40
Chapter 5c Membrane Dynamics

Chapter 5c

  • Upload
    carter

  • View
    44

  • Download
    0

Embed Size (px)

DESCRIPTION

Chapter 5c. Membrane Dynamics. The Body Is Mostly Water. Distribution of water volume in the three body fluid compartments 1 liter water weighs 1 kg or 2.2 lbs 70 kg X 60% = 42 liters for avg 154 lb male. Figure 5-25. Aquaporin. - PowerPoint PPT Presentation

Citation preview

Page 1: Chapter 5c

Chapter 5c

Membrane Dynamics

Page 2: Chapter 5c

Figure 5-25

The Body Is Mostly Water

• Distribution of water volume in the three body fluid compartments

• 1 liter water weighs 1 kg or 2.2 lbs

• 70 kg X 60% = 42 liters for avg 154 lb male

Page 3: Chapter 5c

AquaporinMoves freely through cells by special channels of aquaporin

Page 4: Chapter 5c

Figure 5-26

Osmosis and Osmotic Pressure

• Osmolarity describes the number of particles in solution

Volumesequal

Osmotic pressure isthe pressure that must beapplied to B to oppose osmosis.

Volumeincreased

Volumedecreased

Two compartments areseparated by a membrane that is permeable to water but not glucose.

Water moves byosmosis into the moreconcentrated solution.

Glucosemolecules

Selectivelypermeablemembrane

A B

1

3

2

Page 5: Chapter 5c

Table 5-5

Osmolarity: Comparing SolutionsHyper / Hypo / Iso are relative terms

Osmolarity is total particles in solutionNormal Human body around 280 – 300 mOsM

Page 6: Chapter 5c

Table 5-6

Tonicity

• Solute concentration = tonicity• Tonicity describes the volume change of a

cell placed in a solution

Page 7: Chapter 5c

Figure 5-27a

Tonicity

• Tonicity depends on the relative concentrations of nonpenetrating solutes

Page 8: Chapter 5c

Figure 5-27b

Tonicity

• Tonicity depends on nonpenetrating solutes only

Page 9: Chapter 5c

Figure 5-28

Tonicity

• Tonicity depends on nonpenetrating solutes only

(a)

(b)

(c)

(d)

Cell

Solution

H2O

Page 10: Chapter 5c

Plasmolysis and Crenation

• RBC’s

Page 11: Chapter 5c

Table 5-7

Osmolarity and Tonicity

Page 12: Chapter 5c

Table 5-8

Intravenous Solutions

Page 13: Chapter 5c

Electricity Review

1. Law of conservation of electrical charges2. Opposite charges attract; like charges repel

each other3. Separating positive charges from negative

charges requires energy4. Conductor versus insulator

Page 14: Chapter 5c

Figure 5-29b

Separation of Electrical Charges

• Resting membrane potential is the electrical gradient between ECF and ICF

(b) Cell and solution in chemical and electrical disequilbrium.

Intracellular fluid Extracellular fluid

Page 15: Chapter 5c

Figure 5-29c

Separation of Electrical Charges

• Resting membrane potential is the electrical gradient between ECF and ICF

Page 16: Chapter 5c

Figure 5-30

Measuring Membrane Potential Difference

The voltmeter

Cell

The chart recorder

Saline bath

A recording electrode

Input

The ground ( ) or referenceelectrode

Output

Page 17: Chapter 5c

Figure 5-31a

Potassium Equilibrium PotentialArtificial cell

(a)

Page 18: Chapter 5c

Figure 5-31b

Potassium Equilibrium Potential

(b)

K+ leak channel

Page 19: Chapter 5c

Figure 5-31c

Potassium Equilibrium Potential• Resting membrane potential is due mostly

to potassium• K+ can exit due to [ ] gradient, but electrical gradient will

pull back; when equal resting membrane potential

Concentrationgradient

Electricalgradient

(c)

Page 20: Chapter 5c

Figure 5-32

Sodium Equilibrium Potential• Single ion can be calculated using the Nernst Equation

• Eion = 61/z log ([ion] out / [ion] in)

150 mM0 mV

15 mM+60 mV

Page 21: Chapter 5c

Figure 5-33

Resting Membrane Potential

Extracellular fluid0 mV

Intracellular fluid-70 mV

Page 22: Chapter 5c

Figure 5-34

Changes in Membrane Potential

• Terminology associated with changes in membrane potential

PLAY Interactive Physiology® Animation: Nervous I: The Membrane Potential

Page 23: Chapter 5c

1Low glucose levels in blood.

No insulinsecretion

Metabolismslows.

ATPdecreases.

ATPMetabolismGlucose

Cell at restingmembrane potential.No insulin is released.

KATP

channels open.

Insulin in secretory vesicles

K+ leaks out

of cellVoltage-gated Ca2+ channel closed

GLUT transporter

(a) Beta cell at rest

2 3 4 5

Figure 5-35a

Insulin Secretion and Membrane Transport Processes

Page 24: Chapter 5c

1Low glucose levels in blood.

Glucose

(a) Beta cell at restFigure 5-35a, step 1

Insulin Secretion and Membrane Transport Processes

Page 25: Chapter 5c

1Low glucose levels in blood.

Metabolismslows.

