GAS EXCHANGE Cardio Respiratory System

GAS EXCHANGECardio Respiratory

System

GAS EXCHANGE

1. supplies oxygen for aerobic cellular respiration (reactant)

2. removes carbon dioxide from aerobic cellular respiration (product)

3. Must carry out ventilation - actively moving air in and out of body surfaces

4. Terrestrial – gases in air Aquatic – gases dissolved in water

Fig. 42-2

Circularcanal

Radial canalMouth

(a) The moon jelly Aurelia, a cnidarian The planarian Dugesia, aflatworm

(b)

MouthPharynx

2 mm5 cm

SOME AQUATIC INVERTEBRATES: Thin-wall - Gases diffuse through the membrane

Fig. 42-21

Parapodium (functions as gill)(a) Marine worm

Gills

(b) Crayfish (c) Sea star

Tube foot

Coelom

Gills

OTHER AQUATIC INVERTIEBRATES USE GILLS

Fig. 42-23

Air sacs

Tracheae

Externalopening

Bodycell

AirsacTracheole

Tracheoles Mitochondria Muscle fiber

2.5 µmBody wall

Trachea

Air

Arachnids (Spiders/Scorpians) - Book Lungs

Fig. 42-22

Anatomy of gills

Gillarch

Waterflow Operculum

Gillarch

Gill filamentorganization

Bloodvessels

Oxygen-poor blood

Oxygen-rich blood

Fluid flowthrough

gill filament

Lamella

Blood flow throughcapillaries in lamella

Water flowbetweenlamellae

Countercurrent exchange

PO2 (mm Hg) in water

PO2 (mm Hg) in blood

Net diffu-sion of O2

from waterto blood

150 120 90 60 30

110 80 20Gill filaments

50140

GILLS

Fig. 42-UN4

GAS EXCHANGE THROUGH SKIN ONLY SKIN LUNGS

SKIN ONLY

SNAKE RESPIRATORY

REPTILES

DINOSAUR BIRD BONES

Fig. 42-26

Anteriorair sacs

Posteriorair sacs Lungs

Air

Lungs

Air

1 mm

Trachea

Air tubes(parabronchi)in lung

EXHALATIONAir sacs empty; lungs fill

INHALATIONAir sacs fill

LUNGS

Fig. 42-25

Lung

Diaphragm

Airinhaled

Rib cageexpands asrib musclescontract

Rib cage getssmaller asrib musclesrelax

Airexhaled

EXHALATIONDiaphragm relaxes

(moves up)

INHALATIONDiaphragm contracts

(moves down)

Air Volume

Fig. 42-27

Breathingcontrolcenters

Cerebrospinalfluid

Pons

Medullaoblongata

Carotidarteries

Aorta

DiaphragmRib muscles

Fig. 42-UN2Inhaled air Exhaled air

Alveolarepithelial cells

Alveolar spaces

CO2 O2

CO 2 O2

Alveolarcapillaries of

lung

Pulmonary veinsPulmonary arteries

Systemic veins Systemic arteries

Heart

SystemiccapillariesCO

2 O 2

CO2 O2

Body tissue

Fig. 42-28Alveolus

PO2 = 100 mm Hg

PO2 = 40 PO2

= 100

PO2 = 100PO2

= 40

Circulatorysystem

Body tissuePO2

≤ 40 mm Hg PCO2 ≥ 46 mm Hg

Body tissue

PCO2 = 46 PCO2

= 40

PCO2 = 40PCO2

= 46

Circulatorysystem

PCO2 = 40 mm Hg

Alveolus

(b) Carbon dioxide(a) Oxygen

Fig. 42-UN1

Chains

IronHeme

ChainsHemoglobin

HEMOGLOBIN

OXYGEN EXCHANGE

Fig. 42-29a

O2 unloadedto tissuesat rest

O2 unloadedto tissues

during exercise

100

40

0

20

60

80

0 40 80 100

O2 s

atur

ation

of h

emog

lobi

n (%

)

20 60

Tissues duringexercise

Tissuesat rest

Lungs

PO2 (mm Hg)

(a) PO2 and hemoglobin dissociation at pH 7.4

Fig. 42-29b

O2 s

atur

ation

of h

emog

lobi

n (%

)

40

0

20

60

80

0 40 80 10020 60

100

PO2 (mm Hg)

(b) pH and hemoglobin dissociation

pH 7.4pH 7.2

Hemoglobinretains lessO2 at lower pH(higher CO2

concentration)

Fig. 42-UN3

Fetus

Mother

100

80

60

40

20

00 20 40 60 80

O2 s

atur

ation

of

hem

oglo

bin

(%)

100

PO2 (mm Hg)

Fig. 42-30aBody tissue

CO2 produced

CO2 transportfrom tissues

Interstitialfluid CO2

CO2

CO2

Plasmawithin capillary

Capillarywall

H2O

H2CO3

Carbonic acid

Redbloodcell

Hemoglobinpicks up

CO2 and H+Hb

H+HCO3–

Bicarbonate+

HCO3–

To lungs

Fig. 42-30b

HCO3–

HCO3– H++

CO2 transportto lungs

Hemoglobinreleases

CO2 and H+HbH2CO3

H2O

CO2

Plasma withinlung capillary

CO2

CO2

CO2

Alveolar space in lung

CARBON DIOXIDE