The Respiratory System Flashcards
What are the 3 main functions of the respiratory system?
- Gaseous exchange
2. also involved in speech and smell
How is the respiratory system divided functionally?
Divided into the conducting portion and the respiratory portion
What is the conducting portion and what structures does it consist of?
Tube structure that carries air from the atmosphere into the lungs
Consists of nasal cavities, nasopharynx, larynx, trachea, bronchi and bronchioles
What is the function of the conducting portion?
It transports and conditions air
It conditions air by warming, moistening and filtering it
Why is conditioned air important?
Unconditioned air leads to less efficient gas exchange and increased effort
Why is air moistened?
To ensure it doesn’t damage the delicate alveolar membranes
Why is air filtered?
To eradicate any pathogens
If pathogens reach the respiratory portion, an immune response occurs which often leads to fluid build-up and pneumonia
Where does the conducting portion start and terminate?
It leads from the nasal cavity to the terminal bronchi in the thorax
what are the paranasal sinuses?
air-filled spaces that help with the conditioning of air
What are the 4 paranasal sinuses?
- frontal sinuses
- maxillary sinuses
- ethmoidal air cells
- sphenoidal sinus
What is sinus pain caused by?
Sinus pain is due to the production of mucous
Pathogens entering the paranasal sinuses lead to the production of mucous
What are nasal conchae?
They are undulations within the upper nasal cavity
There is a superior, middle and inferior concha
What is the function of the nasal conchae?
They increase the surface area of the nasal cavity, providing rapid warming and moistening of the air as it passes to the lungs
What is a nasal meatus?
It is the space underneath the corresponding nasal concha
What is the function of the nasal meatuses?
As air is inspired through the meatuses, it creates a turbulent flow of air
Where is mucosa found in the nasal cavity and what is its role?
Meatuses and conchae are covered in mucosa which warms and moistens the air
What is the pharynx?
A membrane-lined cavity that connects the nose and mouth to the oesophagus
what are the 3 divisions of the pharynx?
- nasopharynx
- oropharynx
- laryngopharynx
How does the pharynx differ from the larynx?
The pharynx is continuous with the oesophagus whilst air will enter the larynx
What is the role of the larynx?
Involved in breathing, producing sound and protecting the trachea from food aspiration
It manipulates pitch and volume
What is the role of the epiglottis?
Helps to direct food into the pharynx and oesophagus so that it doesn’t enter the larynx
What is the middle section of the thoracic cavity called and what is found there?
mediastinum
the heart and trachea are found there
What are the 2 lateral sections of the thoracic cavity called and what is found there?
pulmonary cavities
the lungs are found here and the trachea splits into primary bronchi
what is the internal thoracic artery and what does it supply?
it is the large blood vessel in the midline
it supplies the anterior chest wall and the breasts
what is the costal margin?
the lower edge of the chest formed from the bottom edge of the rib cage (7th - 10th rib)
What is the xiphoid process?
A small cartilaginous process of the lower part of the sternum which leads to the costal margins
What is the difference between the right and left lung?
the right lung has 3 lobes but the left lung only has 2 lobes
the left lung cannot develop a third love as the heart is on the left side
Where is the oblique fissure found?
It is present on both lungs and separates the superior and inferior lobes
Where is the horizontal fissure found?
It is only present on the right lung and separates the superior and middle lobes
Why are the lungs different in size?
Due to the structures that surround them
How is the right lung different in size to the left lung?
The right lung is shorter, broader and larger as the dome of the diaphragm is slightly higher on the right hand side
What is the diaphragmatic surface of the lungs?
It has a dome shape due to the underlying diaphragm
What is the apex of the lung?
The rounded part at the top of the lungs which extends into the root of the neck
What is the hilum of the lung?
a large triangular depression on the mediastinal surface of the lung
it is the part of the lung where openings and structures are found
What happens concerning the pleura at the hilum of the lung?
it is where the connection between the parietal pleura and the visceral pleura is made
Where are structures within the hilum located?
The bronchi are at the back
The arteries are above
The veins are at the bottom
What structures make up the hilum?
the right and left primary bronchi, pulmonary arteries and pulmonary veins
what is the root of the lung?
it consists of structures entering and leaving the lung at the hilum
describe the divisions of the bronchi in the conducting portion?
trachea bifurcates into the right and left primary bronchi
primary bronchi divide into lobular bronchi
lobular bronchi divide into segmental bronchi
segmental bronchi divide into terminal bronchioles
terminal bronchioles divide into respiratory bronchioles
What is the benefit of the lungs having a segmentalised structure?
If there is a problem with one segment of the lung, it can be removed without affecting the function of the rest of the lung
What occurs in the respiratory portion?
