The two main cell types of the ovaries:
1. The theca cells produce androgen in the form of androstenedione. The theca cells are not able to convert androgen to oestradiol themselves. The produced androgen is therefore taken up by granulosa cells.
2. The neighbouring granulosa cells then convert the androgen into oestradiol under the enzymatic action of aromatase FSH induces the granulosa cells to produce aromatase for this purpose

Hormones that increase during pregnancy and their roles:

1. Human Chorionic Gonadotropin (hCG): Peaks between the eighth to tenth weeks of gestation and supports the corpus luteum to maintain progesterone production.
2. Progesterone: Initially produced by the corpus luteum and later by the placenta, it rises steadily throughout pregnancy, suppressing the maternal immune response to fetal antigens and preparing the endometrium for implantation.
3. Estrogen: Produced by the placenta from fetal and maternal precursors, estrogen levels increase to promote uterine growth and blood flow.
4. Human Placental Lactogen (hPL): Rises significantly during pregnancy, influencing maternal metabolism by increasing insulin resistance and promoting lipolysis.
5. Relaxin: Increases early in pregnancy to relax the uterine muscles, inhibit contractions, and prepare the cervix and pelvis for childbirth.
6. Prolactin: Levels increase to prepare the breasts for lactation.
7. Corticotropin-Releasing Hormone (CRH): Increases towards the end of pregnancy and is involved in the timing of labor.
8. Adrenocorticotropic Hormone (ACTH): Levels increase, contributing to elevated cortisol levels during pregnancy.
9. Total Thyroxine (T4): Levels increase due to elevated thyroid-binding globulin (TBG) production stimulated by increased estrogen levels, meeting the increased metabolic demands of pregnancy.
10. Parathyroid Hormone (PTH): Levels increase to regulate calcium metabolism, ensuring adequate calcium for fetal bone development.
11. Cortisol: Levels increase due to higher production by the adrenal glands and increased binding to cortisol-binding globulin (CBG), supporting glucose metabolism, managing stress, and aiding fetal development, particularly lung maturation.

During pregnancy, some hormones either remain stable or do not increase significantly. These include:

1. Follicle-Stimulating Hormone (FSH): Levels decrease due to the negative feedback from high levels of estrogen and progesterone.
2. Luteinizing Hormone (LH): Levels also decrease due to negative feedback from elevated estrogen and progesterone.
3. Growth Hormone (GH): Although a variant of growth hormone (hGH-V) is produced by the placenta and increases, the maternal pituitary GH levels may not significantly increase.
4. Melatonin: Generally remains stable during pregnancy, though some studies suggest there may be slight fluctuations.
5. Insulin: While insulin resistance increases due to hPL and other factors, the actual levels of insulin may not increase proportionally; instead, pancreatic beta-cell function adapts to meet the increased demand.

In Cushing’s syndrome there is excess cortisol. Causes are broadly divided into 2 types: ACTH dependent disease: excess ACTH from the pituitary (Cushing’s disease), ectopic ACTH-producing tumours or excess ACTH administration. Non-ACTH-dependent: adrenal adenomas, adrenal carcinomas, excess glucocorticoid administration. The recommended diagnostic tests for the presence of Cushing’s syndrome are 24-hour urinary free cortisol, 1 mg overnight dexamethasone suppression test and late-night salivary cortisol. There are several other tests that may also be performed to find the cause. ACTH and cortisol measured together may show if this is ACTH dependent or not. MRI pituitary and CT abdo and pelvis may show if tumour is the cause.

Premature menopause is most commonly idiopathic.

Osteogenesis imperfect is an autosomal dominant condition. All the rest of the options are autosomal recessive conditions.

Oxytocin acts via the G protein receptors and the calcium-calmodulin complex. It activates phospholipase C which produces IP3 to further trigger the calcium-calmodulin complex increasing intracellular Ca ion release.

Human chorionic gonadotrophin (hCG) has thyrotrophic activity owing to subunit homology with thyroid-stimulating hormone (TSH) and maternal TSH production is suppressed during the first trimester of pregnancy, when hCG levels are highest. The TSH response to thyrotrophin-releasing hormone (TRH) is reduced during the first trimester but returns to normal after this. Thyroid binding globulin increases in the first 2 weeks of pregnancy and reaches a plateau by 20 weeks. This leads to increased production of total T3 (tri-iodothyronine) and T4 (thyroxine).

The chorionic plate represents the fetal surface of the placenta, which in turn is covered by the amnion. The amnion is composed of a single layered epithelium and the amnionic mesenchyme, an avascular connective tissue. The amnionic mesenchyme is only weakly attached to the chorionic mesenchyme and can easily be removed from the delivered placenta. The chorionic mesenchyme contains the chorionic vessels that are continuous with the vessels of the umbilical cord. Within the mesoderm of secondary villi, haematopoietic progenitor cells develop and start to differentiate. At about day 20 post-conception, first placental blood cells and endothelial cells develop independent of the vascular system of the embryo proper.13 14 The development of first placental vessels transforms the respective villi into tertiary villi.

About 97% of the testosterone that is secreted loosely binds to the SHBG and circulates in the blood for several hours in this bound state until it is transported to the target organs.

Causes of Hyperprolactinemia: Prolactinomas, Medication (phenothiazines, metoclopramide, risperidone, selective serotonin reuptake inhibitors, oestrogens, verapamil), Stress, Pregnancy, Hypothyroidism, Kidney disease, Chest trauma