physiology, lecture 2 function of living things (slides)

8/8/2019 Physiology, Lecture 2 Function of Living Things (Slides)

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Introduction to PhysiologyIntroduction to Physiology

Study of the functions of living thingsStudy of the functions of living things

Human body ( machine ) itsHuman body ( machine ) itsmechanisms of action can bemechanisms of action can beexplained in terms of causeexplained in terms of cause--andand--effect sequences of physical andeffect sequences of physical andchemical processes.chemical processes.


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Level of organization in the bodyLevel of organization in the body

11-- Chemical levelChemical level (atoms & molecules) :(atoms & molecules) :H, O, C, N.H, O, C, N.

22-- Cellular levelCellular level (basic units of life)(basic units of life)

basic cellular functions:basic cellular functions:

aa--OO22, nutrients b, nutrients b--chemical rxns.chemical rxns.

cc--COCO22, waste production d, waste production d--protein synthesisprotein synthesis

ee--moving materials within cellmoving materials within cell ff-- control of transportcontrol of transport

gg--sensitivity and response hsensitivity and response h-- reproduction (most ofreproduction (most of

them)them)


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33-- Tissue levelTissue level (group of cells with similar(group of cells with similarspecialization):specialization):

tissue types:tissue types:aa--musclesmuscles

bb--nervesnerves

cc--epitheliumepithelium

dd--connective tissueconnective tissue

44-- Organ levelOrgan level (unit made of several tissue(unit made of several tissuetypes)types)

55-- System levelSystem level (collection of related organs)(collection of related organs)examples:examples:

aa--integumentaryintegumentary

bb--skeletalskeletal

cc--immuneimmune


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Stem cell & TissueengineeringStem cell & Tissueengineering

TypesTypes: a: a--embryonic bembryonic b--adult tissueadult tissue--specificspecific

Have the ability to differentiate when exposed toHave the ability to differentiate when exposed toappropriate chemical signalsappropriate chemical signals

Functions and usesFunctions and uses::aa--replacing dead tissuereplacing dead tissue

bb--growing into customized tissuegrowing into customized tissue

cc--mademade--toto--order replacement organsorder replacement organs

dd--building organs using computer plastic designbuilding organs using computer plastic design

ee--plastic mold seeded with cells from the sameplastic mold seeded with cells from the samepatient to avoid rejection.patient to avoid rejection.

ff--universal stem cells (embryonic)universal stem cells (embryonic)


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Successful accomplishments:Successful accomplishments:

11--skin patchesskin patches

22--artificial bone, teeth, & bladderartificial bone, teeth, & bladder

33--nerve regenerationnerve regeneration

44--growing organsgrowing organs55--growing limbsgrowing limbs


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HomeostasisHomeostasis

SingleSingle--celled organisms obtain Ocelled organisms obtain O22 &&nutrients from external surroundings andnutrients from external surroundings andeliminate wastes back to iteliminate wastes back to it

MultiMulti--cellular organisms need Ocellular organisms need O22 &&nutrients and also eliminate wastenutrients and also eliminate waste

because the cells are isolated from thebecause the cells are isolated from thesurroundings, there is a waterysurroundings, there is a watery

environment in which these cells areenvironment in which these cells arebathed in where they are in direct contactbathed in where they are in direct contactand make lifeand make life--sustaining exchanges.sustaining exchanges.


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Internal EnvironmentInternal Environment

Body fluids located inside the cellsBody fluids located inside the cells((ICFICF))

Body fluids located outside the cellsBody fluids located outside the cells((ECFECF) which includes plasma &) which includes plasma &interstitial fluidinterstitial fluid

You live in the external environmentYou live in the external environmentwhile your cells live within the bodyswhile your cells live within the bodysinternal environmentinternal environment


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Exchange within multiExchange within multi--cellularcellularorganisms:organisms:

thethe external environment with theexternal environment with the

internal environmentinternal environment

the internal environment with cellsthe internal environment with cells

Examples:Examples:

OO22: respiratory system and circulatory: respiratory system and circulatorysystemsystem

nutrients: digestive system andnutrients: digestive system and

circulatory systemcirculatory system


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The body must help in maintainingThe body must help in maintainingthe composition of the internalthe composition of the internal

environment fluid so that this fluidenvironment fluid so that this fluidremains suitable for supporting theremains suitable for supporting theexistence of the bodys cells.existence of the bodys cells.