Gas exchange
What structures make up the respiratory portion?
respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli
Does gas exchange occur at the respiratory bronchioles?
They may have one or two alveolar sacs attached so a very small amount of gas exchange can take place
How is the respiratory system divided anatomically?
Upper respiratory tract and lower respiratory tract which are separated by the larynx
What structures are part of the URT and LRT?
URT - from the nasal cavity to the larynx
LRT - from the trachea to the bronchi and lungs
Why are anatomic divisions of the RT important?
For classifying respiratory tract infections
URT infection - common cold
LRT infection - could be pneumonia
What are the 2 functions of the thoracic cage?
Protection and respiratory movements
How does the thoracic cage provide protection?
It forms a bony cage around vital organs
How to ribs articulate?
They articulate posteriorly to the vertebra
They loop around in a C-shape and attach to the sternum via costal cartilages
What are vertebrae?
Each of a series of small bones forming the backbone
They have several projections for articulation and muscle attachment
What is the sternum?
A long flat bone located in the central part of the chest
What is the function of the sternum?
It connects the ribs via costal cartilages
It forms the front of the rib cage to help protect the heart, lungs and major blood vessels from injury
How is the sternum divided?
Manubrium, body of the sternum, xiphoid process
Where is the sternal angle?
Between the manubrium and the body of the sternum, there is a slight angle change
How is the sternal angle used clinically?
Lateral to the sternal angle is the 2nd rib
Count down to the 5th intercostal space and this is where the stethoscope is placed
What are true ribs?
The first 7 pairs of ribs
They connect directly to the sternum via costal cartilage
What are false ribs?
Ribs 8, 9 and 10
They connect to the costal cartilage of the rib above
What are floating ribs?
Ribs 11 and 12
They do not attach to the sternum or costal cartilages
What are the thoracic inlet and thoracic outlet?
Thoracic inlet is an opening at the top of the thoracic cavity
Thoracic outlet is an opening at the base
What is breathing (external respiration)?
The mechanism in which fresh atmospheric air passes into the alveoli and stale air leaves the alveoli
How does breathing come about?
it involves an alternate increase and decrease in thoracic volume via movements of the thoracic wall
What are the 3 planes of movement of the thoracic wall?
- vertical
- antero-posterior
- transverse
- all 3
What is the function of the diaphragm?
It closes off the thoracic outlet and separates the thorax from the abdomen
What is the diaphragm comprised of?
Radial muscle fibres inserted into a central tendon
Why does the diaphragm contain apertures?
To allow the passage of vessels, nerves and the oesophagus to and from the abdomen
How does the diaphragm change during respiration?
Inspiration - it contracts and flattens
expiration - it relaxes and becomes dome-shaped
How do the ribs move on inspiration?
superiorly and laterally
How is the diaphragm innervated?
By the phrenic nerve (left or right)
It originates in the neck at cervical level 3, 4 and5
C3, C4 and C5 will converge to form the phrenic nerve
Where are intercostal muscles found and how are they arranged?
Found within each intercostal space
There are 3 layers:
external intercostal
internal intercostal
innermost intercostal
How do intercostal muscles get their blood supply and nervous input?
The intercostal bundle is a neurovascular bundle between the internal and innermost intercostal muscles
What structures are found in the intercostal bundle and in what order?
Intercostal vein is superior
Intercostal artery
Intercostal nerve is inferior
How does the sternum and the rib cage move during inspiration?
Sternum moves anterior and superior
Ribcage moves laterally and superiorly
What are pleura?
A pair of serous membranes lining the inside of the thoracic cavity and enveloping the lungs
What are the 2 different types of pleura?
The visceral pleura covers the lungs
The parietal pleura covers the thoracic cavity
What is the purpose of the pleura?
They are an attachment from the lungs to the thoracic cage
How does the lung develop into the pleura?
The lung develops into the pleura and this is continuous with the layer of pleura connecting to the rib and lining the inside of the thoracic cage
What is the pleural cavity?
A space between the two layers of pleura that contains a thin film of pleural fluid
What is the purpose of pleural fluid?
It helps to stick the lung to the parietal pleura by surface tension to aid inspiration
How do the pleura aid inspiration?
During inspiration, the parietal pleura moves
The pleural fluid sticks the 2 pleura together so this leads to movement of the visceral pleura and movement of the lungs
How is the parietal pleura divided?
cervical pleura
costal pleura
diaphragmatic pleura
mediastinal pleura
How is the parietal pleura innervated?
Diaphragmatic and mediastinal pleura are innervated by the phrenic nerve
Cervical and costal pleura and innervated by the intercostal nerves
