Reproductive Flashcards
What 2 processes do sexual reproduction involve
Meiosis & fertilisation
What does reproductive meiosis produce
Haploid gametes, male sperm & female ova
What is a zygote
Cell produced after fertilisation containing 46 chromosomes, full genetic code
How many lobes are found in the mammary glands
Consists of 15-20 lobes, containing small grape like clusters of glands called alveoli which are separated by adipose tissue
How is milk ejected from the breasts
Contraction of myoepithelial cells that surround the alveoli which help propel milk into lactiferous ducts
The milk itself can be stored in lactiferous sinuses
What are the 3 tissue layers of the uterine wall
- Perimetrium - visceral peritoneum outer
- Myometrium - 3 smooth muscle layers
- Endometrium - highly vascular inner layer divided into the ‘stratum basalis’ which is permanent deep layer that regenarates the ‘stratum functionalis’ (sloughs off during menses)
What is the main ligament that keeps the uterus suspended
The ‘broad ligament’
What hormone helps to build up the endometrium vs maintain
Oestrogen helps build
Progesterone helps maintain
What are the functions of the placenta
The site of exchange of nutrients, oxygen & wastes between the mother & foetus, attached to the endometrium through diffusion of blood
It produces hormones that are needed to maintain pregnancy
Nutrient transfer is mediated by proteins called nutrient transporters
Provides a form of protective barrier to separate blood from the two placental systems
What are the two placental systems
Formed in 12th week of gestation, maternal placenta & foetal side
Preventing blood from transferring whilst still allowing mother breathing & eating for the foetus
What 2 main hormones does the placenta produce
Progesterone - maintains endometrial lining
Oestrogen - promotes growth of breast tissue & myometrium
What is the hormone human chorionic gonadotropin (hCG)
only produced during pregnancy by placenta (tests!) which ensures adequate nutrient transfer to foetus & is related to morning sickness
What is the hormone human placental lactogen (hPL)
Increases the amount of glucose & lipids in maternal blood
What is the hormone relaxins role in pregnancy
Targets ligaments & relaxes them in preparation for birth as well as growth in uterus
Produced by corpus luteum & placenta
What is the role of CRH in pregnancy
Produced by placenta
Triggers release of cortisol from adrenals which prevents rejection of foetus / placenta (immunosuppressant)
What are monozygotic twins
(30%)
Identical twins that originate from one fertilised ovum
Zygote splits into 2 embryos but share 1 placenta
What are dizygotic twins
(70%)
Non-identical twins, release of two ova & fertilisation of each. Implanted independently with 2 placentas
What are the main functions of the fallopian tubes
Provide a route for the ova to travel to the uterus & for sperm to travel to the ova
What are fimbriae
Finger-like projections that surround the ovary & sweep the ova into the fallopian tube
They are lined with ciliated columnar epithelium which function to help move the ova towards the uterus
A smooth muscle layer also performs peristalsis to assist ova movement
What hormones do ovaries secrete
Oestrogen & progesterone
What is the function of the ovarian ligament
Anchors the ovaries to the uterus, whilst the broad ligament also assists in maintaining the position of the ovaries
What does oogenesis refer to
The formation of female gametes (ova) in the ovaries
It begins in the foetus
What is a primary oocyte & how is it formed
An immature egg cell
Formed from germ cells during foetal development which stops at birth (approx 20thousand - 2million)
During female lifetime around 400 will mature & ovulate with rest degenerating
What is a germ cell
An embryonic cell capable of becoming a gamete
Why do primary oocytes have follicular cells
The primordial follicles are needed to help primary oocytes to grow & mature
What hormone does the anterior pituitary release to help maturation of primary oocytes
FSH stimulates maturation of the primordial follicles into a mature follicle
This follicular structure remains & becomes the corpus luteum
What hormone triggers ovulation
LH triggers the release of the mature ovum - secondary oocyte
How does the placenta connect from the mother to the baby
Maternal part extends from the endometrium whereas the foetus connects to the embryo through the umbilical cord