Biology 219 Human Physiology

Transcription

1 Biology 219 Human Physiology Instructor- Dr. Adam Ross Tues/ Thurs: 11:00-12:15 Room 2040 (Lecture) Tues/ Thurs: 1:30-4:20 Room 2040 (Lab)

2 Intro to Bio 219: Human Physiology About me: Dr. Adam Ross Ph.D. Ph.D. in Molecular, Cellular, and Integrative Physiology UC Davis 2014 Specialized in development of the head, face and brain M.S. in MCIP UCD 2009 Specialized in regulation of gene expression in skeletal muscle 3 rd semester at Napa Valley College 1 st time teaching BIO 219

3 Expectations for the class Arrive and be ready to start on time Make sure to bring all necessary materials Be quiet when someone else is talking Put all cell phones on silent (turn off vibrate) I don t care if you use your phone in lecture as long as it is silent (no vibration) Be respectful, polite, and behave like someone who will soon be working in a biomedical professional setting Please read entire syllabus and be aware of upcoming important events

4 How to excel at learning:

5 How to succeed in this class: Do reading assignments before class Review material after class (same day) Do all practice problems and study questions Review all reading and problems before test Be able to integrate concepts and think critically *** 2.5 hours of lecture per week = 7.5 hours of studying per week min.

6 What is physiology? Branch of biology that deals with living organisms and their parts Physio- from Greek Phusis physical ; referring to the natural, physical, nature Logy- from Greek (and Latin) Logia to speak ; referring to one who speaks of a certain subject From cells to entire organisms Connects structure to function

7 Why study physiology? Knowing proper structure and function allows us to determine what is being affected by injury and disease How would we diagnose and fix a broken leg if we didn t know how bones work? How would we treat (or vaccinate for) the flu if we didn t know about the immune system and how the body fights off foreign invaders? Often times we study the maintenance of homeostasis How the body maintains the milieu intérieur

8 How do we study science? Scientific Method: Credited to Ibn-al Haytham ( ) Iraqi scientist that demanded reproducibility from experimental results Methodology has been altered over the years Galilelo implemented changes in Two New Sciences in th century saw changes implemented as well

9 Steps in scientific method Ask a question Do background research Construct a hypothesis Test your hypothesis with a reproducible experiment Analyze data and draw conclusions Communicate results Ask a new question now that you have new information

10 Why is scientific method important? It allows for informed investigation into questions by integrating background information It allows for experiments to be validated via repetition It allows for confidence in others results that use sci. method

11 Scientific theories A theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world. Theory of gravity, theory of relativity, theory of evolution, germ theory of disease, theory of heliocentrism

12 Scientific theories Theories will often change slightly over time Does not mean the original theory was wrong, only that it was not complete Evolution is a good example of this Current base of scientific knowledge is built upon proving or disproving the currently accepted dogma If I have seen further, it is by standing upon the shoulders of giants. Isaac Newton

13 Examples of non-scientific arguments Creationism is a perfect example of a non-scientific theory No reproducible experimental evidence No real evidence other than arguments Also uses factually incorrect arguments in attempt to disprove evolution Irreducible Complexity is a popular intelligent design argument

14 Irreducible complexity Argument started by Michael Behe in 1993 Darwin s Black Box Posits that evolution cannot explain irreducibly complex cell systems Mouse trap example

15 Mouse trap argument for irreducible complexity Behe claims that removing any of the parts of a mouse trap would render it non functional A non- functional mouse trap would not be favored during natural selection Behe also claims that science is unable to explain slight adaptive changes in complex cell biochemistry which would render the evolution by natural selection of such systems impossible Evolution of the eye, and flagella are two real world examples used by Behe

16 Problems with the mouse-trap argument Most well known rebuttal comes from Dr. Kenneth R. Miller s book Only a Theory written in 2008 Challenges the claim that a mousetrap is irreducibly complex Various subsets of the components can be used to form viable constructs Remove board and use as spitball launcher or tie clip Remove spring and use as two part key chain Remove the hold down bar and use as a toothpick

