Anatomy of the respiratory system Flashcards
How long is the trachea?
10-12cm in length
Describe the anatomical postioning of the trachea and where it divides.
The trachea lies slightly to the right of the midline and divides into the right and left bronchi at the carina (the carina lies beneath the manubrium sterni and the second right costal cartilage).
Inhaled material is more likely to get inhaled into which lung and why?
The right as the right bronchus is more vertical than the left.
How many lobes does the left and right lungs have?
- Right = three lobes - upper / middle /lower
- Left = …
Physical signs on the right side in the front of the chest are due to lesions of which lobes?
The upper and middle as these lie in front of the lower lobe.
What is the hilum of the lung?
The hilum of the lung is found on the medial aspect of each lung, and it is the only site of entrance or exit of structures (major bronchi and pulmonary arteries and veins) associated with the lungs.
Where do the diaphragm muscle fibres arise, insert and what innervates them?
- Origins - the lower six ribs and their costal cartilages
- Inserts - the central tendon
- Innervation - motor and sensory nerve fibres go seperately to each half of the diaphragm via the phrenic nerves
How are the tracheobronchial lymph nodes arranged?
- pulmonary
- bronchopulmonary
- subcarinal
- superior tracheobronchial
- paratracheal
Describe the nerve supply to the lung.
- The innervation of the lung remains incompletely understood.
- Parasympathetic and sympathetic fibres (from the vagus and sympathetic chain, respectively) accompany the pulmonary arteries and airways.
How is the parietal and visceral pleura innervated?
- The parietal pleura is innervated from intercostal and phrenic nerves
- The visceral pleura has no innervation.
Describe the branching of the left and right main bronchi.
- Right - divides into the upper lobe bronchus and the intermediate bronchus, which further subdivides into the middle and lower lobe bronchi.
- Left - divides into upper and lowed lobe bronchi
- (Fun fact: approx. 25 divisions between trachea and the alveoli)
Describe the properties of the first seven divisions of bronchi? (4)
- Walls consisting of cartilage and smooth muscle
- An epithelial lining with cilia and goblet cells
- Submucosal mucus-secreating glands
- Endocrine cells - amine precursor and uptake decarboxylation (APUD) cells containing 5-HT
Describe the properties of the later 16-18 divisions of the bronchioles. (3)
- No cartilage and a muscular layer that progressively becomes thinner
- A single layer of ciliated cells but very few goblet cells
- Granulated Clara cells that produces a surfactant-like substance
The epethial cells consist mainly of which cells?
- Type 1 pneumocytes
What limits the movement of fluids in and out of the alveoli?
Tight junctions
What allows for communication between alveoli of adjoining lobules?
pores of Kohn
Describe type II pneumocytes and their purpose. (4)
- More numerous than type II
- Cover less of the epethial lining
- Contain lamellar vavuoles which are the source of surfactant
- Are the precursors of type I pnemocytes
Along with type I and II pneumocytes what other cell is present within the alveoli?
Large alveolar macrophages
Describe the path of the visceral pleura. Where is it continuous the parietal pleura?
- Covers the surface of the lung and lines the interlobular fissures
- Continous with the parietal pleura at the hilum. Before joining the parietal pleura the visceral pleura continues alongside the branching bronchial tree for some distance and then reflects back.
What serous membranes line the diaphragm?
- Parietal pleura above
- Peritoneum below
What are the two blood supplies to the lungs?
- Recieves deoxygenated blood from the right ventricle via the pulmonary artery
- Recieves oxygenated blood via the bronchial circulation
Describe the pulmonary circulation.
- Pulmonary artery divides to accompany bronchi
- The pulmonary venules drain laterally to the periphery of the lobules –> pass centrally in the interlobular and intersegmental septa –> join to form the four pulmonary veins
Describe the bronchial circulation.
- Arises from the descending aorta –> bronchial arteries supply arteries down to the level of the respiratory bronchiole.
- The bronchial veins drain into the pulmonary veins, forming part of the normal physological shunt.