HomeostasisHomeostasis : maintenance of a: maintenance of arelatively stable internal environmentrelatively stable internal environment

Body systems maintain homeostasisBody systems maintain homeostasis

Temperature, concentration ofTemperature, concentration ofnutrients, Onutrients, O22, CO, CO22, water, salts,, water, salts,electrolytes, wastes, pH, pressure,electrolytes, wastes, pH, pressure,and volume.and volume.


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Contribution of the body systems toContribution of the body systems tohomeostasis:homeostasis:

-- CVS and lymphatic systemCVS and lymphatic system-- Digestive systemDigestive system-- Muscular system:Muscular system:

aa-- enables the individual to move towardenables the individual to move toward

foodfoodbb-- temperature regulation by muscletemperature regulation by muscle

contractioncontraction

--Integumentary system:Integumentary system:aa-- outer protective barrierouter protective barrierbb-- temperature regulationtemperature regulation


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-- Immune systemImmune system defends the bodydefends the bodyagainst invadersagainst invaders

-- Nervous system & hormonal system:Nervous system & hormonal system:

aa--control and coordinate activitiescontrol and coordinate activities

bb--detect and initiate reactionsdetect and initiate reactionscc--consciousness, memory and creativityconsciousness, memory and creativity

dd--control nutrients and electrolytescontrol nutrients and electrolytescompositioncomposition

-- Reproductive systemReproductive system is responsible foris responsible forspecies survivalspecies survival


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Homeostasis Control SystemHomeostasis Control System

Network of body components that operateNetwork of body components that operateto maintain a given factor in the internalto maintain a given factor in the internalenvironment relatively constant around anenvironment relatively constant around an

optimal leveloptimal level to achieve that , the control systemto achieve that , the control system

must be able to:must be able to:

aa-- detect deviationsdetect deviations

bb-- integrate this information withintegrate this information withother informationother information

cc-- make appropriate adjustmentsmake appropriate adjustments


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11-- Intrinsic (local) controlsIntrinsic (local) controls built intobuilt into

any organ:any organ:

example: muscle exerciseexample: muscle exercise increase O2increase O2

useuse decrease O2 concentration locallydecrease O2 concentration locallylocal chemical effect acts directly on thelocal chemical effect acts directly on thesmooth muscle in the blood vessel in thatsmooth muscle in the blood vessel in thatareaarea causing smooth muscle relaxationcausing smooth muscle relaxation

vessel dilatationvessel dilatation increase blood supplyincrease blood supplyincrease O2 concentrationincrease O2 concentration

Homeostasis Control SystemHomeostasis Control System


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22-- Extrinsic controlsExtrinsic controls (nervous and(nervous andendocrine systems)endocrine systems)

example: Fall in blood pressureexample: Fall in blood pressure

Control systems operate on the principleControl systems operate on the principle

ofofnegative feedbacknegative feedback.. a change in a homeostatically controlleda change in a homeostatically controlledfactor triggers a response that seeks tofactor triggers a response that seeks torestore the factor to its normal state byrestore the factor to its normal state by

moving it in the opposite direction of itsmoving it in the opposite direction of itsinitial change.initial change.


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Temperature regulation:Temperature regulation:

cold weathercold weather

sensors send signals tosensors send signals tothe temperature centrethe temperature centre shivering toshivering to

generate heatgenerate heat increaseincreasetemperaturetemperature nerve cells monitornerve cells monitor

that & turn off the signals.that & turn off the signals.

hot weatherhot weather sensors send signals tosensors send signals to

the temperature centrethe temperature centre actionsactionssweatingsweating decrease temperaturedecrease temperaturesignals terminationsignals termination


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Positive feedbackPositive feedback: the output: the outputenhances or amplifies a change soenhances or amplifies a change so

that the factor continues to move inthat the factor continues to move inthe direction of the initial changethe direction of the initial change

examples:examples:

11-- baby birth: increase oxytocinbaby birth: increase oxytocinuterus contractionuterus contraction cervix stretchingcervix stretching

more oxytocinmore oxytocin more contractionmore contractionuntil the baby is bornuntil the baby is born

22-- action potentialaction potential33-- blood clottingblood clotting


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Feedforward mechanisms:Feedforward mechanisms: thetherespond occurs in anticipation of arespond occurs in anticipation of a

change in a regulated variable.change in a regulated variable.


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THE ENDTHE END

physiology, lecture 2 function of living things (slides)

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