Welcome to SPEP 2009!
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Transcript of Welcome to SPEP 2009!
Welcome toSPEP 2009!
The University of Cincinnati
Heather HaleElise Demitrack
Getting to know you…
• Name• School• Field of interest
Key Terms
• Physiology– Study of Organ function– Regulation/Interaction of organ systems
• Homeostasis– Body performs functions to maintain
constituents of extracellular fluid– Ability to maintain constant internal
environment
• “Steady-state” (equal mixing)
Units
• Mass % (g%) = gram amount per 100 mL (1dL)
• Equivalent (Eq) = gram amount of one mole of a substance divided by it’s valence– i.e. 1Eq of Ca2+ is 40 gm / 2
• Osmoles = # particles released into solution when solute is dissolved in H2O– Osmolar = 1 Osmole/mole dissolved in 1L H2O– Osmolal = 1 Osmole/mole dissolved in 1kg H2O
• One gram-molecular weight of any substance represents and consists of 6 x 1023 molecules
Physiology I
Membrane Physiology
Heather HaleJune 23, 2009
The Plasma Membrane
• Lipid bilayer• Key Constituents:
– Phospholipids• Amphipathic (polar head & non-polar tails)• Fluidity
– Cholesterol• Rigidity
– Glycoproteins (protein + carbohydrate)• “Float” throughout bilayer• Forms receptor substances (glycocalyx)
Head group
Hydrocarbon tail
http://www.cytochemistry.net/Cell-biology/membrane_intro.htm
Membrane Permeability
• Selective!• Simple Diffusion• Rate depends on
molecule’s:– Lipid solubility– Size– Charge
• Assisted by:– Ion channels– Transporters
Crucial for creating an
electrochemical gradient!
http://en.wikipedia.org/wiki/Semipermeable_membrane
Selective Permeability
Plasma Membrane Proteins
• Integral– Permanently associated with
membrane– Transmembrane: spans entire
bilayer
www.ultranet.com/~jkimball/BiologyPages/C/CellMembranes.html
• Peripheral– Associate with
bilayer or another protein
– Temporarily attached
Summary: Plasma Membrane
Membrane Proteins: Channels
• Spans bilayer to form “pore”
• Moves substances across bilayer
• Gating:– Selectivity!– Ligand-gated– Mechanically gated– Voltage-gated
Passive transport!
Membrane proteins: Transporters• “Carrier” proteins
• Transport specific substance across bilayer (selective!)
• Channel changes shape/orientation
Active transport!
http://phy.asu.edu/phy598-bio/D5%20Notes%2006.htm
Types of Transporter Proteins
http://library.thinkquest.org/C004535/cell_membranes.html
Symport videohttp://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/SymporA.gif
Membrane Proteins: Enzymes• Catalyze reactions inside/outside cell
• Associated with membrane to increase efficiency
http://www.biochem.arizona.edu/classes/bioc462/462b/Miesfeld/Photosynthesis.html
• Protein active site (intracellular or extracellular) catalyzes reactions
Examples of Membrane Proteins• Channels: Ca2+ and Na2+ channels
• Transporters:– Proteins transporters– Glucose transporters
• Enzymes: Mitochondrial membrane proteins
Movement Across Plasma Membrane
• Transport of material across bilayer
• Can be direct (non-facilitated)
• Some requires proteins:– Diffusion (facilitated)– Active transport (energy!)
Passive Movement
• No cell energy required!
• Simple diffusion– [high] [low]– Based on molecule‘s
properties– Gases, nutrients, ions
• Limited by diffusion rate of molecule!
http://www.indiana.edu/~phys215/lecture/lecnotes/diff.html
No proteins required!
Passive Movement of Water
• Movement of H2O across cell
• Moves from [H2O]high [H2O]low
• H2O keeps osmotic pressure equal across membrane
http://www.indiana.edu/~phys215/lecture/lecnotes/diff.html
H2O moves toward
compartment with high [solute]
Solutions & Osmotic Pressure
• Solutions– Isotonic: equal [solute] inside/outside– Hypotonic: low [solute]; H2O moves out– Hypertonic: high [solute]; H2O moves in
• Osmotic Pressure– Required to stop osmotic H2O movement– Determined by # particles/unit volume– Osmole = # particles in 1 gram (MW) of un-
dissociated solute
Pressure & Water Movement
• Influenced by two forces– Hydrostatic pressure: caused by
gravity on a column of fluid– Hydraulic pressure: caused by action
of a pump (active!)
• Osmotic pressure = only pressure to initiate water flow in/out of cell
H2O moves from Phigh to Plow
Osmotic Pressure
• Calculated osmotic pressure (π = CsRT)
• Cs = osmolar concentration• R = universal gas constant• T = absolute temperature• (RT = 22.4 ATM/osmole at 37˚C)
• Effective osmotic pressure:– Depends on permeability of
membrane to specific solute
ECF and ICF have [osmotic] = 300 mOs/L
Osmotic Pressure
• Fig A: semipermeable membrane– Solute cannot pass– Pos will equal the
Phydrostatic as water flow into tube
• Fig B: solute-permeable membrane– Solute equilibrates– Effective Pos of solution
is zero
Passive Movement: Facilitated• Requires
membrane proteins!
• Forms water-filled pore
• Solutes move down [conc] gradient (high low)
• Examples:– Glucose transport– K+, Na+, Cl- transport
Active Movement: 1˚ Transport
• Requires cellular energy!
• Transporters bind ATP– Hydrolysis of ATP to ADP + Pi
– Drives transport of solute against concentration gradient!
