Cell Boundaries and Human Health. Why is water balance so important in cells? Among the poor and especially in developing countries, diarrhea is a major.

Cell BoundariesCell Boundariesand Human and Human

HealthHealth

Why is water balance so Why is water balance so important in cells?important in cells?

Among the poor Among the poor and especially in and especially in developing developing countries, diarrhea countries, diarrhea is a major killer. is a major killer.

Why is water balance so Why is water balance so important in cells?important in cells?

4 billion cases of 4 billion cases of diarrhea yearly diarrhea yearly

2.2 million deaths -2.2 million deaths -many under the many under the age of 5age of 5

That’s 4 deaths That’s 4 deaths every minuteevery minute

How do diarrheal diseases How do diarrheal diseases spread?spread?

The Story of Cholera

http://picasaweb.google.com/dmeyer1usa/AfricaTrip2007/photo#5132143011588101730

http://abandoned-orphaned.typepad.com/photos/uncategorized/2007/08/01/matharesewagerut.jpg

Why is there an increase in Why is there an increase in diarrheal diseases after natural diarrheal diseases after natural

disasters?disasters?

Pakistan - FloodingPakistan - Flooding

Haiti - EarthquakeHaiti - Earthquake

Indonesia - TsunamiIndonesia - Tsunami

Philippines - TyphoonPhilippines - Typhoon

What happens next?What happens next?

What are the biggest concerns of the What are the biggest concerns of the medical community?medical community?

http://upload.wikimedia.org/wikipedia/commons/thumb/d/db/Vibrio_cholerae_01.jpg/800px-Vibrio_cholerae_01.jpg

http://microbewiki.kenyon.edu/images/a/a8/V_cholerae.jpg

http://www.msf.org/source/countries/africa/angola/2006/cholera_tent.jpg

To understand why diarrheal To understand why diarrheal disease can be so deadly – disease can be so deadly –

you have first have to you have first have to understand how healthy cells understand how healthy cells

manage water balance manage water balance

http://www.medicalook.com/systems_images/Digestive_System.jpg

Cell MembraneCell Membrane

Moving in & out of cells by Moving in & out of cells by OSMOSISOSMOSIS

WaterWater molecules move from an area of molecules move from an area of high concentration to an area of low high concentration to an area of low concentration through a concentration through a semipermeable* semipermeable* membranemembrane

Does not require extra energyDoes not require extra energy

* Also called “* Also called “selectively permeableselectively permeable””

Effects of Osmosis on Blood CellsEffects of Osmosis on Blood Cells

Water Balance in CellsWater Balance in CellsWater Water

Outside CellOutside CellWater Inside Water Inside

CellCellWhich Way Which Way Will Water Will Water

Move?Move?

SameSame SameSameWater flow is Water flow is equal in and equal in and

out of cellout of cell

Less WaterLess Water More WaterMore Water Net water flow Net water flow out of cellout of cell

More WaterMore Water Less WaterLess Water Net water flow Net water flow into cellinto cell

Effect of Osmosis on Blood CellsEffect of Osmosis on Blood Cells

Body

Intestinal Lumen

Intestinal Cells

Salt

Salt

Salt

Salt

Salt

Salt

Salt

Salt

Skin

The Body Our Model System

Conical Tube

Dialysis Tube

Intestine

One Dialysis Tube per Group

Conical Tube

= water

= salt

Control

One set-up/ClassExperimental

One set-up/Lab Group

Salt Solution Water

What happened to the What happened to the dialysis tube with Salt? dialysis tube with Salt?

Why?Why?

Salt Solutio

n

Water

Water

Water

Water

OsmosisOsmosis

How does your How does your experiment explain experiment explain cholera diarrhea?cholera diarrhea?

Salt

Salt

Salt

Salt

SaltNet Flow of Water Net Flow of Water

How would you treat the How would you treat the patient using osmosis?patient using osmosis?

SaltSugar

SaltSugar

SaltSugar

SaltSugar

SaltSugar

SaltSugar

SaltSugar

SaltSugar

SaltSugar

SaltSugar

SaltSugar

Net Flow of WaterNet Flow of Water

How do diarrheal diseases How do diarrheal diseases spread?spread?

The Story of CholeraThe Story of Cholera