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Beginning at the caudal end total cholesterol level definition buy tricor 160 mg without prescription, cells in the center of the plate degenerate and a vaginal lumen is formed cholesterol medication alzheimers order 160mg tricor visa. The fetal vaginal epithelium is under the influence of maternal hormones and in late fetal life becomes markedly hypertrophied cholesterol in araucana eggs buy tricor 160mg with visa. The external genitalia also pass through an indifferent stage before they develop their definitive sexual characteristics. The caudal end of the primitive hindgut is closed by a cloacal membrane around which the urogenital folds develop. The folds unite at their cranial ends to form the genital tubercle, which, in the female, elongates only slightly to give rise to the clitoris. A pair of genital swellings develops along each side of the genital folds; in the female these remain separate and form the labia majora. Similarly, the urogenital folds do not fuse in the female, and these give rise to the labia minora. Summary the ovary is a cytogenic gland releasing ova and also acts as a cyclic endocrine gland. During its growth in the follicles, the oocyte is nourished by blood vessels of the ovary via the theca interna. When a corpus luteum is formed after ovulation, estrogens and progesterone are produced and are responsible for development of the uterine mucosa prepared for reception of the blastocyst. The periodic nature of hormone production by the ovary establishes the menstrual cycle during which, in the absence of pregnancy, the uterine mucosa is shed. If pregnancy occurs, the corpus luteum persists and its hormonal activity maintains the endometrium in a prepared state. Female reproductive function is regulated primarily by positive and negative feedback loops on neurons in the hypothalamic region of the brain and on cells (gonadotrophs) within the anterior pituitary. Follicle-stimulating hormone influences the growth of late primary and secondary follicles and promotes the formation of estrogens. The oviduct is the site of fertilization of an ovum and also transports the zygote to the uterus as the result of muscular and ciliary actions. Conditions within the oviduct sustain the zygote as it undergoes cleavage during passage through this tube. Nutrition for the zygote is provided by material stored in the cytoplasm of the ovum. On entering the uterine cavity, the blastocyst lies in secretions produced by the endometrium. The secretion is rich in glycogen, polysaccharides, and lipids, providing an excellent "culture medium" for the dividing cells of the blastocyst. The uterine endometrium, to which the blastocyst attaches, provides for the sustenance of the embryo throughout its development. A rich food supply for the implanting blastocyst comes from the secretions of the uterine glands and from products of the uterine stroma as the blastocyst burrows into the endometrium. These products are absorbed by the syncytial trophoblast and diffuse to the developing embryo. As the trophoblast continues to erode into the endometrium, blood-filled spaces form, and the blastocyst is bathed by pools of maternal blood that supply the embryo with nourishment. When a placenta has been established, the nutritional, respiratory, and excretory needs of the embryo are met by this fetal-maternal membrane. The placenta also has protective functions, preventing passage of particulate matter to the embryo. The basal layer of the endometrium is not shed at parturition or at menstruation and provides for the restoration of the uterine mucosa after these events have occurred. Changes in the secretory activities of cervical glands during the menstrual cycle may have some significance in fertility. During most of the cycle, the glands produce a thick, viscous mucus that appears to inhibit passage of sperm. The thin, less viscid mucus elaborated at midcycle appears to favor the movement of sperm into the proximal regions of the female reproductive tract. The mammary glands provide nourishment for the newborn, which is delivered in an immature and dependent state. The first secretion, colostrum, has a high content of immunoglobulins and give passive immunity to the suckling young. Passage of milk from the alveoli into the initial segments of the ducts is accomplished by contraction of myoepithelial cells under the influence of the hormone oxytocin. However, hormones also may be secreted directly into the intercellular space (paracrine secretion) to elicit a local effect on adjacent cells. In some instances cells may secrete a chemical messenger that acts on its own receptors and is self-regulatory (autocrine secretion). Hormones that are secreted into the vascular system eventually enter the tissue fluids and, depending on the specificity of the hormone, can alter the activities of just one organ or influence several. The organs that respond to a specific hormone are the target organs of that hormone. Hormones may be classified into three general categories according to their chemical structure: amino acid polymers (polypeptides, proteins, or glycoproteins), cholesterol derivatives (sterols and steroids), and tyrosine derivatives (thyroid hormones and catecholamines). Many of the peptide and protein hormones exist in the circulation in a free state unbound to other elements in the plasma. In contrast, thyroid and steroid hormones circulate in the blood bound to specific plasma carrier proteins. When the hormone molecules reach their destination they become involved in cell-to-cell signaling and interact with their target cells through specific hormone-receptor interactions. The targeted receptor may reside within the plasmalemma, the cytoplasm, or the nucleus. The resulting hormone-receptor interaction may generate secondary messenger molecules or influence gene expression. In some glands, such as the liver, the epithelial cells have both exocrine and endocrine functions. Hepatocytes fulfill the definition of endocrine cells because they release glucose, proteins, and other substances directly into the blood of the hepatic sinusoids, but the same hepatocytes also secrete bile into adjacent canaliculi (the beginnings of the liver duct system) and thus are exocrine cells also. Organs such as the pancreas, kidney, testis, and ovary are mixtures of endocrine and exocrine components in which separate or isolated groups of cells that secrete directly into the vasculature form the endocrine portion. The placenta is a unique, temporary endocrine organ that persists only for about 9 months in pregnant women. What are termed classic endocrine glands consist of discrete masses of cells with a relatively simple organization into clumps, cords, plates or follicles supported by a delicate vascular connective tissue. Endocrine glands have a rich vascular supply, and the secreting cells have direct access to capillaries. Historically, the classic endocrine system consists of the pineal, parathyroid, thyroid, adrenal, and pituitary glands. A vast system of unicellular endocrine cells (glands) also exists, and collectively these cells form a diffuse endocrine system. It is represented by scattered unicellular glands that often lie at some distance from one another, separated by cells of a different type. These cells are present throughout much of the gastrointestinal tract, in the ducts of the major digestive glands, and in the conducting airways of the lungs.
