PROPERTIES OF TRIACYLGTYCEROLS
1. Hydrolysis : Triacylglycerols undergo stepwise enzymatic hydrolysis to finally liberate free fatty acids and glycerol.
The process of hydrolysis, catalysed by lipases is important for digestion of fat in the gastrointestinal tract and fat mobilization from the adipose tissues.
2. Saponification : The hydrolysis of triacylglycerols by alkali to produce glycerol and soaps is known as saponification.
3.Rancidity: Rancidity is the term used to represent the deterioration of fats and oils resulting in an unpleasant taste. Fats containing unsaturated fatty acids are more susceptible to rancidity.
Hydrolytic rancidity occurs due to partial hydrolysis of triacylglycerols by bacterial enzymes.
Oxidative rancidity is due to oxidation of unsaturated fatty acids.
This results in the formation of unpleasant products such as dicarboxylic acids, aldehydes, ketones etc.
Antioxidants : The substances which can prevent the occurrence of oxidative rancidity are known as antioxidants.
Trace amounts of antioxidants such as tocopherols (vitamin E), hydroquinone, gallic acid and c,-naphthol are added to the commercial preparations of fats and oils to prevent rancidity. Propylgallate, butylatedhydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are the antioxidants used in food preservation.
Lipid peroxidation in vivo: In the living cells, lipids undergo oxidation to produce peroxides and free radicals which can damage the tissue. .
The free radicals are believed to cause inflammatory diseases, ageing, cancer , atherosclerosis etc
Iodine number : lt is defined as the grams (number) of iodine absorbed by 100 g of fat or oil. lodine number is useful to know the relative
unsaturation of fats, and is directly proportional to the content of unsaturated fatty acids
Determination of iodine number will help to know the degree of adulteration of a given oil
Saponification number : lt is defined as the mg (number) of KOH required to hydrolyse (saponify) one gram of fat or oiL
Reichert-Meissl (RM) number: lt is defined as the number of ml 0.1 N KOH required to completely neutralize the soluble volatile fatty acids distilled from 5 g fat. RM number is useful in testing the purity of butter since it contains a good concentration of volatile fatty acids (butyric acid, caproic acid and caprylic acid).
Acid number : lt is defined as the number of mg of KOH required to completely neutralize free fatty acids present in one gram fat or oil. In normal circumstances, refined oils should be free from any free fatty acids.
Alveolar Ventilation: is the volume of air of new air , entering the alveoli and adjacent gas exchange areas each minute . It equals to multiplying of respiratory rate by ( tidal volume - dead space).
Va = R rate X (TV- DsV)
= 12 X ( 500-150)
= 4200 ml of air.
• Is a synthetic analogue of the pituitary antidiuretic hormone (ADH).
• Stimulates the activity of Coagulation Factor VIII
• Use for treatment of hemophilia A with factor VIII levels less than or equal to 5%, treatment of hemophilia B or in clients who have factor VIII antibodies. Treatment of severe classic von Willebrand's disease (type I) and when an abnormal molecular form of factor VIII antigen is present. Use for type IIB von Willebrand's disease.
Agonist, Antagonist, and Partial Agonists
Agonists: molecules that activate receptors. A drug that mimics the body's own regulatory processes.
Antagonists: produce their effects by preventing receptors activation by endogenous regulatory molecules and drugs. Block activation of receptors by agonists.
Noncompetive Antagonist: Bind irreversibly to receptors, and reduce the maximal response that an agonist can elicit.
Competitive Antagonist: Bind reversibly to receptors, competing with agonists for binding sites.
Partial Agonists: Have moderate intrinsic activity, the maximal effect that a partial agonist can produce is lower than that of a full agonist. Act as antagonists as well as agonists.
Digestion within the small intestine produces a mixture of disaccharides, peptides, fatty acids, and monoglycerides. The final digestion and absorption of these substances occurs in the villi, which line the inner surface of the small intestine.
This scanning electron micrograph (courtesy of Keith R. Porter) shows the villi carpeting the inner surface of the small intestine.
The crypts at the base of the villi contain stem cells that continuously divide by mitosis producing
All of these cells replace older cells that continuously die by apoptosis.
The villi increase the surface area of the small intestine to many times what it would be if it were simply a tube with smooth walls. In addition, the apical (exposed) surface of the epithelial cells of each villus is covered with microvilli (also known as a "brush border"). Thanks largely to these, the total surface area of the intestine is almost 200 square meters, about the size of the singles area of a tennis court and some 100 times the surface area of the exterior of the body.
Incorporated in the plasma membrane of the microvilli are a number of enzymes that complete digestion:
Fructose simply diffuses into the villi, but both glucose and galactose are absorbed by active transport.
