Human Physiology
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Transcript of Human Physiology
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Human Physiology
Bio 5Denise Lim, Instructor
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ParScore Scantrons for Lecture Tests
Orange, 8.5" X 11"Do not wait until the day of the exam to buy them
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Use Your Textbook WiselyGlossary/IndexConcept Reviews (Blue Headings) "Focus On…” in Chapter 1
– Concept Mapping– Graphing
Concept Checks– (Answers in Appendix A)
Running Problems (case studies)Chapter SummariesReview Questions (Answers in Appendix A)Appendix B: Physics and Math basics
Some general words of advice
Manage your time wellPay attention to detailLearn to be a good communicatorBe professional
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IntroductionChapter 1
What is Physiology?The integration of function
across many levels of organization
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Organization: small to big
AtomsMoleculesCellsTissuesOrgansOrgan
systems
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Function and Mechanism:"Why" versus "How"
"Why" = Purpose"How" = MechanismNeed to understand both purpose and
mechanistic, but focus on mechanism
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Why is physiology so hard to study?
Complexity– Conditions both inside and outside the
body constantly change– Interplay between body systems change as
conditions changeVariation between individuals
– Genetic predisposition, life styleSafety, ethics
– Investigative methods can be invasive
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Important physiological themesStructure/Function relationshipsEnergy
–Metabolism Communication coordinates functionHomeostasis & Regulation
–Maintaining the constancy or stability of the internal environment within a range of tolerance
What goes in must go outWhat is lost must be replaced 10
Homeostasis is maintained through mass balance and mass
flow
Fig. 1.5, pg. 11
Flow of exchange between the body’s external and internal
environment
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Local versus long-
distance control of
homeostasis
Local response: intrinsic controlReflex response: extrinsic control
Fig. 1-9, pg. 14
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Homeostasis depends on communication and feedback
StimulusReceptor or sensor
– Detects the stimulusIntegrating center
determines setpointEffector produces
response
Fig. 1-10, pg. 15
Activity 1
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Negative feedback counteracts the stimulus, maintains conditions within
a range around a setpoint (range of tolerance)
Fig. 1-11, pg. 16
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Example: blood glucoseGlucose levels
drop after fasting: hungry
Glucose rises after a meal
Insulin brings levels back to setpoint
May overshoot Fig. 22-19, pg. 716
Glucose Homeostasis Stimulus
– Increased blood glucose
Receptor– Beta cells in pancreas
Afferent Pathway– ATP production increases when more glucose is available
Integrating Center– Pancreas: releases insulin when ATP in beta cells is high
Efferent Pathway– Insulin
Effector– Liver and muscle cells: insulin triggers glucose uptake
Response– Decreases blood glucose 17
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Positive feedback amplifies body’s response; NOT
homeostatic
Inflammatory response
Childbirth
Fig. 1-12b, pg. 16
Figure 1.12 A positive feedback loop Baby drops
lower in uterus to initiate labor
Push baby against cervix
Cervicalstretch
causing stimulates
Uterine contractions
Oxytocinrelease
causes
Positive feedback loop
Delivery of baby stops the cycle
Fig. 1.13, pg 17
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Presence of food in stomach activates pepsin
Emptying stomach shuts it offHCl production in stomach