pengantar intercellular communication.ppt

7/21/2019 PENGANTAR INTERCELLULAR COMMUNICATION.ppt

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IntercellularIntercellularCommunicationCommunication

M. Djauhari WidjajakusumahM. Djauhari Widjajakusumah

Departemen FisiologiDepartemen Fisiologi

Fakultas Kedokteran UniversitasFakultas Kedokteran Universitas

IndonesiaIndonesia


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Intercellular CommunicationIntercellular Communication

Intercellular CommunicationIntercellular Communication

Cells communicate with each otherCells communicate with each other via chemical messengervia chemical messenger

Gap junctionGap junction

Chemical messenger move from cell to cell without enteringChemical messenger move from cell to cell without entering

ECFECF

Neural communicationNeural communication

Neurotransmitter released from nerve cells at synaptic junction,Neurotransmitter released from nerve cells at synaptic junction,

act across synaptic cleft on postsynaptic cellact across synaptic cleft on postsynaptic cell

Endocrine communicationEndocrine communication

Hormones reach and bind to receptors of the target cells via theHormones reach and bind to receptors of the target cells via the

circulating bloodcirculating blood

Paracrine communicationParacrine communication

roducts of cells di!use in the ECF to a!ect neighboring cellsroducts of cells di!use in the ECF to a!ect neighboring cells

Autocrine communicationAutocrine communication

Chemical messenger secreted by cell, bind to receptors on theChemical messenger secreted by cell, bind to receptors on thesame cell, i"e" the cell that secreted the messengersame cell, i"e" the cell that secreted the messenger

Cells communicate with each otherCells communicate with each other via chemical messengervia chemical messenger

Gap junctionGap junction

Chemical messenger move from cell to cell without enteringChemical messenger move from cell to cell without entering

ECFECF


Neurotransmitter released from nerve cells at synaptic junction,Neurotransmitter released from nerve cells at synaptic junction,

act across synaptic cleft on postsynaptic cellact across synaptic cleft on postsynaptic cell

Endocrine communicationEndocrine communication

Hormones reach and bind to receptors of the target cells via theHormones reach and bind to receptors of the target cells via the

circulating bloodcirculating blood

Paracrine communicationParacrine communication

roducts of cells di!use in the ECF to a!ect neighboring cellsroducts of cells di!use in the ECF to a!ect neighboring cells

Autocrine communicationAutocrine communication

Chemical messenger secreted by cell, bind to receptors on theChemical messenger secreted by cell, bind to receptors on the

same cell, i"e" the cell that secreted the messengersame cell, i"e" the cell that secreted the messenger


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Intercellular communication by chemicalIntercellular communication by chemical

mediatorsmediators


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#peciali$ed types of junctions#peciali$ed types of junctions

%any cells are physically joined at discrete%any cells are physically joined at discrete

locations along their membranes by speciali$edlocations along their membranes by speciali$ed

types of junctions &nown astypes of junctions &nown as

desmosomesdesmosomes tight junctionstight junctions

gap junctionsgap junctions


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Vander et al.: Human Physiology: The Mechanism ofVander et al.: Human Physiology: The Mechanism of

Body Function, Eighth Edition, 200Body Function, Eighth Edition, 200


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DesmosomesDesmosomes

Consist of a region between two adjacent cells where theConsist of a region between two adjacent cells where theapposed plasma membranes are separated by about '(apposed plasma membranes are separated by about '(nmnm

Have a dense accumulation of protein at the cytoplasmicHave a dense accumulation of protein at the cytoplasmic

surface of each membrane and in the space between thesurface of each membrane and in the space between thetwo membranestwo membranes

rotein )bers e*tend from the cytoplasmic surface ofrotein )bers e*tend from the cytoplasmic surface ofdesmosomes into the cell and are lin&ed to otherdesmosomes into the cell and are lin&ed to otherdesmosomes on the opposite side of the cell"desmosomes on the opposite side of the cell"

