Lecture'1:'homeostasis'• Define'anatomy'and'physiology,'and'name'several'branches'of'these'sciences.''

Anatomy!(ana%!=up;!%tomy=!process!of!cutting)!is!the!science!of!body!structures!and!the!relationships!among!them.!It!was!first!studied!by!dissections!(cutting!apart!of!body!structures!to!study!their!relationships.!!Physiology!(physio%!=!nature;!%logy=!study!of)!is!the!science!of!body!functions%!i.e.!how!the!body!parts!work.!!!Since!structure!and!function!are!closely!interrelated,!the!structure!of!a!part!of!the!body!often!reflects!its!functions.!!E.g.!bones!of!the!skull!join!tightly!to!form!a!rigid!case!that!protects!the!brain.!!E.g.!walls!of!the!air!sacs!are!very!thin,!permitting!rapid!movement!of!inhaled!oxygen!into!the!blood.!!

!• Describe'the'body’s'6'levels'of'structural'organisation.'

1. Chemical!level:!This!basic!level!includes!atoms!(smallest!unit!of!matter!that!participate!in!chemical!reactions)!and!molecules!(two!or!more!atoms!joined!together).!!

• C,!H,!O!N,!P,!Ca,!S!are!the!essential!atoms!for!maintaining!life.!!• DNA!and!glucose!(blood!sugar)!are!the!two!molecules!found!in!the!body.!!

2. Cellular!level:!Molecules!combine!to!form!cells%!the!basic!structural!and!functional!units!of!an!organism!composed!of!chemicals.!!

• Nerve!cells,!epithelial!cells!and!muscle!cells.!!3. Tissue!level:!Groups!of!cells!and!materials!surrounding!them!combine!to!form!tissue!and!they!

work!together!to!perform!a!particular!function.!!• 4!basic!types!of!tissues:!- Nervous!tissue:!carries!information!from!one!part!of!the!body!to!another!through!

nerve!impulses.!- Epithelial!tissue:!covers!body!surfaces,!lines!hollow!organs!and!cavities!and!forms!

glands.!- Muscular!tissue:!contracts!to!make!body!parts!move!and!generates!heat.!- Connective!tissue:!supports,!connects!and!protects!body!organs!while!distributing!

blood!vessels!to!other!tissues.!!4. Organ!level:!Tissues!join!together!to!form!organs.!!5. System!level:!The!digestive!system!which!breaks!down!and!absorbs!food.!It!is!also!known!as!

the!organ'system'level.!6. Organismal!level:!All!the!parts!of!the!human!body!functioning!together.!!

!• List'the'11'systems'of'the'human'body,'representative'organs'present'in'each,'and'their'general'

functions.''Integumentary!system!(skin,!hair,!nails,!sweat!and!oil!glands),!skeletal!system,!muscular!system,!nervous!system,!endocrine!system,!cardiovascular!system,!lymphatic!system,!respiratory!system,!digestive!system,!urinary!system!and!reproductive!systems.!!

• Define'the'important'life'processes'of'the'human'body.'Metabolism:!all!chemical!processes!that!occur!in!the!body.!There!are!2'phases:!catabolism'(breaking'down)'and'anabolism'(making'up).'Responsiveness:!ability!to!detect!and!respond!to!changes%!e.g.!increasing!body!temperature.!Movement:!motion!or!the!whole!body,!individual!organs,!single!cells!and!within!cells.!

- Endocrine!system!includes!many!glands!that!secrete!messenger!molecules!(hormones)!into!the!blood.!!

• Describe'the'components'of'feedback'system.'• Feedback!system!is!a!cycle!of!events!in!which!the!status!of!a!body!condition!is!monitored,!

evaluated,!changed,!remonitored,!reevaluated!etc.!!• Each!monitored!variable!(body"temperature,"blood"pressure"or"blood"glucose"level)!is!known!as!

the!controlled"condition.!Any!disturbances!that!changes!a!controlled!condition!is!known!as!the!stimulus.!!

• The!feedback!system!includes!3'basic'components:'a'receptor,'a'control'centre'and'an'effector.''- Receptor:!body!structure!that!monitors!

changes!in!a!controlled!condition!and!sends!input!to!a!control!centre!through!the!afferent"pathway.!This!information!is!carried!to!the!control!center!and!this!is!detected!by!the!input%!in!the!form!of!nerve!impulses!or!chemical!signals.!Monitors!the!physiological!variable!and!detects!changes!in!the!variable.!!

