Gas ExchangeI.

Introduction

A. Definition

B. Why?

C. Forces & Factors1. What forces drive gas

exchange?

Figure 42.23

2. What factors help to maximize exchange?

D. Transport

Poriferans, Cnidarians, and Platyhelminthes

Constant water movementSimple thin structure

Figure 33.4

What would be required to lead this life style?

A. Direct

1. Structure

2. Forces

II. Strategies

B. Gills1.

StructureMollusca to Vertebrata

Figure 42.22

Fish Gills

2. Forces

Ram ventilation vs.

Gulping

Advantages vs. Disadvantages

a. Passive to

b. Active

Circulation of water coupled with perfusion of blood

Figure 42.23

swim bladder in bony fishes via the gas gland

Figure 34.16

Figure 42.24

C. Tracheal Systems

1. Insecta

direct oxygen delivery system to the muscle fibers

a. Structure

b. Forces

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

a. Amphibians

2. Chordatai. Structure ii. Forces

b. Reptilians

Circulate air to lungs from mouth ==PP breathers

i. Structure ii. Forces

Negative pressure breathers move air into their lungs and air sacs

c. Avians

Figure 42.27

i. Structure ii. Forces

d. Mammalians

i. Air tubesNegative breathers use muscle contractions to

move air

Figure 42.25

pseudostratified ciliated columnar with goblet cells

ii. Lungsalveoli for gas

exchange Type I, Type II cells, and Dust cells

Figure 42.25

Lung expansion == muscle contraction

Quiet versus Forced Inhalation vs. Exhalation

Figure 42.28

iii. ControlPons, Medulla Oblongata, and the

Hypothalamus

Figure 42.29

iv. Transport O2

partial gas pressures

Figure 42.30

Figure 42.31a & b

Respiratory pigments transport OXYGEN and also bufferCO2 is transported via other

mechanisms:Dissolved in plasma about 7%Bound to globin about

23%Travels via the bicarbonate shuttle about 70%

Figure 42.32

iv. Transport CO2