Physiology Chapter 16 Respiratory System: Pulmonary Ventilation

Front 1

Internal respiration

Back 1

Oxidative phosphorylation (Did this already)

Front 2

External respiration

Back 2

Exchange of oxygen and carbon dioxide between atmosphere and body tissues

Front 3

External Respiration (4)

Back 3

-Pulmonary ventilation
-Exchange between lungs and blood
-Transportation in blood
-Exchange between blood and body tissues

Hint 3

Two types of exchanges

Front 4

Structures of the Conducting Zone (3)

Back 4

-Trachea
-Bronchi
-Secondary bronchi
+Right side—3 (to 3 lobes of right lung)
+Left side—2 (to 2 lobes of left lung)

Front 5

Structures of the Respiratory Zone (4)

Back 5

-Respiratory bronchioles
-Alveolar ducts
-Alveoli
-Alveolar sacs

Front 6

Function of the Respiratory Zone (2)

Back 6

-Exchange of gases between air and blood
-Mechanism is by diffusion

Front 7

Alveoli (3)

Back 7

-Alveoli = site of gas exchange
-300 million alveoli in the lungs (tennis court size)
-Rich blood supply—capillaries form sheet over alveoli

Hint 7

What is it?
How many?
What does it have?

Front 8

Alveoli (3) - Two types

Back 8

-Type I alveolar cells—make up wall of alveoli
+Single layer epithelial cells
-Type II alveolar cells—secrete surfactant
-Alveolar macrophages

Front 9

Role of Pressure in Pulmonary Ventilation (2)

Back 9

-Air moves in and out of lungs by bulk flow
-Pressure gradient drives flow
+Air moves from high to low pressure
+Inspiration—pressure in lungs less than atmosphere
+Expiration—pressure in lungs greater than atmosphere

Hint 9

Inspiration
Expiration

Front 10

Pulmonary Pressures (4)

Back 10

-Atmospheric pressure = Patm
-Intra-alveolar pressure = Palv
+Pressure of air in alveoli
-Intrapleural pressure = Pip
+Pressure inside pleural sac
-Transpulmonary pressure = Palv – Pip
+Distending pressure across the lung wall

Front 11

Atmospheric Pressure (4)

Back 11

-760 mm Hg at sea level
-Decreases as altitude increases
-Increases under water
-Other lung pressures given relative to atmospheric (set Patm = 0 mm Hg)

Front 12

Pneumothorax

Back 12

the collapse of one or both lungs, caused by accumulation of gas or air in the pleural cavity, or resulting from injury or disease.

Front 13

Mechanics of Breathing (2)

Back 13

-Movement of air in and out of lungs due to pressure gradients
-Mechanics of breathing describes mechanisms for creating pressure gradients

Front 14

Forces for Air Flow (2)

Back 14

-Boyle’s Law: pressure is inversely related to volume
-Thus, can change alveolar pressure by changing its volume

Front 15

Muscles of Respiration (2)

Back 15

-Inspiratory muscles increase volume of thoracic cavity
+Diaphragm
+External intercostals
-Expiratory muscles decrease volume of thoracic cavity
+Internal intercostals
+Abdominal muscles

Front 16

To Overcome Surface Tension (2)

Back 16

-Surfactant secreted from type II cells
+Surfactant = detergent that decreases surface tension
-Surfactant increases lung compliance
+Makes inspiration easier

Front 17

Spirometry

Back 17

spirometer - an instrument that measures the amount of air moved in and out of the lungs (the amount of inhaled and exhaled air).

