الاثنين، 15 يناير 2018

Lead poisoning

Lead poisoning


Lead poisoning


  • Lead as a metal is usually found deep in the ground between rockets at a depth of 30 km

Uses :

  1. It is the most commonly used metal in the world.The annual production is about 2.5 million ton .
  2. .Batteries
  3. .Printer ink
  4. .Bullets
  5. .Radiation protective clothes
  6. .Plastic production
  7. .Glasses
  8. .Paints
  9. Petroleum
Lead exposure

  1. Natural exposure
  • Air
  • Water
  • Food
  1. Occupational exposure
  • Batteries
  • Printing

Factors affecting intoxication:

  • High temp
  • Vapor
  • Dust
  • Ventilation
  • Cleaning
  • Personal factors

High risk occupations :

  • Batteries industries

Les risk exposure :

  • Police
  • Drivers
  • Petroleum service station
  • Plastic

Home exposure

  • Tomato paste
  • Old Batteries
  •  Lead pipes water
  • Paints
  • Dyes

Metabolism:

Routes of absorption :
  • Respiratory system
  • Skin
  • GIT

  • Absorption through respiratory  system is the most common and depends on:
  • Dust 
  • Mucus membrane motility
  • Effects
  • RBCs .
  • Bones
  • Liver
  • Kidney
  • Excretions (milk)

Blood formation system : 

Anemia due to


  • Hb production suppression 
  • Decrease RBCs half life
Lead encephalopathy

  • Symptoms :
  • Loss of conc
  • Headache
  • Fits
  • Depression
  • Cerebral edema
  • Vomiting
  • Fainting attacks

Peripheral n. system:
  • Lead palsy
  • wrist drop (Rt hand).

Kidneys
  • .RFT, BP

GIT
  • Loss of appetite
  • Constipation
  • Lead colic Recurrent in nature

Circulation
  • Hypertension
  • Tachycardia
  • Arrhythmias
  • Inverted T  Waves

Clinical picture
  • Fatigue
  • Insomnia
  • Headache
  • Anorexia
  • Abd pain & muscle ache
  • Bone & joints pain
  • lead colic
Diagnosis
  • History of exposure
  • Examination
  • Lead blood level
  • 5ug\dl for children (60 ug\dl for symptoms to appear)
  • 10ug\dl  for adult (50ug 60ug\dl for symptoms to appear)
  • Reticulocytes
  • Urine coproporphyrin
  • X ray dense line in the bones of children

Differential Diagnosis:
  • Appendicitis
  • Peptic ulcer
  • Gastritis
  • Renal colic
  • Neuritis
  • Meningitis

Prevention
  • Engineering and technical precautions 
  • Lead dust below 0.15mg \ cubic meter
  • Lead free process
  • Exhaust ventilation
  • Humid environment
  • Cleanliness
  • Blood lead levels measurement
  • Personal protection tools
  • Medical precautions
  • Pre & Periodical clinical examination
  • Cardio vascular diseases
  • Gastric ulcer
  • Psychiatric disorders
  • Liver & renal diseases
  • Pregnancy
  • Hb measurement
  • Lead blood level

  • The mainstays of treatment are :

1- Removal from the source of lead of poisoning,
2-Chelation therapyEDTA, a chelating agent, binds a heavy metal, sequestering it. A chelating agent form complexes nontoxic[140] and can be excreted in the urine,(CaNa2EDTA), dimercaprol (BAL), which are injected, and succimer and d-penicillamine, which are administered orally.
3-Treatment of iron, calcium, and zinc deficiencies, which are associated with increased lead absorption.
4-Anti-convulsants may be given to control seizures
5- Mannitol & CORTICOSTEROIDS.
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Body fluids



Body fluids 


compose of :

  1. water 
  2. dissolved substances (solutes)

Water :

  • Provide form of body structure
  • Protective cushion:  acts as shock absorber e.g amniotic fluid and CSF
  • Transport:  act as a medium for delivery of nutrients and removal metabolic waste
  • Provide medium for metabolic reactions within the cell
  • Act as a solvent:dissolve ions e.g NaCl and protein and solutes within the cell
  • Act as a lubricants e.g synovial fluid
  • Temperature regulation

Solutes:

  • Electrolytes:  Charged particles
  • Cations  à positively charged ions e.g Na+, K+, Ca++ and H+
  • Anions  negatively charged ions e.g Cl-,     HCO3-, and PO4-
  • Non electrolytes: Uncharged particles e.g  urea, glucose, O2 and CO2
  • Electrolytes  are  molecules  that  dissociate  in      water  to  their  cation  and  anion  equivelants.
  •  Why  don’t  they  reassociate  ?? because  of  the  net  charge  on  water  molecules.

