1.Basic Principles of Human Physiology

BASIC PRINCIPLES OF BASIC PRINCIPLES OF HUMAN PHYSIOLOGYHUMAN PHYSIOLOGY

Integrative Teaching Bloc IVIntegrative Teaching Bloc IV

Dr. Swanny, MScDr. Swanny, MSc

The definitionThe definition

Physiology is :Physiology is :

The study of the functions of a living The study of the functions of a living organism and its component parts, organism and its component parts, including all chemical and physical including all chemical and physical processes.processes.

The term The term physiologyphysiology literally means literally means “knowledge of nature.”“knowledge of nature.”

HistoryHistory

Aristotle (384-322 B.C.) : the function of all Aristotle (384-322 B.C.) : the function of all living organisms, not only the human body.living organisms, not only the human body.

Hippocrates (460-377 B.C.) : the healing power Hippocrates (460-377 B.C.) : the healing power of nature, closely associated with medicine.of nature, closely associated with medicine.

In 16In 16thth century : the study of vital functions of century : the study of vital functions of the human body.the human body.

1970s : rapid advances in the fields of cellular 1970s : rapid advances in the fields of cellular and molecular biology.and molecular biology.

Physiologists are trained to think about the Physiologists are trained to think about the INTEGRATION of function across all levels, INTEGRATION of function across all levels, from molecules to living body.from molecules to living body.

(To integrate means to bring varied (To integrate means to bring varied elements together to create a unified elements together to create a unified whole.)whole.)

To reach it To reach it understand the fundamental understand the fundamental principles of physiology principles of physiology to know the to know the way the human body functions.way the human body functions.

Levels of organizationLevels of organization

1. ATOMS1. ATOMS 2. MOLECULES 2. MOLECULES 3. CELLS 3. CELLS 4.TISSUES 4.TISSUES 5. ORGANS 5. ORGANS 6. 6. ORGAN SYSTEMS ORGAN SYSTEMS 7.ORGANISMS 7.ORGANISMS 8. POPULATIONS OF ONE SPECIES 8. POPULATIONS OF ONE SPECIES 9. ECO-SYSTEM of DIFFERENT 9. ECO-SYSTEM of DIFFERENT SPECIES SPECIES 10. BIOSPHERE.10. BIOSPHERE.

Fields of studyFields of study

Level 1, 2 : Chemistry.Level 1, 2 : Chemistry.

Level 2,3 : Molecular biology.Level 2,3 : Molecular biology.

Level 2,3,4 : Cell biology.Level 2,3,4 : Cell biology.

Level 2,3,4,5,6,7,8 : Physiology.Level 2,3,4,5,6,7,8 : Physiology.

Level 7,8,9,10 : Ecology.Level 7,8,9,10 : Ecology.

Organs Systems of human Organs Systems of human bodybody

System NameSystem Name Organs/Organs/tissuestissues

FunctionFunction

1. Circulatory1. Circulatory Heart, blood Heart, blood vessels, bloodvessels, blood

Transport of Transport of materials materials throughout throughout the bodythe body

2. Digestive2. Digestive Stomach, Stomach, intestines, intestines, liver, liver, pancreaspancreas

Conversion of Conversion of food into food into particles that particles that can be taken can be taken into body, into body, elimination of elimination of some wastes.some wastes.

3. Endocrine3. Endocrine Thyroid gland, Thyroid gland,

adrenal glandadrenal glandCoordination Coordination of body of body function function throughout throughout synthesis and synthesis and release of release of regulatory regulatory moleculesmolecules

4. Immune4. Immune Thymus, Thymus, spleen, lymph spleen, lymph nodesnodes

Defense Defense against against foreign foreign invadersinvaders

5. 5. IntegumentarIntegumentaryy

SkinSkin Protection Protection from external from external environment.environment.

