UNIT 7 REVISION DOCUMENT

Question 1

implantation process

Answer 1

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

Question 2

how is the placenta devleoped

Answer 2

• 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

Question 3

hormones secreted by the anterior pituitary

Answer 3

FSH
LH
ACTH
TSH
Prolactin
Ignore
GH

Question 4

what forms blood testes barrier

Answer 4

tight junctions between sertoli cells

Question 5

oogenesis

Answer 5

• 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

Question 6

spermatogenesis

Answer 6

• 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

Question 7

follicularp hase

Answer 7

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

Question 8

luteal phase

Answer 8

2. 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

Question 9

first sign of puberty in females

Answer 9

breast development

Question 10

first sign of puberty in males

Answer 10

testicular development

Question 11

male puberty

Answer 11

Question 12

female puberty

Answer 12

Question 13

hypothalamic pituitary testicular axis

Answer 13

LH to Leydig cells to testosterone release
FSH to Sertoli cells to spermatogenesis
Testosterone has negative feedback effect on hypothalamus and anterior pituitary gland

Question 14

hypothalamic pituitary ovarian axis

Answer 14

LH to theca cells to androgen release
Androgens diffuse from theca cells to granulosa cells
FSH to granulosa cells to convert androgen to oestrogen

Question 15

sperm transport

Answer 15

S – Seminiferous tubules
R – Rete testis
E – Efferent ducts
E – Epididymis
V – Vas deferens
E – Ejaculatory duct
N – Nothing
U – Urethra
P- Penile Urethra

Question 16

placental physiology

Answer 16

Storage
Endocrine
Respiration
Protection
Excretion
Nutrition
Transport

Question 17

stages of labour

Answer 17

• 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

Question 18

different foetal positoins in utero

Answer 18

Question 19

cervical ripening

Answer 19

• 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

Question 20

ferguson reflex

Answer 20

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

Question 21

uterine layers

Answer 21

1. Perimetrium – outermost serous layer (visceral peritoneum)
2. Myometrium – middle layer, interlacing layers of smooth muscle
3. Endometrium – mucosal lining of uterine cavity, changes thickness during menstrual cycle

Question 22

corticotropin releasing hormone

Answer 22

• in response to stress hypothalamus releases CRH
• travels to the anterior pituitary
• stimulates release of adrenocorticotropic hormone
• ACTH travels to adrenal cortex
• stimulate release of cortisol and other steroids that liberate energy stores to cope with the stress
• CRH increases but binding porting decreases
• CRH stimulates PG released and potentially action of oxytocin in stimulating myometrium contractions

Question 23

delivery stages

Answer 23

• Descent
• Engagement
• Neck flexion
• Internal rotation
• Crowning
• Extension of the presenting part
• Restitution
• External rotation
• Lateral flexion

Question 24

two main hormones involved in breast feeding

Answer 24

prolactin and oxytocin

Question 25

prolactin function

Answer 25

- Stimulus: baby's sucking action - Stretch receptors in breast send impulses to the hypothalamus - Inhibits prolactin-inhibiting hormone (PIH) - Stimulates prolactin-releasing hormone (PRH) - Increased PRH causes release of prolactin from anterior pituitary - Prolactin circulates to the alveoli of the mammary gland to stimulate lactation

Question 26

oxytocin function

Answer 26

- Once the milk is formed , oxytocin causes the ejection - Stimulus: baby's sucking action - Stretch receptors in breast send impulses to the hypothalamus - Stimulates the production of oxytocin - Oxytocin circulates to the myoepithelial cells surrounding the mammary glands - Allows contraction of the myoepithelial cells to force milk out of the ducts where it can be suckled by the baby

Question 27

prolactin receptor theory

Answer 27

prolactin in the blood rises, more circulating prolactin= greater activation of prolactin receptors= greater number of primed receptor sites= greater number of functional lactocytes = max triggering of mothering response

Question 28

feedback inhibtor of lactation

Answer 28

supply and demand establishment, breats become full due to ineffective milk removal, FIL slows synthesis by signalling to cells to stop production

Question 29

hormones that change in pregnancy

Answer 29

oestrogen progesterone hCG prolactin relaxin oxytocin prostaglandins

Question 30

oestrogen

Answer 30

produced throughout pregnancy, regulates levels of progesterone, prepares the uterus for baby (stimulates growth of uterine mass), prepares the breasts for lactation, induces synthesis of receptors for oxytocin, first 2 months = supplied by corpus luteum, then by placenta.

