Flashcards in Lecture 3 DA Deck (34):
What significant consequence of being out of breath concerns the shoulders?
Typically, one would inadverdantly fix their humerus by very common actions such as crouching slightly an holding your knees, leaning onto a table or getting on your knees with your hands on the floor.
Why is locking ones shoulders so important, especially when one is out of breath?
Locking the humerus reverses the action of several muscles allowing them to raise the thoracic cage to both facilitate breathing and to expand the cavity within.These muscles are the serratus anterior, pectoralis minor and major.
The cartilage of the trachea are C-shaped. What is the muscle that connects two ends of this C, oesophagus-side, and what is its function?
It is known as the trachealis muscle, and its function is to allow the trachea to expand. It also prevents the airway from collapsing with the help of the cartilage.
What covers the trachealis muscle?
Annular ligament of the lung.
What is the cricoid cartilage, and how does it differ from the other tracheal rings?
The cricoid cartilage is also known as the larynx and is the first tracheal ring. Unlinke the other tracheal rings, it is the only one to form a complete ring, whilst all others are incomplete (C-shaped).
At what dermatome does the first bifurcation fo the trachea occur, what does it give rise to, and what bony structure is present in this area?
The first birfurcation occurs at around T4/5, into two main bronchi. This is about the level of the sternal angle.
How do the right and left bronchi differ?
The right bronchus is more direct and divides before entering the right lung (ie. before the hilum). This results in two lobar bronchi being seen in a right lung hilar cross section.The left lung is less direct and curves upward slightly. It enters the left lung before branching (ie. after the hilum). This results in only one main bronchus being seen in a left lung hilar cross section.
Describe what the trachea branches into all the way until the alveoli.
Trachea > main bronchus > lobar bronchus > segmental bronchus > 25 branches later > alveoli
What can be said about how lobar bronchi are directed?
Each lobar bronchi divides into one lobe, 3 for the right lung, two for the left.
How do bronchi differ from bronchioles?
When bronchi lose their carilaginous support (tracheal rings), they are known as bronchioles.
What are respiratory bronchioles?
Bronchioles that open up directly to alveoli.
What happens in the lungs during athsma?
Smooth muscles of the lower airway spasm. As there are no tracheal rings here (bronchioles), they have no cartilaginous support to prevent collapse.Note - Cold air is thought to aggravate athsma (ie. winter)
How are the lobes of the right and left lung named? What are the names of the fissures that seperate each lobe?
Right lung has a superior, middle and inferior lobe.Superior and middle are seperated by the horizontal fissure, while the middle and inferior are seperated by the oblique fissure.Left lung has a superior and inferior lobe only.Superior and inferior are seperated by the oblique fissure.
Where is the apex of the lung, and why is it significant clinically?
It is located at the very superior end of the lung, and is significant because it is poorly protected by the thoracic cage, making it susceptible to injury and lung collapse.
Which lung does the heart occupy more, and what structure results as a consequence of this?
It occupies the left side more, and the cardiac notch is formed as a result.
Describe the pulmonary circulation.
The pulmonary artery carries blood to the lungs and away from the heart (deoxygenated).The pulmonary vein carries blood away from the lung and to the heart (oxygenated).
How to the pulmonary artery and vein enter the lung relative to each other?
The pulmonary artery enters the lungs superiorly and posteriorly.The pulmonary vein enters the lung inferiorly and anteriorly.
What can be said structurally about the pulmonary artery and vein?
Structurally, they are very similar, due to the similar blood pressure.
What is the lung parenchyma and what supplies and drains it/of with blood? Which structure do they branch off of?
It is all the non-respiratory tissue (connective tissue between alveoli etc.). It is supplied by the bronchial artery, which branches off the descending aorta.It is drained by the bronchial vein, which drains into the azygous system of veins.
What is a bronchopulmonary segment, and how is it significant clinically?
They are pyramid shaped sections of the lung, each one supplied entirely by one segmental bronchus, vein and artery.Clinical significance - can be ressected without affecting the other segments.There are 10 in the right lung (3 s. lobe, 2 m. lobe, 5 i. lobe)There are 8-10 in the left lung (4-5 s. lobe, 4-5 i. lobe)
How do the vagus and phrenic nerves run relative to the hilum?
The vagus nerve runs posterior to the hilum, while the phrenic nerve runs anteriorly.
How many bronchi are found at the hilum of each lung?
Right lung - 2 lobar bronchi, as it divided before the hilum.Left lung - 1 main bronchus, as it hasn't yet divided.
Where does the lung get is sympathetic and parasympathetic innervation from?
Sympathetic - from the sympathetic cord, of T1-4Parasympathetic - vagus nerve
Describe the path of the vagus nerve.
It runs over the arch of the aorta (anteriorly), then bwhind the root of the lung (1st birfurcation).Sympathetic cord branches also head towards the root of the lung.
What are the anterior and posterior pulmonary plexi?
They are formed by branches of the vagus nerve and the sympathetic cord (T1-4). They are a mix of both sympathetic and parasympathetic nerves.
Where do visceral sensory nerves run?
Travels along sympathetics (nociceptive) and parasympathetics (reflexes from bronchiole mucosa/cough)
What colour are hilar lymph nodes, and what is this from?
They are black in colour due to the carbon.
What are the costodiaphragmatic and costomediastinal recesses, and where are they found?
They are potential spaces within the lung, and are occupied during inspiration. They contain only pleural fluid during expiration.Costodiaphragmatic recess is found at the posterior most tip of the cavity.Costomediastinal recess is found along the medial border of the lungs, and is most obvious at the cardiac notch.The costodiaphragmatic recess is much larger in volume than the costomediastinal recess.
What is the ligament at the hilum called, and what structures is it continuous with?
The pulmonary ligament, continuous with the costal and visceral pleura.
What can eb said about the nerve supply of the two pleura (visceral and costal)?
The visceral pleura has its nerve supply shared with the lungs, while the parietal pleura derives it from the intercostal and phrenic nerves.
What is pneumothorax?
When air enters the pleural cavity and disrupts the surface tension.
What is haemothorax?
When blood enters the pleural cavity and disrupts the surface tension, also causing a haematoma.
What is the function of the serratus posterior muscle, and what does it attach to?
There is an anterior and posterior division of the serratus anterior, both with different functions and attachments.
The superior division attach to the angle of the ribs 2 - 5 and insert to the spinous processes of C7 - T3. They act to elevate ribs.
The inferior division attach to the angle of the ribs 9 - 12 and insert to the spinous processes of T11 - L2. They act to depress ribs.