Taking care of business

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Online quiz this weekend: Released Thursday night or early Friday morning and will be due Monday morning at 9am.

Lab next week: We will meet in the first floor lobby of the Tech building (right next to Science Complex) for lab next week. We’re going to try to apply some of the stuff we’ve learned so far in a simulated clinical environment. It’ll be cool.

Online discussions: Reminder-please post ANY questions you might have about anything related to the class to the weekly discussion. Happy to help!

Homeostasis Recap

MembraneDynamics

Chapter 5

Super duperhyper osmotic

Super duperhyper osmotic

What will happen to cell?A. Swell upB. Shrivel

C. Stay the sameD. I don’t know

Our patient for the day

https://www.youtube.com/watch?v=w3uWg4KjX4Y

Name: MatildaAge: 78

In hospital forsevere dehydration

Staff puts her onIV of pure water

Severe fatigue

Dizzy

Yellow eyes

Soon after IV:

Iced tea analogy

On board

Describing how concentrated a solution is:

Molarity= moles solute / Liters solution

Osmolarity= osmoles solute / Liters solution

1 mole of NaCl = 2 osmoles of NaCl1) NaCl dissociates into Na+ and Cl-

2) Glucose does not dissociate in water

Diffusion, osmosis, concentration....

WHO CARES?!?!?

Hippotonic (hypotonic) solution makes cell swell like a hippo

Table 5.3 Tonicity of Solutions

Tonicity describes the volumechange of a cell

Differences between osmolarity and tonicity

Differences between osmolarity and tonicity

•Osmolarity = concentration of particles in a solution.

•Tonicity has no units. It just describes whether cell gained/lost water.

•Osmolarity is used to compare any two solutions, tonicity only can compare a solution to a cell

•Osmolarity alone does not tell you what happens to a cell placed in a solution (as we’ll see).

Table 5.2 Comparing Osmolarities

Osmolarity comparisons

hypo=loweriso=same

hyper=higher

Salt becomes two ions/particles in water. Glucose

doesn’t

Hippotonic (hypotonic) solution makes cell swell like a hippo

Tonicity comparisons

Name: MatildaAge: 78

In hospital forsevere dehydration

Staff puts her onIV of pure water

What do you thinkcaused this?

1.) Think for 1 minute

2.) Pair up

3.) Share your ideas

What do you thinkcaused this?

1.) Think for 1 minute

2.) Pair up

3.) Share your ideas

Hyptonic

Low Na+ osmolarity

Low osmolarity

Figure 5.1a ESSENTIALS – Body Fluid Compartments

KEY

Intracellular fluid

Interstitial fluid

Plasma

The body fluids are in two compartments: the extracellular fluid (ECF) and intracellular fluid (ICF). The ECF and ICF are in osmotic equilibrium but have very different chemical composition.

Intracellular fluid is 2/3 of the total body water volume. Material moving into and out of the ICF must cross the cell membrane.

Extracellular fluid includes all fluid outside the cells. The ECF is 1/3 of the body fluid volume. The ECF consists of:

• Interstitial fluid (IF), which lies between the circulatory system and the cells, is 75% of the ECF volume.

• Plasma, the liquid matrix of blood, is 25% of the ECF volume. Substances moving between the plasma and interstitial fluid must cross the leaky exchange epithelium of the capillary wall.

Sidenote: other cells in body need proper salt, water balance

Following slides have material that will be addressed with discussion topics questions in class worksheet.

Super duperhyper osmotic

Super duperhyper osmotic

What will happen to cell?A. Swell upB. Shrivel

C. Stay the sameD. I don’t know

Part 2: Tonicity depends on what KINDS of solutes are in solution, not just

osmolarity

Can solutes in the solution pass through membrane or not?

Super duperhyper osmotic

Super duperhyper osmotic

Will water flow into or out of the cell?Does the solute penetrate the cell membrane?

Figure 5.3 The relationship between osmolarity and tonicity

Hyperosmotic Hyposmotic Isosmotic

Hypertonic

Isotonic

Hypotonic

TONICITY

OSMOLARITY

If you’re given the osmolarity, what couldtonicity possibly be? *

*Assume all intracellular solutes can’t penetratecell membrane

Figure 5.3 The relationship between osmolarity and tonicity

Hyperosmotic Hyposmotic Isosmotic

Hypertonic

Isotonic

Hypotonic

TONICITY

OSMOLARITY

If you’re given the osmolarity, what couldtonicity possibly be?*

*Assume all intracellular solutes can’t penetratecell membrane

Figure 5.3 The relationship between osmolarity and tonicity

Hyperosmotic Hyposmotic Isosmotic

Hypertonic

Isotonic

Hypotonic

TONICITY

OSMOLARITY

If you’re given the osmolarity, what couldtonicity possibly be? *

*Assume all intracellular solutes can’t penetratecell membrane

Figure 5.3 The relationship between osmolarity and tonicity

Hyperosmotic Hyposmotic Isosmotic

Hypertonic

Isotonic

Hypotonic

TONICITY

OSMOLARITY

If you’re given the osmolarity, what couldtonicity possibly be? *

*Assume all intracellular solutes can’t penetratecell membrane

Steps to determine tonicity of a solution compared to a cell

1.) Assume all particles inside the cell cannot cross cell membrane. They’re stuck.