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Numerous macrophages are present in the luminal network and also project from the boundaries of the sinus zinc cholesterol levels tricor 160 mg mastercard. The cells that form the margins of the sinuses and extend through the sinus space generally are regarded as flattened reticular cells high cholesterol diet definition tricor 160mg overnight delivery. However cholesterol lowering foods list dr oz buy genuine tricor on line, they also have been considered to be attenuated endothelial cells akin to those which line the lymphatic vessels with which they are continuous. Sinuses in the cortex are less numerous than in the medulla and are relatively narrow. Those in the medulla are large and irregular and show repeated branchings and anastomoses. They run a tortuous course in the medullary parenchyma and account for the irregular cordlike arrangement of the lymphatic tissue in this area. The arteries (arterioles) at first run within the trabeculae in the medulla but soon leave these and enter the medullary cords to pass to the cortex. The capillaries regroup to form venules that run from the cortex and enter the medullary cords as small veins. These in turn are tributaries of larger veins that pass out of the node at the hilus. In the deep cortex, the venules take on a special appearance and have been called postcapillary venules. These vessels are characterized by a high endothelium that varies from cuboidal to columnar and at times appears to occlude the lumen. The walls of these vessels often are infiltrated with small lymphocytes that generally are presumed to be passing into the lymph node. The cells pass between adjacent endothelial cells, indenting their lateral walls as they cross through the endothelium. The significance of the tall endothelium is not known, but it has been suggested that as the lymphocytes sink deeper between them, the adjacent endothelial cells resume their original relationship to each other above the lymphocytes and seal off the interendothelial cleft, thereby limiting the loss of plasma from the venule. Broad bands of connective tissue, the trabeculae, extend from the inner surface of the capsule and pass deeply into the substance of the spleen to form a rich, branching and anastomosing framework. As in lymph nodes, the trabeculae subdivide the organ into communicating compartments. The spaces between trabeculae are filled by a reticular network of fibers and associated reticular cells. The meshes vary in size and tend to be smaller around blood vessels and aggregates of lymphatic tissue. The substance of the spleen is called the splenic pulp, and sections from a fresh spleen show a clear separation of the tissue into rounded or elongated grayish areas set in a greater mass of dark red tissue. Collectively, the scattered gray areas form the white pulp and consist of diffuse and nodular lymphatic tissue. The dark red tissue is the red pulp and consists of diffuse lymphatic tissue that is suffused with blood. The red pulp contains large, branching, thin-walled blood vessels called splenic sinusoids (sinuses), and such spleens are said to be sinusal. Spleen the spleen embodies the basic structure of a lymph node and can be regarded as a modified, enlarged lymph node inserted into the blood flow. Unlike lymph nodes, the spleen has no afferent lymphatics and no lymphatic sinus system, and the lymphatic tissue of the spleen is not arranged into a cortex and medulla. It does have a distinctive pattern of blood circulation and specialized vascular channels that facilitate the filtering of blood. The sheaths have the structure of diffuse lymphatic tissue and contain the usual cellular elements of lymphatic tissue. Here and there along the course of the sheath, the lymphatic tissue expands to incorporate lymphatic nodules that resemble the cortical nodules of lymph nodes. At the periphery of the lymphatic sheath, the reticular net is more closely meshed than elsewhere, and the reticular fibers and cells form concentric layers that tend to delimit the lymphatic tissue from the red pulp. Elastic fibers are present between bundles of collagen fibers and are most abundant in the deeper layers of the capsule. Smooth muscle fibers also may be present in small groups or cords, but the amount varies. On the medial surface of the spleen, the capsule is indented to form a cleft-like hilus through which blood vessels, nerves, and lymphatics enter or leave the spleen. These dendritic-like cells are called interdigitating cells and also represent antigenpresenting cells. Branches of the splenic artery enter the spleen at the hilus, divide, and pass within trabeculae into the interior of the organ. These branches have an over-lapping, segmental arrangement, with each main branch serving a defined area of the spleen. The trabecular arteries, as they now are called, branch repeatedly, finally leaving the trabeculae as central arteries that immediately become surrounded by the lymphatic tissue of the periarterial lymphatic sheath. Where the sheath expands to form nodules, the central artery (more appropriately called the follicular arteriole) is displaced to one side and assumes an eccentric position in the nodule. Throughout its course in the white pulp, the central artery provides numerous capillaries that supply the sheath and then pass into the marginal zone surrounding the white pulp. Many arterial branches appear to open directly into the marginal zone, often ending in a funnel-shaped terminal part. There is no direct venous return, and the white pulp is associated only with the arterial supply. Although the term artery commonly is used for the different levels of the splenic vasculature, once the vessel has reached lymphatic tissue, it is actually an arteriole. The central artery continues to branch, and its attenuated stem passes into a splenic cord in the red pulp, where it divides into several short, straight penicillar arteries, some of which show a thickening of their wall and now form sheathed capillaries. The sheath consists of compact masses of concentrically arranged cells and fibers that become continuous with the reticular network of the red pulp. Close to the capillary the cells of the sheath are rounded, while at the periphery of the sheath the cells become stellate. Not all the capillaries are sheathed, and occasionally, a single sheath may enclose more than one capillary. The reticular meshwork is continuous throughout the red pulp and is filled with large numbers of free cells, including all those usually found in the blood. Thus, in addition to the cells of lymphatic tissue, the red pulp is suffused with red cells, granular leukocytes, and platelets. Occasionally, macrophages can be seen that contain ingested red cells or granulocytes or that are laden with a yellowish brown pigment, hemosiderin, derived from the breakdown of hemoglobin. The red pulp is riddled with large, irregular blood vessels, the splenic sinusoids, between which the red pulp assumes a branching, cordlike arrangement to form the splenic cords. Almost the entire wall is made up of elongated, fusiform endothelial cells that lie parallel to the long axis of the vessel. The cells lie side by side around the lumen but are not in contact and are separated by slitlike spaces. Outside the endothelium, the wall is supported by a basement membrane that is not continuous but forms widely spaced, thick bars that encircle the sinusoid.
