UNIT 7 REVISION DOCUMENT Flashcards
implantation process
1) Apposition – unstable adherence of blastocyst to uterine lining
2) Attachment – endometrial epithelial cells and trophoblast cells connect via integrins, causing a strong adhesion
3) Trophoblast differentiation – differentiates into cytotrophoblast and syncytiotrophoblast, this invades the wall of the uterus
4) Invasion
5) Maternal recognition
how is the placenta devleoped
- Blastocyst implants on the endometrium
- Syncytiotrophoblast grows into the endometrium
- Froms finger like projections called the chorionic villi, containing fetal blood vessels
- Chorion fundosum: is the chorionic villi nearest the connecting stalk of the developing embryo, most vascular, contain mesoderm, these proliferate and become the placenta, connecting stalk becomes the umbilical cord
- Umbilical cord: contains 2 arteries and 1 vein, arteries carry blood frombaby to the placenta and is deoxygenated
hormones secreted by the anterior pituitary
FSH
LH
ACTH
TSH
Prolactin
Ignore
GH
what forms blood testes barrier
tight junctions between sertoli cells
oogenesis
- Oogonia
- Mitotic division starts before 12 weeks
- Producing primary oocytes which begin meiosis
- Meiotic arrest – metaphase 1 until puberty
- Primary oocytes go through remainder of meiosis I to make secondary and polar body
- Secondary oocytes go through meiosis 2 producing 1 ovum and 1 polar body (Large ovum as it takes everything needed for production of foetus mitochondria)
- Group of oogonia in ovaries
- Some die and become theca cells and granulosa cells
- Granulosa cells form follicle around ovum
- Theca cells inside the follicle and provide nutrition to maturing ovum
- Once ovum is mature follicle opens and ovulation happens
- Follicle the degrades forming corpus luteum
- Corpus luteum responsible for making progesterone and inhibiting GnRH and therefore LH and FSH
- Eventually degrades
spermatogenesis
- Occurs in the seminiferous tubules in testes
- Spermatogonia are the initial pool of the diploid cells
Type A – replenish pool of spermatogonia
Type B – form mature sperm - Type B spermatagonia repliocate by mitosis to form identical diploid cells linked by cytoplasm bridges these are primary spermatocytes
- Primary spermatocytes undergo meiosis
- Meiosis I produces secondary spermatocytes
- Meiosis II produces spermatids
- Bridges break and spermatids released into lumen of seminiferous tubule – spermiation
- Spermatids undergo spermeogenesis
- Cells travel to rete testis – concentrates the sperm (removes excess water)
- Move to epididymis where they are stored and have final maturation
follicularp hase
follicular phase= start to day 14
- When follicles reach the secondary follicle stage, they develop receptors for FSH. To develop after the secondary follicle stage, they require stimulation from FSH
- As the follicles grow, the granulosa cells secrete increasing amount of oestrogen which has a negative feedback on the pituitary gland, decreasing LH and FSH. Increasing oestrogen also makes the cervical mucus more permeable, allowing sperm to penetrate the cervix around the time of ovulation
- One follicle develops further than the others, becoming the dominant follicle
- LH spikes just before ovulation, causing the dominant follicle to release an ovum from the ovary
- Ovulation happens 14 days before the end of the cycle
luteal phase
- Luteal phase= 14 to 28
- Follicle which release the ovum then collapses and becomes the corpus luteum
- The corpus luteum secretes high levels of progesterone to maintain the endometrial lining and thicken the cervical mucus
- Corpus luteum also secretes a small amount of oestrogen
- At fertilisation, the syncytiotrophoblast of the embryo secrete HCG which maintains the corpus luteum
- If no fertilisation, the corpus luteum degenerates causing a fall in oestrogen and progesterone
- This causes the endometrium to break down and menstruation occurs
- The stromal cells of endometrium release prostaglandins which encourage the breakdown of the endometrium
- Menstruation starts on day 1 of the menstrual cycle
- Negative feedback from oestrogen and progesterone on the hypothalamus and pituitary gland ceases, allowing LH and FSH levels to rise so the cycle restarts
first sign of puberty in females
breast development
first sign of puberty in males
testicular development
male puberty
female puberty
hypothalamic pituitary testicular axis
LH to Leydig cells to testosterone release
FSH to Sertoli cells to spermatogenesis
Testosterone has negative feedback effect on hypothalamus and anterior pituitary gland
hypothalamic pituitary ovarian axis
LH to theca cells to androgen release
Androgens diffuse from theca cells to granulosa cells
FSH to granulosa cells to convert androgen to oestrogen
sperm transport
S – Seminiferous tubules
R – Rete testis
E – Efferent ducts
E – Epididymis
V – Vas deferens
E – Ejaculatory duct
N – Nothing
U – Urethra
P- Penile Urethra
placental physiology
Storage
Endocrine
Respiration
Protection
Excretion
Nutrition
Transport
stages of labour
- spontaneous onset, gestation 37 weeks plus, vertex presentation & completed within ~ 18 hours with no complications.
- Latent phase of labour: presence of uterine contractions, cervical dilatation, effacement up to 4cm
- Active phase of labour: regular contractions and progressive dilatation beyond 4cm
different foetal positoins in utero
cervical ripening
- Occurs in response to oestrogen, relaxin and prostaglandins breaking down cervical connective tissue
- Relative decrease in progesterone in relation to oestrogen increases the excitability of the uterine musculature as well as mechanical stretching of the uterus as the fetus grows. This increases contractility
ferguson reflex
after 36 weeks there is an increase in oxytocin receptors so the uterus respond to the release of oxytocin form the posterior pituitary, contractions cause positive feedback releasing more oxytocin and stronger contractions
uterine layers
- Perimetrium – outermost serous layer (visceral peritoneum)
- Myometrium – middle layer, interlacing layers of smooth muscle
- Endometrium – mucosal lining of uterine cavity, changes thickness during menstrual cycle