body fluids. body fluids are liquids originating from inside the bodies of living humans. they...
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Body Fluids
Body fluids are liquids originating from inside the bodies of living humans.
They include fluids that are excreted or secreted from the body.
Body Fluids
Bodily fluid includes the following: Bile Blood serum Gastric juice Mucus (including nasal
drainage) Saliva Sweat Urine
And Tears.
Body Fluids
Total amount of fluid in the human body is approximately 70% of body weight
Body fluid has been divided into two compartments – – Intracellular fluid (ICF)
Inside the cells 55% of total body water
– Extracellular fluid Outside the cells 45% of total body water
Body Fluid Compartments
Water:
Life as we know it evolved in water and is still absolutely dependent on it.
The properties of water are therefore of fundamental importance to all living things.
Water is composed of H2 and O2.
Its chemical formula is H2O. the H–O–H bond has an angled
Shape.
At temperatures on the earth’s
surface, water is liquid.
1.Polarity: O–H bonds are polarized due to the high
electronegativity of oxygen One side of the molecule carries a partial negative charge (δ).
Whereas the other is correspondingly positively charged.
• Properties of water:
Separation of the positive and negative charges gives the molecule the properties of an electrical dipole.
Water molecules are therefore attracted to one another like tiny magnets, and are also connected by hydrogen bonding.
Hydrogen Bonding.
A hydrogen bond is the attractive force between the hydrogen of one molecule and an electronegative atom of a Another molecule.
Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge.
When liquid water vaporizes, a large amount of energy has to be expended to disrupt these interactions.
2. Hydration
In contrast to most other liquids, water is an excellent solvent for ions.
The dipolar water molecules arrange themselves in a regular fashion
corresponding to the charge of the ion.
They form hydration shells and shield the central ion from oppositely charged
ions.
Water has a high dielectric constant of 78—i. e., the electrostatic
attraction force between ions is reduced to 1/78 by the solvent.
Di electric constant
The dielectric constant means that substances whose molecules contain ionic bonds will tend to dissociate in water producing ions.
The large dielectric constant of water means that the force between the ions in a salt is very much reduced permitting the ions to separate
These separated ions become surrounded by the oppositely
charged ends of the water dipoles and become hydrated. Coulomb's LawF = (k . q1 . q2) / D . r2
where:•F is the force between the two electric charges q1 and q2 at a distance r apart•D is the dielectric constant of the solvent.
Electrically charged groups in organic molecules
(e.g. ,carboxylate, phosphate, and ammonium groups) are
also well hydrated and contribute to water solubility.
Hydroxy groups compounds, such as glycerol (on
the left) or sugars, are also easily soluble,
because they can form H bonds with water
molecules.
Hydrophilic interactions
Water is an excellent solvent for ions and for substances that contain polarized bonds. Substances of this type are referred toas polar or hydrophilic (“water-loving”). In
Hydrophobic interactions
Substances that consist mainly of hydrocarbon structures dissolve only poorly
in water. Such substances are said to be a polaror hydrophobic. Propane CH3-CH2-CH3
Amphipathic substances
Molecules that contain both polar and apolar
groups are called amphipathic or amphiphilic.
This group includes soaps, phospholipids and bile.
Amphipathic compounds form micelles—i. e., spherical aggregates with their head groups facing toward the outside, or extended bi layered double membranes.
Acids and bases
Acids are defined as substances that can donate hydrogen ions (protons),
Bases are compounds that accept protons.
THEORIES OF ACIDS AND BASES
Arrhenius, Bronsted-Lowry, and Lewis Propose Theories of acids and bases, and
explains the relationships between them.
The Arrhenius Theory of acids and bases
Acids are substances which produce hydrogen ions in solution.
Bases are substances which produce hydroxide ions in solution.
The Bronsted-Lowry Theory
An acid is a proton (hydrogen ion) donor. A base is a proton (hydrogen ion) acceptor.
The Lewis Theory
An acid is an electron pair acceptor. A base is an electron pair donor. Comparision:
Acid–base reactions always involve pairs of acids and the associated conjugated bases.
The stronger the acid or base, the weaker the conjugate base or acid, respectively.
For example, the very strongly acidic hydrogen chloride belongs to the very weakly basic chloride ion.
Weak acids and bases
Weak acids and bases are only partially ionized in their solutions, whereas strong acids and bases are completely ionized when dissolve in water.
Common Weak Acids
Acid Formula
Formic HCOOH
Acetic CH3COOH
Trichloroacetic CCl3COOH
Hydrofluoric HF
Hydrocyanic HCN
Hydrogensulfide
H2S
Water H2O
Conjugate acidsof weak bases
NH4+
Ionization of Week Acids
Acetic acid, CH3COOH, is a typical weak acid, and it is the ingradient of vinegar.
It is partially ionized in its solution. CH3COOH = CH3COO- + H+
Weak base
a weak base is a chemical base that does not ionize fully in an aqueous solution.
As Brønsted–Lowry bases are proton acceptors, a weak base may also be defined as a chemical base in which protonation is incomplete.
Ammonia is a typical weak base. Ammonia itself obviously doesn't contain hydroxide ions, but it reacts with water to produce ammonium ions and hydroxide ions.
However, the reaction is reversible, and at any one time about 99% of the ammonia is still present as ammonia molecules.
Only about 1% has actually produced hydroxide ions.
A weak base is one which doesn't convert fully into hydroxide ions in solution.