Session 1: Intro to the Respiratory System Flashcards
Main functions of the nasal cavity.
Induce turbulent flow Warm and moisten inspired air Recover water from expired air Speech production (phonation) Olfaction
How is turbulent flow induced?
By the nasal conchae which are sorts of invaginations that cause turbulent flow.
Why is it important to warm and moisten the inspired air?
Cold air can irritate the airways. Adding water to the air and moisten it increased its efficiency for gas exchange.
What is special about the floor of the nasal cavity? Why is this important?
It is in a horizontal plane. This is important for procedures like inserting a nasogastric tube.
What is the nasal cavity divided into? What is it divided by?
Right and left cavities. By the median nasal septum.
Each nasal cavity contains 3 bony projections. What are they called?
They are called conchae or turbinates.
There are also paranasal sinuses which contain 4 air cavities. Which?
Frontal Ethmoidal Maxillary Spheroidal All are called sinuses
How is the moistening of the air occurring?
Transudation of fluid through the epithelium To lesser extent by mucus secretion
How are large particles which are inhaled by air trapped?
By coarse hair in each nostril. Also mucus secreted by goblet cells traps almost all particles that are larger than 5 micrometers.
What are the three parts of the pharynx?
Nasopharynx Oropharynx Laryngopharynx
What is special about the pharynx which can cause food to get trapped in the trachea?
Inhalation of air via the nose and therefore nasopharynx runs posteriorly to then cross anteriorly in order to go down the trachea. Ingestion of food via mouth will pass anteriorly to cross posteriorly into the oesophagus. Air and food have a common passage through parts of the pharynx which allows them to get interchanged if something goes wrong.
What is the larynx?
A part which links the pharynx to the trachea. It contains the vocal cords also called vocal folds or vocal ligaments.
What is the glottis?
The vocal cords + the aperture between the cords.
Why does food not normally end up in the trachea upon swallowing?
When you swallow the laryngeal inlet becomes narrowed since the epiglottis folds downwards over the laryngeal inlet and the vocal cords come together. The vocal cords act like a sphincter that closes off the entrance to the trachea.
What causes the movements of the vocal cords?
Intrinsic laryngeal muscles.
Innervation of the intrinsic laryngeal muscles
Recurrent laryngeal nerve which supply all the intrinsic muscles except the cricothyroid muscle.
How can an aortic aneurysm or lung cancer relate to the recurrent laryngeal nerve?
The recurrent laryngeal nerve on the left side has a long course and some of it inside of the thoracic cavity. This means that intra thoracic disease can cause compression of the nerve or irritate it.
Clinical presentation of an impaired recurrent laryngeal nerve.
Risk of inhalation (aspiration) of food/liquid
Cough reflex might be impaired as the ability to close the vocal cords is necessary to build up the intra thoracic pressure in order to cough.
Can cause airway obstruction
Voice changes like a hoarse voice can be the first sign of serious intra-thoracic disease.
The trachea has cartilage like a horse shoe. Why is it not all around the trachea?
Because the oesophagus is juxtapositioned posteriorly to the trachea. If the trachea didn’t have a soft muscular portion where the oesophagus lies the oesophagus wouldn’t be able to expand properly.
What is the bony thorax made of?
Sternum
Ribs
Thoracic vertebrae
Costovertebral joins
Rib movements
The sternum has three parts. Which?
Manubrium
Body
Xiphisternum
What is the sternal angle?
What is its clinical relevance?
The junction between the manubrium and the body.
It is felt as a horizontal ridge upon palpation.
The 2nd costal cartilage articulates with the sternum at the level of the sternal angle. This means that it is possible to easily locate the 2nd rib and then find the other ribs with this as template.
Muscles of the intercostal space.
External intercostal muscle
Internal intercostal muscle
Innermost intercostal muscle
Innervation of the intercostal muscles.
Intercostal nerves