2.) Compare solute concentrations for each particle inside the cell vs. outside

3.) Allow any particles that are outside the cell to diffuse into the cell to equalize their own concentration inside vs. outside the cell.

4.) Compare solute concentrations again inside vs. outside the cell.

5.) Determine where water would go based on osmosis (it goes towards higher solute concentration)

Name: MatildaAge: 78

In hospital forsevere dehydration

Staff puts her onIV of water

Why might this IV solution cause Matilda serious

problems?

Severe fatigue

Dizzy

Yellow eyes

Rapidly increasingheartrate

Table 5.5 Intravenous Solutions

Common IV solution properties as comparedto a normal human cell

End material that was covered by discussion questions in class

Simple Diffusion is what we’ve been talking about so far.

Simple Diffusion is when particles, gases,whatever passes directly through the cell

membrane on its own, without any assistance

Figure 5.7 Fick’s law of diffusion

Fick’s Law of Diffusion Membrane Permeability

Factors affecting rate of diffusion through a cell membrane:

Changing the composition of the lipid layer can increase or decrease membrane permeability.

Membrane permeability lipid solubility

molecular size ∝ Rate of diffusion ∝ surface area × concentration gradient × membrane permeability

• Lipid solubility • Molecular size • Concentration gradient • Membrane surface area • Composition of lipid layer

Concentration inside cell

Concentration gradient

Concentration outside cell

Molecular size

Lipid solubility

Membrane surface area

Composition of lipid layer

Intracellular fluid

Extracellular fluid 12

3

4

5

5 factors affect the rate of diffusion

For next time:

Think about how YOU would have treated Matilda differently than the nurses did.

Name: MeganAge: 3

Chronic Resp.Infections

Severe difficultybreathing

Thick mucus in airways

Part II: Transport ProcessesAcross the Membrane via Proteins

The cell membrane is packed with proteinsthat serve many functions

Transport

The cell membrane is packed with proteinsthat serve many functions

SignalingTransport

The cell membrane is packed with proteinsthat serve many functions

SignalingTransport Catalysis

The cell membrane is packed with proteinsthat serve many functions

StructuralCatalysisSignalingTransport

The cell membrane is packed with proteinsthat serve many functions

Transport

Channel protein transporters are like doors

Channel ProteinsOpen

Free Passage

E.g. AquaporinTransports

Water

Channel protein transporters are like doors

Transport

Channel ProteinsOpen Closed

Free Passage

KeyNeeded

X

“Gated”Channels

Chemically Gated Channels Require Molecule Binding

Voltage-Gated Channels Respond to Change in Charge Across Cell Membrane

So, channel proteins, either the open or gated kind, are like doors

Carrier Proteins Change Confirmation to Pass Solute

Carrier Proteins Have a Variety of Unique Properties

•Used to carry large and/or ionic substances•Never make continuous passage to ECF

•Require conformational change

Intro to Physio

Motivation and Relevance

How I learn science

Some Course Deets

Real Intro to Physio: Homeostasis

Negative Feedback

Positive Feedback

Homeostasis v. Equilibrium

Figure 5.12 Facilitated diffusion by means of a carrier protein

Closed gate

Pacific Ocean

Pacific Ocean

Pacific Ocean

Atlantic Ocean

Atlantic Ocean

Atlantic Ocean

Passage open to one side

Transition state with both gates

closed

Passage open to

other side

Molecule to be transported

Gate closed

Gate closed

Carrier

Membrane

Extracellular fluid Intracellular fluid

Carrier Proteins Change Confirmation to Pass Solutes

Intro to Physio

Motivation and Relevance

How I learn science

Some Course Deets

Real Intro to Physio: Homeostasis

Negative Feedback

Positive Feedback

Homeostasis v. Equilibrium

Carrier Proteins Change Confirmation to Pass Solutes

Figure 5.13 Facilitated diffusion of glucose into cells

High glucose concentration

GLUT

Low glucose concentration

[Glucose]out =

[Glucose]in

high[Glucose]out

[Glucose]in stays low

Glycogen

Glycolysis

G-6-P

ATP

ADP

Facilitated diffusion brings glucose into the cell down its concentration gradient.

Diffusion reaches equilibrium when the glucose concentrations inside and outside the cell are equal.

Conversion of imported glucose into glucose 6-phosphate (G-6-P) keeps intracellular glucose concentrations low so that diffusion never reaches equilibrium.

Large and Polar Molecules Use CarriersTo Passively Diffuse Across Membrane

Passive, facilitated diffusion uses no energy

TRANSPORT AGAINST CONCENTRATION

GRADIENT REQUIRES ENERGY

“Active Transport” Uses Energy to Move Solutes Against Gradient

“Active Transport” Uses Energy to Move Solutes Against Gradient

“Active Transport” Uses Energy to Move Solutes Against Gradient

Fun Fact! ~30% of our energy goes to powering the Na+/K+ pump!

“Active Transport” Uses Energy to Move Solutes Against Gradient