+esmosomes function to hold adjacent cells )rmly+esmosomes function to hold adjacent cells )rmlytogether in areas that are subject to considerabletogether in areas that are subject to considerablestretching, such as in the s&in"stretching, such as in the s&in"

he speciali$ed area of the membrane in the region of ahe speciali$ed area of the membrane in the region of adesmosome is usually dis&-shaped, and these membranedesmosome is usually dis&-shaped, and these membrane

junctions could be li&ened to rivets or spot-welds"junctions could be li&ened to rivets or spot-welds"


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Vander et al.: Human Physiology: TheVander et al.: Human Physiology: The

Mechanism of Body Function, EighthMechanism of Body Function, Eighth

Edition, 200Edition, 200


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Tight junction

he e*tracellular surfaces of two adjacent plasma membranes arejoined together, no e*tracellular space between them

.ccurs in a band around the entire circumference of the cell"

%ost epithelial cells are joined by tight junctions

Epithelial cells cover the inner surface of the intestinal tract, come

in contact with the digestion products in the cavity of the tract

+uring absorption, the products of digestion move across theepithelium and enter the blood

For many substances movement through the e*tracellular space isbloc&ed by the tight junctions, and organic nutrients are re/uired

to pass through the cells, rather than between them he selective barrier properties of the plasma membrane can

control the types and amounts of absorbed substances

he ability of tight junctions to impede molecular movementbetween cells is not absolute" Ions and water can move throughthese junctions with varying degrees of ease in di!erent

epithelium"



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0ap 1unction0ap 1unction0ap 1unction0ap 1unction #tructure in plasma membranes of cells that are in direct physical contact#tructure in plasma membranes of cells that are in direct physical contact

with one anotherwith one another

he two opposing plasma membranes come within ' to 2 nm of each other,he two opposing plasma membranes come within ' to 2 nm of each other,which allows speci)c proteins from the two membranes to join, forming small,which allows speci)c proteins from the two membranes to join, forming small,protein-lined channels lin&ing the two cells, lin&ing the cytosols of adjacentprotein-lined channels lin&ing the two cells, lin&ing the cytosols of adjacentcellscells

3llows cells to have direct communication by3llows cells to have direct communication by allowing small molecules to passallowing small molecules to pass

directly from the cytosol of one cell to the cytosol of an adjacent celldirectly from the cytosol of one cell to the cytosol of an adjacent cell 0ap junctions0ap junctions coordinate the activities of adjacent cellscoordinate the activities of adjacent cellsby allowing chemicalby allowing chemical

messengers to move from one cell to anothermessengers to move from one cell to another

he small diameter of the channels 4about 5"6 nm7 lhe small diameter of the channels 4about 5"6 nm7 l imits what can passimits what can passbetween the cytosols of the connected cells to small molecules and ions,between the cytosols of the connected cells to small molecules and ions, suchsuchas sodium and potassium, and e*cludes the e*change of large proteinsas sodium and potassium, and e*cludes the e*change of large proteins

Heart muscle cells and smooth-muscle cellsHeart muscle cells and smooth-muscle cellspossess gap junctions, play apossess gap junctions, play averyvery important role in the transmission of electrical activity between the cells"important role in the transmission of electrical activity between the cells"

#tructure in plasma membranes of cells that are in direct physical contact#tructure in plasma membranes of cells that are in direct physical contactwith one anotherwith one another

he two opposing plasma membranes come within ' to 2 nm of each other,he two opposing plasma membranes come within ' to 2 nm of each other,which allows speci)c proteins from the two membranes to join, forming small,which allows speci)c proteins from the two membranes to join, forming small,protein-lined channels lin&ing the two cells, lin&ing the cytosols of adjacentprotein-lined channels lin&ing the two cells, lin&ing the cytosols of adjacentcellscells

3llows cells to have direct communication by3llows cells to have direct communication by allowing small molecules to passallowing small molecules to pass

directly from the cytosol of one cell to the cytosol of an adjacent celldirectly from the cytosol of one cell to the cytosol of an adjacent cell 0ap junctions0ap junctions coordinate the activities of adjacent cellscoordinate the activities of adjacent cellsby allowing chemicalby allowing chemical

messengers to move from one cell to anothermessengers to move from one cell to another

he small diameter of the channels 4about 5"6 nm7 lhe small diameter of the channels 4about 5"6 nm7 l imits what can passimits what can passbetween the cytosols of the connected cells to small molecules and ions,between the cytosols of the connected cells to small molecules and ions, suchsuchas sodium and potassium, and e*cludes the e*change of large proteinsas sodium and potassium, and e*cludes the e*change of large proteins

