1. Ventilation 

2. External Respiration 

3. Internal respiration 

Layer of fluid 

Secretes pulmonary Surfactant 

Decreases surface tension 

-Result of connective tissue and surface tension in the lungs 

-Surface tension limited by surfactant, it keeps the lungs open

-sacs that each lung is contained in 

-Serous membrane 

1st-- prevents friction 

2nd-- Ventilation:

Air movement is produced by differences in pressure 

Different Pressures in the lungs 

(3 of them) 

-Atmospheric...Sea level 

-intra-alveolar 

-Intra-pleural...always less than IAP 

*These drive inspiration and expiration*

Partial Pressures

Diffusion Rates 

Partial Pressure 

the pressure which the gas would have if it alone occupied the volume

Ex: Nitrogen --> 79% of 760mmHg = Pn (Partial pressure of nitrogen) =600mmHg

Oxygen-->21% of 760mmHg =Po2=160mmHm 

CO2 is negotiable 

Partial Pressure that exists in the lungs (alveoli)

Oxygen, CO2, and Nitrogen

Oxygen: 100mmHg

*air mixing causes it to be lower than 160mmHg, each breath in mixes with old air still in lungs

*Humidification causes the water pressure to rise so oxygen pressure is reduced

Carbon Dioxide: 40mmHg 

*constantly putting CO2 into the blood 

Nitrogen: Isn't exchanged at all

Diffusion Rates:

Process of Exchange 

Starting Atmospheric Pressures 

(oxygen, CO2) 

IN lungs... 

IN blood...

PO2---160 (HIGH)

PCO2---.03 (LOW)

In lungs: 

PO2---100 (High)

PCO2---40 (Low) 

In Blood: 

PO2---100 

PCO2---40 

lungs to heart, heart to tissues, tissues to lungs

PO2 in the lungs 

What happens? 

PO2=100

deoxygenated blood goes to a partial pressure of 40.

Oxygen diffuses down the Partial Pressure gradient from lungs and into blood (100 to 40). 

*everytime blood comes back to lungs it will top off O2 tank to 100, till blood matches the lungs. 

Works the same, but gradients are opposite 

P= 40 

P=46 (When blood arrives) 

*Stays at 40* 

Partial pressure is higher because they produce CO2 

*Diffuses high to low* 

Partial Pressure during exercise 

What will happen? 

PO2 will decrease 

-will diffuse FASTER

Venous Partial pressure will decrease 

PCO2 will increase. 

(Produces more CO2) 

**Opposite would occur if lower than normal metabolism**

Lungs During Exercise 

Effects VENOUS not Arterial 

If change in tissues it WON'T effect venous 

Ability to carry large volumes of O2 is dependant on Hemoglobin (Hb) 

Air-->plasma-->Hb

*plasma can't hold a lot, forces it onto the Hb*

-CO2

-Carbon Monoxide 

-Hydrogen Ions 

**How much O2 Hb will hold depends on the P**

Amount of oxygen bound to Hemoglobin is dependant on the Partial pressure of Oxygen in plasma 

*increased..more forced on, decreased..more dissociated*

O2-Hb Dissociation Curve: 

Percent Saturation 

O2-Hb Dissociation Curve: 

 Saturation Percentages 

-Hb is at 100% saturated, at pressure that exist in the LUNGS. (104mmHg....97.5% saturated) 

-(at capillaries) PO2=40mmHg

-->Hb saturation drops to 75%(venous blood).. to allow Hemoglobin to go to the tissues. 

Arterial-Venous Oxygen Difference (AVO2 DIFF) 

How much oxygen your tissues are consuming overall. 

The AVO2 difference is 25% here. 

Arterial-Venous Oxygen Difference (AVO2 DIFF) 

IF TISSUES ARE HIGHLY METABOLIC? 

AVO2 difference will increase 

**Took more out at the tissues**

Factors that effect Binding of Oxygen to Hemoglobin (2)

**these factors increase dissociation of oxygen from hemoglobin, primarily @ tissues**

1) Bohr Effect 

2) Temperature 

BOHR effect

definition?

What happens? 

- effects of CO2 and Ph on the bond between Hb and CO2

--CO2 and hydrogen ions compete with oxygen for binding spots on Hb.

 
--This makes it so that O2 dissociates 

--An equillibrium exists between CO2 and ph. 

CO2 (+) H2O<-- -->H2CO3<-- -->HCO3-(+) H 

                                carbonic acid   bicarbonate

if right to left...it creates H20 and CO2 

if left to right.. it rids of CO2 and increases H levels. 

 *Both increase*

an increase in CO2 or H+ (Decrease in Ph) will increase the dissociation of oxygen from hemoglobin, this helps get the O2 to the tissue

Factors that effect Binding of Oxygen to Hemoglobin

TEMPERATURE 

As temperature increases it increases dissociation of oxygen from hemoglobin, goes to a warm tissue. 

As temperature decreases, it decreases dissociation of oxygen from hemoglobin. 

CARBON  DIOXIDE 

3 means of transport in the blood 

1. Dissolved in plasma 10% 

2. carbaminohemoglobin 30% 

(how much is bound to Hb) 

3. Bicarbonate ions. 

(acid-base balance equation) 

-H+ are also picked up (buffered) by Hb. 

respiratory muscles are Voluntary muscles that receive Involuntary control. with voluntary override. 

PHRENIC NERVE = Voluntary override 

CONTROLLING VARIABLES OF RESPIRATORY CONTROL  (3) 

Most important: 1) CO2. 

an increase in CO2 increases the rate and depth of breathing.  (involved in acid base balance) 

2) Hydrgoen Ions 

an increase in H+ increases the rate and depth of breathing 

3) Oxygen 

PO2 must fall below 60mmHg before breathing is stimulated. 

Surface tension in the lungs is limited by which of the following?

The pleural sacs around the lungs 

The air pressure in the alveoli

The removal of carbon Dioxide 

Surfactant 

The elastic recoil of the lungs 

How is most carbon dioxide carried through the blood?

Attatched to Hemoglobin

In the form of Bicarbonate Ions 

Dissolved in the Plasma 

Bound to hydrogen Ions

In bubbles 

At rest, our Arterial-Venous Oxygen Difference is normally about . . .

75% 

5%

10% 

50%

25% 

During exercise, the partial pressure of oxygen (pO2) in the tissues (muscles) will .

No Change 

Increase

Decrease 

During exercise, the Venous partial pressure of carbon dioxide (pCO2) will . . .

Increase 

Decrease 

No change 

As the partial pressure of oxygen in the blood decreases . . .

More Oxygen binds to hemoglobin 

The blood becomes more acidic 

none of these are correct 

more oxygen dissociates from hemoglobin 

More carbon dioxide dissociates from hemoglobin 

What is the most controlling variable regulating breathing?

Carbon Dioxide Levels 

RBC count 

Hemoglobin Levels 

Ph Levels 

Oxygen Levels 

During expiration, the pressure in the alveoli (intra-alveolar pressure) will be __________ the pressure in the atmosphere.

Greater than 

Less than 

Equal to 

the same as 

When you exercise, your Arterial-Venous Oxygen Difference will . . .

decrease 

increase

no change 

Which of the following will decrease the dissociation of oxygen from hemoglobin?

an increase in hydrogen ion (H+) concentration in the blood

 a decrease in pH

a decrease in the partial pressure of oxygen

an increase in blood volume