Session 1.1a - Workbook Notes (Anatomy) Flashcards
Pre-Reading
Revise Body Logistics: Respiratory System (Session 9)
See Session
Explore the anatomy of the Respiratory System and relate its structure to function.
Session Aim
Describe how the structure of the nose and paranasal sinuses is conducive to warming, humidifying and filtering /trapping particles in inspired air
ILO
Describe how the larynx protects the airway during swallowing
ILO
Explain why hoarseness of voice/voice change may be a sign of intra-thoracic
disease
ILO
Describe the structure of the bony thorax including the features of a typical rib and thoracic vertebra.
ILO
Describe rib movements during respiration
ILO
Describe the external, internal and innermost intercostal muscles and the diaphragm, their nerve supply and actions in respiration.
ILO
Describe the course of the intercostal nerves, arteries and veins and how to avoid damaging them during pleural aspiration or insertion of a chest drain.
ILO
Describe the pleural cavity & pleura, including its nerve supply and the role of the pleural fluid and the pleural seal in lung expansion
ILO
Describe the lungs and the lower respiratory tract, its blood and nerve supply and lymphatic drainage.
ILO
Describe structures in the root of the neck and mediastinum, which are closely related to the lung and explain the effects of involvement of these structures by pathological processes in the lung or thoracic cavity
ILO
Describe the surface marking of the lungs & lobes of the lung, the extent of the pleural cavity (the lines of pleural reflection) and the dome of the diaphragm and understand the clinical implications of this information.
ILO
Describe the structure (histology) of the airways and alveoli and relate it to the functions and defence of the lungs. (covered in body logistics lecture)
ILO
Distinguish bronchi from bronchioles. Define what is meant by a terminal bronchiole, respiratory bronchiole, alveolar duct and alveolus. (covered in body logistics lecture)
ILO
Distinguish between the conducting zone and the respiratory zone of the airways. (Covered in body logistics lecture).
ILO
Describe the mechanisms which protect the lung from inhaled particles, including function of the muco-ciliary escalator. (Covered in body logistics).
ILO
Name and identify the following on a prosection: (detailed list on page 31)
- Diaphragm, intercostal muscles, intercostal arteries, veins and nerves
ILO
Name and identify the following on a prosection: (detailed list on page 31)
- The Parietal and visceral pleura and the costo-diaphragmatic recess
ILO
Name and identify the following on a prosection: (detailed list on page 31)
- Veins: Internal thoracic arteries and veins, azygous vein, SVC and aorta
ILO
Name and identify the following on a prosection: (detailed list on page 31)
- Nerves: intercostal nerves, phrenic nerves, Sympathetic trunk, Vagus nerves and left recurrent laryngeal nerve (if possible)
ILO
Name and identify the following on a prosection: (detailed list on page 31)
- Lung: surfaces & borders, oblique and horizontal fissures, lobes of the lungs, the hilum of the lungs and the main bronchus, pulmonary artery and pulmonary veins at the hilum.
ILO
What does the anatomy of the respiratory system contain?
- The upper respiratory tract (URT)
- Nose & Paranasal sinuses
- Pharynx
- Larynx
Where does the URT extend from?
The nostrils to the lower border of the cricoid cartilage of the larynx
Where does the URT begin?
The nostrils
What does the URT consist of?
It comprises the nose & paranasal sinuses, Pharynx and Larynx.
Note: These structures & their functions will be studied in depth in H&N. In this unit, focus is limited to their structure & function as relevant to respiration.
How is the nasal cavity divided into right & left cavities?
By the MEDIAN NASAL SEPTUM
The median nasal septum divides what?
The NASAL CAVITY into right & left cavities.
How many bony projections does the lateral wall of each nasal cavity contain?
3
What are the bony projections found on the lateral wall of each nasal cavity called?
CONCHAE or TURBINATES
The nasal conchae, or turbinates, are found where?
On the LATERAL WALL of each nasal cavity
What are the paranasal sinuses?
4 air containing cavities
What are the 4 air containing cavities that surround the nasal cavity called?
THE PARANASAL SINUSES
What are the paranasal sinuses called?
Named for the skull bones within which they are situated, the:
- frontal
- ethmoidal
- maxillary
- spheroidal
sinuses
What lines the paranasal sinuses?
PSEUDO STRATIFIED CILIATED COLUMNAR EPITHELIUM (respiratory epithelium)
What is pseudo stratified ciliated columnar epithelium sometimes known as?
Respiratory epithelium
(- because this type lines most of the URT
- however, it is a misnomer, because there is no significant exchange of O2 and CO2 here)
Where do the paranasal sinuses open into?
The spaces below the turbinates in the nasal cavity.
What does the mucosa lining the area presented by the turbinates and the paranasal sinuses do?
Allows inhaled air to be WARMED AND HUMIDIFIED.
Describe the mucosa lining the area presented by the turbinates and the paranasal sinuses. Hint: it allows the inhaled air to be warmed and humidified.
