This document discusses various physiochemical aspects including acids, bases, pH, buffers, colloids, cell membranes, osmosis, and Donnan's equilibrium. It defines acids and bases, discusses acid-base equilibria using the Henderson-Hasselbalch equation, and explains factors that affect pH. It also describes different types of buffers, colloids, cell membrane structure and functions, osmotic pressure calculations, and Donnan's equilibrium principle of unequal ion distribution across a semipermeable membrane.

1. PHYSIOCHEMICAL
ASPECTS
PRESENTED BY:
PROFESSOR DR. M SHAFIQUE
MBBS, M.Phil., Ph.D

2. PHYSIOCHEMICAL ASPECTS
 Acids
Definition
Types
Examples
 Base
Definition
Types
Examples

3. EQUILIBIUM B/W UNDISSOCIATED ACIDS
HA H+ + A-
H+=Cat ion
A-=Anion
HA=Un dissociated Acid
[H+ ]=Molar Conc. Of Acid
[A-]=Molar Conc. Of Base
Ka+=Ionization Constant of Acid
Kb=Ionization Constant of Base
Higher the value of Ka, Greater the no of H+ and stronger the acid.
Ka measures the strength of an acid.
[H+ ] [A-] = Constant value
[HA]
[H+ ] [A-] = ka
[HA]
[H+ ]=ka [HA] = ka Acid
[A-] Salt
-LOG [H+]= -LOG Ka ACID/SALT= -LOG Ka – LOG ACID/SALT
PH=P Ka - LOG ACID/SALT
PH=P Ka + LOG SALT/ACID
This is HANDERSON-HASSELBALCH EQUATION. It is applied for determining the ph
of a buffer solution.

4. PH (H+ ION CONCENTRATION)
 DEFINATION
 DETERMINATION
 SIGNIFICANCE
 PH OF VARIONS FLUIDS
 PH OF H20
H20=H+ + OH-
Both ions are gram mole/liter of water
Ionic product is expressed as kw.
At 25°C=0.0000000000001=10-14
H20=H+ x OH- =10-14
H+ = OH- = 10-7 gram mole/liter
PH = -(LOG H+)=-(LOG 10-7)
PH = 7 (10-7 M=MOLAR; 10-7 N=NORMAL)

5. LOGS OF SOME NUMBERS
NO EXPONENTS LOG
10,00,000 107 7
10,000 104 4
10 101 1
1 100 0
0.1 10-1 -1
0.0001 10-4 -4
0.0000001 10-7 -7
Q1: PH of 0.1M HCL?
0.1 = 10-1 as completely dissociated
PH= -(LOG H+)= -(LOG 10-1)= -(-1)=1
Q2: PH of 0.1M NaOH?
(H+) x (OH-)=10-14
OH- =0.1=10-1
H+=10-14-10-1=10-13
PH=-LOG H+=-(LOG 10-13)=-(-13)=13

6. BUFFER SOLUTIONS
 DEFINITION
 TYPES OR EXAMPLES
 MECHANISM OF ACTION
 BIOMEDICAL IMPORTANCE
TYPES
 CHEMICAL BUFFERS
 PHYSIOLOGICAL BUFFERS
i. LUNGS
ii. KIDNEYS
CHEMICAL BUFFERS
I. ETRACELLULAR BUFFERS
 BICARBONATE BUFFERS:NaHCO3/H2CO3=20/1
 PHOSPHATE BUFFERS:Na2HPO4/NaH2PO4=4/1
 PROTEIN BUFFER: B. PROTEIN/H. PROTEIN

7. II. INTRACELLULAR BUFFERS
 PHOSPHATE BUFFER( Mainly in ICF + More powerful)
 BICARBONATE BUFFER( Less important in ICF)
 PROTEIN BUFFER
III. BUFFER IN RBCs
 HAEMOGLOBIN: Special Buffer and carries CO2
IV. OTHER CHEMICAL BUFFERS
 ACETATE BUFFER: CH3COONa/CH3COOH
 CITRATE BUFFER: Na CITRATE/CITRIC ACID
 AMMONIUM BUFFER: NH4CL/NH4OH
 BARBITONE BUFFER: Na BARBITURATE/BARBITURIC A.
MECHANISM:WHEN ACID IS ADDED
NaHCO3+HCL----NaCL + H2CO3
2NaHCO3+H2SO4----Na2SO4+H2CO3
NaHCO3+LACTIC ACID----Na-LACTATE+ H2CO3
WHEN ALKALI IS ADDED
H2CO3+NaOH----NaHCO3+H2O

8. BIOMEDICAL IMPORTANCE
 Maintains Normal Blood PH i.e. 7.4
 Shock absorbers against sudden PH
changes
 Very quick and act within seconds and
minutes.