- Control'center:!the!brain!sets!range!of!values!within!which!a!controlled!condition!should!be!maintained!and!evaluates!the!input!it!receives!from!the!nerve/chemical!signals,!and!then!generates!output!commands!if!needed.!Output!from!the!control!center!typically!occurs!as!nerve!impulses,!or!hormones!or!other!chemical!signals!through!the!efferent"pathway.!Our!brain!acts!as!the!control!center,!receiving!nerve!impulses!from!skin!receptors!and!generating!nerve!impulses!as!output.!!

- Effector:!a!body!structure!that!receives!output!from!the!control!center!and!produces!a!response!that!changes"the"controlled"condition.!Organs!and!tissue!in!the!body!can!behave!as!an!effector.!When!body!temperature!decreases,!brain!(control!centre)!sends!nerve!impulses!(output)!to!skeletal!muscles!(effectors)!and!this!

causes!shivering%!this!generates!heat!and!increases!body!temperature.!!! !

• Contrast'the'operation'of'negative'and'positive'feedback'systems.'• Negative'feedback'system:!reverses!a!change!in!a!controlled!condition.!NOT'FAVOURING'

STIMULUS'THUS'NEGATING/DECREASING'THE'EFFECT'OF'THE'ORIGINAL'STIMULUS.'E.g.!when!the!heart!beats!faster!or!harder,!BP!increases.!If!some!internal!or!external!stimulus!causes!blood!pressure!(controlled!condition)!to!rise,!the!following!sequence!of!events!occurs.!Baroreceptors!(the!receptors),!pressure%sensitive!nerve!cells!located!in!the!walls!of!certain!blood!vessels,!detect!the!higher!pressure.!The!baroreceptors!send!nerve!impulses!(input)!to!the!brain!(control!center),!which!interprets!the!impulses!and!responds!by!sending!nerve!impulses!(output)!to!the!heart!and!blood!vessels!(the!effectors).!Heart!

rate!decreases!and!blood!vessels!dilate!(widen),!which!cause!BP!to!decrease!(response).!This!sequence!of!events!quickly!returns!the!controlled!condition—blood!pressure—to!normal,!and!homeostasis!is!restored.!Notice!that!the!activity!of!the!effector!(heart!and!blood!vessels)!causes!BP!to!drop,!a!result!that!negates!the!original!stimulus!(an!increase!in!BP).!!There’s!more!negative!feedback!occurring!than!positive!feed!back!in!the!human!body.!!!

• Positive'feedback'system:!tends!to!strengthen!or!reinforce!a!change!in!one!of!the!body’s!controlled!conditions.!It!provides!short!term!control!over!the!internal!environment.!FAVOURING'STIMULUS'THUS'ENHANCE/AMPLIFYING'EFFECT'OF'ORIGINAL'STIMULUS.!'

! The!control!center!still!provides!commands!to!an!effector!but!unlike!the!negative!feedback!system,!the!effector"produces"a"physiological"response"that"reinforces"the"initial"change"in"the"controlled"condition.!'

! Positive!feedback!also!provides!shortFterm!control!over!the!body’s!internal!environment.!It!also!plays!a!minor!role!in!the!maintenance!of!homeostasis.!!

! Since!positive!feedback!continually!intensifies/reinforce!the!initial!stimulus,!a!mechanism!is!needed!to!terminate!the!physiological!response.!!

E.g.'Normal!childbirth!provides!a!good!example!of!a!positive!feedback!system.!The!first!contractions!of!labor!(stimulus)!push!part!of!the!fetus!into!the!cervix,!the!lowest!part!of!the!uterus,!which!opens!into!the!vagina.!Stretch%sensitive!nerve!cells!(receptors)!monitor!the!amount!of!stretching!of!the!cervix!(controlled!condition).!As!stretching!increases,!they!send!more!nerve!impulses!(input)!to!the!brain!(control!center),!which!in!turn!releases!the!hormone!oxytocin!(output)!into!the!blood.!Oxytocin!causes!muscles!in!the!wall!of!the!uterus!(effector)!to!contract!even!more!forcefully.!The!contractions!push!the!fetus!farther!down!the!uterus,!which!stretches!the!cervix!even!more.!The!cycle!of!stretching,!hormone!release,!and!ever%stronger!contractions!is!interrupted!only!by!the!birth!of!the!baby.!Then,!stretching!of!the!cervix!ceases!and!oxytocin!is!no!longer!released.!'