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Global persistence may be unilateral cholesterol healthy foods order on line tricor, caused by renal artery stenosis cholesterol test kit nz generic 160mg tricor overnight delivery, renal vein thrombosis cholesterol production buy tricor 160 mg low price, or urinary tract obstruction, or due to systemic hypotension, intratubular obstruction, or abnormalities in tubular function. Striated nephrograms are caused by ureteric obstruction, acute pyelonephritis, contusion, renal vein thrombosis, tubular obstruction, hypotension, and autosomal recessive polycystic disease. However, to date, the evaluation of these parameters is more in the field of research than in clinical practice. Anorectal Malformation Nuclear Medicine Because the excretion of radiopharmaceuticals depends on renal function, they cannot be used to evaluate all patients with renal failure. This is particularly true for products (Technetium) excreted primarily by glomerular filtration, whereas products excreted by tubular secretion may demonstrate the kidneys even when renal dysfunction is relatively advanced. In clinical practice, radionuclide studies usually only help exclude arterial occlusion, because images are difficult to interpret when renal function is markedly impaired. Intermittent Imaging Imaging of ultrasound contrast media at a low frame rate (typically one image every second or every few seconds) to minimize bubble destruction caused by the ultrasound itself. Time Intensity Curves I Diagnosis In most cases, the cause of the renal failure is known (diabetic nephropathy, uropathy, polycystic kidney disease) and the goals of imaging will be to look for an aggravating factor (obstacle, stenosis of the renal artery). In some cases, the renal failure is discovered after clinical findings of hyperuremia or is more often revealed by biochemical test results. To seek the cause of the nephropathy: tubular, glomerular, interstitial, or vascular. This diagnostic step is crucial because (a) some diagnoses are obvious on imaging (polycystic kidney disease, bladder outlet obstruction), (b) in some cases it may be possible to treat the cause (surgery of a uropathy, dilatation of a stenosis of the renal artery), (c) the prognosis depends on the cause, (d) some renal diseases (glomerulopathy) may recur on the renal transplant;. In patients with a suspicion of vascular nephropathy, Doppler will look for findings of stenosis of the renal artery. Naturally, the disc with its posterior attachment is located in closed-mouth position on the zenith of the condyle. During the opening of the mouth, the condyle and the disc slide on the tuberculum articulare. In joints presenting a disc displacement, the disc is located in front of the condyle. In other cases, the condyle might not slide on the disc during mouth opening (anterior disc displacement without reduction). Consequently, there is often a limitation of the mouth opening in combination with pain as the disc closes the condyle in its movement. However, many subjects present an anterior disc displacement without suffering from any clinical signs or symptoms (the data vary between 7% and 35%). When the mouth is open, the disc is interposed between the head of the mandible and the tubercle in the sagittal plane. Portions of the articular disc are not infrequently located medial to the head of the mandible in the coronal plane. The head of the mandible is homogeneously structured without bony attachments and/or conspicuous flat areas. The distinction between partial and complete anterior displacement in the closed-mouth position has no clinical relevance. What is clinically important is whether the disc resumes its normal position relative to the condyle when patients open their mouths (anterior disc displacement with reposition) or whether the disc remains anterior to the condyle on mouth opening (anterior disc displacement without reposition. The disc has a posterior attachment to the ligamentous apparatus (the superior and inferior strata of the bilaminar zone). It consists of an avascular anterior part, which is composed of fibrocartilage and a vascularised posterior part. The anterior part includes an anterior band, an intermediary zone and a posterior band. The face of a clock can be used for describing the anatomical location of the disc in relation to the condyle with the head of the mandible in the middle. When the mouth is closed, the posterior attachment of Internal Derangement, Temporomandibular Joint. Figure 1 Schematic drawing of a normal disc in the closed mouth (a) and opened mouth position, sagittal view (b). Internal Derangement, Temporomandibular Joint 983 I Internal Derangement, Temporomandibular Joint. Clinical Presentation and Examination the main clinical symptom is unilateral arthrogenous pain and/or a limited mandibular range of motion. For the clinical examination of the stomatognathic system, standardised criteria should be used and applied by calibrated examiners to obtain a higher reliability (1). A basic distinction should be made between arthrogenic and myogenic changes, which is often difficult, especially in patients with limited mouth opening. Diagnosis is facilitated by detailed information about clinical findings and their diagnostic significance. For this reason, the approach to the patient should include an assessment of psychosocial factors, although arthrogenic disorders are less commonly associated with psychosocial findings than myogenic disorders. Internal Derangement (Coronal View) While there is an extensive literature on the pathology of internal derangement in the sagittal plane, very few studies have focused on the coronal view. Normal and abnormal disc positions in the coronal plane, for example, have not yet been sufficiently defined. A review of the literature shows that there is only one prospective study that describes disc positions in a population of symptomfree subjects. Medial displacement of the disc on mouth opening has been described as a pathological condition in many publications but appears to be within the range of normal variation. By contrast, the absence of a medial orientation seems to be a pathological finding. In addition, the coronal view can help avoid falsenegative results in patients evaluated for disc position in the sagittal plane. In addition, the range of motion of the mandible is assessed by measuring (maximum) mouth opening as well as lateral and protrusive movements. An additional clinical item to be considered is the assessment of joint sounds since grinding sounds, for example, may be indicative of changes in the shape of the condyle. The higher the image quality, the higher will be inter-rater reliability or in other words, the level of agreement between the examiners with regard to disc position (4). For this reason, high image resolution and a good signal-to-noise ratio are important. Further factors that make image acquisition difficult are the pain that most patients feel when opening their mouth and the movements of the mandible that are associated with swallowing. This limits the examination time and requires the use of magnetic resonance systems with a field strength of 1.
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Allergic rhinitis and conjunctivitis (rhinoconjunctivitis) this can be atopic (associated with IgE antibodies to cholesterol lowering foods vitamins purchase genuine tricor online common inhalant allergens) or nonatopic cholesterol what is high order tricor 160mg line. Thosewhohadasevere reaction should carry an epinephrine (adrenaline) autoinjector cholesterol goals generic tricor 160mg on line,andallergenimmunotherapyshouldbe considered. This is usually because viral illnesses, for which children are often prescribed antibiotics, themselves cause skin rashes. Allergyskinandbloodtestscanbeusedtosupport a diagnosis of drug allergy, but a drug challenge maybetheonlywaytoconclusivelyconfirmorrefute the diagnosis. This is contraindicated after a severe allergic reaction and an alternative drug should be sought. Anaphylaxis this serious and potentially lifethreatening allergic reaction is described in Chapter 6 on Paediatric emergencies. Websites (Accessed April 2011) Food Allergy and Anaphylaxis Network: Available at. Mostaremildselflimitingillnessesof theupperrespiratorytract(ear,nose,throat)butsome, such as bronchiolitis or pneumonia, are potentially lifethreatening. The important bacterial pathogens of the respira tory tract are Streptococcus pneumoniae (pneumococ cus) and other streptococci, Haemophilus influenzae, Moraxella catarrhalis,Bordetella pertussis,whichcauses whooping cough, and Mycoplasma pneumoniae. Itisininfancythatseriousres piratory illness requiring hospital admission is most commonandtheriskofdeathisgreatest. Thereisan increased frequency of infections when the child or oldersiblingsstartnurseryorschool. Repeatedupper respiratory tract infection is common and rarely indi catesunderlyingdisease. Pneumonia Bronchiolitis Viral