THE RESPIRATORY SYSTEM

Question 1

What is the thoracic wall comprised of?

Answer 1

• ribs (twelve on each side)
• thoracic vertebrae and their intervertebral discs
• sternum - manubrium, body and xiphoid process
• thoracic muscles - span the intercostal spaces between the ribs

Question 2

superior thoracic aperture (anatomy of the thoracic wall)

Answer 2

• vertebra T1 (posterior)
• medial margin of rib 1
• manubrium (anterior)

What passes through the superior thoracic aperture?

• common carotid artery
• jugular vein
• esophagus
• trachea

Question 3

inferior thoracic aperture (organisation of the thorax)

Answer 3

• vertebral body T12 (posteriorly)
• ribs
• xiphoid process (anteriorly)
• the diaphragm seals the inferior thoracic aperture inferiorly

Question 4

what are the pleural cavities? (organisation of the thorax)

Answer 4

• two pleural cavities are situated on either side of the mediastinum (left and right)
• each pleural cavity is lined by pleura (mesothelial membrane)
• important for accomodating changes in lung volume during breathing

Question 5

parietal pleura (organisation of the thorax)

Answer 5

• lines the thoracic walls (costal, diaphragmatic and medistinal parts)
• thicker and more durable layer
• continuous with the visceral plura at the hilum of the lungs
• innervated by the intercostal nerves and phrenic nerves (sensitive to pain)

Question 6

visceral pleura (organisation of the thorax)

Answer 6

• directly adhered to the outer surface of each lung
• continous with the parietal pleura at the hilum of the lungs
• innervated by the pulmonary plexus (not sensitive to pain but is sensitive to stretch sensation)

Question 7

the mediastinum (organisation of the thorax)

Answer 7

• visceral area in the thoracic cavity that is surrounded by the left and right pleural cavities
• houses the heart, trachea, oesophagus, thoracic nerves, and systemic blood vessels
• divided into the superior and inferior mediastinum via the transverse plane

Question 8

functions of the respiratory system

Answer 8

• mechanical function - musculoskeletal elements
• filtration/conduction function - nasal cavity to terminal branches
• vocalisation - larynx
• gas exchange - respiratory bronchioles to alveoli

Question 9

diaphragm (muscles of the respiratory system)

Answer 9

• double-domed musculotendinous sheet located inferiorly to the rib cage
• separates the thoracic cavity from the abdominal cavity
• undergoes contraction/relaxation, altering the volume of the lungs, producing inspiration and expiration

Question 10

pathways through the diaphragm (muscles of respiration)

Answer 10

caval hiatus (T8)

• inferior vena cava
• phrenic nerve

esophageal hiatus (T10)

• esophagus
• vagus nerves

aortic hiatus (T12)

• aorta
• thoracic duct
• azygous vein

Question 11

External intercostals (respiratory muscles)

Answer 11

• originate at the lower border of the rib and insert into the superior border of the rib below
• anterior is 1/3 membranous
• involved in vigorous inspiration (i.e., during exercise)
• elevates the rib

Question 12

internal intercostals (respiratory muscles)

Answer 12

• originates from lateral edge of costal groove and inserts into superior surface of rib below
• anterior is 1/3 membranous
• depresses the ribs
• involved in expiration

Question 13

innermost intercostal muscles (respiratory muscles)

Answer 13

• originates from the medial edge of the costal groove and inserts into the superior surface of the rib below
• acts to depress the ribs
• involved in expiration