Electrolytes :

  • Electrolytes are the charged particles (ions) that are dissolved in body fluids
  • Electrolytes are major component of body fluids enter in food and drink
  • The major cation and anion in body fluids are :
  1. Major Positive Ions: Cations

  • Sodium ion, Na+
  • Potassium ion, K+
  • Calcium ion, Ca2+
  • Magnesium ion, Mg2+

  1. Major Negative Ions: Anions

  • Chloride ion, Cl-
  • Bicarbonate ion, HCO3-
  • Phosphate ions, H2PO4- & HPO42-
  • Sulfate, SO42-
  • Organic Acids
  • Proteins

  • Electrolytes must be maintained in a narrow concentration range in order for cells to function properly. 
  • Even small deviation can have serious consequences . 
  • Each fluid compartment need  just the right types and levels of electrolytes for proper functioning  of neuron, muscle cells and other cells in the body. 
  • The electrolytes composition of ECF and ICF have significant differences Proteins and phosphate  are the major intracellular ionsOther negative ions found in the intracellular fluid are bicarbonate, chloride, organic acids,  and sulfate 
  • The composition of interstitial fluid is almost identical to that of blood plasma, except for one negative electrolyte - proteinTo summarize, the major positive ion of the extracellular fluid is sodium and the major negative ion is chloride. 
  • The major positive ion of the intracellular fluid is potassium and the major negative ions are protein and phosphates

COMPOSITION OF BODY FLUIDS :

  • The difference between plasma and interstitial fluid that plasma contain protein

Function of electrolytes

  1. Co factor for enzymes: co factors acts together with enzymes to speed up reactions in the body eg Ca, Mg.
  2. Action potentials in neuron and muscle cells
  3. Secretion and action of hormones and neurotransmitters
  4. Muscle contraction
  5. Maintain acid - base balance
  6. Secondary active transport
  7. Control fluid movement  between fluid compartments through osmosis

Role of sodium

  • Nerve conduction and muscle conduction
  • Regulation of water movement à if Na+ level in the plasma change, those changes determine fluid levels in the other compartment
  • Hypernatremia  cell shrink  signs of CNS dysfunction such as confusion

Role of potassium

  • K+ is responsible for intracellular fluid volume(Osmosis)
  • Key role in maintaining resting membrane potential à nerve muscle conduction, muscle contraction and maintenance of cardiac rhythm
  • Acid – base balance. In acidosis H+ enter the cell in exchange for K+ .
  • In Alkasosis K+ enter the cells in exchange for H+

Role of calcium

  • Ca++ is crucial to normal body function, even small change in Ca++ concentration can be deadly.
  • Normally, total Ca++ levels in the plasma vary between 9-11mg/dl
  • Hypercalcaemia à dysrhythmia , Fatigue, confusion and heart arrest (the heart can stop if the Ca++ level gets too high)
  • Hypocalcaemia à muscle spasms can occur
  • If ca++ level is very low a person can go into tetanus and breathing will stop
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Cell Structure and Function



Cell Structure and Function


Types Of cells

  1. Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles.
  2. Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, & animals) .

General Cell structure:

  • 3 principal parts:
  1. Plasma (cell) membrane.
  2. Cytoplasm & organelles.
  3. Nucleus.

Plasma membrane:

  • Surrounds, holds cell together & gives its form.10 nanometer thick.
  • Separates cells internal structures from extracellular environment 
  • Is selectively permeable, & controls passage of materials into & out of cell.
  • Participates in intracellular communication.
  • Plasma (Cell) Membrane Composed of:
  1. Double layer of phospholipids (hydrophobic/ hydrophilic parts).
  2. Proteins span, or partially span the membrane.
  3. Negatively charged carbohydrates attach to the outer surface.
  • General composition of cell membrane
  • Proteins ……………………. 55%
  • Lipids ……………………….. 41%
  • Phospholipids 25%
  • Cholesterol ……. 12% 
  • Glycolipids ……..  4%
  • Carbohydrates ……………  3%

