Anatomy

Question 1

What makes up the Upper Respiratory Tract?

Answer 1

• the right & left nasal cavities or the oral cavity
• the naso- oro- & laryngo- pharynx
• larynx

Question 2

What makes up the Lower Respiratory Tract?

Answer 2

• trachea
• right & left main bronchi
• lobar bronchi
• segmental bronchi
• bronchioles
• alveoli

Question 3

What happens at the level of C6 vertebrae?

Answer 3

the larynx becomes the trachea and the pharynx becomes the oesophagus
Where the lower respiratory tract begins

Question 4

What are the blood supplies for the lungs?

Answer 4

pulmonary arteries & their branches for oxygenation of blood for the systemic circulation
the bronchial arteries to provide oxygenated blood to the lung tissue

Question 5

What is the nerve and blood supply of the intercostal space?

Answer 5

intercostal nerve (anterior ramus of spinal nerve)
intercostal artery

Question 6

What are the phrenic nerves?

Answer 6

The combined anterior rami of cervical spinal nerves C3, 4, 5

Question 7

What is the role of the phrenic nerves?

Answer 7

nerve supply to the diaphragm

Question 8

Describe the 3 steps of inspiration?

Answer 8

1. Diaphragm contracts and descends -Increases vertical chest dimension
2. Intercostal muscles contract elevating ribs -Increases A-P and lateral chest dimensions
3. The chest walls pull the lungs outwards with them (pleura) -Air flows into the lungs, –ve pressure

Question 9

Describe the 3 steps of expiration?

Answer 9

1. Diaphragm relaxes and rises - Decreases vertical thoracic dimension
2. Intercostal muscles relax lowering ribs -Decreases A-P and lateral chest dimensions
3. Elastic tissue of lungs recoils -Air flows out of lungs

Question 10

What is contained in the carotid sheaths?

Answer 10

the vagus nerve
the internal carotid artery
the common carotid artery
the internal jugular vein

Question 11

What are the accessory muscles of deep inspiration?

Answer 11

• Pectoralis major - attaches between sternum/ribs & humerus
  Adducts and medially rotates humerus if the upper limb position is “fixed” e.g. by holding onto the arm of the chair or the thigh)
  the muscle can pull the ribs upwards/outwards
• Pectoralis minor: can pull ribs 3-5 superiorly towards the coracoid process of the scapula
• Sternocleidomastoid: attaches between sternum/clavicle & mastoid process of temporal bone
• Scalenus anterior, medius & posterior: attach between cervical vertebrae & ribs 1 & 2

Question 12

Describe step A of the cough

Answer 12

A. stimulation of sensory receptors in the mucosa of the:

1. oropharynx
2. laryngopharynx
3. larynx
4. respiratory tree (trachea to bronchioles)

Question 13

Describe step B of the cough

Answer 13

B. the CNS responds by rapidly coordinating the following:

1. a DEEP inspiration using the diaphragm (phrenic nerves), intercostal muscles (intercostal nerves) & “accessory muscles of inspiration”
2. adduction of the vocal cords to close the rima glottidis (vagus nerves)
3. contraction of the anterolateral abdominal wall muscles (intercostal nerves) to build up intra-abdominal pressure which pushes the diaphragm superiorly and builds up pressure in the chest/respiratory tree inferior to the adducted vocal cords
4. the vocal cords suddenly abduct to open the rima glottides (vagus nerves)
5. the soft palate tenses (CN V) and elevates (vagus nerves) to close off the entrance into the nasopharynx and direct the stream of air (at ~100mph!!) through the oral cavity as a cough rather than through the nasal cavity as a sneeze!