamous epithelium allows this to happen without causing damage to integrity of surface