Cytoplasm :

  •  The aqueous content of a cell (fluid, jellylike substance), that lies between cell membrane & nucleus in which organelles are suspended.
  •  Serves as matrix substance in which chemical reactions occur.
  • components of cytoplasm:
  1. Interconnected filaments & fibers
  2. Fluid = cytosol
  3. Organelles
  4.  storage substances
  5. Cytoskeleton
  6. Filaments & fibers
  7. Made of 3 fiber types
  8. Microfilaments
  9. Microtubules
  10. Intermediate filaments

  •  functions:

  1.  mechanical support
  2.  anchor organelles
  3.  help move substances

Organelles

  • Subcellular structures within the cytoplasm that perform specific functions.
  • Endoplasmic Reticulum : Helps move substances within cells network of interconnected membranes .

Two types :

  1. Rough endoplasmic reticulum
  2. Smooth endoplasmic reticulum
  • Rough Endoplasmic Reticulum
  • Ribosomes attached to surface
  • Manufacture protiens
  • Not all ribosomes attached to rough ER
  • May modify proteins from ribosomes .

  • Smooth Endoplasmic Reticulum
  • No attached ribosomes
  • Has enzymes that help build molecules
  • Carbohydrates

Lipids : It is composed of two subunits: smaller (lighter) & larger (darker) subunits. The space between the two subunits accommodates a molecule of transfer RNA, needed to bring amino acids to the growing polypeptide chain.
Golgi Apparatus : Involved in synthesis of cell membrane . Packaging & shipping station of cell
Lysosomes : Contain digestive enzymes
  • Functions
  1. Aid in cell renewal
  2. Break down old cell parts
  3. Digests invaders
Mitochondria
  • The structure of a mitochondria. The outer mitochondrial membrane & the infoldings of the inner membrane. The fluid in the center is the matrix.
  • Break down fuel molecules (cellular respiration),Glucose,Fatty acids
  • Release energy,ATP
Centrioles
  • Pairs of microtubular structures
  • Play a role in cell division

NUCLEUS

  • IT CONTROLS ALL CELL ACTIVITIES

Definition

  • It is rounded or elongated organelle present in all mammalian cells except the red blood cell.
  • It plays an important role in heredity, cell division and controlling all cellular functions.

General characteristics

  1. Number: usually one, two may present in some liver cells and many nuclei are present in the skeletal muscle cells.
  2. Size: is variable.
  3. Shape: is variable; rounded, oval, flattened,…
  4. Position: may be central, eccentric or peripheral in position.

Structure of the nucleus :

  1. Nuclear membrane.
  2. Nuclear sap and matrix.
  3. Nucleolus.

The nuclear membrane:
  • Surround the nucleus and disappear during cell division.
  • Nuclear pores: they are the openings in the nuclear membrane.

The nuclear sap and matrix
  • It is a colloidal clear solution, which is formed of:
  • Nucleoproteins, enzymes, and some minerals.
  • According to the amount of the sap nuclei are:
  • Open face type.
  • Condensed (closed) type. 
 Functions: a medium for the ribonucleic acids interaction.


The nucleolus
  • It is a basophilic mass formed of RNA & DNA.
  • It disappear during cell division.
  • Nucleolus size depend on the cell activities.

Functions of nucleolus:
  1. Controls the cell functions.
  2. Store the genetic informations.
  3. Regulates the cell division.
  4. Forms the Ribosomal RNA.



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الأحد، 14 يناير 2018

Body Fluids

Body Fluids 

Body compositions :

  • In the average young adult male:

  1. Water      60% ( TBW)
  2. Protein    18%.
  3. Fat           15%.
  4. Minerals    7 %
  5. carbohydrates < 1 %
  • The cells of the body live in fluid environment  .The interstitial fluid which represent the internal environment.
  • The function of all organ system is to ensure that the physical characteristics of the tissue fluids remain constant within narrow limits.
  • So pH, temp, concentration of chemical components of the internal environment are precisely regulated

Body fluids :

  • Represent 60% of body weight = 40 liters
  • Factors affect body fluids
  1. age: amount varies with age new born  73-82%, adult 60% , old age 45-50%.
  2. loss of body water is a common cause of death in children
  3.  body fats: lean subject more water than obese
  4. sex: women more fat and less water 

Body fluid compartment :

  • Body fluids are distributed into two compartments:
  1. intracellular fluid compartment .
  2. Extracellular fluid compartment .

