Ap2 Ch 22 Pt 3

Front 1

Nonrespiratory Air Movements

Back 1

• Processes other than breathing that
moves air in or out of lungs
• May modify normal respiratory rhythm
• Most result from reflex action; some
voluntary
• Examples include-cough, sneeze, crying,
laughing, hiccups, and yawns

Front 2

External respiration

Back 2

–diffusion of gases in lungs

Front 3

Internal respiration

Back 3

–diffusion of gases at body tissues

Front 4

Both internal and external respiration involve:

Back 4

– Physical properties of gases
– Composition of alveolar gas

Front 5

• Anatomical dead space

Back 5

–No contribution to gas exchange in
alveoli
–TV is 500 ml, ~350ml involved in
ventilation
–Air remaining in passageways; ~150 ml

Front 6

Alveolar dead space

Back 6

–non-functional alveoli due to collapse or obstruction

Front 7

Total dead space

Back 7

-sum of anatomical and alveolar dead space

Front 8

• Dalton’s law

Back 8

how gas behaves when part of a mixture
• Total pressure exerted by mixture of gases
= sum of pressures exerted independently
by each gas

Front 9

Partial pressure

Back 9

– Pressure exerted by each gas in mixture
– Directly proportional to its percentage in
mixture

Front 10

Henry’s law

Back 10

how gases move into and out of liquid
• Gas mixtures in contact with liquid
– when a mixture of gases is in contact with a
liquid each gas will dissolve into the liquid in
proportion it its partial pressure
– Partial pressure abbreviated P followed by
gas formula: Examples: PO2, PCO2

Front 11

Perfusion

Back 11

-blood flow reaching alveoli from pulmonary capillaries

Front 12

Ventilation

Back 12

-amt. of gas reaching alveoli

Front 13

What must be matched (coupled) for efficient gas exchange?

Back 13

Ventilation and perfusion

Front 14

Why are ventilation and perfusion Never balanced for all alveoli?

Back 14

due to
• Regional variations due to effect of
gravity on blood and air flow
• Some alveolar ducts plugged with
mucus

Front 15

Perfusion
–Changes in Po2 in alveoli cause
changes in diameters of arterioles

Back 15

•Where alveolar O2 is high, arterioles
dilate
•Where alveolar O2 is low, arterioles
constrict

Front 16

CO2 transported in blood in three forms

Back 16

– 70% transported as bicarbonate ions
(HCO3
–) in plasma
– 20% bound to globin of hemoglobin
(carbaminohemoglobin)
– 7 to 10% dissolved in plasma

Front 17

• Molecular O2 carried in blood two ways

Back 17

– 98.5% loosely bound to each Fe of
hemoglobin (Hb) in RBCs
– 1.5% dissolved in plasma
• Oxygen is poorly soluble so very little
(~1.5%) is transported dissolved in
plasma

Front 18

Hypoxia

Back 18

– Inadequate O2 delivery to tissues  cyanosis

Front 19

– Anemic hypoxia

Back 19

–too few RBCs; abnormal or too little Hb

Front 20

– Ischemic hypoxia

Back 20

–impaired/blocked circulation

Front 21

– Histotoxic hypoxia

Back 21

–cells unable to use O2, as in metabolic poisons

Front 22

– Hypoxemic hypoxia

Back 22

–abnormal ventilation; pulmonary disease

Front 23

– Carbon monoxide poisoning

Back 23

–especially from
fire; 200X greater affinity for Hb than oxygen

Front 24

Influence of CO2 on Blood pH
• Hypoventilation:

Back 24

allows CO2 to
accumulate in blood (produce CO2 faster
than you exhale) results in raising [H+]
which lowers pH (acidosis)

Front 25

causes of hypoventilation

Back 25

Congestive heart failure, emphysema, sleep
apnea; slip into coma → fatal

Front 26

Hyperventilation:

Back 26

increased depth and
rate of breathing that exceeds the body’s
need to remove CO2 which raises pH i.e.,
alkalosis; change in arrow direction!
CO2 + H2O ← H2CO3 ← HCO3
- + H+

Front 27

causes of hyperventilation

Back 27

– Extreme anxiety and stress or extreme pain,
become dizzy, faints, tetany in hands and face,
overstimulation of CNS, convulsions, fatal if
untreated

Front 28

Carbonic acid–bicarbonate buffer
system

Back 28

–resists changes in blood pH
– If H+ concentration in blood rises, excess H+ is
removed by combining with HCO3
–  H2CO3
– If H+ concentration begins to drop, H2CO3
dissociates, releasing H+
– HCO3
– is alkaline reserve of carbonic cidbicarbonate
buffer system

Front 29

Changes in respiratory rate and depth
affect blood pH

Back 29

– Slow, shallow breathing  increased CO2 in
blood drop in pH
– Rapid, deep breathing  decreased CO2 in
blood  rise in pH