Question 31

progesterone

Answer 31

prevents miscarriage builds up endometrium for support of placenta, inhibits uterine contractility – so fetus is not expelled prematurely. Increases throughout pregnancy. First 2 months = supplied by the corpus luteum.

Question 32

hcg

Answer 32

stimulates Oestrogen / progesterone production by ovary, pregnancy test hormone – diminishes once the placenta is mature enough to take over oestrogen / progesterone production.

Question 33

prolactin

Answer 33

produced by the anterior pituitary gland, increases cells that produce milk, prevent ovulation (unreliably), after birth, oestrogen and progesterone levels decrease, allowing prolactin to stimulate milk production (also controlled by suckling)

Question 34

relaxin

Answer 34

high in early pregnancy, produced by ovary and placenta, helps limit uterine activity, softens cervix & involved in cervical ripening for delivery.

Question 35

oxytocin

Answer 35

triggers ‘caring’ reproductive behaviour, responsible for uterine contractions during pregnancy and labour (drug used to induce labour).

Question 36

prostaglandins

Answer 36

PGF2a = main one (PGE2 10x more powerful). Tissue hormones – role in initiation of labour; synthetic prostaglandins used to induce labour.

Question 37

what are the domains of maternal adaptation

Answer 37

CVS resp GI skin biochem

Question 38

CVS

Answer 38

Increased CO, Decreased systemic BP, Decreased total peripheral resistance, Increased uterine blood flow, Increased blood volume, Increased plasma and blood cell mass, Varicose veins

Question 39

resp

Answer 39

: Increased alveolar ventilation

Question 40

gi

Answer 40

Increased acid reflux, Gastroparesis (delayed emptying)

Question 41

skin changes

Answer 41

Linea nigra, Striae gravidarum, Darkened areola

Question 42

biochemical

Answer 42

Weight gain – maternal and fetoplacental. Obese women don’t put much weight on as have fat stores, Increased protein and lipid synthesis, Insulin resistance

Question 43

what are the different follicles made

Answer 43

- Primordial follicle - Small primary follicle - Secondary/ preantral follicle - Antral follicle then ovlulation - Luteinization - Corpus leuteum - Leutolysis/regression of follicle

Question 44

phases of follicular development

Answer 44

pre antral antral pre ovulatory

Question 45

pre antral

Answer 45

gonadotrophin independent proliferation in granulosa cells oocyte increases in size and activity secretes ZP cytoplasmic processes between granulosa cells and oocyte development of theca cell layters and blood supply

Question 46

antra l

Answer 46

gonadotrophin dpeendent granulosa cells secrete follicular fluid, coalesce in the antrum to increase the follicular size synthetic activity in oocyte maintained morphological changes in the follicle

Question 47

pre ovulatory phase

Answer 47

lh and progesterone dependent meitotic maturation and expulsion of the first polar body withdrawal of cytoplasmic processes oocyte synthesis of cortical granules rapid expansion of volume of antral fluid lh stimulated progesterone secretion by granulosa cells hormone stimulated protease activity

Question 48

foeta lcircualtion

Answer 48

blood flows right atrium to right ventricle but also through the foramen ovale to the LA and LV ductus arteriosus connects the pulmonary artery to the aorta and therefore bypases the lungs due to increased pressure allows right to left shunt and by pass the lungs umbilical vein to the lvier becomes the ductus venosus and joins the IVC

Question 49

circulation at birth

Answer 49

decreased pulmonary resistance increased systemic pressure foramen ovale closes

Question 50

foetal lungs

Answer 50

full of amniotic fluid onset of labour increases glucocorticoids, catecholamines and ADH meaning secretion of lung fluid stops crying clears the fluid

Question 51

what stimulates production of type 2 pneumocytes

Answer 51

cortisol and TSH

Question 52

nutritional supply to the foetus in utero

Answer 52

cortisol triggers storage of glycogen in the liver when maternal glucose supply is good the insulin triggers storage of gluycose not required for growth as fat

Question 53

nutritional supply at birth

Answer 53

decreased plasma glucos by releasing glycogen stores but only lasts 12 hours glucose metabolism begins increased foetal stress increases catecholamine and glucagon decreased insulin= mobilisation of glycogen gluconeogenesis 2 hours after birth by PEPCK activity, allows lactate recycling and hepatic gluconeogenesis 12 hours ketogenesis occurs