9. COLLOIDS
 DEFINITION & EXPLAINATION
 TYPES OF PARTICLES
 TYPES OF COLLOIDAL SOLUTIONS
 SEPARATION OF COLLOIDAL PARTICLES
 PROPERTIES OF COLLOIDAL PARTICLES
 BIOMEDICAL IMPORTANCE
TYPES OF PARTICLES
i. TRUE SOLUTION PARTICLES
ii. COLLOIDAL PARTICLES
iii. SUSPENSION PARTICLES

10. TYPES OF COLLOIDAL SOLUTIONS
i. LYOPHOBIC COLLOIDS(SUSPENSOIDS)
 NO AFFINITY IN SOLUTE & SOLVENT
 METALS IN WATER MAKE THESE SOLUTIONS
 HAVE DEFINITE CHARGE
 THESE ARE LESS STABLE
 AGGREGATION DOES NOT OCCURS
 PRECIPITATION DOES NOT OCCURS,IF OCCURS THEN
DIFFICULT TO REFORM COLLOIDAL SOLUTION.
ii. LYOPHILIC COLLOIDS
 THESE ARE MORE STABLE
 HAVE CHARGE SURROUNDED BY LAYER OF SOLVENT
 AGGREGATION OF PPT DOES NOT OCCUR
 CAN CHANGE TO LYOPHOBIC BY ALCOHOL
 CAN BE RESOLUBILIZED AFTER PPT
 PROTEINS AND AGGAR MAKE THESE SOLUTIONS

11. SEPARATION OF COLLOIDAL PARTICLES
 ELECTROPHORESIS
 ULTRACENTRIUGATION
 ULTRAFILTRATION
 DIALYSIS
 PRECIPITATION BY ELECTROLYTES
 ADSORPTION
PROPERTIES OF COLLOIDAL PARTICLES
 SOLS AND GELS
 THIXSOTROPHY
 IMBIBATION
 BROWNIAN MOVEMENT
 TYNDALL EFFECT
 MUTUAL PPT OF COLLOIDS
 PROTECTIVE COLLOIDS

12. BIOMEDICAL IMPORTANCE
 THEY FORM SUSPENSIONS AND
EMULSIONS
 EXERT COLLOIDAL OSMOTIC PRESSURE
 ACT AS TRANSPORTERS AND CARRIERS

13. CELL MEMBRANE
 STRUCTURE
 FUNCTIONS
 MATERIAL MOVEMENTS

14. STRUCTURE
 Barrier 7-10 nm
 Lipid Bilayer
 Proteins
 Carbohydrates
FLUID MOSAIC MODEL
 Ampipathic Phospholipids
 Integral proteins (globular)
 Glycoprotein with CHO moiety
 Cholesterol
 Peripheral Proteins
Membrane proteins function as
1- Pumps 2- Gates 3-Pores 4- Receptors
5- Energy Transducers 6- Enzymes

15. FUNCTIONS OF CELL MEMBRANE
 Maintains conc. Of electrolytes, non electrolytes,
and water b/w interior and exterior of the cell
 Specific Receptors (Signal Transduction)
 Molecular Interactions i.e. Glycerol PO4 and
Stearoyl Co A
MOVEMENTS OF MATERIALS ACROSS MEMBRANE
(A) PASSIVE TRANSPORT
i. Simple Diffusion: Simplest form depends on solutes
ii. Restricted Diffusion:
• Due to presence of electric charge
• Influx of Na increased and efflux of K decreased
• May be attraction or repulsion of ions
iii.Facilitated Diffusion:
• Carrier mediated diffusion
• Integral proteins favors it
• May be enzyme like role
• Uptake of glucose by BRISCL
• Several GLUTs (Glucose Transporters) are involved

16. MOVEMENTS THROUGH EXCITABLE TISSUE
MEMBRANES
 Involves Na, k , Ca , Cl ions
 Nerve Cells and Muscle cells
 Response of conc. or electrical gradients
 Membrane proteins act as channels & gates
 Specific restrictions e.g. trans membrane voltage
 Voltage regulated gates and channels
IMPORTANT IONIC CHANNELS
 Na+ Channels
 K+ Channels
 Cl- Channels
 Ca+ Channels

