Mod 5A2 Flashcards
Placental mammals:
In placental mammals, the embryo grows inside the uterus, and a placenta allows nutrients and oxygen to be supplied and wastes to be removed via the mothers blood (the umbilical cord).
Offspring are more developed.
Marsupials
They give birth to tiny, partially developed babies that continue to develop after birth, typically inside the mother’s pouch.
Monotremes
Monotremes lay soft-shelled eggs from which a very small puggle (baby) emerges and continues to grow and be nourished by the mothers milk.
What type of fertilisation occurs in all mammals?
Internal fertilisation
What are follicles and where are they located?
Hollow balls of cells with an immature egg in the centre.
Follicles are located in the ovary.
What two cycles occur in females at the same time?
Ovulation and menstruation
What is the Corpus Luteum?
An endocrine structure in females existing within the ovary once the ovarian follicle has released a mature ovum during ovulation
Follicle:
A small sac found in the ovary that contains one immature egg cell. As this structure grows and matures, it releases oestrogen.
Ovary
A female reproductive organ that contains many follicles. Each of these follicles contains one immature egg cell inside of it.
Corpus Luteum:
This structure develops after a follicle ruptures and releases an egg during ovulation. It releases oestrogen and progesterone
Menstruation:
The process in which the endometrium (uterine lining) disintegrates, resulting in menstrual bleeding out of the vagina
Endometrium:
The tissue that lines the mammalian uterus. A fertilised egg implants into this lining.
Oestrogen
A hormone produced by either a mature follicle or the corpus luteum. It stimulates the endometrium (uterine lining) to thicken
Progesterone
A hormone produced in women by the corpus luteum. It helps to maintain the endometrium
Follicular phase:
The first half of the ovarian cycle, characterised by one follicle maturing. Oestrogen levels rise up during this phase
Luteal Phase:
The second half of the ovarian cycle, characterised by the corpus lutueum producing oestrogen and progesterone
Hormones:
Chemical messengers that can travel in the bloodstream, These are often made of proteins or lipids
Hypothalamus
Controls the release of hormones from the pituitary gland.
What is Gonadotrophic Releasing Hormone (GnRH)
The hormone releasing hormone released by the hypothalamus. It triggers the pituitary gland into releasing follicle stimulating hormone (FSH) and luteinising hormone (LH)
FSH - follicle stimulating hormone
Primarily responsible for stimulating follicles to grow in the ovary.
LH - Luteinising Hormon
- Causes the egg to burst out of the mature follicle (an event known as ovulation)
- Causes the remnants of the burst follicle to form the corpus luteum
Blastocyst
The clump of cells created by the zygote undergoing mitosis as it moves down the Fallopian tube
