exactly 18 - Physiology of reproduction- Female reproductive system. Ovogenesis. Female sex hormones (estradiol and progesterone), types, physiologic effect, control of secretion. Regulation of menstrual cycle. Pregnancy and lactation. Tests for early pregnancy.Epiphysis, thymus gland and non-glandular organs with. endocrine functions. Tissue hormones – types, physiological effects and control of secretion.

section

epiphysis

thymus gland

non glandular organs with endocrine function

epiphysis

pineal gland

• Secretes melationin- secretion increases at night

• Role in sleep circardian rhythm

• Inhibits MSH- melanocyte stimulating hormone

• Involutes before puberty, largest in infants

thymus gland

• The gland, is only active until puberty. It is the largest in size at 2 years old

• After puberty, the thymus starts to slowly shrink and become replaced by fat.

• Before birth the thymus is involved in the production and maturation of T-lymphocytes or T cells, it is facilitated by thymosin.

non glandular organs with endocrine function

1. Placenta- an organ which provides connection between the maternal fetus and mother. Secretes:

   • Human chronionic gondatrophan hormone ( this helps in the detection of pregnancy , found in the urine.

   • Produces estrogen and progesterone- help maintain normal pregnancy and facilate breast milk production and breast feeding.

   • HCG is released to maintain secretion of progesterone by the corpus luteum

2. Skin, liver and kidneys

   • Where active vitamin D is made in the skin when a precursor of cholesterol is expressed to UV light.

   • Calcitriol binds to its target cells on the bone, kidneys and small intestine to help maintain and regulate calcium- phosphate homeostatsis.

3. Adipose tissue- secretes adipokines

   • leptin hormone shown to have effect on the regulation of appetite.

   • ghrelin stimulates the secretion of growth hormones.

4. Liver and kidney- erythropoietin

   • Controls erythropoiesis

   • Helps with wound healing

5. Stomach- gastrin

   • Regulates production of gastric acid

   • Provides growth of gastric mucosa

6. Heart- ANP-vasodialotor

section

why is female reproductive system needed

ovogenesis

oogenesis

femal sex hormones

menstrual cycle

pregnancy

lactation

test for early preganancy

why is female reproductive system needed

The female reproductive system is needed for production of female egg cells necessary for reproduction along with the male gametes. Secondary oocyte is needed.

ovogenesis

formation and maturation of the egg cell

process where primary egg cell becomes a mature ovum Oogenesis

oogenesis

• Oogenesis starts with the process of developing oogonia, which occurs via the transformation of primordial follicles →primary oocytes

• Oocytogenesis is complete either before or shortly after birth in humans, and thus during the menstrual cycle primary oocytes complete maturation through further meiotic divisions.

• The first meiotic division is coordinated by hormones: FSH, estrogen, LH and progesterone.

• The oocyte is stopped in cell division prior to the second meiotic division, which only occurs after fertilization.

femal sex hormone

• LH: produced by the anterior pituitary – stimulates secretion of progesterone and oestrogen

  • release is controlled by Gonadotropin-releasing hormone (GnRH) from hypothalamus.

  • responsible for the release of (FSH) and (LH) from the anterior pituitary gland.

• Follicle stimulating hormone :

  • secreted by anterior pituitary stimulates the growth of ovarian follicles

  • FSH→follicle→ estrogens

• Progesterone is a hormone produced by the ovaries in response to the release of LH and FSH from the pituitary gland.

  • Progesterone is involved in preparing the uterus for implantation

  • increasing the amount of cervix mucus

  • decreasing the maternal immune response.

  • Progesterone has a negative feedback on LH and FSH during luteal phase

• Estrogen

  • helps in production of eggs, involved in metabolic functions e.g. bone formation, salt and water retention and increased cortisol levels, breast development, female sex characteristics

mesntrual cycle

Def: cycle in which approx every 28 days,

Menstruation (Day 1–5)

• The endometrial lining of the uterus breaks down and is shed through the vagina as blood and tissue.

• Meanwhile, a new follicle starts developing in one of the ovaries.

2. Follicular Phase (Day 1–13)

• As the follicle grows, it secretes increasing levels of estrogen.

• Estrogen:

  • Stimulates regrowth of the endometrial lining, making it thicker and full of blood vessels and glands.

  • Signals the pituitary gland to release more LH (luteinizing hormone).

3. Ovulation (Around Day 14)

• A sudden surge in LH triggers:

  • Completion of meiosis I in the maturing egg.

  • Ovulation: The secondary oocyte is released from the follicle into the fallopian tube.

4. Luteal Phase (Day 15–28)

• After ovulation, the empty follicle becomes the corpus luteum.

• Stimulated by LH, the corpus luteum secretes high levels of progesterone (and some estrogen).

• These hormones:

  • Support and maintain the endometrium in case of pregnancy.

  • Cause LH and FSH levels to drop via negative feedback, preventing the development of new follicles.

preganancy

High levels of estrogen and progesterogen, hcg- by placenta- prevents regression of corpus luteum

lactation

Lactation is the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her child.

• Lactation is under endocrine control, with several hormones stimulating reponses including progesterone, estrogen, prolactin, and oxytocin.

• Lactogenesis- is the process of changes to the mammary glands to begin producing milk, begins during the late stages of pregnancy.

• The delivery of the placenta, and the decreasing of progesterone, estrogen, and HPL- human placental lactogen levels, stimulates milk production.

• Lactation maintained by suckling

• Colostrum is the first milk a breastfed baby receives. It contains higher amounts of WBCs and antibodies than mature milk.

test for early preganancy

1. Rosette inhibition: a test for the detection of EPF- early pregnancy factor which is an immunosuppressive substance. It can be detected within the blood within 48 hrs of fertilization

2. Obstetric ultrasonography- done as early as 4.5 weeks the embryo can be seen and measured at 5.5 weeks

3. Human chorionic gonadotropin -hCG can be detected in urine or blood after implantation (6-12 days after fertilization). Urine test strips have detection thresholds of 20 - 100 mIU/mL, depending on the brand.