This document discusses natural examples of colloids, including blood and milk. It describes the composition of blood as plasma and formed elements such as red blood cells, white blood cells, and platelets. Milk is also described as a colloid due to its small fat and protein globules that do not settle after standing. The document concludes by explaining that colloidal stability in fluids like blood and milk is achieved through a balance of electrical forces between particles, interactions with the solvent, and stabilization techniques like cloaking and steric effects.

1. ASSIGNMENT # 1
Topic:- Natural example of colloids
Submitted To:- Dr. SHAHANA
Submitted By:- Dil awaiz Rashim
CMS:- 23250
Section:- B
RIPHAH INSTITUTE OF PHARMACEUTICAL SCIENCES
RIPHAH INTERNATIONAL UNIVERSIT, ISLAMABAD

2. Composition of blood:-
Blood is classified as a connective tissue and consists of two main components:
1. Plasma, which is a clear extracellular fluid.
2. Formed elements, which are made up of the blood cells and platelets
The formed elements are so named because they are enclosed in a plasma membrane
and have a definite structure and shape. All formed elements are cells except for the
platelets, which are tiny fragments of bone marrow cells.
Formed elements are:
 Erythrocytes (RBCs)
 Leukocytes (WBCs)
 Platelets
Blood plasma
Blood plasma is a mixture of:-
 Proteins
 Enzymes
 Nutrients
 Wastes
 Hormones
 Gases

3. Blood as a colloide:-
Blood is a colloid which mainly contains red and white blood cells, lymphocytes and
plasma. That's why when we spin it in the special device found in hospitals it becomes
flocculated and plasma is separated from other compounds.
Composition of milk:-
The basic composition of milk is as follows:
• Water: 87.3
• Milk fat: 3.9 %
• Proteins: 3.25%
• Casein: 2.6%
• Serum proteins
• Minor proteins
• Carbohydrates (Lactose)
• Minerals: 0.65%
• Cationic: K, Ca, Mg, K
• Anionic: chloride,carbonate etc
• Organic acids: 0.18%
• Enzymes
• Vitamins
• Gases

4. Milk as a colloid:-
Milk appears to be a homogeneous mixture, it is a
colloid because it has small globules of fat and protein that do not settle out after
standing due to the particles (usually negatively) charged particles. These
particles repel each other so they do not collect into larger particles that would
settle out.
How these colloids remains stable?
Colloidally stable means that the particles do not aggregate at a significant rate:
the preciseconnotation depends on the type of aggregation under consideration.
For example, a concentrated paint is called stable by some people because oil and
pigment do not separate out at a measurablerate, and unstableby others
because the pigment particles aggregate into a continuous network.
This stability is achived by:-
 Balance of forces
 Electrical forces
 Interaction with solvent
 Stabilizatin by cloaking
 Steric stabilization