Patterns Of Reproduction SEM1 Flashcards
What happens with low levels of oestrogen
Little feedback effect on FHS and LH
What happens with higher levels of oestrogen
Negative feedback of FSH
What happens with very high levels of oestrogen
Induces surge in LH and increase in FSH
What does the negative feedback from inc. oestrogen and FSH levels dropping do
Stops other follicles growing and limits number of follicles that ovulate
What are the phases of oestrus
Proestrus
Oestrus
Meteostrus
Dioestrus
What happens during the proestrus phase
Follicular phase:
Follicles grow
Dominant follicle(s) selected
Oestrogen levels rise
What happens during the oestrus phase
Mating behaviour:
Dominant follicle(s) ovulate
What happens during the metoestrus phase
Oestrus ends
Corpus luteum forms
What happens during the dioestrus phase
Corpus luteum size maximal
Progesterone output maximal
How does the oestrus cycle differ from the menstrual cycle
Absence of oestrus behaviour
No outward event revealing cyclicality
Sexual reproduction throughout
What regulates seasonal breeding
Key thing is that birth is timed so offspring have grown up by the time winter comes
What does the pineal gland secrete
Melatonin
When is melatonin produced and what is it regulated by
Produced at night and regulated by circadian rhythm
What can the signal of changing melatonin pattern be picked up by
Can be picked up by hypothalamic pituitary system
What does LH stimulate in males
Testosterone production