MetabolismGlucose

GLUT transporter

(a) Beta cell at rest

2

Figure 5-35a, steps 1–2

Insulin Secretion and Membrane Transport Processes

Page 26: Chapter 5c

1Low glucose levels in blood.

Metabolismslows.

ATPdecreases.

ATPMetabolismGlucose

GLUT transporter

(a) Beta cell at rest

2 3

Figure 5-35a, steps 1–3

Insulin Secretion and Membrane Transport Processes

Page 27: Chapter 5c

1Low glucose levels in blood.

Metabolismslows.

ATPdecreases.

ATPMetabolismGlucose

KATP

channels open.

K+ leaks out

of cell

GLUT transporter

(a) Beta cell at rest

2 3 4

Figure 5-35a, steps 1–4

Insulin Secretion and Membrane Transport Processes

Page 28: Chapter 5c

1Low glucose levels in blood.

No insulinsecretion

Metabolismslows.

ATPdecreases.

ATPMetabolismGlucose

Cell at restingmembrane potential.No insulin is released.

KATP

channels open.

Insulin in secretory vesicles

K+ leaks out

of cellVoltage-gated Ca2+ channel closed

GLUT transporter

(a) Beta cell at rest

2 3 4 5

Figure 5-35a, steps 1–5

Insulin Secretion and Membrane Transport Processes

Page 29: Chapter 5c

1

Glycolysisand citric acid cycle

ATP

Ca2+ signal triggersexocytosis and insulin is secreted.

Ca2+

Ca2+

High glucose levels in blood.

Metabolismincreases.

ATPincreases.

Glucose

Cell depolarizes andcalcium channelsopen.

KATP channels close.

Ca2+ entry acts as anintracellularsignal.

GLUT transporter

(b) Beta cell secretes insulin

2 3 4 5

6

7

Figure 5-35b

Insulin Secretion and Membrane Transport Processes

Page 30: Chapter 5c

1High glucose levels in blood.

(b) Beta cell secretes insulinFigure 5-35b, step 1

Insulin Secretion and Membrane Transport Processes

Glucose

Page 31: Chapter 5c

1

Glycolysisand citric acid cycle

High glucose levels in blood.

GLUT transporter

(b) Beta cell secretes insulin

2

Figure 5-35b, steps 1–2

Insulin Secretion and Membrane Transport Processes

Glucose

Metabolismincreases.

Page 32: Chapter 5c

1

Glycolysisand citric acid cycle

ATP

High glucose levels in blood.

GLUT transporter

(b) Beta cell secretes insulin

2 3

Figure 5-35b, steps 1–3

Insulin Secretion and Membrane Transport Processes

Glucose

Metabolismincreases.

ATPincreases.

Page 33: Chapter 5c

1

Glycolysisand citric acid cycle

ATP

High glucose levels in blood.

KATP channels close.

GLUT transporter

(b) Beta cell secretes insulin

2 3 4

Figure 5-35b, steps 1–4

Insulin Secretion and Membrane Transport Processes

Glucose

Metabolismincreases.

ATPincreases.

Page 34: Chapter 5c

1

Glycolysisand citric acid cycle

ATP

Ca2+

High glucose levels in blood.

Cell depolarizes andcalcium channelsopen.

KATP channels close.

GLUT transporter

(b) Beta cell secretes insulin

2 3 4 5

Figure 5-35b, steps 1–5

Insulin Secretion and Membrane Transport Processes

Glucose

Metabolismincreases.

ATPincreases.

Page 35: Chapter 5c

1

Glycolysisand citric acid cycle

ATP

Ca2+

Ca2+

High glucose levels in blood.

Cell depolarizes andcalcium channelsopen.

KATP channels close.

Ca2+ entry acts as anintracellularsignal.

GLUT transporter

(b) Beta cell secretes insulin

2 3 4 5

6

Figure 5-35b, steps 1–6

Insulin Secretion and Membrane Transport Processes

Glucose

Metabolismincreases.

ATPincreases.

Page 36: Chapter 5c

1

Glycolysisand citric acid cycle

ATP

Ca2+ signal triggersexocytosis and insulin is secreted.

Ca2+

Ca2+

High glucose levels in blood.

Cell depolarizes andcalcium channelsopen.

KATP channels close.

Ca2+ entry acts as anintracellularsignal.

GLUT transporter

(b) Beta cell secretes insulin

2 3 4 5

6

7

Figure 5-35b, steps 1–7

Insulin Secretion and Membrane Transport Processes

Glucose

Metabolismincreases.

ATPincreases.

Page 37: Chapter 5c

Summary

• Mass balance and homeostasis• Law of mass balance• Excretion• Metabolism• Clearance• Chemical disequilibrium• Electrical disequilibrium• Osmotic equilibrium

Page 38: Chapter 5c

Summary

• Diffusion• Protein-mediated transport• Roles of membrane proteins• Channel proteins• Carrier proteins• Active transport

Page 39: Chapter 5c

Summary

• Vesicular transport• Phagocytosis• Endocytosis• Exocytosis

• Transepithelial transport

Page 40: Chapter 5c

Summary

• Osmosis and tonicity• Osmolarity• Nonpenetrating solutes • Tonicity

• The resting membrane potential• Insulin secretion