6. 6. MusculoskeletMusculoskeletalal

Skeletal Skeletal muscles, muscles, bonesbones

Support and Support and movementmovement

7.Reproductiv7.Reproductivee

Ovaries, Ovaries, uterus, testesuterus, testes

Perpetuation Perpetuation of the speciesof the species

8. Urinary8. Urinary Kidneys, Kidneys, bladderbladder

Maintenance Maintenance of water and of water and solutes in the solutes in the internal internal environment; environment; waste waste removalremoval

9. Nervous9. Nervous Brain, spinal Brain, spinal

cordcordCoordination Coordination of body of body function function through through electrical electrical signals and signals and release of release of regulatory regulatory moleculesmolecules

10.Respirator10.Respiratoryy

Lungs, Lungs, airwaysairways

Exchange of Exchange of O2 and CO2 O2 and CO2 between between internal and internal and external external environment.environment.

Integrative PhysiologyIntegrative Physiology

The current challenges in physiology is The current challenges in physiology is INTEGRATING information from the INTEGRATING information from the different body system into a cohesive different body system into a cohesive picture of human body.picture of human body.

One way to do this , is by using One way to do this , is by using MAPPING.MAPPING.

MappingMapping

A non- linear way of organizing material A non- linear way of organizing material that has been shown to improve that has been shown to improve understanding and retention.understanding and retention.

Benefits :Benefits :1. Integrate newly acquired information 1. Integrate newly acquired information

into knowledge base.into knowledge base.2. Steps in experiments.2. Steps in experiments.3. Guide to diagnosis and treatment.3. Guide to diagnosis and treatment.

Maps in physiologyMaps in physiology

1. Structure / function maps : 1. Structure / function maps : relationships between anatomical relationships between anatomical structure and physiological process.structure and physiological process.

2. Process maps / flow charts : normal 2. Process maps / flow charts : normal homeostatic control pathways and homeostatic control pathways and responses to abnormal events/ responses to abnormal events/ pathophysiological condition.pathophysiological condition.

Physiology is an Integrative Physiology is an Integrative sciencescience

On levels of organization On levels of organization cut across many cut across many levels.levels.

Focus : integration among system. e.g. the Focus : integration among system. e.g. the control of blood pressure control of blood pressure cardiovascular cardiovascular system, kidney and body fluid.system, kidney and body fluid.

Challenge : EMERGENT properties of complex Challenge : EMERGENT properties of complex system. E.g. emotion, intelligence, brain system. E.g. emotion, intelligence, brain function that can’t be predicted from function that can’t be predicted from knowing individual properties of nerve cells.knowing individual properties of nerve cells.

Function and ProcessFunction and Process

FUNCTION FUNCTION the “ WHY “ of the system. the “ WHY “ of the system.

PROCESS PROCESS the “HOW” of a system. the “HOW” of a system.

Examples : Why RBC transport O2?Examples : Why RBC transport O2?

Because RBC brings O2 to cells that need Because RBC brings O2 to cells that need it. it.

How ? How ? mechanistic approach mechanistic approach because RBC contains Hemoglobin that because RBC contains Hemoglobin that combines reversibly with O2 molecules. combines reversibly with O2 molecules.

Evolution of physiological Evolution of physiological systemssystems

Human beings are large, mobile, Human beings are large, mobile, terrestrial animals whose bodies are terrestrial animals whose bodies are about 60% water.about 60% water.

The anatomy and physiology of human The anatomy and physiology of human body is designed to survive in a dry, body is designed to survive in a dry, highly variable external environment.highly variable external environment.

Evolution Evolution ADAPTATION. ADAPTATION.

HomeostasisHomeostasis

As a whole As a whole adapted to cope with adapted to cope with variable external environment.variable external environment.

As an individual cell As an individual cell less tolerant to less tolerant to change.change.

Internal stability is important !Internal stability is important !

The body’s ability to maintain internal The body’s ability to maintain internal stability is known as HOMEOSTASIS.stability is known as HOMEOSTASIS.

