Respiratory System Flashcards
In living, healthy people, what are lungs normally like?
Light, Soft, Spongy
What are the two lungs seperated by?
Mediastinum
What does the mediastinum contain
Heart, Great Vessels and Trachea
What is the anatomical location of the lungs?
The lungs are located within the thorax and extend from their apex, just above the 1st rib superiorly, level with T1, TI to the diaphram inferiorly, level with T12 at their most inferior point in the posterious thorax on inspiraton
How does the lung attatch to the heart and trachea?
By the roots of the lung
What is the root of the lung formed by?
Bronchus, Nerves, Lymphatic Vessels, Pulmonary Vessels
Where do the roots of the lung enter and emerge?
At its hilum
What is the fissure on the left lung and where is it found?
Oblique Fissure, between the left upper lobe and left lower lobe
What are the two fissures on the right lung and where are they found?
Horizontal Fissure - between the right upper lobe and right middle lobe
Oblique Fissure - between the right middle lobe and right lower lobe
Where does the visceral pleura reflect to become to parietal pleura?
At the hilium
What is shape of the right lung in comparison to the left lung?
Larger, heavier, shorter, wider
Why is the right lung shorter and wider than the left?
Because the right dome of the diamphram is higher
What does the margin of the left lung contain
A deep cardiac notch
What does the cardiac notch indent?
The anteroinferior aspect of the superior lobe of left lung
What are the three surfaces of the lung?
Costal, Diaphragmatic, Mediastinal
What are the three borders of the lung?
Anterior, inferior, prosterior
What is each lung enclosed by?
A serous pleural sac, consisting of two membranes - the plurae
Describe the visceral pleura
Covers the lungs and is adherent to all its surfaces, including the horizontal and oblique fissures - it cannot be seperated from the lung
Describe the parietal pleura
Lines the pulmonary cavities, it is adherant to the thoracic wall, the mediastinum and diaphram
What are the two pleurae?
Continuous
What can the parietal pleurae further be broken down in to?
Costal pluera, mediastinal pleura, diaphragmatic pleura, cervival pleura
Describe the costal pleura
Covers the interal surfaces of the thoracic wall
Describe the mediastinal pleura
Covers the lateral aspects of the mediastinum
Describe the diaphragmatic pleura
Covers the superior aspect of the diaphram on each side of the mediastinum
Describe the cervical pleura
Extends through the superior throacic aperture forming domed pleura over the apex of the lung
What is the pleural cavity?
The potential space between the layers of pleura
What is it filled with?
Serous pleural fluid
What does the serous pleural fluid do?
Lubricates the pleural surfaces - allows the layers of the pleura to slode smoothly over each other during respiration
Provides surface tension - keeps the surface of the lung in contact with the thoracic wall
What does the upper respiratory system consist of?
Nose (nasal cavity), larynx (voice box, pharynx (throat) to top of trachea
What does the upper respiratory system do?
Conditions inspired air
What happens to inspired air before it reaches the lungs?
Warmed to body temperature, himidified, filtered of particulates (>10micrometres)
What does the lower respiratory system consist of?
Trachea, Bronchi, Bronchioles, Alveoli
What is the lower respiratory system concerned with?
Gas exchange and further trapping and removal of particulates
What is the rythym of breathing controlled by?
The respiratory centres
Where are the respiratory centres found?
The brainstem in the medulla oblongata
What neurons are active during inspiration?
Inspiratory Neurons
What neurons are active during expiration?
Expiratory Neurons
How can breathing rythym be modified?
Afferent information from chemoreceptors in brain and receptors in the lung
What happens is you sever the brainstem below the pons but above the medulla?
Irregular breathing
What happens when you sever the spinal cord?
Cessation of breathing
What muscles are involved in breathing?
Skeletal Muscles
What is the diaphram?
A thin, muscuotendinous, dome shaped sheet of muscle that seperates the thorax from the abdomen
What is the diaphram attatched to?
The lower ribs
What is the diaphram innervated by?
Right and Left phrenic nerves
Where do the right and left phrenic nerved originate?
C3-C5 of spinal cord
While at rest, what is the highest point of the diaphram level with?
T9
While at rest, what is the diaphram inferiourly attatched to the body wall level with?
T12
Where does blood supply to the diaphram originate?
Intercostal Arteries
Where does blood drain from the diaphram to?
Inferior Vena Cava
What does contraction do to the diaphram
Flattens it
How is the concurrent reduction in abdominal volume possible
Due to the maleable nature of many of the abdominal organs
How is the transverse diameter of the thorax increased?
By the up and outward movement of the rib margins
How much does the diaphram apex move during quiet breathing?
Inferiorly by 1-2cm
How much casn the diaphram move during deep breathing?
Inferiorly 10cm
Where are the intercostal muscles located?
Between the ribs
How many sets of each intercostal muscles are there?
11
Where does blood supply for the intercostal muscles come from?
Intercostal arteries
Where does the blood supply to the intercostal muscles drain to?
