Lungs Flashcards
(34 cards)
What is the upper respiratory tract made of?
Nasal cavity, pharynx, larynx
What is the lower respiratory tract made of?
Trachea, main bronchus, lung
Is it our lungs that expand or our thoracic wall?
We don’t make our lungs bigger/smaller, only our thoracic wall.
Explain elasticity of lungs.
Lung tends to be as small as possible (if you remove them from the thoracic wall)
What is the endothoracic fascia?
Between ribs and parietal pleura: Endothoracic fascia: natural cleavage plane for surgical separation (to avoid collapsed lung).
If you were experiencing pain during inhalation, would this indicate a problem with the bone, muscle or joint?
Joint.
Name the two types of joints used within the thorax.
Articulationes costovertebrales: consists of two joints, one has an up and down motion, while the other has a side to side motion.
Articulationes sternocostales (costal cartilage): no motion.
Purpose of muscles in the thorax.
Keep thoracic wall ‘tight’.
How does the purpose of the internal intercostal muscles differ between bone and cartilage?
Intercostal in bone: expiration.
Intercostal in cartilage: inspiration.
Purpose of external intercostal muscles.
Inspiration
Muscles of inspiration (accessory)
sternocleidomastoid, scalene, pectoralis minor.
Muscles of inspiration (primary)
external intercostal, diaphragm
Muscles of expiration (active only)
internal intercostals, abdominals, Quadratus Lumborum
Abdominal respiration refers to the movement of what muscle?
Diaphragm
What nerves innervate the thorax?
Phrenic nerves:
Originate in the neck (C3-5), passes down to the diaphragm between heart and lung.
In the case of abdominal strain (coughing, sneezing, etc.) what muscles might contract?
Simultaneous contraction of diaphragm, abdominal muscles and erector spinae muscles, occasionally contraction pelvic floor.
What is the difference between respiration and breathing?
Respiration is the controlled oxidation of metabolites to provide energy in our body.
Breathing/ventilation is the mechanical process by which gas is transported in and out of our lungs.
Why do we have a negative intrapleural pressure (about -5)?
Lungs have a tendency to collapse. Thorax has a tendency to expand. These contrast each other (pulling in opposite directions).
When are the contrasting forces of the lungs and the thorax balanced?
During functional residual capacity (volume in lungs after exhalation).
What is alveolar pressure?
0.
How do you calculate transpulmonary pressure and what is its value in a healthy person compared to someone with a pneumothorax?
Alveolar pressure - Intrapleural pressure. Normal: 0 - (-5) = +5. Pneumothorax: 0.
Compliance formula:
Change in volume/change in transpulmonary pressure.
What is surfactant and what is it produced by?
Surfactant reduces surface tension. Molecules that make sure alveoli don’t collapse by causing water molecules to be less attracted to one another.
Created by Type II cells (pneumocytes).
If there is reduced surfactant, would the lungs be more or less compliant?
Less.
