Study Guide & Review for Gas Exchange
I. Goal:
The goal of this unit is to provide a basic understanding of the general
principles of gas exchange in plants and animals
II. Reading(s):
Chapter 42.4
III. Objectives:
Upon completion of this unit you should be able to:
-
Define Fick's law.
Identify how each of the terms in the equation influence gas exchange.
-
Compare and contrast
diffusion and bulk flow.
-
Explain why animals
use bulk flow to move gases to respiratory surfaces, while plants and a few
animals like hydra, use diffusion.
-
A necessary evil of
obtaining required gases (carbon dioxide and/or oxygen) is water loss.
Explain how organisms minimize water loss while maximizing gas uptake.
-
Compare and contrast
how frogs, fish and humans get gases to their respiratory surfaces.
-
Define partial pressure and explain how it influences diffusion across
respiratory surfaces.
-
Describe how the need for circulatory and respiratory systems changes with
increasing animal body size.
-
Define gas exchange and distinguish between a respiratory medium and a
respiratory surface.
-
Describe the general requirements for a respiratory surface and list a
variety of respiratory organs that meet these requirements.
-
Describe respiratory adaptations of aquatic animals.
-
Describe the advantages and disadvantages of water as a respiratory medium.
-
Describe countercurrent exchange in fish gills. Explain why it is more
efficient than the concurrent flow of water and blood.
-
Describe the advantages and disadvantages of air as a respiratory medium and
explain how insect tracheal systems are adapted for efficient gas exchange
in a terrestrial environment.
-
For the human respiratory system, describe the movement of air through air
passageways to the alveolus, listing the structures that air must pass
through on its journey.
-
Describe the role of surfactants in alveoli. Explain why the absence of
surfactants may lead to respiratory distress in severely premature infants.
-
Compare positive and negative pressure breathing. Explain how respiratory
movements in humans ventilate the lungs.
-
Compare the respiratory systems of birds and mammals, explaining the greater
efficiency of oxygen exchange in birds.
-
Explain how breathing is controlled in humans.
-
Describe the adaptive advantage of respiratory pigments in circulatory
systems.
-
Describe the
hemoglobin molecules.
-
Draw the Hb-oxygen dissociation curve, explain the significance of its
shape, and explain how the affinity of hemoglobin for oxygen changes with
PO2
and pH. Explain how it differs between a fetus and mom.
-
Describe how carbon dioxide is picked up at the tissues and carried in the
blood.
-
Discuss the advantages and disadvantages of water and of air as respiratory
media.
-
Compare and contrast breathing in adult amphibians, birds and mammals.
-
For humans, describe the exchange of gases in the lungs and in tissues.
-
Draw and explain the hemoglobin-oxygen dissociation curve.
-
Draw the two major types of guard cells. Identify four features common to
all guard cells and the function of each.
-
Explain how guard cells mechanically open/close the stoma.
-
Explain the physiology of guard cell action and response to the environment.
-
If a persons lives
one mile above sea level in Denver (CO) where teh atmospheric pressure is
630 mm Hg, what is the PO2 of the inspired air?
-
Explain why it is
dangerous to voluntarily hyperventilate to lower the arterial PCO2 before
going underwater.
IV. Common Terms/Concepts
(can you use the following terms/concepts conversationally?)
-
Bulk flow
-
Carbonic anhydrase
-
Cellulose microfibril
-
Concentration gradient
-
Counter current mechanisms
-
Diffusion
-
Fick�s law
-
Negative pressure breathing
-
Partial pressure
-
Positive pressure breathing
-
Ventilation
V. Activities (Some learning activities and tips for studying):
-
Check out the tips in the Plant Structure/Function Study Guide
-
Make a concept map for the unit
-
Be
sure to visit the Study Area of the textbook website
VI. Questions:
After completing the activities, write any question(s) that you still have
concerning the objectives or that pertain to related areas. Check the text or
other sources for the answers. Or, contact me!
VII. Application:
Write one or more ways in which you can immediately apply this information to
your daily life.
VIII. Assessment:
Meet with one or more members of the class to help assess that you have attained
the objective and to help deepen your understanding of the material. Answer the
questions at the end of the chapters. Write your own exam questions. Visit the
text book web site.
Last updated: February 19, 2009
� Copyright by SG Saupe