chapter 6 a lecture pp

POWERPOINT® LECTURE SLIDE PRESENTATIONby LYNN CIALDELLA, MA, MBA, The University of Texas at Austin

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

HUMAN PHYSIOLOGYAN INTEGRATED APPROACH FOURTH EDITION

DEE UNGLAUB SILVERTHORN

UNIT 1UNIT 1

PART A

6 Communication, Integration,and Homeostasis


About this Chapter

Cell-to-cell communication

Signal pathways

Novel signal molecules

Modulation of signal pathways

Control pathways Response loops

Feedback loops


Cell-to-Cell Communication: Overview

Physiological signals Electrical signals

Changes in cell’s membrane potential

Chemical signals

Secreted by cells into ECF

Responsible for most communication within the body

Target cells, or targets, receive signals

Four basic methods of communication


Cell-to-Cell Communication: Methods

Direct contact and local cell-to-cell communication

Gap junctions transfer both chemical and electrical signals

Figure 6-1a

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-1b


Direct contact and local cell-to-cell communication

CAMs transfer signals in both directions

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-1c


Paracrine and autocrine are chemical signals

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-2a


Long distance cell-to-cell communication

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-2b


Neurotransmitters have a rapid effect

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-3

Signal Pathways: Overview

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-4 (1 of 2)

Signal Pathways: Receptor locations

Target cell receptors

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-4 (2 of 2)

Signal Pathways: Receptor locations


Signal Pathways: Membrane Receptors

Four categories of membrane receptors


Signal Pathways: Signal Amplification

Transducers convert extracellular signals into intracellular messages which create a response


Signal Pathway: Biological Signal Transduction


Signal Pathway: Signal Transduction

Steps of a cascade

Steps of signal transduction pathway form a cascade


Signal Pathway: Receptor Enzymes

Tyrosine kinase, an example of receptor-enzyme


Signal Pathway: GPCR

Membrane-spanning proteins

Cytoplasmic tail linked to G protein, a three-part transducer molecule

When G proteins are activated, they Open ion channels in the membrane

Alter enzyme activity on the cytoplasmic side of the membrane


GPCR: Adenylyl Cyclase-cAMP

The G protein-coupled adenylyl cyclase-cAMP system

One signalmolecule

Adenylylcyclase

ATP

cAMP

G protein

Proteinkinase A

Phosphorylatedprotein

Cellresponse

G protein-coupledreceptor

Signal molecule binds toG protein-linked receptor,which activates the G protein.

Protein kinase A phosphorylates other proteins, leading ultimatelyto a cellular response.

G protein turns on adenylylcyclase, an amplifier enzyme.

Adenylyl cyclase convertsATP to cyclic AMP.

cAMP activates proteinkinase A.

1

2

3

4

5

1

23

4

5

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-11, step 1


One signalmolecule

G protein



1

1

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 6-11, steps 1–2


One signalmolecule

Adenylylcyclase

G protein




1

2

1

2



One signalmolecule

Adenylylcyclase

ATP

cAMP

G protein





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2

3

1

23



One signalmolecule

Adenylylcyclase

ATP

cAMP

G protein

Proteinkinase A






1

2

3

4

1

23

4



One signalmolecule

Adenylylcyclase

ATP

cAMP

G protein

Proteinkinase A


Cellresponse



Protein kinase A phosphorylates other proteins, leading ultimatelyto a cellular response.




1

2

3

4

5

1

23

4

5


GPCR: The Phospholipase C System

Ca2+

Membrane phospholipid

PL-C

IP3

PK-C

Protein + Pi

Cellmembrane

Extracellularfluid

Intracellularfluid

DAG


KEYPL-C = phospholipase CDAG = diacylglycerolPK-C = protein kinase CIP3 = inositol

trisphosphateER = endoplasmic

reticulum

ER

Receptor G protein

Cellularresponse

Signal molecule

Signal moleculeactivates receptorand associatedG protein.

G protein activatesphospholipase C (PL-C), an amplifier enzyme.

PL-C converts membrane phospholipids intodiacylglycerol (DAG), whichremains in the membrane,and IP3, which diffusesinto the cytoplasm.

DAG activates proteinkinase C (PK-C), whichphosphorylates proteins.

IP3 causes releaseof Ca2+ fromorganelles, creating a Ca2+ signal.

Ca2+ stores

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2 34

5

1 2 3 4 5



Cellmembrane

Extracellularfluid

Intracellularfluid



reticulum

Receptor G protein

Signal molecule


1

1



PL-C

Cellmembrane

Extracellularfluid

Intracellularfluid



reticulum

Receptor G protein

Signal molecule



1

2

1 2




PL-C

IP3

Cellmembrane

Extracellularfluid

Intracellularfluid

DAG



reticulum

Receptor G protein

Signal molecule



PL-C converts membranephospholipids intodiacylglycerol (DAG), whichremains in the membrane,and IP3, which diffusesinto the cytoplasm.

1

2 3

1 2 3




PL-C

IP3

PK-C

Protein + Pi

Cellmembrane

Extracellularfluid

Intracellularfluid

DAG




reticulum

Receptor G protein

Cellularresponse

Signal molecule



PL-C converts membranephospholipids intodiacylglycerol (DAG), whichremains in the membrane,and IP3, which diffusesinto the cytoplasm.


1

2 34

1 2 3 4



Ca2+


PL-C

IP3

PK-C

Protein + Pi

Cellmembrane

Extracellularfluid

Intracellularfluid

DAG




reticulum

ER

Receptor G protein

Cellularresponse

Signal molecule



PL-C converts membrane phospholipids intodiacylglycerol (DAG), whichremains in the membrane,and IP3, which diffusesinto the cytoplasm.


IP3 causes releaseof Ca2+ fromorganelles, creating a Ca2+ signal.

Ca2+ stores

1

2 34

5

1 2 3 4 5


Signal Pathway: Receptor-Channel

How ions create electrical signals

Extracellularsignal

moleculesIons

Ionchannel

G protein

Change in membranepermeability to

Na+, K+, Cl–

Creates electricalsignal

Voltage-sensitiveprotein

Cellularresponse


Intracellularsignal molecules

Receptor-channels open orclose in response to signalmolecule binding.

Some channels are directlylinked to G proteins.

Other ligand-gated channelsrespond to intracellularsecond messenger.

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2

3

1

2

3



Extracellularsignal

moleculesIons

Ionchannel


11



Extracellularsignal

moleculesIons

Ionchannel

G protein




1

2

1

2



Extracellularsignal

moleculesIons

Ionchannel

G protein






1

2

3

1

2

3



Extracellularsignal

moleculesIons

Ionchannel

G protein

Change in membranepermeability to

Na+, K+, Cl–

Creates electricalsignal

Voltage-sensitiveprotein

Cellularresponse






1

2

3

1

2

3


Signal Pathway: Signal Transduction

Summary map of signal transduction systems

chapter 6 a lecture pp

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