17. Active Transport
 From lower solute conc. To higher solute conc.
 Against conc. or electrical gradient
 Also called up thrill transport
 Energy dependent utilizes ATP
 Protein carrier are involved
EXAMPLES
Na Pump (Na+ K+ ATPase Pump)
 Enzyme is transmembrane protein
 Dimer of one alpha and one beta subunit
 Causes efflux of 3 Na and influx of 2 K
Secretion of H+ by Gastric Parietal cells
Calcium ATPase
 In sarcoplasmic reticulum, plasma membranes & organ
cells
 Produces Ca+ gradient

18. Transport Secondary to Active Transport
i. Co Transport
ii. Counter Transport
Co Transport:
 Two ions move in same direction
 Carrier Proteins help which are co transporter
 Na K ATPase is involved
EXAMPLES
 Na and glucose by SGLUT-2 in tubules
(S=Na GLUT=glucose transporter)
 Absorption of glucose from GIT
 Trapping of iodine in Thyroid
In renal tubules other co-transporters are:-
1- Na/CO3 2-Na/Cl
3-Na/Amino Acid 4-Na/Phosphate
5-Na/Lactate 6-NaK/2Cl or K/Cl

19. Counter Transport
 Transport is exchanged
 Exchanger Proteins are involved
EXAMPLES:
 Na+/H+ exchanger in tubules
 Cl-/HCO3 exchanger in tubules
 Na/Ca exchanger in myocardium

20. OSMOSIS & OSMOTIC PRESSURE
 Definition
 Osmotic Pressure
 Measurement
 Calculations
 Biomedical Importance
 Iso-Osmotic and Iso-Tonic solutions

21. Osmosis
Solvent passes from a solution of lower solute
concentration to a solution of higher solute
concentration when these two solutions are
separated by a semi permeable membrane.
Osmotic Pressure
It is a pressure which is applied to the solution to
prevent the passage of solvent into it through
semi permeable membrane separating the two
i.e. the solution and the pure solvent.

22. i. Osmotic pressure is directly proportional to the
concentration of the solute:
 1% NaCl solution has double osmotic pressure
than 0.5 % NaCl solution.
 Depends on No. of particles irrespective of their
size and chemical nature.
 Na ion 23, Glucose 180, Albumin 70,000 will
exert equal osmotic pressure.
ii. Osmotic pressure is directly proportional to the
absolute temperature.
iii. Unit is osmole or milliosmole
1milliosmole = 17mmHg
Plasma = 300(280-295)milliosmole.
Characteristics of Osmotic Pressure

23. Biomedical Importance
 O.P. of plasma proteins = 25-
30mmHg
 O.P. of plasma crystalloids = 5000
mmHg
 In Hypo proteinemia there will be
low O.P.
 Water leaks from blood vessels to
tissue spaces
 Condition is called Edema
 Also called oncotic pressure

24. Explanation of:
 Isosmotic solution
 Isotonic solution
 Hypo tonic solution
 Hypertonic solution
EFFECTS ON RBCs
 In isotonic = RBCs are normal
 In hypertonic = shrinks and crenated
 In hypotonic = swollen and can rupture
Rupturing of RBCs and releasing of Hb is called
Hemolysis.

25. Donnan's Equilibrium
Side 1 Side 2
(K+
1) (K+
2)
(Cl-1) (Cl-
2)
Side 1 Side 2
60K+
1 60K+
2
60R- 60Cl-
2
Side 1 Side 2
80K+
1 40K+
2
60R- 20 Cl- 40Cl-
2

26.  Now we see
[K+
1]>[K+
2]
[Cl-
1]<[Cl-
2]
However the product
(K+
1)(Cl-
1 )=(K+
2)(Cl-
2)
80x20=40x40
160=160
 Conclusion
The presence of colloidal particles on one side of a
semi permeable membrane can affect the
distribution of ions on both sides.
 Unequal distribution of ions on two sides
 Unequal distribution of electrical potential

27. Applications
i. Plasma proteins in blood vessels
ii. Maintenance of oncotic pressure
iii. Changes in resting membrane potential
iv. Muscle fibers electrical potential
v. Renal tubular secretion and excretion
vi. HCl formation by Gastric glands
vii. Distribution of cerebrospinal fluid