• Examples:– Na+/K+ ATPase pump– Ca2+ ATPase
Active Movement: Na+/K+ Pump
videohttp://images.google.com/imgres?imgurl=http://student.ccbcmd.edu/~gkaiser/biotutorials/eustruct/images/sppump.gif&imgrefurl=http://student.ccbcmd.edu/~gkaiser/biotutorials/eustruct/sppump.html&h=290&w=290&sz=515&hl=en&start=1&um=1&tbnid=RE2RGHk1UT
Active Movement: 2˚ Transport
• Uses energy of a “driving ion” moving down [conc] gradient to move a 2nd molecule against [conc] gradient
• Driving ion usually Na+ using gradient created by the Na+/K+ pump
http://courses.cm.utexas.edu/jrobertus/ch339k/overheads-2/ch12_Na-gluc-trans
Examples: -Na+/Ca2+ exchanger -Na+/glu transporter
Active Movement: Bulk Transport• Endocytosis: transport into cell
– Phagocytosis = ingest large particles– Pinocytosis = ingest small vesicles– Receptor-mediated ingestion
• Exocytosis: transport out of cellhttp://upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Endocytosis
Physiology I
Body Fluid SpacesHeather HaleJune 24, 2008
Body Fluid Spaces
• The human body is mostly water• Total H2O content of the human
body = 45-60% of body weight
• Total Body Water (% of body weight)– Males: 60% (ages 17-34)
54% (ages 50+)
– Females: 55% (ages 17-34)46% (ages 50+)
Major Body Fluid Spaces
• Two major “compartments”– Intracellular fluid (ICF):
• fluid contained within cells• Accounts for 40% of body fluid weight
– Extracellular fluid (ECF):• fluid outside of the cell• Accounts for 20% of body fluid weight
• Total body water = ICF + ECF
Major Body Fluid Spaces
• The 60, 40, 20 rule– 60 = All fluid is 60% of total body weight– 40 = ECF is 40% of body weight– 20 = ICF is 20% of body weight
i.e. 70kg × 0.4 = 28 L of ICF fluid
Major Body Fluid Spaces
• ECF is subdivided even further:– Plasma space = 5% of total body
weight– Interstitial fluid (ISF) = 15% of total
body weight
• ISF = ultrafiltrate of plasma
Body Fluids: Hematocrit (Hct)• Ratio of red
blood cell (RBC) volume to whole blood volume
• Hct is typically 40% of whole blood volume
• Whole blood volume = 7-9% of body weight (about 6 L)
Hct = (vol)RBC
(vol)whole blood
1 - Hct = (vol)plasma
(vol)whole
blood
Body Fluids: Cations/Anions
• Total [Osmolar] = 280-296 mOs/L
• Na+ = 13-145 mEq/L• Cl- = 100-106 mEq/L• Ca2+ = 4.3-5.3 mEq/L• Glucose = 70-110 mg%• Total protein = 6-8 g%
Learn these values!
Body Fluids: Cations/Anions
• ECF is high in Na+ & Cl-
• ICF is high in K+
Body Fluid Space Measurements
• To estimate the size of body fluid spaces, use a dye indicator dilution– Based on conservation of mass principle– [conc] vol = mass
• Only applicable during steady-state
• No loss/gain of substance during measurementC1 V1 = C2 V2 V2 = (C1 V1) / C2
Body Fluid Spaces: Fick Principle
• If some solute is lost/gained:– C1 V1 = C2 V2 (+ amount gained)
– or C1 V1 = C2 V2 (- amount lost)
• Analysis represents Fick Principle
• Commonly used to measure blood flow or cardiac output
Body Fluid Space Measurements
• 3 component system (plasma, ISF, ICF)
• Inject substances into plasma
• Assumptions– Equal amnt x, y, z– x, y, z not present
before injection
Body Fluid Space Measurements
• Capillaries– separate
plasma/ISF– Permeable to y and
z but not to x
• Cell membrane– Separate ISF/ICF– Permeable to z only
Body Fluid Space Measurements
• Volume distribution of x = plasma
• Volume distribution of y = plasma + ISF
• Volume distribution of x = ECF + ISF
Body Fluid Spaces: Markers
• Plasma fluid markers (“x”)– Do not cross capillaries– Examples:
• Radioiodinated serum albumin• Evan’s Blue (dye that binds albumin)• RBCs with radioactive iron or chromium
Body Fluid Spaces: Markers
• ECF markers (“y”)– Represents plasma + ISF– Cross capillary but not cell
membrane– Examples:
• Isotopic Cl- or Na+• Inulin• Mannitol
Body Fluid Spaces: Markers
• Markers for total body water (“z”) must be permeable to both capillaries and cell membranes
• Examples:– 3H water (tritiated “heavy” water)– Urea (carbon labeled, or tritiated)– Lipid soluble substances
Capillary Fluid Movement
• Capillaries separate plasma from ISF
• ECF ions move across capillaries between plasma and ISF
• But, proteins are restricted to plasma– Creates osmotic pressure ~15-25
mmHg– This is the colloid osmotic pressure
Starling’s Law of the Capillary
• Principle of pressure differences• Pressures:
– Reabsorptive forces:• Capillary colloid osmotic pressure• ISF hydrostatic pressure
– Filtration forces:• Capillary blood pressure• ISF colloid osmotic pressure
FM = Kf [(BPcap + COPISF) - (COPcap + HPISF)]
Capillary Fluid Movement
FM = Kf [(BPcap + COPISF) - (COPcap + HPISF)]
Reabsorption
Reabsorption
Filtration
Filtration
Contact Info
• Email: [email protected]• Lab location: Health professionals
BuildingRoom 234
(off of Eden Ave, across from Eden Garage and MSB)
Supplementary Figures
Supplementary Figures
Supplementary Figures
Supplementary Figures