croup Epiglottitis Upper respiratory tract infections 16 Respiratory disorders Tonsillitis Tonsillitis is a form of pharyngitis where there is intense inflammation of the tonsils, often with a purulent exudate. Group A haemolytic streptococcus can be cultured from many tonsils; however,itisuncertainwhyitcausesrecurrenttonsil litisinsomechildrenbutnotinothers. Although the surface exudates seen in infectious mononucleosisarereportedtobemoremembranous in appearance compared to bacterial tonsillitis, in realityitisnotpossibletodistinguishclinicallybetween viralandbacterialcauses. Antibiotics(oftenpenicillin,orerythromycinifthere is penicillin allergy) are often prescribed for severe pharyngitisandtonsillitiseventhoughonlyathirdare caused by bacteria. In severe cases, children may require hospital admission for intravenous fluid administration and analgesia if they are unable to swallow solids or liquids. Amoxicillin isbestavoidedasitmaycauseawidespreadmaculo papular rash if the tonsillitis is due to infectious mononucleosis. It is not possible to distinguish clinically between viral and bacterial tonsillitis. Thecommonestpresentationisachildwithacombina tion of nasal discharge and blockage, fever, painful throatandearache. In infants, hospital admission may be required to exclude a more serious infection, if feeding is inade quate,orforparentalreassurance. Infants and young children are prone to acute otitis media because their Eustachian tubes are short, hori zontalandfunctionpoorly. In acute otitis media, the tympanic membrane is seen to be bright redandbulgingwithlossofthenormallightreflection. Occasionally,thereisacuteperforationof the eardrum with pus visible in the external canal. Regular a analgesia is more effective than intermittent (as required)andmaybeneededforuptoaweekuntilthe acuteinflammationhasresolved. Antibioticsmargin ally shorten the duration of pain but have not been the common cold (coryza) Thisisthecommonestinfectionofchildhood. Classical features include a clear or mucopurulent nasal dis chargeandnasalblockage. Health educationtoadviseparentsthatcoldsareselflimiting and have no specific curative treatment may reduce anxiety and save unnecessary visits to doctors. Antibioticsareofnobenefitasthecommoncold is viral in origin and secondary bacterial infection is veryuncommon. Sore throat (pharyngitis) the pharynx and soft palate are inflamed and local lymphnodesareenlargedandtender. Sorethroatsare usually due to viral infection with respiratory viruses (mostlyadenoviruses,enterovirusesandrhinoviruses). Confirmation of otitis media with effusion can be gained by a flat traceontympanometry,inconjunctionwithevidence ofaconductivelossonpuretoneaudiometry(possible if >4 years old), or reduced hearing on a distraction hearingtestinyoungerchildren. Otitismediawitheffu sionisverycommonbetweentheagesof2and7years, with peak incidence between 2. Otitismediawitheffusionisthemostcommoncauseof conductive hearing loss in children and can interfere withnormalspeechdevelopmentandresultinlearning difficultiesinschool. Itisbelievedthattheadenoidscanharbourorganisms within biofilms that contribute to infection spreading uptheEustachiantubes. Inaddition,grosslyhypertro phiedadenoidsmayobstructandaffectthefunctionof theEustachiantubes,leadingtopoorventilationofthe middle ear and subsequent recurrent infections. Occasionally there is secondary bacterial infec tion,withpain,swellingandtendernessoverthecheek from infection of the maxillary sinus. As the frontal sinuses do not develop until late childhood, frontal sinusitisisuncommoninthefirstdecadeoflife. Anti biotics and analgesia are used for acute sinusitis in additiontotopicaldecongestants. Thereissomerecent evidencethattheconcurrentuseofintranasalcortico steroids or antihistamines together with antibiotics hastenrecovery. Tonsillectomy and adenoidectomy Childrenwithrecurrenttonsillitisareoftenreferredfor removaloftheirtonsils,oneofthecommonestopera tions performed in children. Many children have large tonsils but this in itself is not an indication for tonsillectomy, as they shrink spontaneously in late childhood.
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Especially in claudicants cholesterol test new generic tricor 160 mg on line, the risk therefore needs to high cholesterol chart australia cheapest generic tricor uk be well balanced with the potential benefit cholesterol your body makes generic tricor 160 mg online. Clinic of Radiology and Nuclear medicine, University Hospitals Schleswig-Holstein, Campus Luebeck 2 Department of Diagnostic and Interventional Radiology, University of Pisa, Pisa, Italy thomas. Pathology and Histopathology Cholestasis may be related to mechanical, cellular, and metabolic causes. Mechanical biliary obstruction may be due to intrinsic or extrinsic obstruction of bile flow, which can occur either at the intrahepatic or extrahepatic level (Table 1). Extrinsic compression of extrahepatic biliary tract includes benign conditions (Mirizzi syndrome, enlarged lymph nodes, pancreatitis, local benign tumors, and cysts), and malignant conditions (gallbladder carcinoma, malignant lymphadenomegalies, pancreatic head carcinoma, stomach and colon cancers) (1). Clinical Aspects Symptoms are determined by abnormal elevation of primary and secondary bile products in blood and the absence of the extrinsic intestinal bile function. Additionally, cholangitis may represent a concomitant complication in biliary obstruction. Common symptoms are jaundice, pale coloured stools, dark urine, itching, fever, and right upper quadrant pain. Blood tests show increase of bilirubin, alkaline phosphatase, and hepatic enzymes. Imaging Plain radiographs are of limited value to detect abnormalities in the biliary system. Biliary obstruction results in dilatation of bile ducts involving the biliary tree proximally to the obstruction; depending on the site of obstruction, the bile ducts dilatation may involve an isolated lobe or segment or both lobes. Nevertheless, the absence of bile ducts dilatation does not exclude recent or intermittent obstruction. While peripheral ductal branches can be visualized only if dilated, the normal common bile duct is easily displayed (2). The demonstration of common bile duct calculi is strongly dependent on their location within the biliary system; in fact, calculi in the lower part of the common bile duct may be obscured by duodenal gas. Intrahepatic intrinsic biliary obstruction can be due to: congenital affections (biliary atresia, Alagille syndrome, intrahepatic calculi complicating Caroli disease and cystic fibrosis), benign conditions (intrahepatic ductal stones, sclerosing cholangitis, and biliary parasitosis), and malignant conditions, with cholangiocarcinoma as the most important malignant cause. Extrinsic causes of intrahepatic obstruction include compression by benign and malignant tumors. Extrahepatic intrinsic biliary obstruction can be due to: congenital anomalies (choledochal atresia, choledochal cysts), benign conditions Occlusion, Bile Ducts 1393 Occlusion, Bile Ducts. Ultrasound can easily demonstrate dilatation of both intrahepatic and extrahepatic bile ducts in mechanical biliary obstruction. In general, this condition can be clarified by additional unenhanced and contrast-enhanced T1- and T2-weighted axial (and/or multiplanar) sequences. In general, stone-related obstruction can be displayed easily with the concave transition from fluidfilled ductal lumen to the stone and the usually smooth, regular outlining of the lumen. An irregular tapering of the lumen can often be seen in malignant obstructions due to an extrinsic or infiltrating mass that can be uncovered by cross-sectional imaging. Typical examples for that are tumors of the pancreatic head affecting the common bile duct alone or together with the pancreatic duct (so called "double duct sign," in about 5% of cases of pancreatic cancer). O Interventional Radiology Radiologic interventional procedures in biliary obstruction may be performed using either a percutaneous or an endoscopic approach or a combination of both. Possible interventions are catheter placement, biliary stenting, balloon dilatation of biliary strictures, stone removal, and tissue sampling. Stone removal is the most common biliary intervention and generally performed by endoscopy. Usually a papillotomy is necessary, followed by stone extraction by balloon or basket instruments guided by the endoscope. Larger stones (>2 cm in diameter) are less prone to endoscopical removal and present a higher risk of perforation, bleeding, secondary pancreatitis, and cholangitis (3, 4). Sequentially, a stone can be removed or an 1394 Occlusion, Bowel in Childhood obstruction can be treated. In cases of unsuccessful or impractical endoscopic maneuvers, stone removal, or stone fragmentation and stent placement are also percutaneously possible. Balloon dilatation can be necessary both in patients with benign and malignant biliary strictures. Among the benign strictures biliary-enteric