Homeostasis Homeostasis

Failure to maintain homeostasis disrupts Failure to maintain homeostasis disrupts normal function normal function disease state or disease state or pathological condition.pathological condition.

Based on origin :Based on origin :1. Arises from internal failure : abnormal 1. Arises from internal failure : abnormal

growth of cells, autoimmune disease.growth of cells, autoimmune disease.2. Outside sources : toxic chemicals, 2. Outside sources : toxic chemicals,

viruses and bacteria, physical trauma. viruses and bacteria, physical trauma.

Keys concepts in physiologyKeys concepts in physiology

1. Homeostasis and control systems.1. Homeostasis and control systems.

2. Structure and function relationship.2. Structure and function relationship.

3. Communications.3. Communications.

4. Movements of substances across 4. Movements of substances across membrane.membrane.

5. Biological energy.5. Biological energy.

6. Mass balance6. Mass balance

7. Mass flow.7. Mass flow.

Homeostasis and control Homeostasis and control systemsystem

Key functions are REGULATED VARIABLES Key functions are REGULATED VARIABLES that are monitored and regulated by a that are monitored and regulated by a PHYSIOLOGICAL CONTROL SYSTEM.PHYSIOLOGICAL CONTROL SYSTEM.

Example : control of breathing.Example : control of breathing.

central controller central controller output output effector effector /muscle of respiration /muscle of respiration signals to signals to sensors / receptors sensors / receptors input input central. central.

Structure/Function Structure/Function relationshiprelationship

1. Molecular interactions. E.g. enzymes that 1. Molecular interactions. E.g. enzymes that speed up chemical reactions.speed up chemical reactions.

2. Mechanical properties of cells, tissues and 2. Mechanical properties of cells, tissues and organs. Usually direct result of anatomy organs. Usually direct result of anatomy structure. E.g. compliance, elastance.structure. E.g. compliance, elastance.

3. Compartmentation of body and cells. E.g. 3. Compartmentation of body and cells. E.g. membrane cell separates cells from each membrane cell separates cells from each other other different area to specialize different area to specialize function. function.

CommunicationCommunication

Cells to cells communicate with Cells to cells communicate with chemical signals. Nervous system chemical signals. Nervous system uses electrical signals.uses electrical signals.

Communication can be local or long Communication can be local or long distance.distance.

Signals that can’t transferred across Signals that can’t transferred across membrane cell, must translated into membrane cell, must translated into an intra cellular signal an intra cellular signal signal signal transductiontransduction

Movement of substances Movement of substances across membraneacross membrane

Movement of water, gas, other Movement of water, gas, other molecules between the intracellular molecules between the intracellular and extracellular compartments and extracellular compartments requires crossing barrier of cell requires crossing barrier of cell membrane.membrane.

Cells have special process that Cells have special process that selective about what materials they selective about what materials they allow in or out. allow in or out.

Biological energyBiological energy

Synthesis and breakdown of Synthesis and breakdown of molecules, to transport molecules molecules, to transport molecules across the cell membrane, and to across the cell membrane, and to create movement.create movement.

Examples : breakdown of glycogen to Examples : breakdown of glycogen to ATP, the Kreb’s cycle.ATP, the Kreb’s cycle.

Mass balanceMass balance

Law of mass balance :Law of mass balance :

if the amount of a substance in body if the amount of a substance in body is to remain constant, any gain must is to remain constant, any gain must be offset by equal loss.be offset by equal loss.

Example; to maintain body Example; to maintain body temperature constant: Heat gain temperature constant: Heat gain must be equal to heat loss. ( input = must be equal to heat loss. ( input = output )output )

Mass FlowMass Flow

Function of time. Function of time.

Examples : sodium intake per day, CO2 Examples : sodium intake per day, CO2 production per minute.production per minute.

Rate of intake, production, out put.Rate of intake, production, out put.

