Gas Exchange

I. Introduction

A. Why?

B. Forces & Factors

Forces to drive gas exchange?

Figure 42.23

Factors help to maximize exchange?

Surface area

Moisture

C. Transport

II. StrategiesA.

Direct

Direct method = Poriferans, Cnidarians, and Platyhelminthes

Figure 42.21Figure

33.4What would be required to lead this life style?

Constant water movementSimple thin structure

B. Gills1.

Structure

Figure 42.21Figure

33.3

Gills == Mollusca to Vertebrata

Figure 42.22

Figure 42.21Figure

33.3

Fish Gills

2. Forces

Figure 42.21Figure

33.3Ram ventilation vs.

Advantages vs. Disadvantages

Gulping

Figure 42.21Figure

33.3

Circulation of water coupled with perfusion of blood

Figure 42.23

Figure 42.21Figure

33.3

swim bladder in bony fishes via the gas gland

Figure 34.16

C. Tracheal Systems1.

Insecta

Figure 42.21Figure

33.3

direct oxygen delivery system to the muscle fibers

Figure 42.24

2.

Chordata

a. Amphibians

Figure 42.21Figure

33.3

Circulate air to lungs from mouth and skin ==PP breathers

b. Reptilians

Figure 42.21Figure

33.3

PP breathers

c. Avians

Figure 42.21Figure

33.3

Negative pressure breathers move air into their lungs and air sacs

Figure 42.21Figure

33.3

Negative pressure breathers move air into their lungs and air sacs

Figure 42.27

d. Mammalians

i. Air tubes

Figure 42.21Figure

33.3

Negative breathers use muscle contractions to move air

pseudostratified ciliated columnar with goblet cells

Figure 42.25

ii. Lungs

Figure 42.21Figure

33.3

alveoli for gas exchange

Type I and Type II cells

Figure 42.25

Figure 42.21Figure

33.3

alveoli for gas exchange

Figure 42.21Figure

33.3

Lung expansion == muscle contraction

Figure 42.28Quiet versus Forced Inhalation vs.

Exhalation

iii. Control

Figure 42.21Figure

33.3

Pons, Medulla Oblongata, and the Hypothalamus

Figure 42.29

iv. Transport

Figure 42.21Figure

33.3

partial gas pressures

Figure 42.30

Figure 42.31a & b

Figure 42.21Figure

33.3

Respiratory pigments transport oxygen and also bufferCO2 is transported via other mechanisms

Figure 42.28

Dissolved in plasma about 7%Bound to globin about 23%Travels bicarbonate shuttle about 70%

Figure 42.21Figure

33.3

Figure 42.28

Figure 42.32

Quantity doesn’t mean Quality.