Reproduction part 2 Flashcards
(15 cards)
What controls animal reproductive systems?
Hormones, which are secreted by glands around the body.
What is gametogenesis and what are its two types?
Gametogenesis is the formation of gametes (sex cells).
Oogenesis: Formation of ova (egg cells) in females.
Spermatogenesis: Formation of sperm in males.
Define haploid and diploid cells
Haploid: Cells with half the normal number of chromosomes (e.g., gametes).
Diploid: Cells with the full number of chromosomes (e.g., body cells).
What triggers reproductive hormone release?
The hypothalamus releases GnRH (Gonadotropin Releasing Hormone), which stimulates the anterior pituitary gland to secrete LH (Luteinising Hormone) and FSH (Follicle Stimulating Hormone).
What is the hormonal control of spermatogenesis?
- GnRH → stimulates anterior pituitary
- Anterior pituitary releases LH and FSH
- LH → stimulates testosterone production from testes
- FSH + testosterone → stimulate sperm production
- Sertoli cells release inhibin to stop FSH release and regulate sperm production.
What is the hormonal control of ovulation?
- GnRH → stimulates anterior pituitary
- FSH → matures egg in ovary + stimulates oestrogen release
- Oestrogen → inhibits FSH + stimulates LH
- LH → triggers ovulation + corpus luteum formation
What are the phases of the oestrus cycle and their key hormone levels?
Pro-oestrous: ↑ Oestrogen, ↓ Progesterone, GnRH released
Oestrous (heat): ↑ Oestrogen, LH, FSH → Ovulation
Metoestrous: Corpus luteum forms, ↑ Progesterone, ↓ Oestrogen
Dioestrous: High Progesterone, reproductive inactivity
What roles do melatonin and light play in seasonal breeding?
High light → ↑ melatonin → inhibits LH & FSH
Decreasing light → ↓ melatonin → LH & FSH resume → breeding season starts
What is prostaglandin and its function?
Hormone that causes uterine contractions to expel the lining during menstruation.
Also aids cervical dilation and uterine contractions during parturition.
What are the pre- and during-pregnancy roles of progesterone?
Before implantation: Prepares uterus, nourishes embryo, builds placenta.
During pregnancy: Maintains uterine lining, supports foetal development, breast preparation, prevents lactation, strengthens pelvic muscles.
What hormones are involved in parturition?
Oxytocin: Stimulates uterine contractions and milk let-down.
Prostaglandin: Dilates cervix, assists contractions.
Cortisol: Stress hormone; can reduce progesterone, risking early labour.
What hormones are involved in lactation?
Prolactin: Initiates and maintains milk production; affects reproductive cycles.
Oxytocin: Stimulates milk let-down after birth.
What is the placenta and its function?
Temporary organ that connects mother and foetus.
Functions: nutrient supply, gas exchange, waste removal, immune protection.
Maternal and foetal blood do not mix to avoid immune reactions and disease transmission.
What are species-specific parturition terms?
Sheep: Lambing
Goats: Kidding
Dogs: Whelping
Cattle: Calving
What happens during delayed implantation?
Fertilisation occurs, but the embryo delays attaching to the uterus lining.
Allows timing of birth to match optimal environmental conditions.