• Explain'how'homeostatic'imbalances'are'related'to'disorders.''• Factors'that'contribute'to'homeostatic'imbalances:'

- Environment!and!personal!behaviour!- Genetic!makeup'- Air,!food,!thoughts'

• Homeostatic!imbalances!will!result!in!many!diseases!as!a!result!of!years!of!poor!health!behaviour!that!interferes!with!the!body’s!natural!drive!to!maintain!homeostasis.!This!will!also!affect!a!tissue,!organ!or!a!system!within!the!human!body.!'

• Should!one!or!more!components!of!the!body!lose!their!ability!to!contribute!to!homeostasis,!the!normal!balance!among!all!of!the!body’s!processes!may!be!disturbed.!If!this!disturbance!on!the!homeostasis!is!severe,!death,!disease!or!disorder!may!result.!''

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Lecture'2:'Organisation'of'matter'• Identify'the'main'chemical'elements'of'the'human'body'

'CHEMICAL'ELEMENT' %'OF'TOTAL'BODY'MASS' SIGNIFICANCE'MAJOR'ELEMENTS' ~'96' '

O! 65.0! Part!of!water!and!many!organic!(carbon%containing)!molecules;!used!to!generate!ATP,!a!molecule!used!by!

cells!to!temporarily!store!chemical!energy.!C! 18.5! Forms!backbone!chains!and!rings!of!all!organic!

molecules:!carbohydrates,!lipids!(fats),!proteins,!and!nucleic!acids!(DNA!and!RNA).!

H! 9.5! Constituent!of!water!and!most!organic!molecules;!ionized!form!(H+)!makes!body!fluids!more!acidic.!

N! 3.2! Component!of!all!proteins!and!nucleic!acids.!LESSER'ELEMENTS' ~'3.6' !

Ca! 1.5! Contributes!to!hardness!of!bones!and!teeth;!ionized!form!(Ca2+)!needed!for!blood!clotting,!release!of!some!hormones,!contraction!of!muscle,!and!many!other!

processes.!P! 1.0! Component!of!nucleic!acids!and!ATP;!required!for!

normal!bone!and!tooth!structure.!K! 0.35! Ionized!form!(K+)!is!the!most!plentiful!cation!(positively!

charged!particle)!in!intracellular!fluid;!needed!to!generate!action!potentials.!

S! 0.25! Component!of!some!vitamins!and!many!proteins.!Na! 0.2! Ionized!form!(Na+)!is!the!most!plentiful!cation!in!

extracellular!fluid;!essential!for!maintaining!water!balance;!needed!to!generate!action!potentials.!

Cl! 0.2! Ionized!form!(Cl−)!is!the!most!plentiful!anion!(negatively!charged!particle)!in!extracellular!fluid;!essential!for!

maintaining!water!balance.!Mg! 0.1! Ionized!form!(Mg2+)!needed!for!action!of!many!enzymes!

(molecules!that!increase!the!rate!of!chemical!reactions!in!organisms).!

Fe! 0.005! Ionized!forms!(Fe2+!and!Fe3+)!are!part!of!hemoglobin!(oxygen%carrying!protein!in!red!blood!cells)!and!some!

enzymes.!'

• Distinguish'between'inorganic'and'organic'compounds.'Organic'compounds:!always!contain!carbon!and!always!have!covalent!bonds%!!Inorganic'compound:'usually!lack!carbon!and!are!structurally!simple.!May!have!ionic!or!covalent!bonds!e.g.!acid,!bases,!many!salts!and!water!(most!abundant!and!important!inorganic!compound).!When!inorganic'compounds!dissolve!in!water,!they!dissociate.!An!acid!is!a!proton!donor!(H+!is!given)!and!a!base!is!a!proton!acceptor!(H+!is!removed!from!solution).!!

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- Low`density'lipoproteins'(LDL)!'! Steroids:'are'large'lipid'molecules'with'complex'4`ring'structure'e.g.'cholesterol,'

estradiol,'testosterone,'cortisol.'!• Cholesterol!synthesises!to!make!estradiol!(female!sex!hormone).!There!is!no!

hydrocarbon!tail!for!estradiol.!• Cholesterol!also!makes!testosterone!(male!sex!hormone).!There!is!no!

hydrocarbon!tail!for!testosterone.!!• The!steroid!cholesterol,!plays!an!important!role!in!cell!membrane!structure.!• Steroids!regulate!sexual!function!(estradio!and!testosterone),!metabolism!and!

mineral!balance!(calcitrol),!and!bile!salts!needed!for!normal!processing!of!dietary!fats.!!

