DIFFUSION

Electrocardiogram Because the body fluids are good conductors (ie, because the body is a volume conductor), fluctuations in potential, representing the algebraic sum of the action potentials of myocardial fibers, can be recorded extracellularly. The record of these fluctuations in potential during the cardiac cycle is the ECG. The ECG may be recorded by using an active or exploring electrode connected to an indifferent electrode at zero potential (unipolar recording) or by using two active electrodes (bipolar recording). In a volume conductor, the sum of the potentials at the points of an equilateral triangle with a current source in the center is zero at all times. A triangle with the heart at its center (Einthoven triangle, see below) can be approximated by placing electrodes on both arms and on the left leg. These are the three standard limb leads used in electrocardiography. If these electrodes are connected to a common terminal, an indifferent electrode that stays near zero potent...

 Color Blindness The most common test for color blindness uses the Ishihara charts, which are plates containing figures made up of colored spots on a background of similarly shaped colored spots. The figures are intentionally made up of colors that are liable to look the same as the background to an individual who is color blind. Some color-blind individuals are unable to distinguish certain colors, whereas others have only a color weakness. The prefixes “prot-,” “deuter-,” and “trit-” refer to defects of the red, green, and blue cone systems, respectively. Individuals with normal color vision are called trichromats. Dichromats are individuals with only two cone systems; they may have protanopia, deuteranopia, or tritanopia. Monochromats have only one cone system. Dichromats can match their color spectrum by mixing only two primary colors, and monochromats match theirs by varying the intensity of only one. Abnormal color vision is present as an inherited abnormality in white popula...

IMPLANTATION (2ND WEEK) Implantation of the blastocyst begins at the end of the first week and is complited by end of the second week. The cellular and molecular events related to implantation are complex. It involves a receptive endometrium and hormonal factors  Estrogen  progesteron  prolactin growth factors HOX genes T he Zona pellucida degenerates (day 5). Its disappearence results from enlargement of the blastocyst and degeneration caused by enzymatic lysis. The lytic enzymes releases from the acrosomes of the sperm that surround and partially penetrate the  zona pellucida. The blastocyst adheres to the endometrial epithelium mainly seen at (DAY 6) The trophoblast differentiate into two layers  syncytiotrophoblast  cytotrophoblast (Day 7) The syncytiotrophoblast  erodes enometrial tissues and the blastocyst starts to embed in the endometrium (day 8) Blood filled lacunae appear in the syncytiotrophoblast (day 9) The blastocysts sinks beneath the en...

  Oocytes are produced by the ovaries and expelled from them during ovulation.The fimbriae of the uterine tube sweep the oocyte into yhe ampilla where it may be fertilized.     Sperms are produced in the testes and stored in epididymis, Ejaculation of semen during sexual intercourse results in the deposit of millions of sperms in the vagina . several hundread sperms pass through the uterus and enter the uterine tubes.                 When oocyte contacted by a sperm ,it completes the second meiotic division . As a result a mature oocyte and a second polar body are formed . the nucleus of the mature oocyte constitutes the female pronucleus.     After the sperm enters the oocyte ,the head of the sperm seperates  from the tail and enlarge to become the male pronucleus. Fertilization is complete when the male and female pronuclei unite and maternal and paternal chromosomes intermingle during metaphase  of the fr...

  TYPE A HEPATITIS Type A Hepatitis(infectious hepatitis) is a subacute disease of global distribution effecting mainly children and young adults. CLINICAL FEATURES  : The large majority of infections are asymptomatic. Overt illness is seen in only about 5% . Incubation period is about 2-6 weeks. clinical disease consists of two stages: prodromal or preicteric icteric onset may be acute or insidious, with fever,malaise,anorexia,nausea,vomiting,and liver tenderness.Recovery is slow, over a periode of 4-6weeks. Very rarely a rapidly fatal fulminant hepatitis may occur. Mortality is low 0.1-1% with most of the deaths occurs in adults. HEPATITIS A VIRUS Morphology : HAV is a 27-nm,non enveloped RNA virus belongs to picornavirus family. HAV is recognised as the prototype of new genus  HEPATOVIRUS. Resistance :  HAV is resistant to inactivation by heat at 60'C for an hour, either and acid at  pH 3,but it is inactivated by boiling for 1 minute,1:4000 formaldehyde at 37...

Subscribe to RSS headline updates from: Powered by FeedBurner   URINARY TRACT ,from the calyces of the kidney to the urethra,is lined with a sheet of epithelium that is continuous with that of skin. Types Of UTI infection of the urinary tract can be anatomically classified as: Uppper UTI : Involves kidney and ureter. Lower UTI : Involves infectionfrom urinary bladder downwards INFECTIONS IN UPPER UTI Acute pyelitis -- Infection of the pelvis of the kidney. Acute pyelonephritis --  Infection of the parenchyma of the kidney. INFECTION IN LOWER UTI Urethritis -  Infection of the urethra. Cystitis -     Infection of the urinary bladder, Prostatitis - Infection in prostate.  PREDISPOSING FACTORS Age - Incidence increases with age. Sex-  Sexually active females are more prone to UTI due to the short urethra ,proximity to the anus and urethral trauma during intercourse. Pregnency-  Due to hormonal changes and dilatation of ureters and renal pelv...

  SUTURE is used by the doctor to close any wounds of your skin and other tissues. TYPES OF SUTURE:  I t is classified as either absorbable or nonabsorbable. ABSORBABLE SUTURE:  Doesnt required any doctor to remove them.[ Dont waste your money in dr clinic] Now the reason why you dont require any doctor because your own body doctor having the potential to release enzymes from tissues capable to digest them. NONABSORBABLE SUTURE:(need doctors) This suture need a doctor to remove them on specific date given by them after surgery. Some cases left in permanently. Types of absorbable suture: Polydioxanose :     synthetic monofilament suture used for the soft tissues wound repair eg:abdominal closures as well as for pediatric cardiac procedures. Gut :    natural microfilament suture used for repairing internal soft tissue wounds. gut should not be used for cardiovascularar or neurological surgery. scars may be visible . Poliglecaprone: synthetic monofilame...