Respiratory Anatomy Review Sheet

Respiratory Physiology – outline notes
By at September 15, 2011 | 6:43 am | Print
Respiratory System
I. Functions:
A. Provides area for gas exchange between air and blood
B. Moves air to and from area of gas exchange
C. Protects gas exchange surfaces
D. Sound production
E. Provides olfactory sensations to the CNS
F. Capillaries in lungs produce angiotensin converting enzyme (ACE)
II. 4 Respiratory processes
A. Pulmonary ventilation (breathing)
1. Move air in and out of lungs
B. External respiration
1. Gas diffusion across respiratory membrane
2. O2 loading / CO2 unloading
C. Internal respiration
1. Gas diffusion to tissues of the body
2. O2 unloading / CO2 loading
D. Transport of O2 and CO2
III. Pulmonary ventilation
atelectasis – lung collapse
H. Modes of Breathing
1. Quiet breathing
a. Inhalation – muscle contraction
b. Exhalation – passive (elastic rebound)
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c. Deep breathing – use diaphragm
d. Shallow breathing – external intercostals
1) Pregnancy – due to pressure on diaphragm
2. Forced breathing
a. Accessory muscles
IV. Respiratory Rates and Volumes
A. Respiratory minute volume (VE) – ml / min
1. VE = Respiratory rate (f) x Tidal volume (VT)
2. 6.0 L = 12 breaths/min x 500 ml
B. Alveolar ventilation (VA)
1. VD – anatomic dead space
a. 150 ml of tidal volume never reaches alveoli
2. VA = f x (VT – VD)
3. 4.2 L = 12 x (500 – 150)
C. Overhead of Volumes and Capacities
V. Gas Laws
A. Partial Pressure (Dalton’s Law)
1. Total pressure exerted by a mixture of gases is the sum of individual pressures exerted by each gas.
2. Sum of partial pressures = total pressure .21 x 760 mmHg = 159 mmHg3. O2 = 21% —— pp = 5974. N2 = 78.6% ——–
B. Henry’s Law
1. Amount of gas in solution is proportional to pp of that gas
2. At gas and liquid contact – gas under pressure will force gas into liquid until equilibrium
3. Ex) soda under pressure in can until opened
4. At given pp and temp – gas solubility determines am’t
Large surface area
a) Emphysema
VII. Internal respiration – at systemic tissues
1. OVERHEAD
2. Exchange between systemic capillaries and tissue
3. Review capillary exchange
VIII. Gas Transport – Oxygen
A. Oxygen has low solubility 20 ml of O21. 100 ml of blood (alveolar capillaries)—
a. 0.3 ml of dissolved O2 (1.5%)
b. 98.5 % – bound to Hemoglobin (iron in Heme group)
2. Hemoglobin saturation
a. 4 O2 = 100%
b. 2 O2 = 50%
c. Hb binds O2 reversibly
B. Oxygen-Hemoglobin dissociation curve
1. Relates saturation of Hb with pO2 increase Hb saturation ( ↑ affinity)2. increase pO2 ——
a. Hb stores O2 decrease Hb saturation (↓affinity)3. decrease pO2 —–
a. Hb releases O2
4. Normal tissue 75% (pO2 = 40 mmHg)a. 97% (pO2 = 95 mmHg) —–
b. Venous blood has large O2 reserve
5. Active tissue
a. drops to 20% saturation (pO2 = 15-20 mmHg)
b. uses 3.5 more O2
6 Carbon Monoxide (CO) poisoning
C. Hemoglobin and pH
1. Bohr Effect ↓Hb affinity for O2a. systemic tissue – decrease pH —— H+ + HCO3-– H2CO3 —b. CO2 + H2O ↑acid ↓pH –c. ↑H+ —- ↑Hb affinity for O2d. lungs - ↓pCO2 —
D. Hb and Temperature ↓ Hb affinity for O21. ↑Temp —-
2. Active skeletal muscle
E. Hb and 2,3-bisphosphoglycerate