Anatomy And Physiology Of Placenta 5n3k62

Anatomy and Physiology

The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. The word placenta comes from the Latin for cake, from Greek plakóenta/plakoúnta, "flat, slablike", in reference to its round, flat appearance in humans. The placenta averages 22 cm (9 inch) in length and 2–2.5 cm (0.8–1 inch) in thickness (greatest thickness at the center and become thinner peripherally). It typically weighs approximately 500 grams (1 lb). It has a dark reddish-blue or maroon color. It connects to the fetus by an umbilical cord of approximately 55–60 cm (22–24 inch) in length that contains two arteries and one vein. The umbilical cord inserts into the chorionic plate (has an eccentric attachment). Vessels branch out over the surface of the placenta and further divide to form a network covered by a thin layer of cells. This results in the formation of villous tree structures. On the maternal side, these villous tree structures are grouped into lobules called cotyledons. The placenta begins to develop upon implantation of the blastocyst into the maternalendometrium. The outer layer of the blastocyst becomes the trophoblast, which forms the outer layer of the placenta. This outer layer is divided into two further layers: the underlying cytotrophoblast layer and the overlying syncytiotrophoblast layer. The syncytiotrophoblast is a multinucleated continuous cell layer that covers the surface of the placenta. It forms as a result of differentiation and fusion of the underlying cytotrophoblast cells, a process that continues throughout placental development. The syncytiotrophoblast (otherwise known as syncytium), thereby contributes to the barrier function of the placenta. The placenta grows throughout pregnancy. Development of the maternal blood supply to the placenta is complete by the end of the first trimester of pregnancy (approximately 12–13 weeks).

Diagnostic Exams for CHORIOCARCINOMA

History: The most common symptom is abnormal bleeding from the vagina not associated with a menstrual period. The woman may have a history of previous hydatidiform mole, delivery of a normal pregnancy, an abortion, or termination of an ectopic pregnancy. If a woman is pregnant and does not detect fetal movement at the expected gestational stage, choriocarcinoma should be considered. If the cancer has metastasized to the lung the patient will cough frequently, they may even cough up blood, and have chest pain. If the cancer has spread to the GI tract they will have blood loss and anemia. Patients with brain metastasis will have headaches and neurological symptoms. Physical exam: During an internal (pelvic) examination, the uterus may exhibit bumps or an unusual size or shape. In pregnant women, the size from the top of the uterus (fundus) to the pubic bone is measured on every prenatal visit and compared to the average uterine size expected for the gestational age. If the physical examination shows the uterus to be significantly larger than would be expected for the age of the fetus, then multiple births, hydatidiform mole, choriocarcinoma, or other potential complications should be suspected. The woman may also show abnormal nipple discharge. Tests: In a woman who is not pregnant, evidence of the hormone beta human chorionic gonadotropin (hCG) in the blood may be a sign of choriocarcinoma. The tumor may be seen by ultrasound imaging. A CT scan may be done to detect potential metastatic tumor in other areas including lungs, abdomen, pelvis, and head. Other helpful laboratory tests include complete blood count (CBC), liver function tests (LFTs), kidney function tests, and serum chemistries. Diagnostic ultrasound (sonography) is a noninvasive diagnostic imaging technique that uses high-frequency sound waves to produce images of structures within the body. The sound waves are sent through the body tissues with a device called a transducer. Objects inside the body reflect a part of the sound waves back to a sensor, where the waves are recorded, analyzed, and displayed for viewing on a screen. Modern sonographic equipment can display live images of moving tissues (real-time viewing) and can also provide 3-dimensional reconstruction information about different structures. The area covered by the ultrasound beam depends on equipment design.

Computerized tomography (CT), is a noninvasive diagnostic form of x-ray that makes crosssectional images (slices), in different planes, of the interior of the body. Unlike the flat films of conventional radiography, the CT scanner circles the body measuring the transmission of x-rays as they through body structures, and taking multiple x-rays as it repeats this measurement (called a projection) in many different directions through the same section or slice of the body. When a sufficient number of projections in different directions are measured, the resulting data can create a single, unique arrangement in two- dimensions of the intervening body structure. Adjacent two-dimensional slices can then be reconstructed to produce three-dimensional structures for visualization of abnormalities, or for surgical planning

Blood Tests. Many conditions can be confirmed by testing the blood for numerous substances and properties. There are literally hundreds of different types of blood tests.

Laboratory Tests

Abnormal Lab Findings (Non Measured) Cytogenetics Abnormal Cytogenetics Isochromosome 12(i12p) Abnormal Maternal MSAFP/Quad test (Inhibin A/HG/UE3/AFP) Maternal triple test (APF/HG/Estriol) abnormal (labs) MSAFP test (maternal) abnormal (labs) Testosterone Increased Females Tumor markers/present (Lab)

Abnormal Lab Findings - Decreased Human Placental Lactogen (Lab)

Abnormal Lab Findings - Increased Alpha Fetoprotein, serum (Lab) Estrogen, serum (Lab) Gonadotropin, pituitary (plasma) (Lab) HCG (beta), serum/Beta sub unit HCG serum (Lab) Human Placental Lactogen (Lab) Progesterone (Lab) Testosterone Total (Lab) URINE Gonadotropins chorionic URINE Pregnanediol (Lab)

Diagnostic Test Results Other Tests & Procedures

Amniocentesis/Placental akaline phosphatase/present

Pathology BX/Endometrial biopsy/abnormal PATH/Uterine Dilatation and curettage/abnormal (D&C) PATH/Trophoblastic cells/specimen PATH/Syncyticial trophoblast/cytotrophoblast elements

SURGICAL MANAGEMENT Since the proof of chemotherapy has more effect, surgical treatment is important as in the past, but in some cases, such as large lesions, chemotherapy can not fully estimate the conqueror or course of treatment by HCG decreased slowly; liver metastases of uterine perforation and bleeding, to save the patient's life, surgery is still an important method of treatment of choriocarcinoma. The 2 common surgical treatment for choriocarcinoma are:  

Dilation and curettage Hysterectomy

Dilation and curettage A dilation and curettage (D and C) is a surgical procedure where the inner lining of the uterus, called the endometrium, is removed. Before this can be done the cervix needs to be dilated. The dilation portion of the procedure refers to opening the cervix. This allows for the age of special surgical instruments that are used to remove the endometrium. One of these instruments is called a curette. It is used to gently scrape away the endometrial lining. Recovery

from a D and Cin most cases is very rapid. There may be some vaginal bleeding and mild pain for about one day. Within a few days, most women resume normal activities. Risks of dilation and curettage include:   

Persistent vaginal bleeding Endometritis Injury to the uterus

Hysterectomy

Doctors don't often use surgery to treat persistent trophoblastic disease or choriocarcinoma. But a few women may need an operation to remove their uterus (hysterectomy) if 

Their tumor does not respond to chemotherapy  The choriocarcinoma is causing a lot of bleeding from the uterus