Changes to female repro system + placenta growth Flashcards

1
Q

State the functions of the placenta using ‘serpent’

A
S - storage
E - endocrine
R - respiration
P - protection
E - excretion
N - nutrition
T - transfer
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2
Q

Explain the placental function ‘storage’

A

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

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3
Q

Explain the placental function ‘endocrine’

A

oestrogen and progesterone

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4
Q

Explain the placental function ‘respiration’

A

gaseous exchange to and from the foetus by diffusion

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5
Q

Explain the placental function ‘protection’

A

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

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6
Q

Explain the placental function ‘excretion’

A

carbon dioxide and bilirubin

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7
Q

Explain the placental function ‘nutrition’

A

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

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8
Q

Explain the placental function ‘transfer’

A

of substances e.g. glucose

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9
Q

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

A

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

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10
Q

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

A

decidualisation

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11
Q

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

A
  • decidua basalis
  • decidua capsularis
  • decidua vera/parietalis
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12
Q

Describe the decidua basalis

A

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

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13
Q

Describe the decidua capsularis

A

covers the developing embryo separating it from the uterine cavity

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14
Q

Describe the decidua vera/parietalis

A

line the remainder of the cavity

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15
Q

What are the two stages of implantation?

A

1 prelacunar

2 lacunar

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16
Q

Explain the ‘prelacunar’ stage of implantation

A
  • 7 days post conception
  • blastocyst makes contact with decidua
  • placentation begins
  • maternal connective tissue invaded
  • trophoblasts differentiate in to two layers - cytotrophoblasts, syncytiotrophoblasts
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17
Q

When implantation occurs, the trophoblasts differentiate into two layers:

A

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

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18
Q

Explain the ‘lacunar’ stage of implantation

A
  • 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
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19
Q

What are chorionic villi?

A

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

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20
Q

Define vasculogenesis

A

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

21
Q

Define angiogenesis

A

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

22
Q

The villi differentiate and specialise in to:

A

anchoring villi and nutritive villi

23
Q

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

A

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

24
Q

Explain the process of syncytiptrophoblasts creating ‘small lakes’

A

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

25
Q

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

A

8 weeks

26
Q

What happens to the chorionic villi touching the decidua capsularis?

A

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

27
Q

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

A

capsularis bulges into the uterine cavity and fuses with the parietalis

28
Q

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

A

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

29
Q

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

A
  • provides a buoyant environment that protects the embryo

- helps maintain a homeostatic temperature

30
Q

Where does amniotic fluid come from?

A

initially from maternal blood and later, fetal urine

31
Q

What are the 3 layers of the uterus?

A
  • perimetrium
  • myometrium
  • endometrium
32
Q

Describe the perimetrium

A
  • thin layer of peritoneum over the uterus and uterine tubes
  • connective tissue made up of collagen and elastin fibres
  • continuous with broad ligaments
33
Q

What happens to the perimetrium during pregnancy?

A
  • distorted during pregnancy
  • increases stress and stretch on ligaments
  • ligaments stretching will make it hard to localise pain later in pregnancy
34
Q

What are the ligaments associated to the perimetrium?

A

suspensory ligaments
round ligaments
broad ligaments

35
Q

What changes occur to the myometrium in pregnancy?

A
  • smooth muscle cells increased length 10 fold

- oestrogen and progesterone increase mass and composition of extracellular matrix

36
Q

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

A

proliferative, synthetic, contractile

37
Q

What happens in proliferative phases of myometrial development?

A

increase in number of smooth muscle cells (myocytes)

38
Q

What happens in synthetic phase of myometrial development?

A

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

39
Q

What happens in the contractile phase of myometrial development?

A

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

40
Q

Define uterine quiescence

A

a state of quietness or inactivity

hormone control

41
Q

At what gestation can braxton hicks begin?

A

12 weeks

42
Q

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

A
  • decidualisation - nourishment and dampening of the local immune response
  • increased vascularity
  • placental development
43
Q

What happens to the cervix during pregnancy?

A

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

44
Q

Cervix: What is ‘hegar’s sign’?

A

softening of the cervix due to progesterone

45
Q

Cervix: What is ‘goodell’s sign’?

A

blue/purple colouration due to increased blood flow

46
Q

What is the ‘cervical plug’?

A

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

47
Q

Vagina: What is ‘chadwick’s sign’?

A

blue/purple colour due to increased blood flow

48
Q

What changes occur to the vagina in pregnancy?

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