anastomotic strictures respond best to dilatation whereas a temporarily support by a drainage tube may enhance the result (5). Malignant strictures, due to the high radial force compressing the ductal system or the intruding mass within the duct, often require the combination of balloon dilatation, temporarily drainage and stent placement. There are three types of stents, which are used in biliary intervention: plastic endoprostheses (polyethylene stents), balloon-expandable metallic stents, and self-expandable metallic stents with and without covering. Metallic stents become strongly adherent to the bile duct and are impossible to remove. In the setting of malignancy, stents are mainly indicated for the palliation of patients with unresectable tumors. In such cases, metallic stents are preferred because they remain patent much longer than polyethylene stents and usually a single session of metal stenting maintain ductal patency for the reminding lifetime of the patients (6). Occlusion of metallic stents usually is determined by tumoral in-growth and can create the need for further interventions. For treatment of benign biliary strictures, plastic endoprostheses are preferred, since they are needed in most cases only for limited time. Nevertheless, in chronic recurrent biliary stenoses where a long-term treatment is needed, they may be occluded by biliary encrustations, while in metallic stents reactive epithelial hyperplasia may occur. Associated cross-sectional images adequately demonstrate extra-ductal findings (1). Currently they should be performed only to guide interventional procedures and cannot be recommended as diagnostic imaging techniques (2). N Engl J Med 24, 328(25)1855 Portincasa P, Moschetta A, and Palasciano G (2007) Cholesterol gallstone disease. Imaging has the role to confirm biliary obstruction and to establish the level and the cause of obstruction. This may be due to extrinsic compression of the bowel, an intrinsic abnormality of the wall or lumen of the bowel, or due to a filling defect in the lumen of the bowel. Occlusion, Bowel in Childhood 1395 Pathology/Histopathology Any of the pathologies listed in the tables may give rise to bowel obstruction and if the diagnosis is delayed this may go on to cause bowel ischaemia with necrosis and possible perforation. Clinical Presentation the infant or child will usually present with abdominal distension, irritability, pain and vomiting, or high nasogastric aspirates if a tube is in place. The timing of the clinical presentation may be partly determined by the underlying causes: congenital causes will usually present in the first few hours or days of birth and 95% of small bowel obstruction in the perinatal period is due to an atresia of some type. Meconium ileus will present within the first 48h of life and occurs almost exclusively in patients with cystic fibrosis. Small left colon syndrome (also termed meconium plug syndrome and functional immaturity of the colon) presents with failure to pass meconium and an increasingly dilated abdomen. Intussusception is the most common cause of obstruction in infants of 3 to 6 months. Post-operative adhesions may occur at any time but most frequently in the first 6 months following surgery and in approximately 2% of patients who have had a laparotomy, accounting for 7% of small bowel obstruction overall.
Mg (Magnesium). Tricor.
- Decreasing the risk of stroke.
- Dyspepsia (heartburn or "sour stomach") as an antacid.
- Use as a laxative for constipation or preparation of the bowel for surgical or diagnostic procedures.
- Premenstrual syndrome (PMS).
- Helping to restart the heart.
- Conditions that occur during pregnancy called pre-eclampsia or eclampsia.
- Irregular heartbeat (arrhythmia).
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Normal transplanted pancreas appears homogeneous high cholesterol chart usa cheap tricor 160mg online, with echogenicity similar to cholesterol definition quizlet buy tricor cheap online that of muscles and surrounded by more echogenic omental and peritoneal fat; expected dimensions of the normal pancreatic head cholesterol lowering snack foods generic 160mg tricor otc, body, and tail are no greater than 3 cm, 2. Color or power Doppler imaging can aid in locating the pancreas, by showing vascular anastomoses and intraparenchymal major vessels. Furthermore color and power Doppler sonography are able to assess vascularization and spectral analysis of intraparenchymal and peduncular venous and arterial flow can be performed. Figure 1 Left image: anatomical representation of the systemic-bladder pancreatic drainage. The duodenum (d) is anastomosed with bladder (b), while the arterial and venous grafts of the pancreas (p) are anastomosed with the common iliac artery (arrow) and with the common iliac vein (double arrow), respectively. Figure 2 Left image: anatomical representation of the enteric-portal pancreatic drainage. The duodenum (d) drains the exocrine secretion of the pancreas (p) in a small bowel loop (l), while the venous graft is anastomosed with the superior mesenteric vein (arrow). Graft Acute and Chronic Rejection Graft rejection represents the most fearful complication of transplantation. Acute rejection is characterized by mononuclear inflammation and usually responds to increased immunosuppression, while chronic rejection consists of luminal narrowing and intimal thickening of the vessels, which leads to fibrosis and hypoperfusion, with consequent poor pancreatic exocrine and endocrine function without improvement with therapy. Therefore early detection of acute rejection is of critical importance to institute an adequate immunosuppressive therapy to prevent further graft loss. Unfortunately the early sign of both acute and chronic rejection may be subtle and aspecific. Delayed finding include hyperglicemia, because endocrine function may continue with only 25% of endocrine cells functioning. Because renal rejection could easily be diagnosed by monitoring serum creatinine levels, the accepted practice is to use renal rejection to determine pancreas rejection. Ultrasound abnormalities that have been associated with acute rejection include gland enlargement and either focal or diffuse areas of decreased echogenicity, peripancreatic fluid, without pancreatic duct dilatation; however the demonstration of early signs of rejection with ultrasound remains inconstant. Moreover, these findings are also seen in cases of vascular compromise and pancreatitis. Unlike renal transplants for which specific resistive index values have been proved to be accurate predictors of acute rejection, no reliable resistive index measurement has been established for at-risk pancreatic grafts, because the pancreatic graft lacks a capsule, and an edematous pancreatic graft may not possess adequate intraparenchymal pressure to produce a reliable measurement of vascular resistance. Although changes in resistive index are a poor indicator of acute rejection, the absolute value of the resistive index results elevated in cases of chronic rejection. In cases of suspected acute graft rejection often histopathologic diagnosis remains the most effective and reliable method. In chronic rejection the pancreas appears small, with inhomogeneous parenchymal structure or completely calcified, and vascular abnormalities (stenosis or obstructions) can be found. T Vascular Complications Vascular complications of pancreatic grafts are common, with vascular thrombosis second only to acute rejection in abnormalities leading to graft loss. Late thrombosis which 1850 Transplantation, Pancreas occurs more than 1 month after surgery, can results from severe acute rejection, leading to arteritis. Early graft thrombosis has been attributed to a variety of etiologic factors, such as surgical vascular graft lesions, procurement and perfusion injury, poor preservation, reperfusion injury reflecting total cold ischemia time, and, in arterial thrombosis, anastomosis to atherosclerotic vessels. Moreover splenectomy causes low-flow in splenic vessels, predisposing to thrombosis. Partial early venous or arterial thrombosis may be completely asymptomatic, without causing pancreatic dysfunction; partial venous thrombosis can be treated by means of systemic heparin, while partial arterial thrombosis may not require treatment. In case of complete vascular thrombosis prompt treatment is necessary, by means of surgical thrombectomy, Fogarty chateters or transchateter fibrinolysis or heparin, to avoid parenchymal infarction, which require immediate remove of the organ. Other possible vascular complications include arterial stenoses which are usually secondary to intimal damage in the site of surgical anastomoses or caused by clamping of the artery or by the catheter used for perfusion of the organ. Other arterial lesions that may occur include pseudoaneurysms and arteriovenous fistula secondary to percutaneous biopsy. An arteriovenous fistula between the superior mesenteric artery and superior mesenteric vein occurs occasionally