!! Eicosanoids:'

• Have!diverse!effects!on!modifying!responses!to!hormones,!blood!clotting,!inflammation,!immunity!and!smooth!muscle!contraction.!!

• Derived!from!arachidonic!acid.!Fatty!acid!must!be!absorbed!in!the!diet.!!• Two!major!classes:!- Leukotrienes=!produced!by!cells!coordinating!responses!to!injury!or!disease!- Prostaglandins=!direct!local!cellular!activities!i.e.!a!local!hormone.!!

!Lecture'5'–'Introduction'to'Nucleic'Acids'and'Proteins'• Describe'the'building'blocks'and'functions'of'proteins'

• Most!abundant!organic!components!of!the!human!body!and!account'for'20%'of'body'weight.!

• Proteins!are!large!molecules!that!contain:!C,'H,'O,'and'N'(C:2H:O).!Some!may'also'contain'S.'!!

Functions!of!Proteins:!• Mainly!responsible'for'the'structure'and'support'of'body'tissues'(e.g.'collagen).!!• Some'responsible'for'driving'muscle'contraction'(actin,'myosin)!and!movement!of!

individual'cells'(sperm'cells).'!• Also'responsible'for'transport'for!insoluble!lipids!(protein!carrier!molecule!transport!

insoluble!lipids),!respiratory!gases,!minerals!and!hormones.!!• Also'acts'as'a'buffering'system%!minimises'changes'in'pH!of!cells!and!tissues.!!• Enzymes'are'proteins'that'act'as'catalysts'to'speed'up'biochemical'reactions.'!• Coordination'and'control:!protein!hormones!(e.g.!growth!hormones).!!• Defence:'waterproofing!effect!in!skin!by!keratin,!antibodies!and!blood!clotting.!!

!Protein!structure:!

• Amino'acids'are!the!building!blocks!for!proteins!(protein!monomers)!• Typical'protein'contains'1000'amino'acids!and!a!large'protein'molecule'would'contain'

100,000'amino'acids.!The!length!depends!on!the!function'of'the'protein.!• 20!different!amino!acids!exist.!12!non%essential!amino!acids!synthesised!by!the!body!and!

8!essential!amino!acids!from!food.!!

another!way!to!close!it.!Channels!may!randomly!alternate!between!open!and!closed!positions!and!others!may!be!regulated!by!chemical!or!electrical!changes!inside!or!out!of!the!cell.!!!

Carrier'mediated:!- Moves!a!solute!down'its'concentration'gradient!across!the!plasma!membrane.!!- Solute'binds'to'a'specific'carrier!on!one!side!of!the!membrane!and!is!released'on'

the'other'side!after!the!carrier!undergoes!a!change!in!shape.!Binding'occurs'on'the'side'of'the'membrane'with'a'higher'concentration.!!

- Once!concentration!is!equal!on!both!sides!of!membrane,!solute!molecules!bind!to!the!carrier!on!the!cytosolic!side!and!move!out!to!the!extracellular!fluid.!

- Saturation'is'exhibited'when!all!the!carriers!are!occupied!and!transport!maximum!is!reached.!The!concentration'gradient'at'this'stage'does'not'increase.!!

- Glucose'(body’s!preferred!energy!source!for!making!ATP)'enters'many'body'cells'by'carrierXmediated'diffusion.'!!

Osmosis:'- Describes!water'movement!across!cell!membranes!by'diffusion.!- Occurs!across!a!selectively'permeable'membrane.!!- Osmosis!only'occurs'when'a'membrane'is'permeable'to'water!but!is!impermeable!

to!certain!solutes.!!- Water!moves!through!a!selectively!permeable!membrane!from'an'area'of'lower'

solute'concentration'to'an'area'of'higher'solute'concentration.!This!means!that!water'flows'across'a'membrane'toward'the'solution'with'a'higher'concentration'of'solutes.!Since!this!is!where!the!concentration!of!water!is!lowest.!WATER!MOVE!DOWN!ITS!CONCENTRATION!GRADIENT.!!

!- Water!molecules!pass!through!a!plasma'membrane'in'two'ways:!

i) Moving'between'phospholipid!molecules!in!lipid!bilayer!via!simple!diffusion!and!by!

ii) Moving'through!aquaporins=!integral!membrane!proteins!that!function!as!water!channels.!!

- Pressure!exerted!by!a!liquid!forces!water!molecules!to!move!back!to!a!lower!concentration!to!achieve!equilibrium.!This!is!known!as!hydrostatic'pressure.!!