Front 18

Diffusion of Gases (2)

Back 18

-Partial pressures of gases
-Solubility of gases in liquids

Front 19

Partial Pressure of Gases: Ideal Gas Law (3)

Back 19

Pressure of gas depends on temperature, number of gas molecules, and volume
PV = nRT
P = nRT/V

Front 20

Gas Mixtures (2)

Back 20

-Many gases are mixtures of different molecules
-Partial pressure of a gas = proportion of pressure of entire gas that is due to presence of the individual gas

Front 21

Gas Mixtures (2)

Back 21

Ptotal = P1 + P2 + P3 + … Pn
-Partial pressure of a gas depends on
+Fractional concentration of the gas

Front 22

Gas Composition of Air

Back 22

-Composition of air
+79% Nitrogen
+21% Oxygen
+Trace amounts carbon dioxide, helium, argon, etc.
+Water can be a factor depending on humidity

Front 23

Gas Composition of Air

Back 23

- Pair = 760 mm Hg = PN2 + PO2
+ PN2 = 0.79 x 760 mm Hg = 600 mm Hg
+ PO2 = 0.21 x 760 mm Hg = 160 mm Hg
+ Air is only 0.03% carbon dioxide
= PCO2 = 0.0003 x 760 mm Hg = 0.23 mm Hg

Front 24

Composition of Air at 100% Humidity

Back 24

Pair = 760 mm Hg = PN2 + PO2+ PH2O
PN2 = 0.741 x 760 mm Hg = 563 mm Hg
PO2 = 0.196 x 760 mm Hg = 149 mm Hg
PH2O = 0.062 x 760 mm Hg = 47 mm Hg
PCO2 = 0.00027 x 760 mm Hg = 0.21 mm Hg

Front 25

Exchange of Oxygen and Carbon Dioxide (2)

Back 25

-Gas exchange in the lungs
-Gas exchange in respiring tissue

Front 26

Diffusion of Gases (3)

Back 26

-Gases diffuse down pressure gradients
+High pressure  low pressure
-In gas mixtures, gases diffuse down partial pressure gradients
+High partial pressure  low partial pressure
-A particular gas diffuses down its own partial pressure gradient
+Presence of other gases irrelevant

Front 27

Rate of Diffusion in Lungs

Back 27

-Diffusion between alveoli and blood is rapid
+Small diffusion barrier
+Large surface area

Front 28

Gas Exchange in Respiring Tissue (5)

Back 28

-Gases diffuse down partial pressure gradients
-PO2 cells  40 mm Hg ;
-PO2 systemic arteries =100 mmHg
+Oxygen diffuses from blood to cells
+PO2 systemic veins = 40 mm Hg
-PCO2 cells  46 mm Hg ;
-PCO2 systemic arteries = 40 mmHg
+Carbon dioxide diffuses from cells to blood
+PCO2 systemic veins = 46 mm Hg

Front 29

Mixed Venous Blood

Back 29

-Actual amount of oxygen and carbon dioxide that is exchanged in any given vascular bed depends on metabolic activity of tissue
+Greater rate of metabolism  Greater exchange

Front 30

Matching Ventilation to Need (2)

Back 30

-Hypoventilation = ventilation does not meet demands
Arterial PO2 decreases
Arterial PCO2 increases
-Hyperventilation = ventilation exceeds demands
Arterial PO2 increases
Arterial PCO2 decreases

Front 31

Transport of Gases in Blood (2)

Back 31

-transport in blood
-Carbon dioxide transport in blood

Front 32

Oxygen Transport in Blood (3)

Back 32

1. Oxygen transport by hemoglobin
2. The hemoglobin-oxygen dissociation curve
3. Other factors affecting affinity of hemoglobin for O2

Front 33

Oxygen Transport in the Blood (3)

Back 33

-Oxygen not very soluble in plasma
-Thus only 3.0 mL/200 ml arterial blood oxygen dissolved in plasma (1.5%)
-Other 197 mL arterial blood oxygen transported by hemoglobin

Front 34

Oxygen Binding to Hemoglobin

Back 34

Hb + O2 <--> Hb*O2
Hb = deoxyhemoglobin
Hb*O2 = oxyhemoglobin

Front 35

Saturation of Hemoglobin (3)

Back 35

-Hemoglobin can bind up to four oxygen molecules
-Binding of oxygen to hemoglobin follows law of mass action
+More oxygen -> more binds to hemoglobin
-Saturation of hemoglobin is a measure of how much oxygen is bound to hemoglobin
+100% saturation -> all four binding sites on hemoglobin have oxygen bound to them