  • Intracellular fluid :
  •  2/3 of body water
  •  40% of body weight = 25 liters

  • Extracellular fluid :
  •  1/3 of body water
  •   20% of body weight=15 liters
  •   Further divided into 3 compartment:
  1. interstitial fluids:
  • surround the cells
  • comprises ¾ of  ECF = 15% of Body Weight =12 liters
  • include lymph which cannot be measured separately
  1. Plasma:
  • intravascular fluids
  • comprises ¼ of ECF = 5% of BW =   3liters
  1. Transcellular fluid:
  • Fluid which are found out side normal compartment
  • Secreted by epithelium lining eg cerebrospinal fluid, GIT and urinary fluids, fluids in potential spaces eg joint cavities, and in pleural and peritoneal spaces
  • Total amount is small (.5 L) but large volumes can be formed in disease state eg ascites.
 VOLUME OF BODY FLUIDS IN 70 kg MAN TOTAL VOLUME 40 L .




  • ECF:  ICF 
  • Is  larger in infants and children than in adults but the absolute  ECF volume is smaller in children than in  adults. 
  • That’s why children tend to dehydrate more  rapidly  and  more  sever.

  • TBW : BW
  • The  ratio varies with  the  amount  of fat  present.   this variable   leads   to the   variation  due to age   and  gender
.

Many functions of body fluid :

  1. Lubrication
  2. Medium for cellular activities
  3. Transport of nutrients
  4. Temperature regulation
  5. Elimination/excretion of waste

Measurement of body fluids :

  • Volumes in various compartments measured using dilution method

V (Volume) = Q (Quantity) - E (excreted) /C (Concentration)


Ficks Principle :

  • Amount = vol. X conc.
  • Vol. = A/C  (in plasma)

Measurement of body fluid compartment:

  • Using indicator (dye)dilution method.
  • A known quantity of substance(e.g. a dye) Is injected and allowed to distribute in the compartment of interest.
  • measure the final concentration of the dye from the compartment then the volume of compartment(=volume of distribution of the dye ) .Calculated using the formula: volume of distribution =Q-e /c

Characteristic of substance :

  1. Not toxic
  2. Distribute itself in the certain compartment to be measured
  3. Should distribute it self uniformly in all part of the fluid to be measured
  4. No effect of its own on distribution of water or other substances in the body
  5. Must be unchanged  by the body during mixing or amount changed must be known
  6. Easy to measure   

Measurement of total body water :

  • Using dilution method by injecting a substance which diffuse freely in all fluid compartment Substance used :

  1. Deuterium oxide (D2O)
  2. Tritiated water 3(H2O)
  3. antipyrine and amino-antipyrine

  • Sample of plasma obtained to measure concentration=Q/C

Measurement of ECF :


  • Two types of substance used:

  1. Saccharides: eg inulin, sucrose, manitol
  2. diffusable ions: eg chloride, bromide, Na+

Measurement of ICF :

  • No substances can diffuse only in ICF
  • Total body water – ECF

 Measurement of plasma :

  • Substance used

  1. Evans blue; which bind to plasma protein
  2. Albumins labeled with radioactive iodine

Measurement of blood :

  • Dilution method using red blood cells labeled with radioactive chromium 51(Cr) By use of plasma volume 

Interstitial fluid :


  • Interstitial fluid = ECF – plasma volume

Factors affecting the body fluids :

  1. Osmosis: Movement of solvent molecules into a region in which there is a higher concentration of solute to which the membrane is  semi permeable.   
  2. Diffusion: It is expansion of a gas or substance through a cell membrane, due to continuous random movement of its molecules. Water will follow this  molecules into or out of the cell 
  3. Gibbs Donnan effect: the presence of non diffusible anions like proteins and organic phosphate within the cell will affect distribution of diffusible Anions –ve charged and Cations +ve charged .  [K+ X] [Cl-X] = [K+Y ] [Cl-Y ]




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Dynamics of capillary exchange

Dynamics of capillary exchange

  • 5 main types  of blood vessels :

  1. Arteries – carry blood AWAY from the heart
  2. Arterioles
  3. Capillaries – site of exchange
  4. Venules
  5. Veins – carry blood TO the heart


  • What is hydrostatic pressure?

