Mammal Reproduction Flashcards
Define puberty in terms of mammals
Period where secondary sex characteristics start o form and capability of sexual reproduction is attained
Puberty stops what
long bone growth stops
(epiphyses close under influence of estrogen)
Rats and mice are what type of estrous?
poly estrous
Define polyestrous
- cycle rom puberty until old age
- average length: 4-5 days
What is estrous cycle divided into?
Proestrous, estrus, etestrus, diestrus
Proestrus
1day
- FSH level increases
- some follicles start to grow and mature
- Estrogen produced from stimulated follicles
FSH
Follicle stimulating hormone
- from the anterior pituitary gland
- acts on ovary to stimulate growth of follicles
- stimulates testes to produce sperm and is important to start this process during puberty
Estrogen
- produced by cells in follicle
- produces secondary sexual development in females
- stimulates estrus (heat)
Estrus
12-24 hours “in heat”
Sexual Receptivity
- At high levels: FSH and Estrogen
- At low levels: Progesterone
- The only time female will accept male
- Surge levels: LH
Progesterone
- produced by corpus luteum
- maintains pregnancy
- Prevents ovulation: acting at pituitary to block the LH surge
LH
Luteinizing Hormone
- from anterior pituitary gland
- causes ovulation
- acts on cells in testes to stimulate testosterone production
Which hormones are from the anterior pituitary gland?
FSH and LH
Metestrus
12 hours
Ovulation
- follicle opens and releases ovum
- rats and mice are spontaneous ovulators
Which animal(s) is/are spontaneous ovulators
Rats and mice
Diestrus
2 days
Period before NEXT proestrus
- Corpus luteum (CL) forms in ruptured follicle
- Progesterone level is high (secreted by CL)
- If not pregnant, CL regresses and new cycle begins
- Prostaglandin causes CL regression
When does corpus luteum form in ruptured follicle?
Diestrus during estrous cycle
When is progesterone level high?
Diestrus during estrous cycle
What needs to happen in order for CL to regress and a new estrous cycle begins?
For there to be no pregnancy
Prostaglandin causes what?
CL regression
What causes CL regression?
Prostaglandin, when no pregnancy