Biology 219Human Physiology

Instructor- Dr. Adam Rossaross@napavalley.edu

Tues/ Thurs: 11:00-12:15 Room 2040 (Lecture)Tues/ Thurs: 1:30-4:20 Room 2040 (Lab)

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

• 3rd semester at Napa Valley College• 1st time teaching BIO 219

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

How to excel at learning:

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.

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

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”

How do we study science?

• Scientific Method: Credited to Ibn-al Haytham (965-1039)• Iraqi scientist that demanded reproducibility from experimental

results

• Methodology has been altered over the years

• Galilelo implemented changes in Two New Sciences in 1638

• 20th century saw changes implemented as well

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

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

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

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

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”

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

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

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

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

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

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

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

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

Intro to physiology

• Themes for semester• Physical- chemical basis of body function

• Structure and function

• Energetics

• Homeostasis

• Integration

Levels of biological organization

• From smallest to biggest:• Atoms or Ions

• Molecules

• Macromolecules

• Organelles

• Cells

• Tissues

• Organs

• Organ Systems

• Organism

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

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)

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

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

7 essential variables

• Body temp: 37⁰C

• Mean arterial blood pressure: 90 mmHg (varies from 80-120)

• Arterial pH: 7.4

• Arterial pC02: 40 mmHg

• Arterial p02: 100 mmHg

• Blood glucose: 90mg/dL

• Plasma osmolarity: 290 mOsm

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

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

Positive feedback

• Non- homeostatic response• Results in rapid change of a variable

• Involved in sleep/ wake cycle (and other things)