17 Evolution of the eye Fairly well understood process Actually outlined by Darwin in On The Origin of Species Has become better understood over time without violating Darwin s theory of natural selection Began with photoreceptors that could sense light but not direction Eventually a random mutation put some receptors in a depression Those receptors had some ability to sense direction This provided a selective advantage and was passed on

18 Evolution of the eye Happened independently in vertebrates and invertebrates Inverted retina and blind spot in vertebrates Non-inverted (no blind spot) in animals like octopi

19 Evolution of flagella Flagella consist of over 50 working parts in order to produce movement Behe argues that these parts could not all arise at once, and without any of them the others are useless He s wrong. (Surprise) The basal body of the flagella is similar to a secretion system present in bacteria used to inject toxin into eukaryotic cells This basal element contains 10 flagellar proteins but is missing 40 proteins necessary for it to work as a flagella Negates the irreducible complexity argument

20 Other theories being attacked Germ theory of disease Anti-vaccine movement AIDS in Africa/ Middle East False information being spread about disease People are told that condoms are actually spreading the disease Global climate change IPCC findings prove without a doubt that global climate change is happening AND it is being caused by the actions of humans

21 Take home message Scientific theories are not just an idea They are tested, confirmed facts about the physical universe Stand up to rigorous scientific testing Arguments against well-tested theories are often not based on science but heresay Use of sound scientific reasoning and experimental deduction allows these arguments to be rebuked

22 Intro to physiology Themes for semester Physical- chemical basis of body function Structure and function Energetics Homeostasis Integration

23 Levels of biological organization From smallest to biggest: Atoms or Ions Molecules Macromolecules Organelles Cells Tissues Organs Organ Systems Organism

24 Body fluid compartments Intracellular fluid (ICF) 2/3 of total body water (TBW) Major solutes are K+, organic anions (A-) Extracellular fluid (ECF) 1/3 TBW Interstitial fluid Blood plasma (3 L) Major solutes are Na+, Cl- ECF acts as buffer between cells and external environment

25 Boundaries between fluids Plasma membrane Seperates ICF and ECF Helps to maintain composition of both Selective permeability and active transport Epithelial Tissue Forms barrier between ECF and external environment Protective barrier Free surface faces external environment (or lumen of hollow organ)

26 Homeostasis First called Milieu intérieur by Claude Bernard in the mid 1800s The fixity of the milieu supposes a perfection of the organism such that the external variations are at each instant compensated for and equilibrated... All of the vital mechanisms, however varied they may be, have always one goal, to maintain the uniformity of the conditions of life in the internal environment... The stability of the internal environment is the condition for the free and independent life Walter Cannon then defined homeostasis in 1929 Steady-state conditions- all changes are met with forces that resist change

27 Homeostasis Steady state process Inputs must be matched by outputs in order to maintain balance Eat a bag of sea salt potato chips ; must excrete salt and metabolize starch Process requires energy Na-K ATPase, others Body fluids are regulated to maintain suitable cell conditions

28 7 essential variables Body temp: 37⁰C Mean arterial blood pressure: 90 mmhg (varies from ) Arterial ph: 7.4 Arterial pc02: 40 mmhg Arterial p02: 100 mmhg Blood glucose: 90mg/dL Plasma osmolarity: 290 mosm

29 Homeostasis is maintained by negative feedback Sensors detect change in a variable Osmoreceptors detect increased salt Insulin receptors detect increase in blood glucose Signal is sent to integrating center Often in the brain Integrating center produces output Output goes to effectors Effectors provide response Kidneys excrete more salt Cells take up glucose to lower blood sugar

30 Body temperature regulation Negative feedback control around 37⁰C Sensors: skin and hypothalamus Integrating center: hypothalamus Response to hot Effectors = sweat glands and skin blood vessels Sweat, and increase surface blood flow (vasodilation) Causes decrease in temp Response to cold Effectors = skeletal muscle, skin blood vessels Shivering, reduce surface blood flow (vasoconstriction) Causes increase in temp

31 Positive feedback Non- homeostatic response Results in rapid change of a variable Involved in sleep/ wake cycle (and other things)