Pulmonary

Question 1

What is upper respiratory anatomy?

Answer 1

(above the larynx) nose, nasal cavity, paranasal sinuses, nasopharynx, oropharynx, laryngopharynx. These function to filter, warm and humidify incoming air

Question 2

What are three parts of the larynx?

Answer 2

Thyroid cartilage (hyaline, forms anterior walls of larynx); cricoid cartilage (hyaline, forms posterior walls of larynx); epiglottis (elastic, ligaments attach to hyoid bone)

Question 3

Describe the bronchi

Answer 3

Right bronchus is larger and steeper, inhaled objects usually get stuck in right. Primary to secondary (to each lobe of lung) to tertiary (to each segment)

Question 4

Describe the lungs

Answer 4

Right lung has 3 lobes, with horizontal and oblique fissure. Right lung has 10 segments. Left lung has cardiac notch. Left lung has 8 or 9 segments.

Question 5

Describe anatomy of alveoli

Answer 5

Bronchiole leads to alveolar duct with leads to alveolar sac. Alveolar epithelium is simple squamous epithelium with pneumocyte type I (maintain structure) and pneumocyte type II (septal; produce surfactant)

Question 6

What are vascular components of respiratory system?

Answer 6

Respiratory portion (pulmonary arteries carry deoxygenated blood from right ventricle, enter lungs at hilum. Oxygenated blood leaves through pulmonary veins for left atrium. Low pressure, 30 mmHg);
Conducting portion (supplied by bronchial arteries which branch off thoracic aorta. Provide perfusion to lung tissues, and some of deoxygenated blood returns via pulmonary veins, decreasing partial pressure of oxygen.)

Question 7

What are muscles involved with inhalation?

Answer 7

Diaphragm, external intercostals, serratus anterior, pectoralis minor, scalenes, sternocleidomastoid

Question 8

What are muscles involved with exhalation?

Answer 8

Transversus thoracis, internal intercostals, rectus abdominis, external and internal obliques

Question 9

How does ventilation occur?

Answer 9

Boyle’s law: P=1/V. Diaphragm contracts, increases volume, air flows from high pressure to low pressure.

Question 10

What is the respiratory pump?

Answer 10

Decrease of pressure in the pleural cavity pulls air into lungs. and also pulls blood into inferior vena cava and right atrium from smaller veins of abdominal cavity and lower body. Exhalation also pushes blood into right atrium

Question 11

What is pleural pressure?

Answer 11

Pressure in intrapleural cavity. Atmospheric pressure is normally 760; intrapleural pressure is -3 at rest and decreases to -6 during inspiration

Question 12

What is alveolar pressure?

Answer 12

Pressure inside lungs (a.k.a. intrapulmonary pressure). With quiet breathing, difference between atmospheric pressure is -1 (759) with inspiration and with expiration +1 (761)

Question 13

How does pleural and alveolar pressure affect inspiration?

Answer 13

Inspiration caused by decrease in pleural pressure. Pleural pressure decreases from -3 to -6, and alveolar pressure decreases from 760 to 759.

Question 14

What is tidal volume?

Answer 14

Amount of air moved in/out of lungs during a single respiratory cycle (500 mL)

Question 15

What is inspiratory reserve volume?

Answer 15

Amount of air that can be inhaled over and above the tidal volume (males 3300 mL, females 1900 mL)

Question 16

What is expiratory reserve volume?

Answer 16

Amount of air voluntarily expelled after a normal, quiet expiration. (males 1000 mL, females 700 mL)

Question 17

What is residual volume?

Answer 17

Amount of air remaining in lungs after maximal exhalation (males 1200 mL, females 1100 mL)

Question 18

What is inspiratory capacity?

Answer 18

Total amount of air that can be inhaled. IC= TV + IRV

Question 19

What is functional residual capacity?

Answer 19

Total amount of air remaining in lungs after a quiet respiratory cycle. FRC= ERV + RV

Question 20

What is vital capacity?

Answer 20

Maximum amount of air that can move in/out of lungs. VC= ERV + TV + IRV

Question 21

What is total lung capacity?

Answer 21

Total volume of lungs. TLC = VC + RV

Question 22

What is dead space?

Answer 22

Volume of inhaled air that does not take part in gas exchange

Question 23

What is Bohr effect?

Answer 23

Decrease in blood pH causes lower affinity of hemoglobin bonding to oxygen, lower O2 saturation

Question 24

How does surfactant affect surface tension?

Answer 24

Surface tension is caused by attraction between water molecules in an air-water boundary. Surface tension tends to collapse small air bubbles and would collapse alveoli without surfactant. Surfactant consists of phospholipids and proteins that interact with water molecules and reduce surface tension.

Question 25

What factors affect gases diffusing across respiratory membrane?

Answer 25

1. Significant differences in partial pressures of gases across respiratory membrane (move from high to low pressure)
2. Very short distance of capillary and alveolar basement membrane (very thin)
3. Oxygen and carbon dioxide are lipid soluble
4. Large total surface area of alveolar surface
5. Blood flow and airflow are coordinated, blood flow is highest around alveoli with high partial pressure of oxygen.

Question 26

How do gases diffuse in external respiration?

Answer 26

Membrane between alveolus and alveolar capillary. PO2 in alveolus is 100 and PCO2 in alveolus is 40. In capillary, PO2 is 40 and PCO2 is 45. Gas exchange results so that new capillary pressures: PO2 is 100 and PCO2 is 40

Question 27

How do gases diffuse in internal respiration?

Answer 27

Between interstitial fluid and capillary. In interstitial fluid, PO2 is 40 and PCO2 is 45. In capillary, PO2 is 95 and PCO2 is 40. After exchange, capillary pressures: PO2 is 40 and PCO2 is 45.

Question 28

What areas of brain control breathing?

Answer 28

1. Medulla oblongata:
   - Dorsal ventral group (inspiratory center, functions in quiet breathing & forced breathing, innervates external intercostals and diaphragm.
   - Ventral respiratory group (functions in forced breathing only, innervates accessory muscles.)
2. Pons:
   - Apneustic center (continuously stimulates DRG for inspiratory function).
   - Pneumotaxic center (inhibits apneustic center to promote exhalation)

Question 29

How do CO2 levels affect respiratory regulation?

Answer 29

Slight rise in PCO2 has greater effect on respiratory rate compared to decrease in PO2. Chemoreceptors monitoring CO2 levels are sensitive to pH.
Hypercapnia: increase in PCO2 of arterial blood and drop in pH. Chemoreceptors in carotid, aortic bodies and CNS are stimulated to increase RR and depth of breathing.
Hypocapnia: decrease in PCO2 of arterial blood and rise of pH causes RR to decrease until PCO2 returns to normal.

Question 30

How is oxygen transported in the blood?

Answer 30

Over 98% is bound to hemoglobin of RBCs

Question 31

What is nitrogen washout (absorption atelectasis)?

Answer 31

If large volume of nitrogen in lungs is replaced by oxygen, high PO2 in alveoli causes rapid O2 diffusion into capillary which causes alveolar collapse.

Question 32

What are clinical issues secondary to smoking?

Answer 32

Lung cancer, emphysema, smoker’s cough, bronchitis, increased mucous production, damaged cilia.