Front 36

Effects of O2 Affinity Changes

Back 36

-Shift right
+Less loading of O2
+And less unloading
-Shift left
+More loading of O2
+And less unloading

Front 37

Temperature Effects: O2 Saturation

Back 37

-Higher temperature
+Active tissues
+Shift right
+More O2 unloading in tissues
+More O2 delivery to tissues

Front 38

pH Effects: O2 Saturation

Back 38

-Bohr effect
+Lower pH increases O2 unloading
-Active tissues
+Produce more acid pH decreases in tissues
+Decreased pH causes shift right in saturation curve
+More O2 is unloaded to tissues

Front 39

Effects of CO2 — Carbamino Effect (4)

Back 39

-Carbon dioxide reacts with hemoglobin to form carbaminohemoglobin
Hb + CO2 <--> HbCO2
-HbCO2 has lower affinity for oxygen than Hb
-Increased metabolic activity -> increases CO2
-oxygen unloading in active tissue

Front 40

Carbon Monoxide (2)

Back 40

-Hemoglobin has greater affinity for carbon monoxide (CO) than for oxygen
-Prevents oxygen from binding to hemoglobin

Front 41

C02 Transport

Back 41

-C02 transported in blood as dissolved C02 (5.8%), carbaminohemoglobin (7%), & bicarbonate ion, HC03-, (87%)

-Workbook
7%
23%
70%

Front 42

Chloride Shift (4)

Back 42

-High C02 levels cause the reaction C02 + H2O  H2C03  H+ + HC03- to shift right
+Results in high H+ & HC03- levels in RBCs
=H+ is buffered by proteins
=HC03- diffuses down concentration & charge gradient into blood causing RBC to become more +
++So Cl- moves into RBC (chloride shift)

Front 43

Reverse Chloride Shift (3)

Back 43

-In lungs, C02 + H2O <--> H2C03 <--> H+ + HC03-, moves to left as C02 is breathed out
-Binding of 02 to Hb decreases its affinity for H+
+H+ combines with HC03- & more C02 is formed
-Cl- diffuses down concentration & charge gradient out of RBC (reverse chloride shift)

Front 44

Blood pH (3)

Back 44

-Normal blood pH = 7.4 (range 7.35 –7.45)
-Respiratory and renal systems regulate blood pH
-Small changes in pH have large physiological effects
+Alter protein activity

Front 45

Blood pH (2)

Back 45

-Acidosis = blood pH < 7.35
+CNS depression
-Alkalosis = blood pH > 7.45
+CNS over-excitation

Front 46

Respiratory System in Acid–Base Balance (3)

Back 46

-Hemoglobin functions as a buffer
+Deoxyhemoglobin has greater affinity for H+
+Hb + H+ <- -> HbH
-Bicarbonate ions as a buffer
+HCO3- + H+ <- -> H2CO3 <- -> CO2 + H2O
-Can regulate pH by regulating CO2 levels

Front 47

Respiratory Acid-Base Disturbances (2)

Back 47

-Respiratory acidosis
+Caused by increased [CO2]
-Respiratory alkalosis
+Caused by decreased [CO2]

Front 48

Disorders Caused by High Partial Pressures of Gases (3)

Back 48

-Total atmospheric pressure increases by an atmosphere for every 10m below sea level

-At depth, increased O2 & N2 can be dangerous to body

-Breathing a high concentration of O2

+O2 toxicity can develop rapidly at >2 atmospheres

Front 49

Disorders Caused by High Partial Pressures of Gases (3)

Back 49

-At sea level, nitrogen dissolves slowly in blood
-Under pressure accumulation is much faster
+Nitrogen narcosis resembles alcohol intoxication
-Amount of nitrogen dissolved in blood as diver ascends decreases
+If ascent is too rapid, decompression sickness occurs as bubbles of nitrogen gas form in tissues & enter blood, blocking small blood vessels & producing “bends”