and is related to the surgical technique of stapling the mesenteric vessels together rather than separate dissection and ligature of the vessels. Doppler sonography has been particularly important in detecting vascular complications such as thrombosis, anastomotic strictures, and pseudoaneurysm formation. Thrombosis is demonstrated by the absence of perceptible arterial or venous tracings as well as by direct visualization of intraluminal echogenic material that occludes blood flow. High velocity or turbulence at the arterial or venous anastomoses suggests strictures, and arterial flow within a perianastomotic fluid collection, the presence of swirling blood flow at color flow sonography indicates a complicating pseudoaneurysm. Parenchymal ischemic infarction is suggested in the absence of contrast enhancement in the arterial and venous phases. Pancreatitis Pancreatitis of the allograft occurs to some degree in all patients postoperatively. In bladder-drained pancreas transplantation pancreatitis can occur because of the reflux of urine through the ampulla and into the pancreatic ducts. It is possible to observe a complete arterial (arrow) and venous (double arrow) thrombotic obstruction and the absence of parenchymal enhancement in both arterial and venous phases. The radiological findings in pancreatitis are nonspecific and similar to the features seen in acute rejection. A small amount of fluid around the pancreatic allograft due to leakage at the site of the anastomosis is commonly seen. In some cases infection of fluid collections and sepsis may occur, favored by immunosuppression. In such cases systemic antibiotic therapy and sometimes image-guided percutaneous fine needle aspiration with chemical analysis and bacterial culture are required; fluid collection can be drained, if appropriate, by percutaneous image-guided techniques. Infection of peripancreatic collection may result in necrosis of the transplanted organ and necessitate its surgical removal. In bladder exocrine drainage some fluid collections may originate from leak of the duodenocystostomy, while in enteric-drained pancreas transplantation leak of duodenoenterostomy can occur, leading in both cases to severe infectious peritonitis. This serious complication requires prompt imaging diagnosis to perform operative repair. Sonography is a suitable method for detecting retroperitoneal or intraperitoneal fluid collections; however, the findings are usually nonspecific. Hematomas, abscesses, urinary leaks, ascites, and anastomotic leaks can appear as anechoic, hypoechoic, or complex, debris-filled, irregular collections. Transvaginal Sonography An imaging technique used to examine the female genital organs, i. For the transvaginal appraoch, a high resolution probe is inserted into the vagina that causes sound waves to bounce off organs inside the pelvis. These ultrasound waves creates echoes that a re sent to a computer, which creates a picture called a sonogram.
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Explain that as long as the patient has decisionmaking capacity and does not indicate otherwise cholesterol coconut oil order cheap tricor on-line, communication of information concerning his/her care will not be withheld cholesterol test drink water order 160mg tricor free shipping. However cholesterol eggs buy cheap tricor 160 mg on line, if you believe the patient might seriously harm himself or others if informed, then you may invoke therapeutic privilege and withhold the information. The patient retains the right to make decisions regarding her child, even if her parents disagree. Provide information to the teenager about the practical issues of caring for a baby. Encourage discussion between the teenager and her parents to reach the best decision. In the overwhelming majority of states, refuse involvement in any form of physicianassisted suicide. If it is serious, suggest that the patient remain in the hospital voluntarily; patient can be hospitalized involuntarily if he/she refuses. Suggest that the patient speak directly to that physician regarding his/her concerns. If the problem is with a member of the office staff, tell the patient you will speak to that person. Regardless of the outcome, a physician is ethically obligated to inform a patient that a mistake has been made. A terminally ill patient requests physician assistance in ending his/her own life. Discuss all treatment options with patients, even if some are not covered by their insurance companies. Do not necessarily pressure patient to leave his or her partner, or disclose the incident to the authorities (unless required by state law). Find out why and allow patient to do so as long as there are no contraindications, medication interactions, or adverse effects to the new treatment. Gently explain to family that there is no chance of recovery, and that brain death is equivalent to death. Bring case to appropriate ethics board regarding futility of care and withdrawal of life support. Generally, decline gifts and sponsorships to avoid any appearance of conflict of interest. Work with the patient by either explaining the treatment or pursuing alternative treatments. A pharmaceutical company offers you a sponsorship in exchange for advertising its new drug. Emergent care can be refused by the are unresponsive following a car healthcare proxy for an adult, particularly when patient preferences are known or accident and are bleeding internally. Children not meeting milestones may need assessment for potential developmental delay. Language-1000 words by age 3 (3 zeros), uses complete sentences and prepositions (by 4 yr) Legends-can tell detailed stories (by 4 yr) Car seats for children Children should ride in rear-facing car seats until they are 2 years old and in car seats with a harness until they are 4 years. Older children should use a booster seat until they are 8 years old or until the seat belt fits properly. Payment is denied for any service that does not meet established, evidence-based guidelines. Patients are allowed to see providers outside of the network, but have higher out-of-pocket costs, including higher copays and deductibles, for out-of-network services. Patients are limited (except in emergencies) to a network of doctors, specialists, and hospitals. Patient pays for all expenses associated with a single incident of care with a single payment. Most commonly used during elective surgeries, as it covers the cost of surgery as well as the necessary pre- and postoperative visits. Medicare and Medicaid Medicare and Medicaid-federal social healthcare programs that originated from amendments to the Social Security Act. Medicare is available to patients 65 years old, < 65 with certain disabilities, and those with end-stage renal disease. Medicaid is joint federal and state health assistance for people with limited income and/ or resources. Available to patients on Medicare or Medicaid and in most private insurance plans whose life expectancy is < 6 months. Facilitating comfort is prioritized over potential side effects (eg, respiratory depression). This prioritization of positive effects over negative effects is known as the principle of double effect. Event reporting systems collect data on errors for internal and external monitoring. Standardization improves process reliability (eg, clinical pathways, guidelines, checklists). Impact on patients: Plan-define problem and solution Do-test new process Study-measure and analyze data Act-integrate new process into regular workflow Act Plan Study Do Quality measurements Plotted on run and control charts. The risk of a threat becoming a reality is mitigated by differing layers and types of defenses. Patient harm can occur despite multiple safeguards when "the holes in the cheese line up. Medical error analysis Root cause analysis Uses records and participant interviews to identify all the underlying problems that led to an error. Categories of causes include process, people (providers or patients), environment, equipment, materials, management. Uses inductive reasoning to identify all the ways a process might fail and prioritize these by their probability of occurrence and impact on patients. Forward-looking approach applied before process implementation to prevent failure occurrence. Within each Organ System are several subsections, including Embryology, Anatomy, Physiology, Pathology, and Pharmacology. As you progress through each Organ System, refer back to information in the previous subsections to organize these basic science subsections into a "vertically integrated" framework for learning. Embryology tends to correspond well with the relevant anatomy, especially with regard to congenital malformations. Anatomy Several topics fall under this heading, including gross anatomy, histology, and neuroanatomy. The first step is to identify a structure on anatomic cross section, electron micrograph, or photomicrograph. The second step may require an understanding of the clinical significance of the structure.
