Oestrus cycle

• What is pyometra?


  A serious infection of the uterus caused by bacterial infection
• What can happen if pyometra is left untreated?

  It can lead to kidney failure, toxaemia, dehydration, and death
• What is the definition of the oestrous cycle?

  It is the reproductive cycle in most mammalian placental females with recurring fertile and non-fertile periods
• The key stages in the oestrous cycle?(5)

  • Pro-oestrus
  • Oestrus
  • Met-oestrus
  • Di-oestrus
  • An-oestrus
• What hormones are involved in controlling the oestrous cycle?

  GnRH, LH, FSH, Oestrogen, Progesterone
• hypothalamus role in the oestrous cycle?

  It acts as the main control centre for hormonal regulation. the hormonal control of oogenesis through positive feedback
• What happens during ovulation?

  The follicle ruptures, releasing the ovum
• What is the corpus luteum?

  It is the empty follicle that forms after ovulation and secretes progesterone
• What occurs during the pro-oestrus stage of the oestrous cycle?

  The female prepares her body for heat, and FSH secreted
• What happens during the oestrus stage?

  The female allows mating and is fertile and sexually active
• What is the role of progesterone during metoestrus?

  It helps prepare the uterus lining to receive the fertilized egg
• What occurs during dioestrus?

  The corpus luteum secretes progesterone to maintain conditions for pregnancy
• What is anoestrus?

  It is the period between oestrous cycles with low reproductive hormone levels
• What is gestation?

  The period of pregnancy from fertilization until birth
• What hormone maintains the uterine lining during pregnancy?

  Progesterone
• What triggers labor during parturition?

  Increased fetal size and increased oestrogen levels
• What are the three stages of labor?

  1. Cervical relaxation and dilation
  2. Production of young
  3. Expulsion of the placenta
• What is the role of relaxin during labor?

  It softens birth canal tissue
• 5 hormones involved in controlling the oestrous cycle

  GnRH ( Gonadotrophic Releasing Hormone)

  LH ( Luteinising hormone )

  FSH (Follicle Stimulating Hormone)

  oestrogen

  progesterone
• at ovulation

  • the follicle ruptures at the ovary surface - releases ovum
  • ovum enters the infundibulum in the uterine tubes ( ovarian ducts )
  • empty follicle forms the corpus luteum then corpus ablicans
• what is the hormone involved with oestrus ?

  LH
• metoestrus

  • female returns back to normal - no mating
  • empty follicle shrivels up once egg has been released - corpus luteum
  • secrete progesterone - helps to prepare lining of uterus - receive the fertilised egg
  • progesterone inhibits futher production of FSH & LH
• dioestrus

  • corpus luteum secretes progesterone maintain condition for pregnancy
  • if not pregnant corpus luteum degenerates and secretion of progesterone is inhibited - false pregnancy can develop
• anoestrus

  • period between oestrous cycles
  • female returns normal
• gestation

  • the period of pregnancy from fertilisation to birth
  • pregnancy is maintained by progesterone - maintains uterine lining, placenta & prevents uterine contractions
  • at the end gestation period progesterone production falls & oxytocin is released = contractions