Transcript mineral v.final

Minerals
According to the body needs, minerals are divided into 2 groups:
I. Macrominerals:
They are required in amounts greater than 100 mg/day.
They include: calcium, phosphorus, magnesium, sodium,
potassium and chloride
II. Microminerals (trace elements):
They are required in amounts less than 100 mg/day. They
include: iron, copper, fluoride, iodine, manganese,
selenium and zinc.
I. Macrominerals
Calcium
Sources:
Milk, milk products, beans and egg yolk.
Absorption:
By active transport system in the upper small intestine by the
help of vitamin D (1,25 dihydroxy cholicalciferol).
Body calcium:
calcium is the most abundant mineral in the body. Most of
calcium (99%) is present in the skeleton (bones and teeth),
the remaining 1% are present in body fluids and other tissues
Plasma calcium:
normal level ranges from 9-11 mg/dl
Hormonal regulation of Plasma calcium:
1. Calcitonin: is secreted from thyroid gland in response to increased
blood Ca level. It decreases Ca through:
A. Mobilization of calcium from blood into bone
B. Decrease Ca reabsorption by renal tubules
2. Parathyroid hormone (PTH): secreted from parathyroid gland in
response to decreased calcium levels. It increase calcium by:
A. Mobilization of calcium from bone to blood (bone
resorption)
B. Increases Ca reabsorption by renal tubules
C. Increase absorption of calcium from small intestine
through stimulation of vitamin D activation.
Factors affecting calcium
absorption

A- Factors affecting Ca absorption:
1-High protein diet: amino acid forms soluble
salt with calcium.
2-Ph: an acidic PH is essential for calcium
absorption.
3- High lactate or citrate that form soluble
salts with calcium.
Factors affecting calcium
absorption
B- Factors inhibiting Ca absorption:
1- High diet phosphate, oxalate,
phytate form insoluble salt with CA.
2- Alkalinity: Ca absorption(
treatment of peptic ulcer).
3- Fatty acid: insoluble Ca soaps with
Ca.
Function of Calcium
1- Unionized Calcium:
A- It enters in the structure of bone and teeth.
2- Ionized calcium:

A- Transmission of nerve impulses.
B-Contraction of muscles.
C- Decrease of neuromuscular excitability. Deficiency of ionized
calcium lead to tetany.
D- Blood and milk clotting.
E-Maintenance of cell membrane permeability.
F- Activation of certain enzyme e.g. pyruvate kinase.
G- Medication of some hormone responses e.g. it acts together
with calmodulin as third messenger for hormone depending
on cyclic AMP.
Hypercacemia: may be due to:
1. Hyperparethyrodism due to adenoma ( benign tumor of the gland)
2. Excess intake of vitamin D or calcium
3. Milk-alkali syndrome : patients who receive milk and alkalies for long
time, for treatment of peptic ulcer
4. Drugs such as thiazide diuretics
Hypocacemia: due to:
1. Hypoparathyrodism
2. Renal disease where activation of vitamin D is inhibited
Requirments:
1. Adult: 800 mg/day
2. Children, pregnant and lactating women: 800-1200 mg/day
Phosphorus
Source: Milk meat and leafy vegetables
 Absorption: By active transorport and
regulated by Vitamin D
 Factors affect of ca absorption also affect
that of Phosphorus.
 Body Phosphorus : Most of it present in
bone and teeth. In the form hydroxy
apatite: 3 Ca3(PO4)2.Ca(OH)2
 Blood phosphorus 3-5 mg/dl.

Factors Affecting blood phosphorus

1- Parathyroid hormone:
A- PTH decrease blood phosphorus by stimulating its excretion
(through inhibiting its renal tubular re absorption).

2- Active Vitamin D (calcitriol):

A- Hypophosphatemia stimulates directly the renal hydroxylation of
25 (OH)D3 into 1,25 (OH)D3 (Calcitriol).
B- Calcitriol increases blood phosphorus through stimulation of:
1- Absorption of phosphorus from the intestine .
Bone resorption i.e. mobilization of phosphorus from bone.
Renal reabsorption by renal tubules.