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The most well-known study compared the use of rigid sigmoidoscopic screening in 261 patients who died from cancer of the distal colon or rectum to cholesterol definition biology online cheap generic tricor canada 868 control subjects cholesterol ldl hdl order discount tricor on line. Screening reduced the rectosigmoid cancer mortality rate by 60% cholesterol test wiki cheap tricor 160mg line, and the protective effect of sigmoidoscopy was noted to last for up to 10 years. This reduction in mortality may have resulted from earlier detection of cancer and removal of premalignant polyps. Sigmoidoscopic screening allows the lower third of the colorectal mucosa to be visualized directly and diagnostic biopsy to be performed at the time of examination. Both the sensitivity and the specificity are high for detection of polyps and cancer in the segment of the bowel examined. Neoplasms, Nasopharynx 1261 Unfortunately, however, nearly 50% of polyps and cancers are beyond the limits of detection of the longest. Opinions vary regarding the need for colonoscopy for patients in whom a single, small adenoma (<1 cm) is found on flexible sigmoidoscopy. Many studies have shown that the prevalence of advanced proximal neoplasms in patients with distal adenomas is up to 9%. Therefore, the use of colonoscopy to detect proximal neoplasia in patients with distal adenomas is strongly recommended. Colonoscopy: Colonoscopy is the "gold standard" for the detection of colonic neoplasms and the preferred colorectal cancer screening strategy. The incidence rate of colorectal cancer has been shown to be reduced up to 90% in subjects who had polypectomy versus patients in three reference groups, including two cohorts in which colonic polyps were not removed and one general-population registry. Colonoscopic screening in individuals with average risk has been found to be cost effective, and similar to cervical or breast cancer screening techniques in cost-effectiveness per life-year saved. Definition Neoplasms of the nasopharynx include all the malignant lesions originating from the nasopharyngeal mucosa. Pathology/Histopathology the mucosa covering the walls of the nasopharynx is composed of squamous pseudostratified epithelium associated with a submucosal lymphoid stroma and seromucinous glands. It is the reason why a wide variety of malignant neoplasms can originate in the nasopharynx. The most frequent malignant lesion arising in the nasopharynx is squamous cell carcinoma, which accounts for about 70% of cases. The remaining 10% of malignant tumors include neoplasms stemming from seromucinous minor salivary glands (adenoid cystic carcinoma, mucoepidermoid carcinoma, adenocarcinoma, malignant mixed tumors, acinic cell carcinoma). Squamous cell carcinoma of the nasopharynx is a worldwide diffuse tumor and one of the most common malignancies in adults in China, where it is characterized by an epidemic incidence. The latter is very similar to a large cell lymphoma and includes some subtypes of malignancies such as lymphoepithelioma, spindle cell carcinoma, clear cell carcinoma, and anaplastic carcinoma. More common is the involvement of the nasopharynx in the presence of systemic and advanced disease. Localization in the nasopharynx of tumors derived by seromucinous glands is a rare event because the minor Bibliography 1. A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. Such tumors are typically characterized by submucosal spreading, perineural diffusion, and low propensity to give nodal metastasis. Finally, plasma cell tumors of the nasopharynx are mainly represented by extramedullary plasmocytoma, which accounts for 20% of all plasma cell neoplasms. Ancillary and nonspecific symptoms include nasal obstruction, epistaxis, headaches, sore throat, proptosis, and trismus. Clinical Presentation the clinical presentation of malignant tumors of the nasopharynx is closely related to their localization, size, and pattern of spreading. In most cases, the neoplasm is represented by a mass centered in the posterolateral recess of the nasopharynx because of its origin in the Rosenmuller fossa. Superior diffusion toward the base of the skull, which can be involved by direct bony invasion and/or by perivascular diffusion (along the internal carotid artery or middle meningeal artery) and perineural diffusion (along the mandibular nerve). Invasion of the base of the skull can lead to intracranial progression of the disease with involvement of the cavernous sinus. On the basis of the above features, patients with nasopharyngeal tumors can be described in the following manner: 1. Patients with serous otitis media due to Eustachian tube obstruction; in many cases, symptoms of a chronic otitis are the only signs of the presence of a nasopharyngeal malignancy. Imaging Conventional radiographs are no longer performed for diagnosing nasopharyngeal neoplasms. Both techniques have dramatically improved the accuracy in defining the tumor extent as well as the presence of regional nodal metastasis. Liver ultrasound and chest X-ray are generally routinely performed as part of the overall staging procedure, whereas bone scans are reserved for clinical suspicion of osseous metastasis. In typical cases, a huge, poorly marginated soft-tissue mass, centered in the lateral pharyngeal recess with occupation of the nasopharyngeal lumen, is seen, with a variable degree of deep extension and infiltration. On contrast-enhanced imaging, the tumor shows mild inhomogeneous uptake, which reflects the degree of vascularization as well as the intratumoral necrosis. The most common direction of tumoral spreading is lateral, where the soft-tissue tumoral mass obliterates and/ or infiltrates the fat of the parapharyngeal space with displacement of the pterygoid muscles; further lateral spread involves the masticatory and infratemporal spaces with infiltration of the muscles of mastication. In such cases, the presence of fluid within the middle ear and mastoid cells due to serous otomastoiditis is often demonstrated. A huge mass (m) centered on the right lateral wall and Rosenmuller fossa is shown. Note also the involvement of the ipsilateral parapharyngeal space and posterior infiltration of the prevertebral muscles. The obliteration of the fat content of this fundamental anatomical landmark is the hallmark of involvement. Inferior spread can occasionally occur, with a subtle submucosal soft tissue causing oropharyngeal wall thickening. Posterior spread is characterized by obliteration of the retropharyngeal space and infiltration of the prevertebral muscles; posterosuperior neoplastic extension may involve the jugular foramen and the adjacent hypoglossal canal. Finally, but not infrequently, carcinoma of the nasopharynx can spread superiorly involving the skull base. Figure 2 (a) On coronal T1-weighted magnetic resonance image, a soft-tissue mass (m) abutting right superior-lateral wall of the nasopharynx is well demonstrated. Figure 3 (a) Axial T1-weighted magnetic resonance image shows a mass (m) involving the left wall of the nasopharynx with infiltration of the elevator and tensor veli palatine muscles and partial obliteration of the fat in the anterior parapharyngeal space.
