The Pleura and the Lungs

Question 1

What is the thoracic cavity divided into

Answer 1

Left pleural cavity, right pleural cavity and mediastinum

Question 2

What does the pleural cavity contain

Answer 2

lungs

Question 3

what does the mediastinum contain

Answer 3

trachea, oesophagus, heart, blood vessels, nerves

Question 4

Where does the respiratory system develop from

Answer 4

endoderm layer at 4-6 weeks

Question 5

How does respiratory system development occur

Answer 5

endodermal out pouches form lung and bronchial buds,

rapid division of airways so lungs push out into primitive thoracic cavity (take visceral pleural lining with them)

Question 6

what are the two types of pleurae

Answer 6

visceral and parietal (perimeter, outer)

Question 7

what is visceral pleura like

Answer 7

closely adheres to lungs including fissures

Smooth and slippery surface

Question 8

what does visceral pleura do

Answer 8

connects parietal pleura to hilum/ root of lung

Question 9

what does parietal pleura do

Answer 9

lines internal aspects of thoracic wall

Question 10

what are the 4 parts of the parietal pleura

Answer 10

costal (internal rib cage)
mediastinal (lateral wall of mediastinum)
diaphragmatic (superior diaphragm)
cervical (cervical region)

Question 11

what is the pleural cavity

Answer 11

space between 2 layers of pleura containing a thin layer of serous fluid

Question 12

what is the function of serous fluid

Answer 12

the surface tension of fluid holds lungs against the thoracic wall so the lungs as the thoracic cavity expands

Question 13

what is a pneumothorax/ haemothorax

Answer 13

the surface tension of the pleural layers is lost

Question 14

what are pleural cavity recesses

Answer 14

exist in pleural cavity
not symmetrical due to the heart
occupied by the lung during forced inspiration

Question 15

what are the types of recesses

Answer 15

costomediastinal recess (LHS only, dip where heart is)
costodiaphragmatic recess (both sides, below lungs)

Question 16

what are the innervations of the parietal pleura

Answer 16

cervical - 1st intercostal nerve
costal - intercostal nerves
mediastinal (phrenic nerve, inside of lung)
diaphragmatic (lower intercostal and phrenic nerves)

Question 17

what is the innervation of the visceral pleura

Answer 17

autonomic nervous system (sympathetic and parasympathetic) from the pulmonary plexus

Question 18

what are the 3 surfaces of the lungs

Answer 18

mediastinal, costal and diaphragmatic 
plus top (apex) and bottom (base)

Question 19

what are the 3 borders of the lungs

Answer 19

anterior, posterior and inferior

Question 20

what is the structure of the hilum

Answer 20

bronchi, pulmonary artery and pulmonary veins
surrounded by the parietal mediastinal pleura
ends in the pulmonary ligament

Question 21

what is also contained in the structure of the hilum

Answer 21

bronchial arteries and veins
pulmonary plexus
lymph vessels and nodes

Question 22

what is the function of the bronchial arteries

Answer 22

supply oxygen and nutrients to lung and visceral pleura

Question 23

where do the left bronchial arteries originate from

Answer 23

descending aorta

Question 24

where do the right bronchial arteries originate from

Answer 24

intercostal arteries

Question 25

where do the left and right bronchial veins terminate

Answer 25

azygous system of veins

Question 26

how are the lungs innervated

Answer 26

sympathetic (from sympathetic trunk) = bronchial musculature dilates and pulmonary vasculature constricts parasympathetic (vagus nerve) = opposite

Question 27

where does lymph from the lungs drain

Answer 27

towards hilum via bronchopulmonary (hilar) nodes -> tracheobronchial nodes -> paratracheal nodes

Question 28

what is the structure of the respiratory tree

Answer 28

``` trachea primary bronchi (main) secondary bronchi (lobar) tertiary bronchi (segmental) bronchioles (terminal/respiratory) alveolar sacs alveoli ```

Question 29

what is the trachea

Answer 29

flexible tube, distal to the larynx (runs c6 to t4/5)

Question 30

what is the structure of the trachea

Answer 30

anteriorly C shaped cartilage rings posteriorly trachealis muscle bifurcates at level of sternal angle lined with mucous membrane and cilia

Question 31

what is the structure of the primary bronchi

Answer 31

pass into lung at hilum, 1 for each lung (right is wider, shorter and runs more vertically) contain cartilage

Question 32

what is the structure of the secondary bronchi

Answer 32

3 in right lung and 2 in left lung

Question 33

what is the function of the tertiary bronchi

Answer 33

each one supplies a bronchopulmonary segment (10 in right lung and 8-10 in left lung)

Question 34

what are the bronchopulmonary segments

Answer 34

supplied by a single tertiary bronchus receives a single branch of pulmonary artery separated by connective tissue surgically resectable/ removable in isolation

Question 35

what are bronchioles

Answer 35

20-25 generations of conducting bronchioles | no cartilage in walls

Question 36

what do terminal bronchioles give rise to

Answer 36

several generations of respiratory bronchioles (characterised by out pockets of alveoli) which lead to alveolar ducts and then sacs

Question 37

what are alveolar ducts

Answer 37

elongated airways lined by alveoli which lead to common spaces called alveolar sacs each alveolus is surrounded by two capillaries

Question 38

what are the two alveolar cell types

Answer 38

type 1 pneumocytes (95%) type 2 pneumocytes (5%) they secrete pulmonary surfactant to keep alveoli inflated

Question 39

what borders separate the costal and mediastinal surfaces of the lung

Answer 39

anterior and posterior borders (inferior is between costal and diaphragmatic surfaces)

Question 40

what effect does the heart have on the left lung

Answer 40

cardiac impression (cardiac notch and impression from aorta)

Question 41

what impressions are made on the right lung

Answer 41

made by superior vena cava, oesophagus, azygous vein

Question 42

where are the parts of the hilum usually located

Answer 42

artery superior bronchi posterior veins inferior