630 likes | 868 Views
Zool 4409/5409 Comparative Animal Physiology. Introduction. Introduction Basic Principles of Physiology. Introduction. Animal physiology is an attempt to answer the question- How do animals work? Requires a background in chemistry, physics, anatomy and zoology
E N D
Zool 4409/5409Comparative Animal Physiology Zool 4409/5409
Introduction • Introduction • Basic Principles of Physiology Zool 4409/5409
Introduction • Animal physiology is an attempt to answer the question- How do animals work? • Requires a background in chemistry, physics, anatomy and zoology • physiological principles follow basic laws of physics and chemistry • Principally a science of the last 3 centuries Zool 4409/5409
Hemodynamics Q = blood flow rate (mL/sec) P= pressure difference between ends of vessels R = resistance P = Q R P2 P1 Zool 4409/5409
Georg Simon Ohm OHM'S LAW • V = I x R • V/R = I • I, current; R, resistance; V, voltage
Introduction (con’t) I. Search for generalizations • Can we study the heart of a frog and make predictions about how the human heart works? • Can we study nerve function in an invertebrate and learn how our nervous system works? Zool 4409/5409
YES! Zool 4409/5409
At the cellular level, there are many similarities in function among all animals • Animals cells use ion movement across the cell membrane to maintain water balance. • Plant cells use a thick cell wall in plants. Zool 4409/5409
At the organ system level, many similarities amongst the vertebrates • Frog skeletal muscle is great for lab study. • Can be maintained at low temps. • Low oxygen demands. • Most of what we know about how human muscle works is based on frog studies. Zool 4409/5409
All animals are faced with the same sorts of physiological problems • obtain and digest food • supply oxygen to tissues • get rid of carbon dioxide and other wastes • maintain body fluids • study how a system works in a simple model and learn how this works in humans Zool 4409/5409
Introduction (con’t) II. Search for oddities(“gee-whiz” physiology) • How do fish survive in the seas off antarctica? • How do some animals such as turtles survive after their body fluids have frozen? Zool 4409/5409
Fish around Antarctica spend their entire lives at body temperatures near –1.9°C Zool 4409/5409
McMurdo Sound, Antarctica Trematomusbernacchii Zool 4409/5409
Antifreeze glycoproteins Zool 4409/5409
Introduction (con’t) Knowledge of how animals adapt to extreme environmental problems may be useful for learning about human performance in extreme situations; eg. Space, underseas, etc. Zool 4409/5409
Bar-headed Goose- Fly at 30,000 feet Unique hemoglobin
III. Knowledge for Knowledge’s sake • basic science is required for all advances and applications in science • emphasis on “product-oriented” science will result in fewer new discoveries. Zool 4409/5409
Introduction (con’t) IV. Physiology is the cornerstone of human medicine. • Good physicians must have a solid understanding of how the body functions normally in order to diagnose disease Zool 4409/5409
Basic Principles of Physiology I. Form follows function over time (geologic time), form evolves with function Zool 4409/5409
Basic Principles of Physiology II. Homeostasis • Ability to regulate internal environment within narrow limits Homeostasis = balance • Claude Bernard (maintenance of the internal milieu, late 1800s) • Walter Cannon (coined the term homeostasis, early 1900s).
Basic Principles of Physiology II. Homeostasis (con’t) • Maintained by multiple control systems • eg. Blood pressure is regulated by both short-term (seconds) and long-term (min, hr, days, wks) Zool 4409/5409
Control systems involved in blood pressure regulation Zool 4409/5409
Disruption of homeostasis- stress Stressor Zool 4409/5409
Figure 1.6 Mixed conformity and regulation in a single species Zool 4409/5409
Basic Principles of Physiology III. Regulatory systems • Nervous system integrate learning DETECT INTEGRATE RESPOND storage retrieval Zool 4409/5409
Basic Principles of Physiology III. Regulatory systems (con’t) • Endocrine system blood hormone endocrine cell stimulus Target RESPONSE Zool 4409/5409
Neuroendocrine Integration Endocrine system Nervous system Neuroendocrine system Endocrine organs cannot detect environmental changes on their own- they require input from nervous system Zool 4409/5409
Basic Principles of Physiology IV. Feedback control • Negative feedback • reduces the difference between the output and setpoint. eg. thermostat Zool 4409/5409
Positive feedback • increases difference between outpoint and setpoint Zool 4409/5409
Feedback Control of Body Temperature HBC Higher brain center Set point = 98.6o F - THERMORECEPTORS integration hypothalamus coordination hypothalamus effector eg., muscle Response
Basic Principles of Physiology V. Critical thinking and the scientific method A. Inductive reasoning B. Hypothesis C. Deductive reasoning D. Testing hypothesis Zool 4409/5409
Basic Principles of Physiology A. Inductive reasoning-Francis Bacon, 1620 • Collecting information in an unbiased way. • In 1620 Bacon published Novum Organum (Or True Directions Concerning the Interpretation of Nature)
Without inductive reasoning: Example of bad science: • >400 years ago, Bishop Usher concluded that the earth began on October 9th, 4004 BC, 9:30 AM by counting the number of “begats”. Zool 4409/5409
TRUE DIRECTIONS CONCERNING THE INTERPRETATION OF NATUREFrancis Bacon1620 • “The formation of ideas and axioms by true induction is no doubt the proper remedy to be applied for the keeping off and clearing away of idols. To point them out, however, is of great use. “
The Four Idols of Bacon that Prevent Accurate Interpretations of Nature • The Idols of the Tribe-erroneous preconceived ideas common to one’s tribe or community
The Four Idols of Bacon that Prevent Accurate Interpretations of Nature • The Idols of the Cave- erroneous beliefs of one’s mind; individuals tend to favor their own ideas Zool 4409/5409
The Four Idols of Bacon that Prevent Accurate Interpretations of Nature • The Idols of the Marketplace- everyday language is not sufficient for describing scientific ideas Zool 4409/5409
The Four Idols of Bacon that Prevent Accurate Interpretations of Nature • The Idols of the Theatre- adherence to theological and philosophical modes of thought where truth is deduced from what is assumed to be true.