. Hyperthyroidism: Elevation of both T4 and T3 values along with decrease of TSH are indicative of primary hyperthyroidism. Increased thyroxine-binding: If concentration of TBG increases, free hormone level falls, release of TSH from pituitary is stimulated, and free hormone concentration is restored to normal. Reverse occurs if concentration of binding falls.

• 48 Hour Chick Embryo Serial Cross Section 1

Students will observe embryonic neurulation in the 4mm frog embryo by observing prepared whole mounts, examining selected transverse sections and serial sagittal. Serial cross sectioning of the 48 hour chick begins at the midbrain region rather than at the forebrain region due to the cranial flexure of the embryo. Dextro-dorsal view ( X 14) of entire chick embryo of 36 somites (about three days incubation). The cranial and cervical flexures which appeared in embryos during the second day have increased so that in three-day and four-day chicks the long axis of the embryo shows nearly right-angled bends in the mid-brain and in the neck region. 48hr chicken embryo viewed with 2X objective (anterior) 48hr chicken embryo viewed with 2X objective (mid) 48hr chicken embryo viewed with 2X objective (posterior). 72hr chicken embryo serial cross-section viewed with 1X objective 72hr chicken embryo serial cross-section viewed with 1X objective Search for: Recent Posts.

In either case, level of free hormones remains normal, while concentration of total hormone is altered. Therefore, estimation of only total T4 concentration can cause misinterpretation of results in situations that alter concentration of TBG. Factitious hyperthyroidism. Pituitary TSH-secreting. This is a direct test that assesses the trapping of iodide by thyroid gland (through the iodine symporters or pumps in follicular cells) for thyroid hormone synthesis. Patient is administered a dose of radioactive iodine ( 131I or 123I) orally. This is followed by measurement of amount of radioactivity over the thyroid gland at 2 to 6 hours and again at 24 hours. RAIU correlates directly with the functional activity of the thyroid gland.

48 Hour Chick Embryo Serial Cross Section 1

Normal RAIU is about 10-30% of administered dose at 24 hours, but varies according to the geographic location due to differences in dietary intake. Hypothyroidism is a condition caused by deficiency of thyroid hormones. Causes of hypothyroidism are listed in Table 863.3. Primary hypothyroidism results from deficient thyroid hormone biosynthesis that is not due to disorders of hypothalamus or pituitary.

Secondary hypothyroidism results from deficient secretion of TSH from pituitary. Deficient or loss of secretion of thyro-tropin releasing hormone from hypothalamus results in tertiary hypothyroidism. Secondary and tertiary hypothyroidism are much less common than primary. TSH is high in primary and low in secondary and tertiary hypothyroidism. Differences between primary and secondary hypothyroidism are shown in Table 863.4. The ovaries are the sites of production of female gametes or by the process of oogenesis. The ova are released by the process of ovulation in a cyclical manner at regular intervals.

Ovary contains numerous follicles that contain ova in various of development. During each menstrual cycle, up to 20 primordial follicles are activated for maturation; however, only one follicle becomes fully mature; this dominant follicle ruptures to release the secondary oocyte from the ovary. Maturation of the follicle is stimulated by follicle stimulating hormone (FSH) secreted by pituitary (Figure 862.1). Maturing follicle secretes estrogen that causes proliferation of endometrium of the uterus (proliferative phase). Follicular cells also secrete inhibin which regulates release of FSH by the anterior pituitary. Fall in FSH level is followed by secretion of luteinizing hormone (LH) by the anterior pituitary (LH surge). This causes follicle to rupture and the is expelled into the peritoneal cavity near the fimbrial end of the fallopian tube. The fallopian tubes conduct ova from the ovaries to the uterus.

Fertilization of ovum by the sperm occurs in the fallopian tube. The ovum consists of the secondary oocyte, zona pellucida and corona radiata.

The ruptured follicle in the ovary collapses and fills with blood clot ( ). LH converts granulose cells in the follicle to lutein cells which begin to secrete progesterone. Progesterone stimulates secretion from the endometrial glands (secretory phase) that were earlier under the influence of estrogen. Rising progesterone levels inhibit LH production from the anterior pituitary.

Without LH, the corpus luteum regresses and becomes functionless corpus albicans. After regression of corpus luteum, production of estrogen and progesterone stops and endometrium collapses, causing onset of menstruation. If the ovum is fertilized and implanted in the uterine wall, human chorionic gonadotropin (hCG) is secreted by the developing into the maternal circulation. Human chorionic gonadotropin maintains the corpus luteum for secetion of estrogen and progesterone till 12th week of pregnancy. After 12th week, corpus luteum regresses to corpus albicans and the function of synthesis of estrogen and progesterone is taken over by placenta till parturition.