Heart muscle cells and smooth-muscle cellsHeart muscle cells and smooth-muscle cellspossess gap junctions, play apossess gap junctions, play averyvery important role in the transmission of electrical activity between the cells"important role in the transmission of electrical activity between the cells"


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!es"o"oulos, #olor $tlas of Physiology %!es"o"oulos, #olor $tlas of Physiology %THTHed & 200' Thiemeed & 200' Thieme


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aracrine Communicationaracrine Communicationaracrine Communicationaracrine Communication

roducts of cells 4paracrines, local chemicalroducts of cells 4paracrines, local chemicalmessengers7 di!use in the ECF to a!ect neighboringmessengers7 di!use in the ECF to a!ect neighboring

cells, in the immediate environment of their site ofcells, in the immediate environment of their site of

secretionsecretion

+istributed by simple di!usion, do not enter the+istributed by simple di!usion, do not enter the

blood in any signi)cant /uantity because they areblood in any signi)cant /uantity because they are

rapidly inactivated by locally e*isting en$ymesrapidly inactivated by locally e*isting en$ymes

he action is restricted to short distances"he action is restricted to short distances"

roducts of cells 4paracrines, local chemicalroducts of cells 4paracrines, local chemicalmessengers7 di!use in the ECF to a!ect neighboringmessengers7 di!use in the ECF to a!ect neighboring

cells, in the immediate environment of their site ofcells, in the immediate environment of their site of

secretionsecretion

+istributed by simple di!usion, do not enter the+istributed by simple di!usion, do not enter the

blood in any signi)cant /uantity because they areblood in any signi)cant /uantity because they are

rapidly inactivated by locally e*isting en$ymesrapidly inactivated by locally e*isting en$ymes

he action is restricted to short distances"he action is restricted to short distances"


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Motor neuron with a myelinated axon.$ motor neuron is com"rised of a cell (ody

)soma* +ith a nucleus, seeral "rocesses called dendrites, and a long fi(rous a-on that

originates from the a-on hilloc. The first "ortion of the a-on is called the initial

segment. $ myelin sheath forms from /ch+ann cells and surrounds the a-on e-ce"t at

its ending and at the nodes of anier. Terminal (uttons )(outons* are located at the

terminal endings.



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SnapticSnaptic

TransmissionTransmission


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The neuromuscular junction. (a)/canning electronmicrogra"h sho+ing (ranching of

motor a-ons +ith terminals em(edded in grooes in the muscle fi(er1s surface.

(b)/tructure of a neuromuscular unction.

)From 3idmaier EP, aff H, /trang 4T: Vanders Human Physiology.Mc5ra+6Hill, 2007.*


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Intercellular communication ! chemical mediatorIntercellular communication ! chemical mediator


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FI"U#$ %&'(FI"U#$ %&'(

Mechanism o) action o) lipid*Mechanism o) action o) lipid*

solu!le messengers. Thissolu!le messengers. This

+gure sho,s the receptor )or+gure sho,s the receptor )or

these messengers as !eing inthese messengers as !eing in

the nucleus. In some cases- thethe nucleus. In some cases- the

un!ound receptor is in theun!ound receptor is in thectosol rather than thectosol rather than the

nucleus- in ,hich case thenucleus- in ,hich case the

!inding!inding

occurs there- and theoccurs there- and the

messenger*receptor complemessenger*receptor comple

moves into the nucleus.moves into the nucleus.

8ander et al"9 Human hysiology9 he8ander et al"9 Human hysiology9 he

%echanism of :ody Function, ;th Ed '((5%echanism of :ody Function, ;th Ed '((5


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/ander 0uman/ander 0uman

1hsiol-1hsiol-

TheThe

Mechanism o)Mechanism o)

2od Function2od Function33ththeded


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than& youthan& you


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pengantar intercellular communication.ppt

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