lungs and pleura

Question 1

what makes up the thoracic cavity? 3

Answer 1

• left pleural cavity
• right pleural cavity
• mediastinum (space between 2 pleural cavities)

Question 2

what is in the mediastinum?

Answer 2

• heart
• trachea
• esophagus
• blood vessels
• nerves

Question 3

explain the development of the respiratory system? 6

Answer 3

• 4-6 weeks
• from endoderm layer
• endodermal out pouches form lung buds and bronchial buds
• rapid division of airways
• lungs push their way into the primitive thoracic cavity
• they take the lining with them, which becomes the visceral pleura

Question 4

what is each lung surrounded by?

Answer 4

• 2 layers of pleura
• visceral
• parietal

Question 5

what is the visceral pleura? 3

Answer 5

• closely adheres to lungs including the fissures
• creates a smooth and slippery surface
• connects to parietal pleura and hilum(root of lung)

Question 6

what is the parietal pleura? 5

Answer 6

• lines the internal aspect of the thoracic wall
• costal- internal rib cage
• mediastinal- lateral wall of mediastinum
• diaphragmatic- superior diaphragm
• cervical- cervical region

Question 7

what is the pleural cavity? 5

Answer 7

• space between 2 layers of pleura
• contains a thin layer of serous fluid
• surface tension holds lungs against the thoracic wall
• lungs expand as thoracic cavity expands
• pneumothorax/ haemothorax- surface tension between the pleural layers is lost

Question 8

explain pleural cavity recesses?

Answer 8

• not symmetrical due to the heart
• can be occupied by the lung during forced expiration
• costodiaphragmatic recesses (posterior)
• costomediastinal recess

Question 9

explain pleural innervation?

Answer 9

• parietal-
• cervical- 1st intercostal nerve
• mediastinal- phrenic nerve
• costal- intercostal nerve
• diaphragmatic- lower intercostals and phrenic nerves
• visceral
• autonomic (sympathetic and parasympathetic) form pulmonary plexus

Question 10

describe the left lung? 4

Answer 10

• 2 lobes
• oblique fissure
• impression for the heart (cardiac notch)
• lingula

Question 11

describe the right lung? 2

Answer 11

• 3 lobes

- horizontal and oblique fissures

Question 12

what is the pulmonary ligament? 2

Answer 12

• formed from the parietal pleura and hangs inferiorly from the hilum of the lung
• allows space or the hilum to move up and down with lung movement

Question 13

explain bronchial circulation? 4

Answer 13

• bronchial arteries supply O2 to the lung and visceral pleura
• left arteries branch from the descending aorta
• right arteries branch from the intercostal arteries
• bronchial veins terminate in the azygos system of the veins

Question 14

explain lymph drainage of the lungs? 4

Answer 14

• lymph drains towards the hilum
• bronchopulmonary nodes
• tracheobronchial nodes
• paratracheal nodes

Question 15

explain the innervation of the lungs? 3

Answer 15

• from autonomic
• sympathetic comes from the sympathetic trunk, causes bronchial musculature to dilate and pulmonary vasculature to constrict
• parasympathetic comes from the vagus, bronchial musculature constricts and pulmonary vasculature dilates

Question 16

describe the respiratory tree? 7

Answer 16

• trachea
• primary/main bronchi
• secondary/lobar bronchi
• tertiary/segmental bronchi
• bronchopulmonary segments
• bronchioles
• alveoli

Question 17

describe the trachea? 8

Answer 17

• flexible tube
• C6-T4/5
• distal to larynx
• anterior view shows c shaped cartilage rings
• posterior view shows trachealis muscle
• bifurcates at the level of the sternal angle
• lined by mucous membrane and cilia
• carina separates the trachea into the main bronchi

Question 18

describe the primary bronchi? 4

Answer 18

• one for each lung
• pass into lung at the hilum
• right is wider and more vertical, so more unwanted objects pass into the left lung
• contains cartilage

Question 19

describe the secondary bronchi? 2

Answer 19

• 3 in right lung

- 2 in left

Question 20

describe the tertiary bronchi?

Answer 20

each supplies a bronchopulmonary segment

Question 21

what is a bronchopulmonary segment? 6

Answer 21

• 10 in right
• 8-10 in left
• each is supplied by a single tertiary bronchi
• receives a single branch of pulmonary artery
• separated by connective tissue
• surgically resectable/ removable in isolation

Question 22

describe the bronchioles? 3

Answer 22

20-25 generations of conducting bronchioles

• no cartilage in walls
• terminal gives rise to several generations of respiratory bronchioles which lead to alveoli

Question 23

describe the alveoli? 4

Answer 23

• alveolar ducts are elongated airways lined by alveoli which lead to common spaces called alveolar sacs
• each is surrounded by capillaries
• type 1 pneumocytes (95%)
• type 2 pneumocytes (5%) these secrete pulmonary surfactant which prevents surface tension in alveoli