Lecture'8:'Intracellular'Compartments'!

• Describe'the'structure'and'function'of'cytoplasm,'cytosol'and'organelles'(including'cytoskeleton,'centrosome,'cilia'and'flagella,'ribosomes,'endoplasmic'reticulum,'Golgi'complex,'lysosomes,'peroxisomes,'proteasomes,'mitochondria)'

!" Cytoplasm:!consists!of!all!the!cellular!contents!between!the!plasma!membrane!and!

the!nucleus.!It!has!two!components:!cytosol!and!organelles!(tiny!structures!that!perform!different!functions!in!the!cell.!!

" Cytosol'(intracellular'fluid):!fluid!portion!of!the!cytoplasm!that!surrounds!the!organelles!and!makes!up!55%!of!the!total!cell!volume.!It!is!the!site!of!many!chemical!reactions!required!for!the!cell’s!existence.!!

" Cytoskeleton:!network!of!protein!filaments!that!extends!throughout!the!cytosol.!It'is'an'internal'protein'network'that'provides'strength'and'stability.!There!are!3'types'of'filaments!that!contribute!to!the!cytoskeleton!structure:!microfilaments,!intermediate!filaments!and!microtubules.!!Microfilaments:!" Thinnest!elements!of!the!cytoskeleton!composed!of!the!proteins!actin'and'

myosin.!!" Help!generate!movement'and'provide'mechanical'support.!!" Involved!in!muscle'contraction,'cell'division,'and'cell'locomotion!(migration!of!

embryonic!cells!during!development,!white!blood!cells!to!fight!infection,!skin!cells!during!wound!healing).!!

" Anchor'the'cytoskeleton'to'integral'proteins!in!plasma!membrane.!They!also!provide!mechanical!support!for!cell!extensions!(microvilli).!Microvillis'are'finger'like'projections!of!the!plasma!membrane!and!greatly!increase!the!surface!area!of!the!cell.!!

!Intermediate'filaments:'" Strengthen!and!maintain!cell!shape!" Stabilise!position!of!organelles!within!cells!to!the!nucleus!" Help!attach!cells!to!one!another!

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Peroxisomes:'" Contain!enzymes!produced!by!free!ribosomes.!" Are!able!to!self"replicate.!!" Absorb!and!break!down!fatty!acids,!amino!acids!as!part!of!normal!

metabolism.!Also!oxidise!toxic!substances!such!as!alcohol"!thus!peroxisomes!are!abundant!in!liver.!

" Hydrogen!peroxide!is!produces!as!a!by!product!of!oxidation.!This!toxic!free!radical!is!decomposed!by!the!enzyme!catalase!(in!peroxisomes).!!

" Without!peroxisomes,!by!products!or!metabolism!could!accumulate!inside!a!cell!and!result!in!cellular!death.!!

!Proteasomes:!

" Contain!proteases!to!remove!and!recycle!damaged!or!denatured!proteins,!and!abnormal!proteins.!

" Caps!of!proteasomes!binds!proteins!that!have!been!‘tagged’!for!destruction.!!!Mitochondria:!

" An!aerobic'process,!thus!named!aerobic'metabolism'or'cellular'respiration.!!" Generate!the!most!of!the!ATP'through'aerobic'respiration,!mitochondria!are!

the!powerhouses!of!the!cell.!Aerobic'metabolism'produces'95%'of'the'ATP'needed'to'keep'a'cell'alive.!

" Active'cells!that!use!ATP!at!a!high!rate!(muscles,!kidney,!liver)!have!a!large!amount!of!mitochondria"!regular!exercise=!increase!mitochondria!in!muscle!cells!for!more!efficient!functioning.!!

" Consists!of!an'outer'mitochondrial'membrane'and'inner'mitochondrial'membrane.'!

" Inner'membrane!consists!of!a!series!of!folds=!mitochondrial'cristae.!!

" Central!fluid"filled!cavity!in!the!inner!membrane=!mitochondrial'matrix.!!

" The!number!of!folds!increases'the'surface'area'for'chemical'reactions!that!are!part!of!the!aerobic'phase'of'cellular'respiration"!reactions'involved'in'producing'ATP.!!

" Also!plays!an!important!role!in!apoptosis'(genetic'death'of'cell).!

" Have!their!own'DNA.!The!genes!can!code!2!rRNAs,!22!tRNAs,!13!mitochondrial!proteins.!

" DNA!is!inherited!maternally.!