Mass flow = concentration x volume flowMass flow = concentration x volume flow

(amount/min) (amount/vol) (vol/min)(amount/min) (amount/vol) (vol/min)

Mass flowMass flow

Movement of substances within and Movement of substances within and between compartments of body.between compartments of body.

Blood flow, air flow, gases, nutrients Blood flow, air flow, gases, nutrients and wastes move into and out of and wastes move into and out of cells.cells.

Flow is created by a driving force, such Flow is created by a driving force, such as a pressure or concentration as a pressure or concentration difference / gradient.difference / gradient.

Concepts of Cell FunctionConcepts of Cell Function

Cells are smallest functional units of Cells are smallest functional units of living things.living things.

Cells are living because they are able Cells are living because they are able to carry on metabolic activities that to carry on metabolic activities that provide energy sustain themselves, provide energy sustain themselves, to grow and reproduce and to to grow and reproduce and to respond to short and long terms respond to short and long terms changes in environment.changes in environment.

Chemical organizationChemical organization

Some important chemical reactions.Some important chemical reactions.

1. Law of Mass reaction.1. Law of Mass reaction.

2. Oxidation – Reduction reaction.2. Oxidation – Reduction reaction.

3. Enzyme – assisted reactions.3. Enzyme – assisted reactions.

Translocation of materialsTranslocation of materials

1. Diffusion of gases.1. Diffusion of gases.

2. Movement across cell membrane:2. Movement across cell membrane:

a. physical transport processa. physical transport process

b. physiological transport processb. physiological transport process

Physical transportPhysical transport

1. Diffusion1. Diffusion

2. Osmosis2. Osmosis

3. Filtration3. Filtration

Physiological transportPhysiological transport

1. Carrier –mediated transport:1. Carrier –mediated transport:

-facilitated diffusion-facilitated diffusion

-active transport-active transport

2. Transport of large molecules2. Transport of large molecules

- Endocytosis : phagocytosis, - Endocytosis : phagocytosis, pinocytosispinocytosis

- Exocytosis : secretion process.- Exocytosis : secretion process.

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Electrical phenomenaElectrical phenomena

Electrical activity is an essential for Electrical activity is an essential for energy –releasing activities.energy –releasing activities.

Characteristic of living things :Characteristic of living things :

- properties of live- properties of live

- in absence of electrical activity in - in absence of electrical activity in nervous system is important criterion nervous system is important criterion for determining clinical death.for determining clinical death.

Electrical conceptsElectrical concepts

The force of attraction of negative and The force of attraction of negative and positive charges positive charges potential energy potential energy capable of doing work. capable of doing work.

It is referred as :It is referred as :

VoltageVoltage

Electrical potentialElectrical potential

Potential differencePotential difference

Skeletal muscle systemSkeletal muscle system

Skeletal muscles acting upon a system Skeletal muscles acting upon a system of levers formed by bones and joints of levers formed by bones and joints that cause movement.that cause movement.

Muscle is characterized by the ability Muscle is characterized by the ability of its cells to change shapes, that is, of its cells to change shapes, that is, to contract and to shorten.to contract and to shorten.

Arrangement of muscle Arrangement of muscle fibersfibers

1. Longitudinal or parallel.1. Longitudinal or parallel.

2. Unipendate2. Unipendate

3. Bipendate3. Bipendate

4. Multipendate4. Multipendate

5. Radiate.5. Radiate.

Muscle contractionMuscle contraction

Skeletal muscle is known as striated Skeletal muscle is known as striated muscle because its fibers show muscle because its fibers show alternating light and dark stripes.alternating light and dark stripes.

Also known as voluntary muscle Also known as voluntary muscle because its contraction can be because its contraction can be voluntarily initiated.voluntarily initiated.

Muscle contraction is due to the Muscle contraction is due to the arrangement of myofibrils within it.arrangement of myofibrils within it.

