2. Introduction
• Chief cation of the
extracellular fluid
• 50% of body Na is
present in bones
• 40% in the extracellular
fluid
• 10% in soft tissues
3. BIOCHEMICAL FUNCTIONS
Necessary
for normal
muscle
irritability
and cell
permeability
Regulates
body’s
acid-base
balance
Maintenance
of osmotic
pressure
and fluid
balance
Involves in
the
intestinal
absorption
of glucose
galactose
and amino
acids
Necessary
for initiating
and
maintaining
heartbeat
1 2 3 4 5
4. DIETARY REQUIREMENTS
• For normal individuals ,
the requirement of Na is about 5-10 g/day which is mainly
consumed as NaCl
• Person with a family history - Hypertension
the daily NaCl intake should be less than 5 g.
• Patients of hypertension , around 1g/day is recommend.
• 10g of NaCl has 4g of Na
• Daily consumption of Na is generally higher than required due to
its flavour.
5. Sources
• Common salt (NaCl) in cooking - major source of Na
• Ingested foods also contribute to Na
• Good sources of Na - bread , whole grains , leafy vegetables , nuts
, eggs and milk
Aborption
• Na is readily absorbed in the gastrointestinal tract
• <2% is normally found in feces
• large quantites of Na is lost in feces - Diarrhea
6. Plasma sodium
• In plasma - normal concentration of na = 135-145mEq/l
• Extracellular cation , therefore ,the blood cells contain 35mEq/l
• Mineralocorticoids - secreted by adrenal cortex - influence Na
metabolism
• Decrease in plasma Na & Increase in its urinary excretion -
observed - adrenocortical insufficiency
7. Excretion
• Kidney - major route od Na excretion - body
• 800g Na/day - filtered - glomeruli
• 99% - is reabsorbed by renal tubules - active process
• Controlled by aldosterone
• Extreme sweating - causes considerable amount of Na loss in
body
• individual variation - Na loss through sweat
8. 1.Hyponatremia:
• Serum Na level falls below the normal
• Occur due to - diarrhea, vomiting, chornic renal diseases,
adrenocortical insufficiency(Addison’s disease)
• Administration of salt free fluids to patients - may cause
hyponatremia - due to overhydration
• decreased serum Na concentration - observed - edema -
occurs in cirrhosis /congestive heart failure
• Manifestation of hypontremia - reduced blood pressure &
circulatory failure
Disease states
9. 2.Hypernatremia
• Elevation in Na serum level
• Sym- Increase in blood volume & blood pressure
• Occur due to hyperactivity of adrenal cortex(cushing
syndrome),prolonged administration of cortisone , ACTH & sex
hormones
• loss of water - body causing dehydration , as it occurs in
diabetes insipidus , result in hypernatremia
• rapid adminstration of Na salts - increases serum Na
concentration
• In pregnancy - steriod & placental hormones cause Na & water
retention in the body - leading to edema
10. • In edema , along with water ,Na concentration in the body is-
elevated
• administration of diuretic drugs increases the urinary output of
water along with Na
• Patients of hypertension &congestive cardiac failure salt -
restriction is advocated