Intercostal veins
What are the intercostal muscles innervated by?
Intercostal nerves
Where do the external intercostal muscles extend from and to?
The tubercles of the superior ribs of the intercostal space posteriorly, to the cartilages of the ribs anteriorly on the inferior rib
Where do the external intercostal muscles end?
Anteriorly in thin membranes - the anterior (external) intercostal membranes which continue forward to the sternum
What do the external intercostal muscles do?
They pull the ribs upwards and forwards during inspiration
What does the movement of the external intercostal muscles do?
Cause an increase in both the lateral and anteroposterior diameters
Where do the internal intercostal muscles begin?
Anteriorly at the sternum in the interspaces between the cartilages of the true ribs (ribs 1-7) and at the anterior extremeties of the cartilages of the false ribs (8-12)
Where do the internal intercostal muscles extend to?
Down to the angles of the ribs, where they continue to the vertebral column as thin membranes called the prosterior (internal) intercostal membranes
What do the internal intercostal muscles do?
They pull the ribs down and inward during ACTIVE respiration (excercise)
What are the innermost intercostal muscles?
Incomplete and variable
Where are the innermost intercostal muscles found?
Deep to the internal intercostals
Which direction do the fibres of the innermost intercostals pass in and how are they seperated from the internal intercostals?
Same direction as internal intercostals but are seperated by a bundle of intercostal blood vessel and nerve
Which muscles are used for inspiration and expiration during QUIET BREATHING?
The diaphram provides most of the inspiratory force, however the external intercostal muscles may be used. Expiration is mostly passive (elastic recoil and weight of ribcage)
Which muscles are used for inspiration and expiration during FORCED BREATHING?
The accesory muscles (sternocleiomastoids and scalenes) are used in conjucntion with the diaphram and external intercostals to bring large volumes of air in to the lungs. Internal intercostals and abdominals can be used to force air out of lungs.
What airway is responsible for most resistance?
Trachea
How is the trachea prevented from collapse of inspiration?
It is surrounded and supported by rings of hylaine cartilage which can be easily felt at the base of the neck
What does the trachea bifurcate in to?
Two primary bronchi
How many times does each bronchi divide?
11
What forms the conducting zone of the lower respiratory system?
The first 17 generations of the airway i.e. trache and 16 successive airway branches.
How are the bronchi and their 11 succesive divisions supported?
By rings of cartilage
Where can bronchioles be found?
At the 12th division of the bronchi
What are bronchioles?
Small, collapsible airways with smooth muscle walls
How many times to the bronchioles further divide and what do they eventually form?
up to 11 times - the respiratory bronchioles
Where do respiratory bronchioles terminate at?
Alveoli ducts which lead to alveoli
What is each alveoli supplied by?
A single respiratory bronchiole
What is the apical membrane of alveoli covered in and what does it aid?
Surfactant - diffusion
What are the respiratory tact cavities lined with?
Psuedostratified colmnar epthelial cells which have numerous cillia on their surface
What does the epithelium also contain?
Mucous secreting goblet cells
What type of epithelium is present in the upper respiratory system?
Respiratory type epithelium
What happens to the epithelium in the more peripheral branches on the airways?
it becomes thinner but is still cilliated and contains goblet cells
What are the bronchioles lined with?
Simple (not psuedostratified) ciliated columnaar epithelium - goblet cells are sparse
What are the walls of the trachea supported by?
Hyaline cartalige and have incomplete smooth muscle support
What happens to the cartalige as the airways become smaller?
Cartalige rings are replaced by cartalige plates and eventually smooth muslce
What are respiratory bronchioles lined with?
cuboidal ciliated eptihelium
What are the aleveolar ducts lined with?
flattened epithelium
What pneumocytes are presnt in the alveoli
type 1 and 2
Where do tyoe 1 and 2 pneumocytes lie?
On the basement membrane
What does the alveolar wall contain?
considerable amounts of elastin
What do type 1 pneumocytes allow?`
gaseous diffusion
What do type 1 pneumocytes represent?
40% of the number of alveolar cells but 90% of the surface area of the alveoli
What are type 1 pneumocytes like?
Flattened, thin cells with flattened nuclei and few organelles
What are type 1 pneumocytes joined by?
Tight junctions
What do type 2 pneumocytes do?
Secrete surfactant
What do type 2 pneumocytes represent?
60% of the number of cells but only 5-10% of the surface area lining of the alveoli
What are type 2 pneumocytes like?
Rounded and contain numerous mitochondria
What does surfactant do?
Acts as a detergent, reduc do ing alveolar surface tension
What do type 2 pneumocytes sometimes act as?
Precursor stem cells for type 1 pneuomocytes
Where do alveolar macrophages ‘patrol’?
The alveolar air spaces and the interalveolar septa
What happens to alveolar macrophages following phagocytosis of debris or pathogen?
They may pass in to the lymphatic system or adhere to mucous coated ciliated epithelium and be cleared by coughing