Contraction – Sliding Contraction – Sliding filamentsfilaments

For contraction , muscle needs energy For contraction , muscle needs energy ATP. ATP.

Energy release from ATP Energy release from ATP exert a force that exert a force that causes a rotation of myosin head and cross causes a rotation of myosin head and cross bridge( which is bound to actin), causing a bridge( which is bound to actin), causing a slight displacement between thick and thin slight displacement between thick and thin filaments. The thin filaments are moved filaments. The thin filaments are moved toward the center of sarcomere, increasing toward the center of sarcomere, increasing the area of overlap of thick and thin the area of overlap of thick and thin filaments.filaments.

Stimulation of isolated skeletal Stimulation of isolated skeletal musclemuscle

Stimulus increases permeability of Stimulus increases permeability of membrane to sodium ions, sodium membrane to sodium ions, sodium ions diffuses into cell ions diffuses into cell reducing its reducing its internal negativity internal negativity Depolarization. Depolarization.

A single stimulus produces a single A single stimulus produces a single Action Potential and a single brief Action Potential and a single brief contraction known as a muscle contraction known as a muscle twitch. twitch.

Types of contractionTypes of contraction

1. Isotonic contraction : muscle 1. Isotonic contraction : muscle shortens and moves the recording shortens and moves the recording levers ( isotonic = equal tension ).levers ( isotonic = equal tension ).

2. Isometric contraction : the load is so 2. Isometric contraction : the load is so heavy that muscle cannot shorten heavy that muscle cannot shorten ( isometric = equal length).( isometric = equal length).

Smooth muscleSmooth muscle

1. Single unit ( visceral ) smooth muscle 1. Single unit ( visceral ) smooth muscle is organized to function as a single is organized to function as a single unit.unit.Single unit has Automaticity or Single unit has Automaticity or inherent rhythmicity.inherent rhythmicity.

2. Multiunit smooth muscle. It is more like 2. Multiunit smooth muscle. It is more like skeletal muscle , organized in bundles skeletal muscle , organized in bundles and does not have automaticity. and does not have automaticity. Examples: walls of blood vessels. Examples: walls of blood vessels.

Cardiac muscleCardiac muscle

Intermediate between smooth and Intermediate between smooth and skeletal muscle.skeletal muscle.

Cardiac muscle are both involuntary Cardiac muscle are both involuntary and striated, but it is found only in and striated, but it is found only in heart.heart.

Characteristic : Automaticity Characteristic : Automaticity due to due to pacemaker cells that depolarize pacemaker cells that depolarize spontaneously and develop an action spontaneously and develop an action potential.potential.

Nervous systemNervous system

The nervous system is a The nervous system is a communication system based on the communication system based on the conduction of impulses that provide conduction of impulses that provide information and give direction.information and give direction.

Its organization and Its organization and componentscomponents

Nerve cells are called : NEURON.Nerve cells are called : NEURON.

Structure called RECEPTOR are sensitive to Structure called RECEPTOR are sensitive to certain changes in their immediate certain changes in their immediate environment. Impulses ( information ) environment. Impulses ( information ) from receptor are transmitted to SPINAL from receptor are transmitted to SPINAL CORD or BRAIN. Then, other nerve fibers CORD or BRAIN. Then, other nerve fibers carry impulses from spinal cord/brain to carry impulses from spinal cord/brain to EFFECTORS, such as skeletal, smooth, EFFECTORS, such as skeletal, smooth, cardiac muscle and gland.cardiac muscle and gland.

The process in nervous The process in nervous systemsystem

The operation of the nervous system The operation of the nervous system involves RECEIVING and involves RECEIVING and PROCESSING information ( impulses ) PROCESSING information ( impulses ) generated by many receptors in generated by many receptors in many parts of the body, and many parts of the body, and directing the responses of many directing the responses of many EFFECTORS to bring about EFFECTORS to bring about appropriate responses.appropriate responses.

