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1 Taking care of business Go to this page and enter room SJ123: Take 2 minutes to complete this survey: 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!

2 Homeostasis Recap Membrane Dynamics Chapter 5

3 Super duper hyper osmotic Super duper hyper osmotic What will happen to cell? A. Swell up B. Shrivel C. Stay the same D. I don t know

4 Our patient for the day

5 Name: Matilda Age: 78 In hospital for severe dehydration Staff puts her on IV of pure water

6 Soon after IV: Severe fatigue Dizzy Yellow eyes

7 Iced tea analogy On board

8 Describing how concentrated a solution is: Molarity= moles solute / Liters solution Osmolarity= osmoles solute / Liters solution 1 mole of NaCl = 2 osmoles of NaCl

9 Diffusion, osmosis, concentration... WHO CARES?!?!?

10 Hippotonic (hypotonic) solution makes cell swell like a hippo

11 Table 5.3 Tonicity of Solutions Tonicity describes the volume change of a cell

12 Differences between osmolarity and tonicity

13 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).

14 Table 5.2 Comparing Osmolarities Osmolarity comparisons hypo=lower iso=same hyper=higher Salt becomes two ions/ particles in water. Glucose doesn t

15 Tonicity comparisons Hippotonic (hypotonic) solution makes cell swell like a hippo

16 Name: Matilda Age: 78 In hospital for severe dehydration Staff puts her on IV of pure water

17 What do you think caused this? 1.) Think for 1 minute 2.) Pair up 3.) Share your ideas

18 What do you think caused this? Hyptonic Low osmolarity 1.) Think for 1 minute 2.) Pair up Low 3.) Share Na+ osmolarity your ideas

19 Figure 5.1a ESSENTIALS Body Fluid Compartments Sidenote: other cells in body need proper salt, water balance 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. KEY Intracellular fluid Interstitial fluid 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 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.

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

21 Super duper hyper osmotic Super duper hyper osmotic What will happen to cell? A. Swell up B. Shrivel C. Stay the same D. I don t know

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

23 Can solutes in the solution pass through membrane or not?

24 Super duper hyper osmotic Does the solute penetrate thecell? cell Will water flow into or out of the membrane? Super duper hyper osmotic

25 Figure 5.3 The relationship between osmolarity and tonicity If you re given the osmolarity, what could tonicity possibly be? * OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can t penetrate cell membrane

26 Figure 5.3 The relationship between osmolarity and tonicity If you re given the osmolarity, what could tonicity possibly be?* OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can t penetrate cell membrane

27 Figure 5.3 The relationship between osmolarity and tonicity If you re given the osmolarity, what could tonicity possibly be? * OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can t penetrate cell membrane

28 Figure 5.3 The relationship between osmolarity and tonicity If you re given the osmolarity, what could tonicity possibly be? * OSMOLARITY TONICITY Hyposmotic Isosmotic Hyperosmotic Hypotonic Isotonic Hypertonic *Assume all intracellular solutes can t penetrate cell membrane

29 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)

30 Name: Matilda Age: 78 In hospital for severe dehydration Staff puts her on IV of water Why might this IV solution cause Matilda serious problems?

31 Severe fatigue Dizzy Yellow eyes Rapidly increasing heartrate

32 Table 5.5 Intravenous Solutions Common IV solution properties as compared to a normal human cell

33 End material that was covered by discussion questions in class

34 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

35 Figure 5.7 Fick s law of diffusion 5 Composition of lipid layer 4 Membrane surface area 5 factors affect the rate of diffusion 1Extracellular fluid Lipid solubility Molecular size 2 3 Concentration outside cell Concentration gradient Factors affecting rate of diffusion through a cell membrane: Lipid solubility Molecular size Concentration gradient Membrane surface area Composition of lipid layer Intracellular fluid Concentration inside cell Fick s Law of Diffusion Membrane Permeability Rate of diffusion surface area concentration gradient membrane permeability Membrane permeability lipid solubility molecular size Changing the composition of the lipid layer can increase or decrease membrane permeability.

36 For next time: Think about how YOU would have treated Matilda differently than the nurses did.

37 Name: Megan Age: 3 Chronic Resp. Infections Thick mucus in airways Severe difficulty breathing

38 Part II: Transport Processes Across the Membrane via Proteins

39 The cell membrane is packed with proteins that serve many functions Transport

40 The cell membrane is packed with proteins that serve many functions Transport Signaling

41 The cell membrane is packed with proteins that serve many functions Transport Signaling Catalysis

42 The cell membrane is packed with proteins that serve many functions Transport Signaling Catalysis Structural

43 The cell membrane is packed with proteins that serve many functions Transport

44 Channel protein transporters are like doors Open Channel Proteins Free Passage E.g. Aquaporin Transports Water

45 Channel protein transporters are like doors X Open Free Passage Channel Proteins Closed Key Needed Transport Gated Channels

46 Chemically Gated Channels Require Molecule Binding

47 Voltage-Gated Channels Respond to Change in Charge Across Cell Membrane So, channel proteins, either the open or gated kind, are like doors

48

49 Carrier Proteins Change Confirmation to Pass Solute

50 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

51 Figure 5.12 Facilitated diffusion by means of a carrier protein Intro to Physio Carrier Proteins Change Confirmation to Pass Solutes Closed gate Extracellular fluid Intracellular fluid Pacific Motivation Ocean and Relevance Atlantic Ocean Passage open to one side Molecule to be transported Gate closed Carrier Membrane How I learn science Pacific Ocean Some Course Deets Atlantic Ocean Transition state with both gates closed Real Intro to Physio: Homeostasis Negative Pacific Feedback Ocean Atlantic Ocean Passage open to other side Gate closed Positive Feedback Homeostasis v. Equilibrium

52 Figure 5.13 Facilitated diffusion of glucose into cells Intro to Physio Carrier Large and Proteins Polar Change Molecules Confirmation Use Carriers to To Passively Diffuse Pass Solutes Across Membrane Motivation and Relevance High glucose concentration [Glucose] out = high[glucose] out GLUT How I learn science Some Course Deets Low glucose concentration [Glucose] in [Glucose] in stays low Glycogen G-6-P Glycolysis ATP ADP Real Intro to Physio: Homeostasis Facilitated diffusion brings glucose into the cell down its concentration Negative gradient. Feedback 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. Positive Feedback Homeostasis v. Equilibrium Passive, facilitated diffusion uses no energy

53 TRANSPORT AGAINST CONCENTRATION GRADIENT REQUIRES ENERGY

54 Active Transport Uses Energy to Move Solutes Against Gradient

55 Active Transport Uses Energy to Move Solutes Against Gradient

56 Active Transport Uses Energy to Move Solutes Against Gradient

57 Active Transport Uses Energy to Move Solutes Against Gradient Fun Fact! ~30% of our energy goes to powering the Na+/K+ pump!