It is VASCULAR
Describe the area presented by the turbinates and the paranasal sinuses. Hint: it is lined by vascular mucosa
The turbinates and the paranasal sinuses present a LARGE SURFACE area.
As well as the vascular mucosa aiding in warming and humidifying inhaled air, how else is this achieved?
The turbinates also cause turbulence & slow down airflow, increasing the time available for warming and humidification.
Which structure(s) cause turbulence and slow down airflow to aid in warming and humidificaiton of inhaled air?
The turbinates
How do the turbinates warm and humidify inhaled air?
- They have VASCULAR mucosa which line the LARGE SURFACE area presented by them (and the paranasal sinuses)
- They cause turbulence & slow down airflow, increasing the time available for warming and humidification
Air is heated to what temperature on passage through the nose?
Approximately to body temperature
Inhaled air is heated approximately to body temperature. Where?
On passage through the nose
How is inhaled air humidified?
This is achieved by transudation of fluid through the epithelium and to a lesser extent by mucus secretion.
What is the main mechanisms of air humidification in the nose?
Transudation of fluid through the epithelium
The epithelium plays the main role in humidifying air in the nose. How else can it be humidified?
To a lesser extent, by mucus secretion.
What is transudation?
Passage of a fluid or solute through a membrane by a hydrostatic or oncotic pressure gradient.
What is each nostril lined with?
Coarse hairs
What is the function of the coarse hairs which line each nostril?
To trap large particles in inhaled air.
What is mucus secreted from?
Goblet cells
What do goblet cells secrete?
Mucus
What is the function of the mucus secreted by the goblet cells?
Traps almost all particles >5 micrometres.
How do we ‘dispose’ of the mucus?
The cilia waft the mucus to oropharynx where it is swallowed.
What structure gets rid of the mucus?
The cilia
Describe the role of the pharynx in the aerodigestive tract.
AIR & FOOD HAVE A COMMON PASSAGE THROUGH PARTS OF THE PHARYNX.
Air & food have a common passage through parts of the pharynx. Why is this important to note physiologically?
Mechanisms to prevent aspiration (inhalation) of food particles during swallowing are important (see later).
What complications can occur if physiological mechanisms to prevent aspiration fail?
Failure of these mechanisms can cause aspiration of food particles/liquid, leading to potentially life-threatening airway obstruction and/or infection (aspiration pneumonia).
What does the larynx link?
It links the pharynx to the trachea
What does the larynx contain?
The VOCAL CORDS
Where are the vocal cords found?
They guard the entrance to the trachea.
What are the vocal cords also known as?
The VOCAL FOLDS, OR VOCAL LIGAMENTS.
The vocal cords + the aperture (holes) between the cords are together termed as ___?
The ‘GLOTTIS’.
What is this glottis?
The vocal cords + the aperture between the cords together.
What happens to the laryngeal inlet during swallowing?
It becomes narrowed
What narrows during swallowing?
The laryngeal inlet
What happens to the epiglottis during swallowing?
It folds downwards (like a lid) over the laryngeal inlet
What happens to the vocal cords during swallowing?
They come together (are adducted)
Why do the vocal cords adduct during swallowing?
To act as a SPHINCTER CLOSING OFF THE ENTRANCE TO THE TRACHEA.
What happens during swallowing?
- The laryngeal inlet becomes narrowed
- The epiglottis folds downwards (like a lid) over the laryngeal inlet
- The vocal cords come together (are adducted) to act as a SPHINCTER CLOSING OFF THE ENTRANCE TO THE TRACHEA.)
The movements of the vocal cords are caused by the action of ___?
The INTRINSIC LARYNGEAL MUSCLES
The intrinsic laryngeal muscles control ___?
The movement of the vocal cords
What nerve supplies all intrinsic muscles (except the cricothyroid muscle)?
The RECURRENT LARYNGEAL NERVE
What does the recurrent laryngeal nerve supply?
All intrinsic muscles, except the cricothyroid muscle
The recurrent laryngeal nerve on the ____ side has a long course.
left
The recurrent laryngeal nerve on the left side has a ____ course.
long
The recurrent laryngeal nerve on the left side has a long course, part of which is ___?
inside the thoracic cavity
How can intra-thoracic disease result in a hoarse voice?
It can compress or infiltrate the left recurrent laryngeal nerve, which runs into the thoracic cavity, paralysing the left vocal cord and resulting in a hoarse voice.
Give examples of intra-thoracic disease.
- Aortic aneurysm
- Lung cancer
What can intra-thoracic disease do to the left recurrent laryngeal nerve?
It can compress or infiltrate it
What symptom, related to the larynx, can result from intra-thoracic disease?
A hoarse voice
Compression or infiltration of the recurrent laryngeal nerve can cause what ___?
Paralysis of the ipsilateral vocal cord.
What problems can occur if there is dysfunction in the vocal cords?
- Aspiration
- Cough reflex
- Airway obstruction
- Voice change
What occurs in aspiration?