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Germinal cells from the basal layer are exceedingly rare in smears from normal adults cholesterol medication beginning with l order tricor 160mg on line, and the basal and parabasal cells recognized cytologically are derived from different levels of the intermediate layer cholesterol medication starting with v purchase tricor line. They do represent less mature cells cholesterol test costco generic 160 mg tricor mastercard, and their presence indicates that immature cells are at higher than normal levels in the epithelium. These cells are associated with marked deficiency of estrogens and are common before puberty and during menopause. Basal cells arise from the lower levels of the transitional zone and are rounded or oval cells, about 4 to 5 times the size of a granular leukocyte. The central nucleus is deeply stained, but a pattern of fine chromatin granules and dense patches can be made out. Parabasal cells arise higher up in the transitional zone and also are round or oval cells, but they are larger than basal cells with a more abundant cytoplasm that is less basophilic and often shows a somewhat "blotchy" pattern. The central nucleus remains about the same size but may be more dense than that of a basal cell. Vagina the vagina is the lower-most portion of the female reproductive tract and is a muscular tube that joins the uterus to the exterior of the body. Ordinarily the lumen is collapsed and the anterior and posterior walls make contact. The mucosa is thrown into folds (rugae) and consists of a thick surface layer of nonkeratinized stratified squamous epithelium overlying a lamina propria. The glycogen of sloughed cells is broken down by commensal lactobacilli within the vaginal lumen and results in lactic acid being formed. The acid pH creates an environment favorable to the commensal bacterial flora and deters growth of fungi (Candida albicans) and bacterial pathogens. The lamina propria consists of a fairly dense connective tissue that becomes more loosely arranged near the muscle coat. Diffuse and nodular lymphatic tissues are found occasionally, and many lymphocytes, along with granular leukocytes, invade the epithelium. The vagina lacks glands, and the epithelium is kept moist by secretions from the cervix. The muscularis consists of bundles of smooth muscle cells that are arranged circularly in the inner layer and longitudinally in the outer layer. The longitudinally oriented smooth muscle cells become continuous with similarly oriented cells in the myometrium. It merges imperceptibly 248 Intermediate squamous cells vary in size, but all appear as thin, polygonal plates with abundant transparent cytoplasm. The cytoplasm stains somewhat variably and may be lightly basophilic or show some degree of eosinophilia. They are large, with voluminous eosinophilic cytoplasm that is thin and transparent with sharply defined borders. The nucleus is very small - about one-half to one-third that of an intermediate squamous cell - and is densely stained and pyknotic. They have a somewhat shriveled appearance, and the site of the nucleus is suggested by a pale central zone. Cells that originate from the endocervix also may be present and often occur in small sheets or strips; their appearance depends on the orientation. From end on, the cells appear as groups or nests of small polyhedral or round cells with sharp cell boundaries and relatively large central nuclei. In profile, the cells show their columnar shape with the nuclei close to one pole. Both surfaces of the labia minora are devoid of hair, but large sebaceous glands are present. It consists of two corpora cavernosa enclosed in a layer of fibrous connective tissue and separated by an incomplete septum. The free end of the clitoris terminates in a small, rounded tubercle, the glans clitoridis, which consists of spongy erectile tissue. The clitoris is covered by a thin layer of nonkeratinized stratified squamous epithelium with high papillae associated with many specialized nerve endings. It is lined by stratified squamous epithelium and contains numerous small vestibular glands concentrated about the openings of the vagina and urethra. A pair of larger glands, the greater or major vestibular glands, are present in the lateral walls of the vestibule. They are compound tubuloalveolar glands that secrete a clear, mucoid lubricating fluid. External Genitalia the external genitalia of the female consist of the labia, clitoris, and vestibular glands. In the adult, the outer surface is covered by coarse hair with many sweat and sebaceous glands. The inner surface is smooth and hairless and also contains sweat and sebaceous glands. The labia minora consist of a core of highly vascular, loose connective tissue covered by stratified squamous epithelium that is deeply indented by connective Pregnancy Pregnancy involves implantation of a blastocyst into a prepared uterine endometrium and subsequent formation of a placenta to nourish and maintain the developing embryo. The oocyte passes through the early stages of the first meiotic division during fetal life, and it is only just before ovulation that the division is completed and the first polar body is given off. The resulting secondary oocyte immediately enters the second meiotic division, which, however, proceeds only to metaphase and is not completed until fertilization occurs. At the time of ovulation, the oviduct shows active movements that bring the infundibulum and fimbria close to the ovary. Cilia on the surface of the fimbria sweep the ovum into the ampulla of the oviduct where fertilization, if it is to occur, takes place. The human ovum remains fertile for between 24 and 48 hours, after which it degenerates if fertilization does not occur. Approximately 300 million sperm are released into the vaginal lumen during coitus but it is estimated that only 300-500 spermatozoa reach the site of fertilization. Muscular contractions within the walls of the uterus and oviduct propel the spermatozoa to the proximal region (ampulla) of the oviduct where fertilization takes place. The smooth muscle cells are thought to contract in response to prostaglandins and/or oxytocin released during sexual intercourse. Of the millions of sperm initially deposited in the female tract, only one penetrates the ovum. There is no evidence for chemotactic attraction, and random movement brings sperm and ovum together. The zona pellucida is important in fertilization as it provides sperm recognition sites for sperm binding and is the most efficient trigger of the sperm acrosome reaction. The acrosome reaction results in the release of acrosomal enzymes (acrosin and trypsinlike enzymes) needed to digest a hole in the zona pellucida. At the time of fertilization, when a spermatozoon pushes through the hole in the zona pellucida to enter the ovum, a period of hyperactivity of flagellar beat occurs, propelling the spermatozoon into the ovum. Thus, flagellar beat appears to be more important at the moment of fertilization rather than getting to the site of fertilization. Electron micrographs suggest that the plasma membranes of the sperm and ovum fuse, that of the spermatozoon being left at the surface of the ovum.