Pulmonary Circulation

Question 0

Pulmonary Circulation

Answer 0

Is low-resistance, low-pressure, and high compliance; also has less vascular muscle

Question 1

Bronchial Circulation

Answer 1

Supplies nutrient flow to the trachea and bronchioles; renters @ the pulmonary veins

Question 2

Pulmonary Vascular Resistance

Answer 2

PVR= MPAP-MLAP/PBF

• Resistance is evenly distributed throughout the pulmonary circulation
• is lowest at FRC

Question 3

Extravascular components of PVR

Answer 3

Gravity
Intrathoracic pressure
Intraalveolar pressure
Right Ventricular output
Body Position

Question 4

Ptm effects on intraalveolar vessels

Answer 4

Inspiration => compression of intraaveolar vessels; distention of extra alveolar vessels (decreased Ppl)

Forced expiration=> compression of extraalveolar vessels (positive Ppl); distention of intraalveolar vessels

Question 5

PVR during exercise

Answer 5

Decreases due to:

1. Recruitment of pulmonary capillaries that were previously collapsed
2. Increased distention of already open capillaries
   * is needed because lungs are unable to autoregulate flow rate

Question 6

Adverse effects of Increased PVR

Answer 6

1. Increased afterload on right ventricle

2. Increased pulmonary capillary hydrostatic pressure => pulmonary edema

Question 7

Zone 1

Answer 7

PA > Pa

• Leads to compression of the vessels supplying this area; occurs during hemorrhage of positive pressure breathing
• Not present during normal breathing

Question 8

Zone 2

Answer 8

Pa > PA

Blood flow is dictated by the difference b/w these two pressures

Question 9

Zone 3

Answer 9

Pa > Pv

Greatest # of capillaries is open => Greatest blood flow

Question 10

Hypoxic Pulmonary Vasoconstriction

Answer 10

Atelectasis and hypoxia can cause vasoconstriction via the smooth muscle in order to prevent the wasting of blood flow

-Occurs possibly via an outward K+ current or thru the inhibition of NO-synthase

Question 11

Conditions that lead to Pulmonary Edema

Answer 11

Increased capillary permeability: due to insult

Increased capillary hydrostatic pressure: Occurs due to left heart failure; overadministration of IV fluids

Decreased interstitial hydrostatic pressure: Rapid chest evacuation

Decreased plasma colloid pressure: Hypoproteinemia, malnutrition

Increased interstitial colloid pressure

Lymphatic blockages/insufficiencies

Question 12

ARDS

Answer 12

Adult Respiratory Distress Syndrome

-Severe form of lung injury marked by chronic inflammation and increased capillary permeability

Symptoms include: breathlessness, rapid breathing, dry cough, chest pain

*Often caused by the inhalation of an insulting chemical