Respiratory Phys (Chapter 23)

Question 1

Which muscles are responsible for inspiration?

Answer 1

the diaphragm, and, to a lesser extent, the external intercostal muscles are responsible for inspiration; expiration is generally passive.

Question 2

Where does trachea begin?

Answer 2

The trachea begins at the lower border of the cricoid cartilage

Question 3

Narrowest part of trachea:

Answer 3

Cricoid cartilage

Question 4

T/F-tracheal bifurcation located at the level of the sternal angle.

Answer 4

True

Question 5

Right mainstream bronchus continues to become what?

Answer 5

The right main stem bronchus continues as the bronchus intermedius after the take-off of the right upper lobe bronchus.

Question 6

Type 1 vs Type 2 pneumocytes:

Answer 6

Unlike type I cells, type II pneumocytes are capable of cell division and can produce type I pneumocytes if the latter are destroyed. They are also resistant to O2 toxicity. Type 2 makes surfactant.

Question 7

How many systems in the lungs (blood systems)

Answer 7

The lungs are supplied by two circulations, pulmonary and bronchial. The bronchial circulation arises from the left heart and sustains the metabolic needs of the tracheobronchial tree.

Question 8

Diff between pressure in plum vs systemic circulation:

Answer 8

Although flows through the systemic and pulmonary circulations are equal, the lower pulmonary vascular resistance results in pulmonary vascular pressures that are one-sixth of those in the systemic circulation; as a result, both pulmonary arteries and veins normally have thinner walls than systemic vessels with less smooth muscle.

Question 9

How much does unilateral Phoenix nerve block impair patients?

Answer 9

Unilateral phrenic nerve block or palsy only modestly reduces most indices of pulmonary function (about 25%) in normal subjects.

Question 10

T/F: Intercostal muscles are innervated by their respective thoracic nerve roots

Answer 10

TRUE

Question 11

Innervation of tracheobrobchial tree

Answer 11

The vagus nerves provide sensory innervation to the tracheobronchial tree. Both sympathetic and parasympathetic autonomic innervation of bronchial smooth muscle and secretory glands is present. Vagal activity mediates bronchoconstriction and increases bronchial secretions via muscarinic receptors. Sympathetic activity (T1-T4) mediates bronchodilation and also decreases secretions via β2-receptors

Question 12

Parasympathetic vasodilatory activity seems to be mediated via the release of nitric oxide. T/F

Answer 12

TRUE

Question 13

Formula for compliance:

Answer 13

compliance (C), which is defined as the change in volume divided by the change in distending pressure

Question 14

Dynamic compliance:

Answer 14

Dynamic lung compliance [Cdyn,L], which is measured during rhythmic breathing, is also dependent on airway resistance.)

Question 15

The greatest change with FRC:

Answer 15

The greatest change occurs between 0° and 60° of inclination. No further decrease is observed with a head-down position of up to 30°.

Question 16

Volume at which small airways begin to close

Answer 16

The volume at which these airways begin to close in dependent areas of the lung is called the closing capacity.

Question 17

Closing Capacity and age

Answer 17

Closing capacity is normally well below FRC (Figure 23-6), but rises steadily with age (Figure 23-7). This increase is probably responsible for the normal age-related decline in arterial O2 tension. At an average age of 44 years, closing capacity equals FRC in the supine position; by age 66, closing capacity equals or exceeds FRC in the upright position in most individuals. Unlike FRC, closing capacity is unaffected by posture.