Anatomy & Physiology Intro(Part 2)

BME 100 - Introduction toBiomedical Engineering

James A. SmithOriginal Reference:

http://lpc1.clpccd.cc.ca.us/lpc/jgallagher/

Physiology

Overview

• What is physiology?• From cell to human (levels of organization)• A review of the organ systems• Introduction of the concept of homeostasis• Themes in Physiology• The science of Physiology

Experimental designData

Physiology is…

•the study of the function of all plants andanimals in their normal state.•an integrative science

Levels of Organization

Organ Systems

operate as integrated units

How many? Can you listthem?

Examples:Regulation of•Plasma calciumconcentration•Blood pressure•etc.

Function and Process:Approach to Science

What is purpose or function? Why does something exist? Why does it need to be done?

What are processes involved? How does something work?

Distinguish between Process & Function

Integrate both for complete picture!

How do we breathe?

How does bloodflow?

How do RBCstransport O2?

Why do we breathe?

Why does bloodflow?

Why do RBCtransport O2?

Focus on . . . . (Concept)Mapping

1. Structure – function maps

2. Process maps or FlowchartsFollow process in sequence

Key Themes in Physiology:

HomeostasisBody systems work together (Integration of

function)Internal vs. external failure of homeostasis

Communication and movementacross cell membranes

Vital to integration & homeostasisCells communicate with other cells, tissues

& organs

• Inorganic Chemistry– C, O, H, Na, S, P, Mg, K, Ca, Fe + trace elements– Ions (variable electrons)

• Neural pathways– Isotopes (variable neutrons)

• Nuclear Medicine

• Organic Chemistry– Carbon, Hydrogen & Oxygen in Biomolecules– Proteins– Fats– Nucleotides (RNA, DNA)

Molecular Interactions

Cells & Tissues

• Cells are dynamic– Stem cells: general to specialized– Apoptosis: programmed cell death

• Tissues are dynamic– How do organs change over time?

Metabolism• “All chemical reactions that take place

within an organism”• Energy - for synthesis & movement• Enzymes = Biological Catalysts

– Lower energy requirements in conversion

ATP Cycle

Membrane Dynamics

•• Cell membraneCell membranestructures and functionsstructures and functions–– Membranes form fluidMembranes form fluid

body compartmentsbody compartments–– Membranes as barriersMembranes as barriers

and gatekeepersand gatekeepers–– Products move acrossProducts move across

membranesmembranes–– Distribution of water andDistribution of water and

solutes in cells & the bodysolutes in cells & the body

Homeostasis• Control Systems

– Sense & Regulate subsystems

Temperature Regulation

• Video…– http://videos.howstuffworks.com/hsw/11965-heat-how-the-human-

body-regulates-its-temperature-video.htm

Matlab Control Demo

• Switch to Matlab & VR Toolbox (vpend)

Endocrine System• The study of hormones, their receptors, the

intracellular signaling pathways they invoke, and thediseases and conditions associated with them.

• Hormones– Secreted by cells into blood– Rapid effects– Limited duration– Combinations can be useful!

Neurons: Electrifying!

• Electrical signaling• Changes in membrane

electrical potential are thebasis for electrical signaling

• Only nerve and musclecells are excitable (= ableto propagate electricalsignals)

Sensory Systems

•• Receptors are transducers Receptors are transducers → → convertconvertstimuli into electrical potentialstimuli into electrical potential•• Chemo- Chemo- (specific (specific ligandsligands)) and and Osmo- Osmo- ((concconc. of. of

solutes)solutes)

•• Mechano- Mechano- (touch, pressure, vibration, stretch)(touch, pressure, vibration, stretch)

•• Thermo- Thermo- (temp. change)(temp. change)•• Cold receptorsCold receptors lower than body temp.lower than body temp.•• Warm receptorsWarm receptors ((37 - 4537 - 45ooC) > 45C) > 45ooC C ??

•• Photo- Photo- (light)(light)

Muscles: Molecular Interaction

ATP ADP + Pi

• Tight binding betweenG-actin and myosin• No nucleotide bound

ATP binds ⇒ dissociation

Myosin head acts asATPase

Released energy changesangle between head & longaxis of myosin

Rotation and weakbinding to new G-actin

Relaxedmuscle statewhensufficient ATP

Power stroke beginsas Pi released

ADP released

Tight binding to actin

Myosin crossbridge movement pushes actin

Heart

Depolarization

Blood Flow• Blood pressure must be regulated• Flow from high to low pressure• Resistance: radius, viscosity and length• Too Low

– Pumping (force) cannot overcome gravity– Oxygen diminished to brain

• Too High– Weakened arterial walls -> rupture!– Cerebral hemorrhage

Blood ControlHemostasis Hemostasis = = Opposite of hemorrhage Opposite of hemorrhage ⇒⇒ stops bleeding stops bleeding

Too little Too little hemostasis hemostasis ⇒⇒ too much bleeding too much bleeding

Too much Too much hemostasis hemostasis ⇒⇒ thrombi / emboli thrombi / emboli

Vessel damage exposes collagen fibersVessel damage exposes collagen fibers

Platelets adhere to collagen & release factorsPlatelets adhere to collagen & release factors

local vasoconstrictionlocal vasoconstriction & & platelet aggregationplatelet aggregation

decreased blood flowdecreased blood flow platelet plug formation platelet plug formation

+ feedback loop

Functions of theRespiratory System

•• Oxygen exchangeOxygen exchange–– Air to bloodAir to blood–– Blood to cells (?)Blood to cells (?)

•• Carbon dioxide exchangeCarbon dioxide exchange–– Cells to bloodCells to blood–– Blood to airBlood to air

•• Regulation of body pHRegulation of body pH–– COCO22+H+H22OO⇌⇌HH22COCO33⇌⇌HH+++HCO+HCO33--

•• Protection from pathogens,Protection from pathogens,irritantsirritants

•• VocalizationVocalization

The Kidneys

• Urinary Processes

180 L / day filtered, >99% reabsorbed,180 L / day filtered, >99% reabsorbed,

1.5 L/day excreted1.5 L/day excreted

1.1. Filtration, Filtration, 2.2. ReabsorptionReabsorption, , 3.3. Secretion, Secretion, 4.4. ExcretionExcretion5.5. MicturitionMicturition

Fluid Balance

• Many subsystems!• Kidneys: key role

– Balance water viaurine concentration

– React to osmolarity,volume, bloodpressure

The Digestive SystemMajorprocessesofdigestivesystem:1.1. MotilityMotility2.2. SecretionSecretion3.3. DigestionDigestion4.4. AbsorptionAbsorption

The Immune System•• Three Major FunctionsThree Major Functions

1.1. Protection from disease-causing invadersProtection from disease-causing invaders

2.2. Removal of dead /damaged tissues & cellsRemoval of dead /damaged tissues & cells

3.3. Recognition & removal of abnormal cellsRecognition & removal of abnormal cells

• Immunologic “mistakes:”1. Incorrect responses: autoimmunity2. Overactive responses: allergy3. Lack of response: immune deficiency