1. the oestrus cycle Flashcards
what is meant by the oestrus cycle
- repetitve patterns of hormones and behaviour which lead to ovulation of a follicle (oocyte release)
in which 3 ways is the oestrus cycle described
- behavioural stages
- hormonal stages
- state of the ovaries
list the behavioural stages of the oestrus cycle and what is occuring hormonally
- pro-oestrus = phase immediately before oestrus. increased oestradiol
- oestrus = high oestradiol, increased behaviours that attract mate. leads to ovulation
- met-oestrus: corpus luteum forms, decreasing levels of oestradiol, increasing levels of progesterone
- dioestrus = high progesterone, rejection behaviours
is the female receptive to a male in the oestrus or dioestrus phase
oestrus
high levels of oestradiol leads to
surge in LH = ovulation and increase in receptive behaviour
the follicular phase encompasses
pro-oestrus and oestrus
- ovarian follicles mature
- secrete increasing concentrations of oestradiol into blood
- oestrus behaviour
the luteal phase encompasses
metoestrus and dioestrus
- ovarian follicles ovulate to produce >= 1 corpora lutea
- CL secretes progesterone into blood
- ends with luteolysis of the CL y prostaglandin
- follicles continue to develop but fail to ovulate
Describe the female’s two main behaviours during the oestrous cycle
oestrus and dioestrus
Which two hormones govern behaviour during oestrous cycle?
oestrogen or progesterone
What are the ovarian phases of the oestrous cycle?
follicular and luteal
Name two steroid hormones
progesterone and eostrogen
Name two gonadotrophin hormones
FSH and LH
What is ovulation?
Ovulation: rupture of mature follicle on the ovary to release an oocyte into the oviduct, ready for fertilisation (if female is mated)
which hormone primarily leads to ovulation
LH
what is polyoestrus
multiple cycles throughout the year
