Changes to female repro system + placenta growth

Question 1

State the functions of the placenta using ‘serpent’

Answer 1

S - storage
E - endocrine
R - respiration
P - protection
E - excretion
N - nutrition
T - transfer

Question 2

Explain the placental function ‘storage’

Answer 2

metabolises glucose and stores it as glycogen. Iron and fat-soluble vitamins

Question 3

Explain the placental function ‘endocrine’

Answer 3

oestrogen and progesterone

Question 4

Explain the placental function ‘respiration’

Answer 4

gaseous exchange to and from the foetus by diffusion

Question 5

Explain the placental function ‘protection’

Answer 5

limited barrier to infection and some medication e.g chicken pox, syphillis, TB

Question 6

Explain the placental function ‘excretion’

Answer 6

carbon dioxide and bilirubin

Question 7

Explain the placental function ‘nutrition’

Answer 7

transferred from the maternal to fetal blood for baby to grow and develop

Question 8

Explain the placental function ‘transfer’

Answer 8

of substances e.g. glucose

Question 9

Within a few days of fertilisation, how doe the endometrium get prepared for the embryo?

Answer 9

trophoblasts produce human chorionic gonadotrophin (hCG) to prepare the endometrium

Question 10

What is the term for structural changes and increased vascularity within the endometrium?

Answer 10

decidualisation

Question 11

The endometrium is referred to as the decidua in pregnancy. What are the 3 regions of the decidua?

Answer 11

• decidua basalis
• decidua capsularis
• decidua vera/parietalis

Question 12

Describe the decidua basalis

Answer 12

lies between the developing embryo and the stratum basalis of the uterus at the implantation site

Question 13

Describe the decidua capsularis

Answer 13

covers the developing embryo separating it from the uterine cavity

Question 14

Describe the decidua vera/parietalis

Answer 14

line the remainder of the cavity

Question 15

What are the two stages of implantation?

Answer 15

1 prelacunar

2 lacunar

Question 16

Explain the ‘prelacunar’ stage of implantation

Answer 16

• 7 days post conception
• blastocyst makes contact with decidua
• placentation begins
• maternal connective tissue invaded
• trophoblasts differentiate in to two layers - cytotrophoblasts, syncytiotrophoblasts

Question 17

When implantation occurs, the trophoblasts differentiate into two layers:

Answer 17

cytotrophoblasts - cells of the inner layer that retain their cell boundaries
syncytiotrophoblasts - cells in the outer layer that retain their cell boundaries

Question 18

Explain the ‘lacunar’ stage of implantation

Answer 18

• increasing number of syncytiotrophoblasts invading blood vessels
• ‘lacunae’ - small lakes form within these cells
• the lacunae will become the intervillous spaces, bathed in blood 10-12 weeks following conception
• placenta accreta - abnormally adhered placenta due to excessive trophoblastic invasion

Question 19

What are chorionic villi?

Answer 19

finger-like projections of chorion surround by cyto and syncytotrophoblastic layers

Question 20

Define vasculogenesis

Answer 20

new blood vessels develop in response to a low level of oxygen

Question 21

Define angiogenesis

Answer 21

further growth of blood vessels produce a vascular network which connect blood vessels developed in the embryo via umbilical arteries and veins

Question 22

The villi differentiate and specialise in to:

Answer 22

anchoring villi and nutritive villi

Question 23

Where does the villi mostly profuse before development of the placenta?

Answer 23

into the decidua basalis where the blood supply is greatest - known as the chorion fronosum - this then develops in to the placenta

Question 24

Explain the process of syncytiptrophoblasts creating ‘small lakes’

Answer 24

the syncytiotrophoblasts surrounded the villi erode the walls of the maternal vessels as the penetrate the low myometrium, opening them up in a funnel shape. This forms a lake of maternal blood which the villi float in

Question 25

Until what gestation doe the villi cover the entire chorionic sac?

Answer 25

8 weeks

Question 26

What happens to the chorionic villi touching the decidua capsularis?

Answer 26

degenerate after 8 weeks due to limited blood supply and come the chorion laeve which become the chronic membrane

Question 27

As the conceptus grows what happens to the decidua capsularis an parietalis?

Answer 27

capsularis bulges into the uterine cavity and fuses with the parietalis

Question 28

What is the amnion? Where is it? What does it contain?

Answer 28

The amnion is a tough, smooth, translucent membrane, lining the chorion, surface of the placenta and umbilical cord. It contains cells which produce amniotic fluid and prostaglandins

Question 29

The amniotic cavity is filled with amniotic fluid. What is it's function?

Answer 29

- provides a buoyant environment that protects the embryo | - helps maintain a homeostatic temperature

Question 30

Where does amniotic fluid come from?

Answer 30

initially from maternal blood and later, fetal urine

Question 31

What are the 3 layers of the uterus?

Answer 31

- perimetrium - myometrium - endometrium

Question 32

Describe the perimetrium

Answer 32

- thin layer of peritoneum over the uterus and uterine tubes - connective tissue made up of collagen and elastin fibres - continuous with broad ligaments

Question 33

What happens to the perimetrium during pregnancy?

Answer 33

- distorted during pregnancy - increases stress and stretch on ligaments - ligaments stretching will make it hard to localise pain later in pregnancy

Question 34

What are the ligaments associated to the perimetrium?

Answer 34

suspensory ligaments round ligaments broad ligaments

Question 35

What changes occur to the myometrium in pregnancy?

Answer 35

- smooth muscle cells increased length 10 fold | - oestrogen and progesterone increase mass and composition of extracellular matrix

Question 36

There are 3 phases of myometrial development. What are they?

Answer 36

proliferative, synthetic, contractile

Question 37

What happens in proliferative phases of myometrial development?

Answer 37

increase in number of smooth muscle cells (myocytes)

Question 38

What happens in synthetic phase of myometrial development?

Answer 38

increase size of myocytes and remodelling of ECM (extracellular matrix)

Question 39

What happens in the contractile phase of myometrial development?

Answer 39

muscle cell size stabilises and muscle prepare prepares for the labour phase

Question 40

Define uterine quiescence

Answer 40

a state of quietness or inactivity | hormone control

Question 41

At what gestation can braxton hicks begin?

Answer 41

12 weeks

Question 42

What changes occur to the endometrium (decidua) in pregnancy?

Answer 42

- decidualisation - nourishment and dampening of the local immune response - increased vascularity - placental development

Question 43

What happens to the cervix during pregnancy?

Answer 43

the closed, rigid structure becomes soft, distensible and effaced (thinning out) by term

Question 44

Cervix: What is 'hegar's sign'?

Answer 44

softening of the cervix due to progesterone

Question 45

Cervix: What is 'goodell's sign'?

Answer 45

blue/purple colouration due to increased blood flow

Question 46

What is the 'cervical plug'?

Answer 46

thick mucus secreted to form a plug known as the operculum. The operculum prevents ascending infections (through vagina, up to cervix, travelling up)

Question 47

Vagina: What is 'chadwick's sign'?

Answer 47

blue/purple colour due to increased blood flow

Question 48

What changes occur to the vagina in pregnancy?

Answer 48

- vaginal walls - mucosa thickens, connective tissue loosens, smooth muscle cells increase in size - leucorrhea - thick, white discharge - increased acidity to protect from infection