Endocrine systemEndocrine system

The organ of endocrine system is The organ of endocrine system is GLAND which secretes HORMONES GLAND which secretes HORMONES which affect many cell functions that which affect many cell functions that are not under neural control.are not under neural control.

Together the endocrine glands Together the endocrine glands constitute a control system that constitute a control system that parallels, but does not duplicate , the parallels, but does not duplicate , the nervous system.nervous system.

Endocrine glandsEndocrine glands

1.Pituitary gland/hypophysis1.Pituitary gland/hypophysis

2.Adrenal gland2.Adrenal gland

3.Thyroid gland3.Thyroid gland

4.Parathyroid gland4.Parathyroid gland

5.Pancreatic islands/islets of 5.Pancreatic islands/islets of LangerhansLangerhans

6.Gonads( ovary, testis )6.Gonads( ovary, testis )

HormoneHormone

Hormones are chemical messenger.Hormones are chemical messenger.

Based on its nature , hormones are Based on its nature , hormones are divided into :divided into :

1. Protein 1. Protein

2. Amino acids derivative2. Amino acids derivative

3. Steroid.3. Steroid.

Hormone action and Hormone action and regulationregulation

To act on target organ, hormone needs To act on target organ, hormone needs RECEPTOR.RECEPTOR.

Hormone action depends on its nature.Hormone action depends on its nature.

The major control of endocrine glands The major control of endocrine glands is chemical in nature. It is exerted by is chemical in nature. It is exerted by what is known as a NEGATIVE FEED what is known as a NEGATIVE FEED BACK MECHANISM.BACK MECHANISM.

BloodBlood

Blood is a FLUID TISSUE.Blood is a FLUID TISSUE.

Great numbers of cells are suspended Great numbers of cells are suspended in the fluid (PLASMA), and a variety in the fluid (PLASMA), and a variety of solutes are dissolved in it. of solutes are dissolved in it.

Blood is vital for TRANSPORT.Blood is vital for TRANSPORT.

Composition of bloodComposition of blood

1. Plasma1. Plasma

2. The cells : erythrocytes/ RBC, 2. The cells : erythrocytes/ RBC, leukocyte/ WBCleukocyte/ WBC

3. Platelets 3. Platelets formed elements, which formed elements, which are not actually whole cells.are not actually whole cells.

Cardiovascular systemCardiovascular system

Consists of HEART as the driving force Consists of HEART as the driving force that causes blood to move through that causes blood to move through BLOOD VESSELS.BLOOD VESSELS.

The CIRCULATION of blood is vital to The CIRCULATION of blood is vital to the survival of all cells of the body.the survival of all cells of the body.

Respiratory systemRespiratory system

Structure :Structure :

1. Upper respiratory tract, consisting 1. Upper respiratory tract, consisting structure from nasal cavity through structure from nasal cavity through larynxlarynx

2. Lower respiratory tract, consisting 2. Lower respiratory tract, consisting trachea through the lung.trachea through the lung.

3. Thoracic cavity3. Thoracic cavity

Digestive systemDigestive system

The organs of digestive system occupy most The organs of digestive system occupy most the abdominal cavity.the abdominal cavity.

The process The process Digestion/breakdown of Digestion/breakdown of nutrients, Transport them to appropriate nutrients, Transport them to appropriate sites for Absorption into blood stream. sites for Absorption into blood stream. Inside the TD, the nutrients also mixed Inside the TD, the nutrients also mixed with Secretion of TD to help digestion with Secretion of TD to help digestion process.process.

Urinary systemUrinary system

The important structure is Kidney.The important structure is Kidney.

Kidney is an EXCRETORY organ.Kidney is an EXCRETORY organ.

The process in kidney :The process in kidney :

-filtration-filtration

-secretion-secretion

-excretion-excretion

-maintain the composition of extracellular -maintain the composition of extracellular fluid.fluid.

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