1. Introductory Physiology Biol 141
Instructor: Lara LaDage
Office: 214 Hawthorn
Phone:
Office hours: Tuesdays 1-2pm, or by appointment

2. My background

3. Why are you here? It fit my schedule Bad idea I need it to graduate
Dr. LaDage is too cool for words
Bad idea
Bad idea
Lie

4. You should be here if you…
Are interested in integrating biological disciplines
Are academically inclined
Enjoy working hard

5. What does your future hold?

6. I hope you can appreciate the value of showing up to class.

7. How to succeed in this class…
Be in class, on time, every day
Prep for class by reading and reviewing book and previous material
Take effective notes
Actively participate in class and ask questions
Rework class notes within 24 hours of class
Use practice questions as self quizzes
Come to office hours if you need help!

8. Course management Syllabus Tour of Canvas Register your iClicker
Pre-assessment

9. In this course, you will…
Become familiar with the mechanisms that underlie physiological systems

10. In this course, you will…
Understand how different physiological systems integrate with others

11. What is physiology?
The study of the normal functioning of living organisms, including all chemical and physical processes

12. Why study physiology?

13. Why study physiology? Integration across disciplines
e.g., biochemistry, genetics, ecology, evolution
CHEMISTRY
Atoms
Cells
Tissues
Molecules
Organs
PHYSIOLOGY
CELL BIOLOGY
MOLECULAR BIOLOGY
ECOLOGY
Organ
systems
Organisms
Populations of
one species
Ecosystem of
different species
Biosphere

14. Why study physiology?
Integration across systems

15. Why study physiology?
Emergent properties of complex systems

16. Themes in Physiology
Structure and function are closely related

17. Themes in Physiology
Pathways/transformation of energy

18. Themes in Physiology
Information flow coordinates body function

19. Themes in Physiology
Homeostasis maintains internal stability

20. Homeostasis Maintains internal balance- a rough status quo
Keeps parameters more or less constant
Does not mean “no change” or equilibrium

21. Homeostasis Regulation of the body’s internal environment
Keeping internal environment stable

23. Why?
Why keep the internal environment relatively constant?

24. Biological reactions have optima

25. Biological reactions have optima
Maintaining optima requires regulation
How systems regulate is one of the key concerns of physiology

26. Regulating homeostasis
External or internal change
Loss of homeostasis
Body senses this and physiologically attempts to compensate

27. Homeostasis Successful compensation Failure to compensate
Compensation fails
Internal change
results in loss
of homeostasis
Organism in
homeostasis
Organism attempts
to compensate
External
change
Internal
Compensation succeeds
Wellness
Illness or disease
Successful compensation
Homeostasis reestablished
Failure to compensate
Disease
Study of failure to compensate is pathophysiology

28. How is homeostasis maintained?
Regulated variables are kept within normal range by control mechanisms
Keeps near set point, or optimum value
Control systems
Input signal
Integrating center
Output signal

29. Reflex steps RESPONSE Water temperature increases. TARGET OUTPUT
SIGNAL
Signal passes
through wire to
heater.
Heater turns on.
INTEGRATING
CENTER
Control box is
programmed
to respond to
temperature below
29 degrees.
INPUT
Signal passes from
sensor to control
box through the wire.
STIMULUS
Water temperature is
below the setpoint.
SENSOR
Thermometer
senses temperature
decrease.
Reflex steps
Feedback loop
is 25° C
Water
temperature
increases
Control
box
Wire
Wire to heater
Heater
Feedback
loop

30. But why doesn’t the temperature just keep going up???

31. Feedback loops Response to perturbations in the system Two types:
Negative feedback stabilizes variable
Positive feedback reinforces stimulus

32. Negative feedback loops
Dampen/decrease amount of change
Maintain parameters at or near optimum levels

33. Negative feedback loops
Permit only small fluctuations around a set point (optimum)
When fluctuations get too large, response dampens fluctuations

34. Time
Response loop
turns on
Setpoint
of function
Normal
range of
function
Negative feedback turns
response loop off
Temperature (°C) 28 29 30 31 32

35. Set point- your optimum

37. Set point- your optimum

39. Another example…

40. Body temperature- Too Hot!

41. Body temperature- Too Cold!

42. Positive feedback loop
Change is accentuated rather than opposed (pushes beyond set point and normal range)
Enhances the response, keeps building
Drives a process to completion
Fairly rare, unstable

43. Positive feedback loop

44. Baby drops
lower in uterus to
initiate labor
Cervical
stretch
causing
stimulates
Push baby
against
cervix
Oxytocin
release
Positive feedback loop
causes
Uterine
contractions
Delivery of baby
stops the cycle