If the larynx and vocal folds are dysfunctional, the trachea may not be properly closed off during swallowing, hence there is a risk of inhalation (aspiration) of food/liquid.
What should occur normally during swallowing?
The larynx and vocal cords come together, to close off the entrance to the trachea.
What can a dysfunctional larynx/vocal cord lead to?
Aspiration (inhalation) of food/liquid - as the trachea may not be properly closed off during swallowing.
How are the vocal cords involved in the cough reflex?
The ability to close the vocal cords is necessary to build up intra-thoracic pressure during the early part of the cough reflex. This is followed by the sudden opening of the vocal folds which then causes the air to be expelled at high velocity.
What is the cough reflex?
A protective mechanism to expel inhaled particles. It also serves as a clearance mechanism for disposing of excessive secretions from the airways.
How are the vocal folds involved in airway obstruction?
The opening between the vocal folds can present as airway obstruction & difficulty in breathing (choking), which can be an emergency.
Voice change can be one of the first signs of ___?
Serious intra-thoracic disease
Why is voice change one of the first signs of intra-thoracic disease?
Due to involvement of the left recurrent laryngeal nerve in the thorax.
The thoracic cavity and lungs include:
- The bony thorax: sternum, ribs, thoracic vertebrae, costovertebral joints and rib movements
- Intercostal muscles
- Pleura and pleural cavity
- The trachea and bronchial tree
How do the structures of the thoracic cavity work together?
The bony thorax, intercostal muscles and the diaphragm function together as a “respiratory pump” to ventilate the lungs, while the organisation of airways and blood vessels provides the interface for gas exchange.
Which bits of the thoracic cavity act as the respiratory pump, and which acts as an interface for gas exchange?
- Respiratory pump (for lung ventilation): bony thorax, intercostal muscles, diaphragm
- Gas exchange: organisation of airways and blood vessels
Describe the bony thorax
https://teachmeanatomy.info/thorax/bones/
What does the sternum consist of?
The manubrium, body and the xiphisternum
What happens to the xiphisternum?
It remains cartilaginous into adult life.
What do the manubrium, body and the xiphisternum make up?
THE STERNUM
What is the junction of the manubrium & body known as?
The STERNAL ANGLE
What is the sternal angle?
The junction of the manubrium & body.
How can you find your sternal angle?
It is felt as a transverse ridge on palpation of the sternum.
What articulates with the sternum at the level of the sternal angle?
The 2nd costal cartilage
What does the 2nd costal cartilage articulate with?
The sternum at the level of the sternal angle.
How can you identify which rib you are palpating?
Hint: think 2nd rib
The 2nd costal cartilage articulates with the sternum at the level of the sternal angle. This enables the 2nd rib to be identified, and the rest of the ribs can be counted downwards from here.
What are the bony landmarks of a typical rib?
THE RIBS: ‘A ‘typical’ rib (ribs 3-9) has a head, a neck, a turbercle, and a shaft. (see lecture slides)
Describe the head of the rib.
The HEAD has 2 articular facets which articulate with the body of the corresponding vertebra and the vertebra above.
What do the 2 articular facets at the head of the rib articulate with?
With the body of the corresponding vertebra and the vertebra above.
Describe the tubercle of the rib.
The TUBERCLE has one articular facet for articulation with the transverse process of the corresponding thoracic vertebra.
What does the articular facet at the tubercle articulate with?
The transverse process of the corresponding thoracic vertebra.
Describe the shaft of the rib.
The flat, CURVED SHAFT has a groove (the costal groove) on its inner aspect, near the lower border in which the intercostal vessels & nerve run.
Where do the intercostal vessels & nerve run?
In the costal groove, found on the inner aspect near the lower border of the flat, CURVED SHAFT.
Describe the costovertebral joints.
There are 2 synovial joints which connect the ribs with the thoracic vertebrae. The movements of the ribs during respiration take place at these joints.
What type of joint connects the ribs with the thoracic vertebrae?
Synovial joints.
The movements of the ribs during respiration occurs where?
At THE COSTOVERTEBRAL JOINTS.
How many intercostal muscles are there?
3 - external, internal and innermost.
What are the intercostal muscles innervated by?
The intercostal nerves
Describe the role of the intercostal muscle in respiration.
See other questions
What does each intercostal space contain?
3 muscles: the external, internal and innermost intercostal muscles.
Where are the intercostal muscles found?
All 3 are found in each intercostal space.
Name the intercostal muscles from superficial to deep.
- THE EXTERNAL INTERCOSTAL MUSCLES
- INTERNAL INTERCOSTAL MUSCLES
- INNERMOST INTERCOSTAL MUSCLES
Describe the fibres of the external intercostal muscles.
The fibres of these muscles run downwards & anteriorly from the inferior margin of the rib above to superior margin of the rib below.
What are the external intercostal muscles responsible for?
RESPONSIBLE FOR ABOUT 30% OF CHEST EXPANSION DURING QUIET RESPIRATION.