The pressure that the fluid exerts on the walls of its container.
Capillary pressure means Hydrostatic pressure
Colloid osmotic pressure means Oncotic pressure


  • What is osmotic pressure?

The pressure required to prevent the flow of water across a semipermeable membrane via osmosis .
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الخميس، 11 يناير 2018

PURINES, PYRIMIDINES, NUCLEOSIDE, & NUCLEOTIDE

 PURINES, PYRIMIDINES, NUCLEOSIDE
&
NUCLEOTIDE


Related image


  • DNA Stores Genetic Information.

  • The transformation was inherited permanently by subsequent generations.
  • The early x-ray diffraction results indicated that DNA was composed of two strands of the polymer wound into a helix. 

  • The observation that DNA was double-stranded was of crucial significance and provided one of the major clues that led to the Watson-Crick structure of DNA. 

 Purines and pyrimidines

  • Purines and pyrimidines are nitrogen-containing heterocycles.
  • cyclic compounds whose rings contain both carbon and other elements.
  • They form Nucleosides and Nucleotides .

Nucleosides: 

  • these Are derivatives of purines and pyrimidines that have a sugar linked to a ring nitrogen.The sugar in ribonucleosides is D-ribose, and in deoxyribonucleosides it is 2-deoxy-D-ribose.
  •  ribonucleoside 
  • deoxyribonucleoside  
  • ribonucleosides 
  • deoxyribonucleoside

Structure of purine and pyrimidine nucleotides

  • nucleotide = ester of phosphoric acid and a nucleoside
  • nucleoside = N-containing base + monosaccharide
b-N-glycosidic bond between base and saccharide
almost always to N-1 of a pyrimidine or to N-9 of a purine
  • Nucleotides are the building blocks of nucleic acids.
  •  Numerals with a prime ( 5′ or 3′) distinguish atoms of the sugar from those of the heterocyclic base.
  • Mononucleotides are nucleosides with a phosphoryl group esterified to a hydroxyl group of the sugar.
  •  Since most nucleotides are 5′-, the prefix “5′-” is usually omitted when naming them.

Functions of Nucleotides

  1. monomeric units of RNA and DNA  substrates: nucleoside triphosphate
  2. energetic metabolism    
    ATP = principal form of chemical energy                                        available to cells.
  3. physiological mediators ; cAMP, cGMP   („second messengers“)
  4. components of coenzyme ; NAD+, NADP+, FAD
  5. allosteric efectors : regulation of key enzymes of metabolic pathways
SYNTHETIC NUCLEOTIDE ANALOGS ARE USED IN CHEMOTHERAPY

        Nucleic Acid Structure & Function

Structure of DNA

  • DNA Contains Four Deoxynucleotides
  • Nucleotides have three characteristic components:
  1. nitrogenous (nitrogen-containing) base, pyrimidine and purine.
  2.  pentose,
  3. phosphate. 
  • The molecule without the phosphate group is called a nucleoside. Both DNA and RNA contain two major purine bases,
  1. adenine (A) and
  2. guanine (G) Two major pyrimidines. In both DNA and RNA one of the pyrimidines is
  3. cytosine (C), but The second major pyrimidine is not the same in both: it is 
  4. thymine (T) in DNA and 
  5. uracil(U) in RNA.
  • I.e; (A, G, C, T) in DNA , (A, G, C, U) in RNA
  • These monomeric units of DNA are held in polymeric form by 3′,5′-phosphodiester bridges constituting a single strand
  • The informational content of DNA (the genetic code) resides in the sequence in which these monomers are ordered.
  • Together with x-ray data from the DNA molecule and the observation of Chargaff: That in DNA molecules the concentration of deoxyadenosine (A) nucleotides equals that of  (T) nucleotides (A = T), while the concentration of (G) nucleotides equals that of (C) nucleotides  (G = C),  led Watson, Crick, and Wilkins to propose a model of a double stranded DNA molecule.
  • The two strands of this double-stranded helix are held together by hydrogen bonds between the purine and pyrimidine bases.
  •  The pairings between the purine and pyrimidine nucleotides on the opposite strands are very specific; A with T and G with C .
  • The two strands of the double-helical molecule, each of which possesses a polarity, are antiparallel; ie, one strand runs in the 5′ to 3′ direction and The other in the 3′ to 5′ direction.
  • DNA PROVIDES A TEMPLATE FOR REPLICATION & TRANSCRIPTION