Function of Phosporus
1-It enters in the structure of bone and teeth.
2- It enters in the structure of the following cellular
components:
a- Nucleic acids DNA RNA
B- Phospholipids e.g. lecithin , cephalin.
C- Phosphproteins.
D- Coenzyme e.g. NAD, NADP.
E- High energy phospate compounds e.g Atp, GTP,creatine
phosphate.
F- Cyclic Amp and Cuclic GTP.
G- Carbohydrate intermediates e.g. glucose 6 phospate, fructose -1p.
3- it enters in the formation of blood buffers.
Sodium
Sources:
The main source is table salt
Absorption:
from small intestine (ileum). It is nearly completely absorbed.
Body sodium:
2/3 of sodium is present in tissues and body fluids. About 1/3 is
present in skeleton (bone and teeth)
Requirements: 5 g/day
Alterations of plasma sodium:
Hypernatremia: excess plasma sodium is caused by:
1. Cushing syndrome.
2. Conn's disease due to excessive aldosterone secretion
3. Diabetes inspidus due to rapid loss of water
4. Drugs such as cortisone
Hyponatremia: decrease plasma sodium caused by:
1. Addison's disease: due to deficiency of aldosterone
2. Renal failure where renal reabsorption of sodium is inhibited
3. Dehydration: due to loss of water and sodium
4. Thaizide diuretics which block renal reabsorption of sodium
Toxicity of sodium: Hypertension in susceptible individuals.
Functions:
1- maintentance of osmotic pressure and volume of plasma and
extracellular fluid.
2-Transmission of nerve impulses.
3-Contraction of muscle.
4-Regulation of acid base balance.
Potassium






Sources:
vegetables, fruits and nuts
Absorption:
Readily occur from small intestine
Body K:
2/3 of potassium is present in tissues and body fluids. About
1/3 is present in skeleton (bone and teeth)

Requirements: 4 g/day
Functions of potassium:
The same of sodium except it act in intercellular fluid.
Alterations of plasma potassium:
Hyperkalemia: excess plasma potassium is caused by:
1. Addison's disease: due to deficiency of aldosterone
2. Acidosis
3. Tissue necrosis e.g. major trauma and burns due to leakage of tissue
potassium
4. Chronic renal failure with oliguria
5. Uncontrolled D. M. Lack of insulin prevent potassium from entering
cells
Hypokalemia: decrease plasma potassium caused by:
1. alkalosis
2. treatment of hyperglycemia with insulin without taking potassium, as
insulin helps potassium ion to enter cells
3. Excessive vomiting and diarrhea
4. Cushing syndrome
5. Diuretics therapy.
Chloride
Functions:
 Chloride is the main extracellular
anion.Together with sodium, it
maintains the osmotic pressure and
volume of plasma and extracellular
fluid.
 Chloride ions is essential for formation
of HCl in the stomach.
 Activation of enzyme:Cl activates
salivary and pancreatic amylase
enzymes.
Maganisum
Functions:
1- it enters in the structure of skeleton (bone
and teeth).
2-It activates many enzyme e.g. kinase enzyme.
3- it is required for transport of other cation
(Ca. Na, K) across the cell membrane .
4- it is important for muscle contraction,
nerve impulse transmission and it decrease
neuromuscular excitability.

Microminerals (Trace elements)
IRON
Sources:
Liver, heart, kidney, spleen, and fish
Sugarcane syrup (molasses), dates and egg yolk
N.B. Most of dietary iron is present in the ferric state.
Absorption:
from small intestine. Usually 10-20% of dietary iron is
only absorbed. Iron is absorbed in ferrous state.
Reducing substances such as vitamin C and SH- of cysteine
of dietary protein help the reducing of ferric ions into the
absorbable form (ferrous state).
Body iron:
The total body iron of adult is 3-5 g distributed as follows:
I -RBCs iron ( haemoglobin) is about 65% of total iron
II- Tissue iron (32%): includes
Available forms (28%) i.e. can be used when there body need
1-Ferritin : is the main storage form of iron. Composed of protein (apoferritin
+ iron). Present in iron stores: liver, spleen, bone marrow and
intestine.
2- Haemosiderin: These are granules composed of iron, protein and
polysaccharides. Used as another store of iron
Non available forms (4%): can not be used even there is body need. All these
forms are hemoprotein i.e. contain heme ring. Examples are:
1. Myoglobin: present in muscle and heart
2. Cytochromes: a, b and c: act as electron carriers
3. Catalase and peroxidase: act to destroy H2O2
III- Plasma iron: present in the form of:
1-plasma iron : ranges from 60- 160 μg/ dl
2- Transferrin : is a glycoprotein which carry iron in ferric state.
Transport and storage of iron:
1. Absorbed iron enters in the portal blood in the ferrous state.
2. In the plama it is rapidly oxidized to ferric state by the help of proteincontaining copper called: Ceruloplasmin
3. Then ferric ions are carried by transferring, which is\taken mostly by
bone marrow to synthesize hemoglobin
4. Iron from iron stores (ferritin) can be released into plasma and carried
by transferring to be used by B.M. and other tissues
Requirements:
1. adults: 10 mg/day
2. Pregnant and lactating female: 30 mg/day
Copper
Sources
: Most diet provides the amount of copper needed per day.
Absorption
: Mainly in the upper small intestine
Body copper
: 64% of copper are found in muscles and the remaining in
other tissues including liver and bones.
Plasma copper :
90 μg/ dl.
Functions:
1- copper is essential for:
A-Homoglobuin synthesis.
B- Bone formation.
C- mantence of mylin of the nerve.
2-Copper is essential component of several metaloenzymes such
as:
A-Ceruloplasmin: which oxidizes ferrous into ferric in plasma
B-Superoxide desmutase: antioxidant enzyme
C-Cytochrome oxidase
3- copper activates many enzyme e.g. uricase and dopamine hydroxylase.
Requirements: 2-3 mg/day
Alterations of plasma copper:
Hyper cupremia (Excess copper and ceruloplasmin) occur in infections
and malignancies
Hypocupremia (decreased plasma copper): occure in a disease called
Wilson's disease in which copper accumulate in large amounts in:
1. Liver causing liver cirrhosis
2. cornea causing greenish- brown color of the corneal margine
Kidney causing damage of renal tubules leading to increased excretion of
copper and ceruloplasmin resulting in low plasma copper.
Iodine

