Post on 18-Mar-2022
Taking care of business
Go to this page and enter room SJ123: http://tinyurl.com/PhysClicker
Take 2 minutes to complete this survey: http://tinyurl.com/PhysDis
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!
Super duperhyper osmotic
Super duperhyper osmotic
What will happen to cell?A. Swell upB. Shrivel
C. Stay the sameD. I don’t know
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
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
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
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?
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
The cell membrane is packed with proteinsthat serve many functions
StructuralCatalysisSignalingTransport
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
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 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