DNA functions :

  1. Store genetic information & transferring it to daughter cells during mitosis by replication 
  2. Transfer of genetic information from DNA to RNA to be expressed as proteins
  • THE CHEMICAL NATURE OF RNA DIFFERS FROM THAT OF DNA
  • In RNA, the sugar moiety is ribose rather than the 2′-deoxyribose of DNA.
  • The pyrimidine components of RNA differ from those of DNA. thymine (T) in DNA and uracil (U) in RNA.
  • RNA exists as a single strand, whereas DNA exists as a double-stranded helical molecule.
  •  : RNA  
A. MESSENGER RNA (mRNA)
B. TRANSFER RNA (tRNA)
C. RIBOSOMAL RNA (rRNA)

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الثلاثاء، 9 يناير 2018

lipids

 lipids 


Image result for lipids

BIOMEDICAL IMPORTANCE

  • The lipids are a heterogeneous group of compounds, including fats, oils, steroids, waxes, and related compounds, that are related more by their physicalthan by their chemical properties.
  • Lipids have the common property of being:
  1. relatively insoluble in water .
  2. soluble in non polar solvent such as either and chloroform . 
  • Lipids are important dietary constituents because:
  1. high energy value .
  2.  fat soluble vitamin (  A,D,E,K ) .
  3.  essential fatty acids .

Functions of lipids :

  • Fat is stored in adipose tissue, where it also serves as a thermal insulator in the subcutaneous tissues and around certain organ .
  • non polar lipids act as electrical insulators ( myelinated nerve  ) .
  • lipoprotein serve as a mean transporting lipids in the blood .
Biomedical Problems that are associated with lipids :
  • diabetes mellitus 
  • obesity
  • atherosclerosis . 

Lipids are classified as simple or complex :

  • Simple lipids
  • Complex lipids
  • Precursor and derived lipids

1. Simple lipids: 

  • Fats: Esters of fatty acids with glycerol. Oils are fats in the liquid state.
  • Waxes: Esters of fatty acids with higher molecular weight monohydric alcohols.

2. Complex lipids: 

  • Esters of fatty acids containing groups in addition to an alcohol and a fatty acid.
  • Phospholipids: Lipids containing, in addition to fatty acids and an alcohol, a phosphoric acid residue. They frequently have nitrogen containing bases and other substituents, eg, in glycerophospholipids the alcohol is glycerol and in sphingophospholipids the alcohol is sphingosine.
  • Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine, and carbohydrate.
  • Other complex lipids: Lipids such as sulfolipids and aminolipids. Lipoproteins may also be placed in this category.

3. Precursor and derived lipids: 


  • These include fatty acids, glycerol, steroids, other alcohols, fatty aldehydes, ketone bodies, hydrocarbons, lipid-soluble vitamins, and hormones. 

Fatty acids:

  • these are aliphatic carboxylic acids
  • occur mainly as esters in natural fats and oils but do occur in the unesterified form as free fatty acids, a transport form found in the plasma.
  • that occur in natural fats are usually straightchain derivatives containing an even number of carbon atoms.
  • The carbon atoms adjacent to the carboxyl carbon (Nos. 2, 3, and 4) are also known as the α, β, and γ carbons, respectively, and the terminal methyl carbon is known as the ω or n-carbon.
  • Saturated acids end in –anoic (no double bond)
  • Unsaturated acids with double bonds end in -enoic .

Unsaturated Fatty Acids Contain One or More Double Bonds

  1. Monounsaturated (monoethenoid, monoenoic) acids, containing one double bond.
  2. Polyunsaturated (polyenoic) acids, containing two or more double bonds.
  3. Eicosanoids: These compounds, derived from eicosa (20-carbon) polyenoic fatty acids, comprise the prostanoids, leukotrienes (LTs), and lipoxins (LXs). Prostanoids include prostaglandins (PGs), prostacyclins (PGIs), and thromboxanes (TXs).
  • Most naturally occurring unsaturated fatty acids have cis double bonds
  • Double bonds in naturally occurring unsaturated longchain fatty acids are nearly all in the cis configuration.

  • Trans fatty acids are present in certain foods, arising as a by-product of the saturation of fatty acids during hydrogenation, or "hardening," of natural oils in the manufacture of margarine ( increased risk of diseases including cardio-vascular disease and diabetes mellitus).
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