Reproduction 1, 2 and 3 Flashcards
What are the layers of the uterus?
Endometrium
Myometrium
What is the menstrual cycle?
2 cycles which make reproduction possible
Ovarian and uterine cycle
What happens in the ovarian cycle? What happens in the uterine cycle?
Development of follicle
Thickening and shedding of endometrium
What is the 1st menstruation called? What is the stopping of menstruation called?
Menarche
Menopause
Describe the levels of GnRH prepubertal
Constant low amount
When is the follicular phase in a 28 day cycle?
1 day - 2 weeks
Describe the follicular phase
Hypothalamus produces GnRH
This stimulates the anterior pituitary to produce FSH and LH
Follicles compete to grow fastest and become dominant
Other follicles die
Describe the structure of a follicle
Immature oocyte surrounded by zona pellucida
Granulosa cells around zona pellucida
Surrounded by theca cells
What receptors do theca and granulosa cells have?
Theca - LH
Granulosa - FSH
Lots of oestrogen causes lots of FSH/LH. What does this cause at the end of the follicular phase?
Follicle ruptures releasing oocyte
After ovulation, which hormone remains high?
LH
The remain of follicles become what? What cells are found in this?
Corpus luteum
Luteinized theca and granulosa cells
What do theca cells produce in the corpus luteum? What does this hormone do?
Progesterone
Inhibit FSH/LH
What do granulosa cells in the corpus luteum produce? WHere does this go to? What does it do?
Inhibin
Goes to pituitary gland, stops FSH (and oestrogen) production
What is the secretory phase? When does this take place?
After progesterone production Uterine glands produce more mucous Spiral arteries grow longer Corpus luteum becomes corpus albicans Menstruation
Which hormone do the follicles produce?
Oestrogen
What is the function of the ovaries?
Production and release of female gamete
Maintenance of pregnancy
Which animals menstruate?
Primates only
What is luteinzation?
Formation of corpus luteum from a follicle
When are females in oestrus?
When they are sexullay receptive to a male
What is a oestrogen? What does it do?
Group of hormones - oestrodiol most common
Drive sexual behaviour
What is proestrus phase?
Follicular phase
Not sexually receptive
What is dioestrus?
Progesterone dominant phase
Phase with corpus luteum
What is anoestrus and what type of problems cause this?
No cyclic ovarian activity
Pathological or physiological
Which animals are non-seasonal polyestrus?
Cow
Queen
Pig
Rodents
Polyestrus means multiple cycles per year. What differs about the dominant follicles in polyestrus animals?
Can have multiple
What animals are seasonal polyestrus?
Horse - long day breeders
Sheep/doe - short day breeders/autumn
How long is the horse ovarian cycle
21 days
+- 4
What are reflex/induced ovulators? Why is this?
Need to mate to induce ovulation
GnRH doesn’t produce enough LH for ovulation
Spontaneous ovulators do not need stimulation. How many times do they ovulate per cycle?
Once
Describe the ovarian cycle in a bitch and what type of ovulators they are
Spontaneous monoestrus
Very long porestrus
Oestrus
Dioestrus - 60-70 days
How long is proestrus in a bitch? What are symptoms
9 days
Bloody discharge and swollen vulva attracts male
How long is a bitch’s oestrus? When is ovulation? What colour is the discharge?
9 days
Day 2
Straw coloured
Ovulation takes place how many days after the LH surge? How can bitches have multiple fathers?
2-3
Ovulation takes many days
What is different about the luteolytic mechanism in bitches?
There isn’t one
What type of reproduces are cows?
Polyestrus spontaneous
What does FSH stimulate? Which cells does it bind to and what does this cause?
Growth of immature follicles
Granulosa cells
Oestradiol production
What does LH stimulate?Which cells does it bind to?
Produces oestrogen precursors (including testosterone)
Stimulates maturation, luteinization and ovulation
Theca cells
How does the oestrus cycle differ from the menstrual phase?
Shorter follicular phase
Long literal phase
No bleeding
Day 0 high oestrogen (menstrual cycle day 0 = low oestrogen
Why does spotting occur in the oestrus cycle?
High oestrogen levels
What does progesterone do? What cannot happen if progesterone levels are too low?
Inhibits GnRH
Ovulation
What are luteolytic signals and which species produce them?
Prostaglandin released by endometrium
Oxytocin secreted by corpus luteum
Germ cells there at birth and undergo 1st mitotic division, no 2nd until fertilisation
Ruminants/horses/pigs
Oxytocin is secreted by the corpus luteum in luteolytic signalling. How is this ensured to reach the endometrium?
Counter current system
During ejaculation, semen is deposited where?
Vagina
Cervix (horse/pigs)
How is sperm moved into the site of fertilisation? Where does fertilisation take place?
Smooth muscle contraction of female reproductive tract and sperm motility
Fallopian tubes
The majority of sperm die and do not reach the egg. Why is this?
Phagocytosis
Sperm in the epididymis are mature but not fertile. How do they become fertile? Can this be reversed?
Remove ‘mask molecules’ whilst in female reproductive tract
Yes
What is the fusion of gametes called?
Syngamy
Which layer of the oocyte do sperm need to bind to? What happens as they do this?
Zona pellucida
Undergo acrosomal reactions to prevent polyspermy
Fuses with oocyte membrane
What is polyspermy?
Multiple sperm entering and fertilising an egg
What is the sperm viability length for cows and bitches?
Cow 18 hrs
Bitches 5 days
Progesterone is essential in pregnancy. It is secreted by the placenta. Which structure can secrete it whilst the placenta develops, and what might be prevented by this?
Corpus luteum
Luteolysis
