Lungs and breathing Flashcards
What is the Mediastinum?
A central wall of tissue dividing the thoracic cavity
Consists of:
- heart
- great vessels
- fat
- remnants of the thymus gland
What does the mediastinum divide the thorax into?
Divides the thorax into 2 pleural cavities:
- Parietal pleura - well supplied by sensory nerves, covers the rib cage
- Visceral pleura - no sensory nerve innervation, covers the lungs
What is found in between the two pleura?
Pleural cavity contains a small amount of lubricating fluid
What is the costodiaphragmatic recess?
Gap between the base of the lung and the base of the pleural cavity
Allows lungs can slide and expand when fully inflated
Describe basic lung structure
- Right and left lung
- Fissures
- Hilum
- Bronchial tree
Describe basic lung anatomy
Each lung has an:
- Apex - top
- Base - bottom
The surface of the lung can either be:
- Costal - facing the ribs
- Mesiastinal - facing the mediastinum
How many fissures are there in the right lung?
2
What are the names of the fissures of the right lung?
Horizontal
Oblique
What are the name of the lobes of the right lungs?
Upper
Middle
Lower
How many fissures are there in the left lung?
1
What are the names of the fissures of the left lung?
Oblique
+ cardiac notch
How many lobes are there in the left lung?
2
What are the names of the lobes of the left lung?
Upper
Lower
Lingula
What is the hilum of the lung?
The hilum is a large triangular depression where the connection between the parietal pleura and the visceral pleura is made, marking the meeting point between the mediastinum and pleural cavities
What are the structures found in the hilum of the lung?
Pulmonary artery
2 pulmonary veins
Main bronchus
Lymphatics
Bronchial vessel
Autonomic nerves - parasympathetic and sympathetic to the smooth muscles of the bronchi and vessels
What are the components of the bronchial tree?
- Trachea
- Main primary bronchus
- Lobal bronchus
- Segmental bronchus
- Bronchiole
- Terminal bronchiole
- Respiratory bronchiole
- Alveoli
What are bronchopulmonary segments?
Each lobe of the lung is divided into sub-lobes called bronchopulmonary segments.
Each segment is supplied by:
- A segmental artery
- A segmental vein
- A segmental bronchus
What is the goal of inspiratory movements?
Increase the volume of the thorax
Decrease the pressure of the thorax
This causes the internal pressure to fall and air to increase
What are the three ways to achieve the goals of inspiration?
- Increasing the superior-inferior height
- Increase the bilateral diameter
- Increase the anterioposterior diameter
How do the ribs increase the anteroposterior diameter during breathing?
Upper ribs slope downwards at rest
Raising them increase the anteroposterior diameter of the chest and pushes the sternum forwards
Requires flexion at the manubrio-sternal joint
What 3 movements are involved in increasing the bilateral diameter of the ribcage?
- Sliding of top ribs
- Bucket-handle movement in the true lower ribs
- Caliper movement in floating ribs
Which ribs take part in increasing the bilateral diameter of the ribcage?
Lower ribs (5 and below)
Describe the buckle-handle movement of the lower ribs
Anterior and posterior attachments of the lower ribs lie weel above the midpoint of the rib, so raising the ribs raises the midpoint
What enhances the movement of the ribs increasing the bilateral diameter of the ribcage?
The flattening of the diaphragm
Contracts to flatten, pushing against the abdominal organs
Also aids in raising intra-abdominal pressure