Use - for removal of soft debris by light brushing and then rinsing of denture; hard deposits require professional repolishing
a. Alkaline perborates-do not remove bad stains; may harm liners .
b. Alkaline peroxides-harmful to denture liners
c. Alkaline hypochlorites-may cause bleaching, corrode base-metal alloys, and leave residual taste on appliance
d. Dilute acids-may corrode base-metal alloys
e. Abrasive powders and creams-can abrade denture surfaces
Denture cleaning Method
a. Full dentures without soft liners-immerse denture in solution of one part 5% sodium hypochlorite in three parts of water
b. Full or partial dentures without soft-liners immerse denture in solution of 1 teaspoon of hypochlorite with 2 teaspoons of glassy phosphate in a half of a glass of water
c. Lined dentures -- clean any soft liner with a cotton swab and cold water while cleaning the denture with a soft brush
1. Chemical-can swell plastic surfaces or corrode metal frameworks
2. Mechanical-can scratch the surfaces of denture bases or denture teeth
Pharmacology is the study of drugs and the way they interact with living systems. Clinical pharmacology is the study of drugs in humans.
A drug is any chemical that can effect living processes.
Therapeutics: the medical use of drugs.
An ideal drug has several important properties. Three of these properties are of utmost importance: effectiveness, safety and selectivity.
Effectiveness: This is the most important quality that a drug can have. Effectiveness refers to the drug's ability to do what it is supposed to do.
Safety: Although no drug can be totally safe, proper usage can lessen the risks of adverse effects.
Selectivity: A truly selective drug would have no side effects, and would effect only the body process' for which it is designed and given. Therefore, there is no such thing as a selective drug.
Pharmacokinetics: The way the body deals with a drug. Pharmacokinetics is concerned with the processes of absorption, distribution, metabolism and excretion.
Pharmacodynamics: What a drug does to the body.
Pharmacokinetics and pharmacodynamics are two of the processes that determine how a person will respond to a drug. Other factors include how a drug is administered (dose, route, and timing of administration), interactions with other drugs, and individual physiological variables (weight, age, function of body systems).
GnRH is a peptide of 10 amino acids. Its secretion at the onset of puberty triggers sexual development.
FSH and LH Relaese
Increases estrogen and progesterone (in females)
testosterone Relaese (in males)
GHRH is a mixture of two peptides, one containing 40 amino acids, the other 44. GHRH stimulates cells in the anterior lobe of the pituitary to secrete growth hormone (GH).
CRH is a peptide of 41 amino acids. Its acts on cells in the anterior lobe of the pituitary to release adrenocorticotropic hormone (ACTH) CRH is also synthesized by the placenta and seems to determine the duration of pregnancy. It may also play a role in keeping the T cells of the mother from mounting an immune attack against the fetus
Somatostatin is a mixture of two peptides, one of 14 amino acids, the other of 28. Somatostatin acts on the anterior lobe of the pituitary to
Somatostatin is also secreted by cells in the pancreas and in the intestine where it inhibits the secretion of a variety of other hormones.
These peptides are released from the posterior lobe of the pituitary
Effects and Toxic Actions on Organ Systems
1. Local anesthetics (dose dependent) interfere with transmission in any excitable tissue (e.g. CNS and CVS).
2. CNS effects
a. Central neurons very sensitive.
b. Excitatory-dizziness, visual and auditory disturbances, apprehension, disorientation and muscle twitching more common with ester type agents.
c. Depression manifested as slurred speech, drowsiness and unconsciousness more common with amide type agents (e.g. lidocaine).
d. Higher concentrations of local anesthetic may eventually produce tonic-clonic[grand mal] convulsions.
e. Very large doses may produce respiratory depression which can be fatal. Artificial respiration may be life-saving.
a. Local anesthetics have direct action on the myocardium and peripheral vasculature by closing the sodium channel, thereby limiting the inward flux of sodium ions.
b. Myocardium usually depressed both in rate and force of contraction. Depression of ectopic pacemakers useful in treating cardiac arrhythmias.
c. Concentrations employed clinically usually cause vasodilation in area of injection.
d. Vasoconstrictors such as epinephrine may counteract these effects on myocardium and vasculature.
4. Local Tissue Responses
a. Occasionally focal necrosis in skeletal muscle at injection site, decreased cell motility and delayed wound healing.
b. Tissue hypoxia may be produced by action of excessive amounts of vasoconstrictors.
The amino acids buffer system
Amino acids contain in their molecule both an acidic (− COOH) and a basic (− NH2) group. They can be visualized as existing in the form of a neutral zwitterion in which a hydrogen atom can pass between the carboxyl and amino groups.
By the addition or subtraction of a hydrogen ion to or from the zwitterion, either the cation or anion form will be produced
Thus, when OH− ions are added to the solution of amino acid, they take up H+ from it to form water, and the anion is produced. If H+ ions are added, they are taken up by the zwitterion to produce the cation form. In practice, if NaOH is added, the salt H2N - CH2 - COONa would be formed. and the addition of HCl would result in the formation of amino acid hydrochloride.