Ovarian dysfunction:. Polycystic ovarian disease (Stein-Leventhal syndrome). Luteinized unruptured follicle. Turner’s syndrome. Radiation or. Surgical removal of ovaries. Idiopathic 3.

Dysfunction in passages:. Fallopian tubes –: Tuberculosis, gonorrhea, Chlamydia – Previous surgery (e.g.

Laparotomy) – Tubectomy – hypoplasia, non-canalization –. Uterus – Uterine malformations – Asherman’s syndrome – Tuberculous endometritis –. Cervix: Sperm antibodies. Vagina: Septum 4. Dysfunction of sexual act: Dyspareunia.

Regular cycles, mastalgia, and laparoscopic direct visualization of corpus luteum indicate ovulatory cycles. Anovulatory cycles are clinically characterized by, oligomenorrhea, or irregular menstruation. However, apparently regular cycles may be associated with anovulation. Endometrial: Endometrial biopsy is done during premenstrual period (21st-23rd day of the cycle). The secretory endometrium during the later half of the cycle is an evidence of ovulation. Ultrasonography (USG): Serial ultrasonography is done from 10th day of the cycle and the size of the dominant follicle is measured. Size 18 mm is indicative of imminent ovulation.

Collapse of the follicle with presence of few ml of fluid in the pouch of Douglas is suggestive of ovulation. USG also is helpful for treatment (i.e. Timing of coitus or of intrauterine insemination) and diagnosis of luteinized unruptured follicle (absence of collapse of dominant follicle). Transvaginal USG is more sensitive than abdominal USG. Basal body temperature (BBT): Patient takes her temperature at the same time every morning before arising.

BBT falls by about 0.5°F at the time of ovulation. During the second (progestational) half of the cycle, temperature is slightly raised above the preovulatory level (rise of 0.5° to 1°F). This is due to the slight pyrogenic action of progesterone and is therefore evidence of functional corpus luteum.

Cervical mucus study:. Fern test: During estrogenic phase, a characteristic pattern of fern formation is seen when cervical mucus is spread on a glass slide (Figure 862.4). This ferning disappears after the 21st day of the cycle. If previously observed, its disappearance is presumptive evidence of corpus luteum activity. Spinnbarkeit test: Cervical mucus is elastic and withstands stretching upto a distance of over 10 cm. This phenomenon is called Spinnbarkeit or the thread test for the estrogen activity.

During the secretory phase, of the cervical mucus increases and it gets fractured when stretched. This change in cervical mucus is evidence of ovulation. Vaginal: Karyopyknotic index (KI) is high during estrogenic phase, while it becomes low in secretory phase. This refers to percentage of super-ficial squamous cells with pyknotic nuclei to all mature squamous cells in a lateral vaginal wall smear. Usually minimum of 300 cells are evaluated. The peak KI usually corresponds with time of ovulation and may reach upto 50 to 85.

Estimation of progesterone in mid-luteal phase (day 21 or 7 days before expected menstruation): Progesterone level 10 nmol/L is a reliable evidence of ovulation if cycles are regular (Figure 862.5). A mistimed sample is a common cause of abnormal result. Measurement of LH, FSH, and estradiol during days 2 to 6: All values are low in hypogonadotropic (hypothalamic or pituitary failure). Measurement of TSH, prolactin, and testosterone if cycles are irregular or absent: Increased TSH: Hypothyroidism Increased prolactin: Pituitary adenoma Increased testosterone: Polycystic ovarian disease (PCOD), congenital adrenal (To PCOD from congenital adrenal hyperplasia, ultrasound and estimation of dihydroepiandrosterone or DHEA are done). Transvaginal ultrasonography: This is done for detection of PCOD.

Infectious disease: These tests include endometrial biopsy for tuberculosis and test for chlamydial IgG antibodies for tubal factor in infertility. Hysterosalpingography (HSG): HSG is a radiological contrast study for investigation of the shape of the uterine cavity and for blockage of fallopian tubes (Figure 862.6). A is introduced into the cervical canal and a radiocontrast dye is injected into the uterine cavity. A real time X-ray imaging is carried out to observe the flow of the dye into the uterine cavity, tubes, and spillage into the uterine cavity. Hysterosalpingo-contrast sonography: A catheter is introduced into the cervical canal and an echocontrast fluid is introduced into the uterine cavity. Shape of the uterine cavity, filling of fallopian tubes, and spillage of contrast fluid are noted. In addition, ultrasound scan of the pelvis provides information about any fibroids or polycystic ovarian disease.

Laparoscopy and dye hydrotubation test with hysteroscopy: In this test, a cannula is inserted into the cervix and methylene blue dye is introduced into the uterine cavity. If tubes are patent, spillage of the dye is observed from the ends of both tubes.

This technique also allows visualization of pelvic, endometriosis, and pelvic adhesions. If required, endometriosis and tubal blockage can be treated during the procedure.