(Human Physiology From Cells to Systems, 5th Canadian Edition, 5e Lauralee Sherwood, Christopher Ward)
(Instructor Manual)
Chapter 1
The Foundation of Physiology
SYNOPSIS OF CHAPTER
The human body is incredibly complex in that it is made up of a multitude of single cells that
come together to form tissues and organ systems. These cells and systems depend on many
daily processes that occur in our body to keep us alive. We usually take these life-sustaining
activities for granted and don’t really think about what makes us tick, but that’s what
physiology is about. Specifically, in this textbook, we will study human physiology, the
scientific study of the functions of our body. We will also discuss other disciplines that rely on
understanding human physiology, such as nursing, medicine, and physical therapy, to name
but a few. In special topic boxes called Concepts, Challenges, and Controversies, we address
information related to human physiology that you may find interesting. As you read through
the text, you will find another box called Why It Matters, which conveys the importance and
relevance of material covered in the chapter. A Clinical Connection feature presents a clinical
case at the beginning of the chapter and then revisits it throughout the chapter to highlight
the relevant physiology. To bring it all together, you will also find Check Your Understanding
sections that let you pause and see if you have understood the topic so far.
TABLE OF CONTENTS
1.1 Introduction to physiology
Approaches to understanding
Structure and function
1.2 Levels of organization in the body
Chemical level
Cellular level
Tissue level
Organ level
Body system level
Organism level
1.3 Concepts of homeostasis
Homeostasis
Body cells
Body systems
1.4 Homeostatic control systems
Local or body-wide control
Negative feedback
Positive feedback
Feedforward mechanisms and anticipation
Disruptions in homeostasis
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,FEATURE BOXES
Concepts, Challenges, and Controversies: The Science and Direction of Stem Cell
Research in Canada
1. ESSENTIAL OUTCOME: IF NOTHING ELSE,
MY STUDENTS SHOULD LEARN…
1. To be familiar with the term physiology and approaches to understanding physiology.
2. The levels of organization in the body.
3. The concept of homeostasis.
4. The principles of homeostatic control systems.
2. LEARNING OUTCOMES: WHAT SHOULD STUDENTS
LEARN? (INCLUDING BLOOM’S TAXONOMY)
1. Define physiology and understand its importance as a field of study.
[Remember/Understand]
2. Explain the hierarchy of complexity of different levels of organization of the body
from the chemical level to the organism level. [Understand]
3. Define homeostasis. [Remember]
4. Describe the concept of homeostasis and the importance of negative feedback in
homeostatic control. [Understand]
5. Differentiate between negative and positive feedback and feedforward mechanisms.
[Analyze]
3. KEY CONCEPTS: WHY IS THIS CHAPTER IMPORTANT
TO LIFE SCIENCES?
1. This chapter expands on the physiology of the body and the importance of the
disciplines relevant to understanding the functions of our bodies.
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, 2. It discusses the levels from the single cell up to the multicellular organism.
3. This chapter unveils the necessity of homeostasis and the significance of the internal
environment, how homeostasis is maintained, and the contributions of each body
system to homeostasis.
4. The chapter provides a better understanding of the control systems.
4. STUDENT MOTIVATION: WHY STUDENTS
SHOULD CARE
1. The chapter provides students with a more in-depth understanding of the physiology
behind what makes us “tick.”
2. Students get a better understanding of the purpose of body functions and the
underlying mechanisms of body functions.
5. BARRIERS TO LEARNING: WHAT ARE COMMON
STUDENT MISCONCEPTIONS/STUMBLING BLOCKS?
1. Common misconception: cells are within the body. Rather, cells make up the body.
2. Common misconception: homeostasis maintains regulated variables at a single set
point that stays constant. In fact, the set point will vary over daily, monthly, and
yearly cycles, as well as over the entire lifespan of the organism, and the body will
work to maintain that set point (whatever the variation).
3. Common misconception: negative feedback is just the inhibition of the release of a
product or system (A inhibits B). Negative feedback is actually a control loop that
can stimulate the release of a product or system when it is too low or inhibit the
release of a product or system when it is too high.
4. Common misconception: positive feedback is the stimulation of the release of a
product or system (A stimulates B). Instead, positive feedback is a control system
that promotes the amplification of a product or system. Once it is amplified, it will
cause further amplification (A stimulates B, which stimulates C, which stimulated A;
thus, C will continue to be amplified through this process).
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, 6. ENGAGEMENT STRATEGIES: WHAT CAN I DO
IN CLASS?
1. Let students take individual time to compare and contrast the concepts of positive
feedback, negative feedback, and feedforward; then work in small groups to compare
answers; and then discuss as a class to clear up misconceptions.
2. Draw a diagram that shows the negative-feedback loop to control temperature.
Demonstrate how the negative-feedback loop works to decrease temperature when
temperature increases and how the negative-feedback loop works to increase
temperature when temperature decreases. Discuss why the latter part of the example
is not positive feedback or feedforward.
3. Think of similarities between how the body is organized and how a city is organized.
Include ideas regarding communication between cells of the body and parts of
the city.
4. Using examples of positive and negative feedback that students are not aware of yet,
have them identify what type of feedback they see and make sure they justify their
answers. Example of positive feedback: In the intrinsic pathway of the blood
coagulation cascade, collagen activates factor XII to produce Active XII, which in
turn activates factor XI to increase levels of Active XI, which in turn activates factor
IX to increase Active IX, which activates factor X to produce Active X, which
converts prothrombin to thrombin. Thrombin converts fibrinogen to fibrin and also
acts to activate factor XI. Example of negative feedback: An increase in your blood
pressure will be sensed by pressure sensors that will send information to the blood
pressure regulating centres in the hypothalamus, which will in turn send impulses
using the sympathetic nervous system to stimulate the heart to decrease the heart
rate and vasodilate arteriolar blood vessels, thereby decreasing your blood pressure.
5. Use a cell model, prepared slides, and electron micrographs to show students the
major components of a cell.
6. Describe primary tissue functions. Use figures found in the chapter as illustrations.
Some students could benefit from photomicrographs of actual tissue preparations.
7. The hierarchy of complexity can be illustrated using a pyramid with blocks
representing various levels of organization, beginning with atoms on the lowest level,
progressing through cells, tissues, etc., with the organism represented by the top of
the pyramid.
8. Use an anatomical model to illustrate the organs that comprise each body system.
9. Use a laboratory animal (e.g., fetal pig, rat, cat) to illustrate the various organ systems.
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