Your body and how it worksYour body and how it works

Dr. Eric McElroy Dr. Eric McElroy

RHSC 235 RHSC 235

Tel: Tel: 953-3707 953-3707

e-mail: mcelroye@cofc.edue-mail: mcelroye@cofc.edu

BIOL 201BIOL 201

Where to find Lecture Slides

http://mcelroye.people.cofc.edu

Textbooks: Save money, buy used online!

Silverthorne (4th or 5th editions) Bruyere

http://iclicker.com/registration/

Student ID = xxx-xx-xxx

Registration ID

1st QUIZ is NEXT WED!

BASIC ASSUMPTIONSBASIC ASSUMPTIONS

1. The Universe is lawful

2. Biological systems are lawful

3. There is NO VITAL FORCE no MAGIC!

Physiological processes are mechanistic and governed by chemistry and physics

What is What is Physiology?Physiology?1) functions of anatomical structures 1) functions of anatomical structures

2) the mechanisms driving function.2) the mechanisms driving function.

Structure:Muscle and bones

Function:Support & Movement

Physiological Mechanism:Sliding Filament Model

Levels of OrganizationLevels of Organization

Membranes & Ions Neurons & Nerves Spinal Cord & Brain

Organism:Organism: Integration of SystemsIntegration of Systems

HOMEOSTASIS

Maintaining constant Internal EnvironmentMaintaining constant Internal Environment

External Environment = changing

Internal Environment

ICFECF

Plasma

60% of blood

Interstitial fluid(ISF)

Intracellular fluid(ICF)

Bloodvessel

Cell membrane

Cellmembrane

Bloodcells

Capillary wall

Internal Environment: Fluid CompartmentsInternal Environment: Fluid Compartments

Cells are Dynamic!

HomeostasisHomeostasis = = relative constancyrelative constancy

of the of the

ISF and BLOOD PLASMAISF and BLOOD PLASMA

BloodPlasma

Interstitial fluid(ISF)

Intracellular fluid(ICF)

EXTERNALENVIRONMENT

Exchange Cells

BloodPlasma

Interstitial fluid(ISF)

Intracellular fluid(ICF)

EXTERNALENVIRONMENT

Exchange Cells

DigestiveRespiratory

UrinaryIntegument

MusclesSkeletalNervous

HeartReproductive

Endocrine

Vascular

1) Receptor – Senses Deviation from NORMAL levels

2) Integrator – Interprets deviation and signals for a response

3) Effector – Returns body to NORMAL level

3 Basic Parts to All Homeostatic Mechanisms

Homeostatic Mechanism are REFLEX ARCS!

Reflex Arcs

Extreme Reflex

Knee Jerk Reflex

Reflex Arcs are EVERYWHERE

2 Main Types of Homeostatic Mechanisms

1) Negative Feedback Loop Deviation from NORMAL results in a return to

normal via feedback loop

2) Positive Feedback LoopDeviation from NORMAL results in a FURTHER

deviation from normal

RECEPTORRECEPTOR INTEGRATOR INTEGRATOR EFFECTOREFFECTOR

Baroreceptor Baroreceptor (Carotid Sinus)(Carotid Sinus)

BrainBrain(Cardiovascular Center)(Cardiovascular Center)

HeartHeart

MAP MAP

Time (min.)Time (min.)

93 mm Hg93 mm Hg

Decrease in blood pressure

Incr

ease

in S

troke

Vol

ume

& H

eart

Rat

e

CLASSIC Negative feedback loop

Example: Positive Feedback Loop

Parturition = Childbirth

Body compartments expressed as the % body weight Body compartments expressed as the % body weight of a 21 year old,70 kg (154 lbs) maleof a 21 year old,70 kg (154 lbs) male

40% Solids 60% Body Fluids40% Solids 60% Body Fluids

IntracellularIntracellular Interstitial Interstitial PlasmaPlasma (40% TBW)(40% TBW) (40% TBW) (40% TBW) (16% TBW)(16% TBW) (4% TBW)(4% TBW) 28 kg 28 kg 11 kg 3 kg28 kg 28 kg 11 kg 3 kg Bone Bone Potassium, KPotassium, K++ Sodium, NaSodium, Na++ Na Na++ Protein Protein Chloride, ClChloride, Cl-- ClCl--

Adipose Tissue Adipose Tissue HCO HCO33- - HCOHCO33

--

Glucose GlucoseGlucose Glucose Amino acids Amino acids.Amino acids Amino acids.

Fatty acids Fatty acids.Fatty acids Fatty acids. NoNo plasma Plasma plasma Plasma proteins proteinsproteins proteins

Extracellular Fluid (20%)Extracellular Fluid (20%)