The only function is formation of T3 and T4 from thyroid gland, so
deficiency of iodine leading to hypothyroidism and disease called
Simple Goiter.

Requirements: 100-150 μg/day
Zinc
Functions of zinc:
1. Zinc is essential for growth and reproduction.
2. It plays a role in tissue repair and wound healing
3. Zinc forms a complex with insulin in β cells of the
pancreases. this helps crystallization ,storage and
release of insulin.
4. Zinc is essential component of a number of
enzymes e.g.:




A- alkaline phoshatase.
B- Carbonic anhyrase.
C- Superoxide dismutase.
D- Carboxy peptidase.
Zinc
5- Zinc is required for mobilization of vitamin
A from the liver and subsequently maintain
the normal concentration of vitamin A in
plasma.
Zinc deficiency: it causes:
1. Hypogonadism.
2. Poor healing of wounds.
3. Poor appetite and retard growth in
children.
4. Liver cirrhosis.
Selenium
A_selenium is an essential component of the
enzyme glutathione peroxide (GSH-PX) which
catalyzes the reaction:
2 GSH+H2O2
GSH-PX
GSSG +2
H2O


1.
2.
3.
B- This reactions as protective mechanism agonist
the oxidative damage of hydrogen peroxide
(H2O2) and fatty acid hydroperoxide by
destroying them:
In RBCs, it protect heamoglobin and red cell membrane.
In the liver, it is important for detoxifying liquid hydroperoxides.
In the lens tissue of the eye< it prevents its oxidative damage.
Selenium

1.
2.
3.
Deficiency of selenium (GSH-PX): it
causes:
Hemolytic anemia.
Liver cirrhosis
Cataract.
Manganese

1.
2.
3.

1.
2.

A- Manganese is essential for:
Normal bone structure.
Reproduction (spermatogenesis and
ovulation).
Normal function of the CNS.
B- Manganese is component of:
Pyruvate carboxylase enzyme.
Superoxide dismutase enzyme.
C- Manganese activates the arginase
enzyme.
Cobalt
A- coblet is a component of Vitamin B12
which is nessary for normal blood cell
formation.
 B- Cobalt gives vitamin B12 its red colour.
 C- Enzyme requrining Vitamin B12 for their
activites are:
1. Methylmalonyl COA mutase.
2. Methyletrahydrofolate oxidoreductase.
3. Homocystenine methytransferase.
4. Ribonuclotide reductase.
 D- Deficiency of Vitamin B12 causes
pernicious anaemia .

Chromium
It acts only together with insulin to
promote glucose utilization.
 Its deficiency leads to impairment of
glucose utilization by tissue.

Molybdenum

It is a component of oxidase enzymes
e.g.Xanthine oxidase.
Flouride
It increase the hardness of bone and
teeth.
 Its deficiency causes dental carries and
osteoporosis.
 Nowadays, it is supplied in drinking water.
 Excess fluoride leads to fluorosis: mottling
and discoloration of the enamel of teeth
and changes in bones.
