Pregnancy I Flashcards

1
Q

Function of Ovaries

A

Gametogenic Function:
Oogenesis and cyclical release of ovum

Endocrine Function:
Production of oestrogen, progesterone, relaxin, inhibin

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2
Q

Function of Fallopian tubes

A

Collect and transport of zygote into the uterine cavity by means of fimbriae, ciliary activity and peristalsis

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3
Q

Function of uterine body

A

The endometrium accommodates and nourishes the zygote

The myometrium expels foetus at parturition

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4
Q

State the change in level of Oestrogen throughout the Menstrual Cycle

A
  1. Oestrogen level is high during Follicular Phase (Day 1 to Day 14)
  2. Sudden increase of Oestrogen level right before Ovulation (Day 14)
  3. Level of Oestrogen drops after ovulation
  4. Oestrogen level rise slightly during mid Luteal Phase (Around day 20)
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5
Q

State the changes of Progesterone level throughout Menstrual Cycle

A
  1. Progesterone level is low during Follicular Phase
  2. With the formation of Corpus Luteum, progesterone level increases after ovulation.
  3. Progesterone level reaches its peak at mid Luteal Phase
  4. With the degeneration of Corpus Luteum, progesterone level decreases toward the end of Luteal Phase.
  5. Progesterone level decreases to its baseline level at Day 1 of Menstrual Cycle
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6
Q

What are the hormones secreted in the pituitary glands that control the activities of the ovaries?

A
Follicle stimulating hormone (FSH)
Luteinising hormone (LH)
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7
Q

What is the changes in FSH and LH throughout the Menstrual cycle?

A
  1. In the beginning (day 1) , FSH level is slightly higher than LH level
  2. During mid Follicular phase (around day 7), LH level surpass FSH level
  3. LH and FSH level spike right before the release of ovum (Ovulation)
  4. After ovulation, LH and FSH level decrease to the normal level
  5. Towards the end of the Luteal Phase, FSH level rises slightly higher than LH level
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8
Q

Function of FSH

A

Control the development of Ovarian Follicle

Follicular Stimulating Hormone (FSH)

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9
Q

Function of Corpus Luteum

A

Secrete Progesterone

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10
Q

What is the negative feedback mechanism for the hormones involved in the Menstrual cycle?

A
  1. Hypothalamus secrete Gonadotropin-releasing hormone (GnRH)
  2. GnRH directs the pituitary glands to release FSH and LH, which controls the ovaries to produce progesterone and oestrogen
  3. High level of Progesterone and Oestrogen subsequently inhibit Hypothalamus and pituitary glands, reduces the secretion of GnRH, LH and FSH
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11
Q

What is the first menstrual cycle called?

A

Menarche /mi nar ki/

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12
Q

What is the function of Basilar zone of endometrium?

A
  1. Attached the endometrium to the layer beneath it
  2. Place where resources come for building of endometrium

The basal layer, adjacent to the myometrium and below the functional layer, is not shed at any time during the menstrual cycle. The functional layer develops on top of it.
In the absence of progesterone, the arteries supplying blood to the functional layer constrict, so that cells in that layer become ischaemic and die, leading to menstruation.

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13
Q

What are the functions of Functional zone of endometrium?

A

It is adapted to provide an optimum environment for the implantation (by developing glands which stores food for embryo) and growth of the embryo.

The functional layer is adjacent to the uterine cavity. This layer is built up after the end of menstruation during the first part of the previous menstrual cycle. Proliferation is induced by estrogen (follicular phase of menstrual cycle), and later changes in this layer are engendered by progesterone from the corpus luteum (luteal phase). This layer is completely shed during menstruation.

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14
Q

What is conception?

A

Successful fertilisation and implantation following unprotected mating or artificial insemination

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15
Q

What are the layers of the ovum starting from the outermost layer?

A

Corona radiata, zona pellucida, perivitelline space, cell membrane

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16
Q

How long can an ovum (after fertilisation) and sperm (after in female genital tract or Fallopian tube) survive?

And what is the most fertile period?

A

Ovum: 72 hours after ovulation
* Fertilisation period much shorter

Sperm/Spermatozoa: Able to fertilise for a period of 120 hours

Most fertile period: 48 hours before ovulation

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17
Q

What is the development timeline of a fertilised ovum (zygote) ?

A

Secondary oocyte

Day 0 (Fertilisation)
egg cell nucleus + sperm cell nucleus
zygote

Day 1 (Cleavage)
2-cell stage
Day 2 (Cleavage)
4-cell stage
Day 3 (Cleavage)
8-cell uncompacted morula 

Day 4
8-cell compacted morula

Day 5
Early blastocyst

Day 6-7 (Hatching, removal of zona pellucida)
Late-stage blastocyst

Day 8-9
Implantation of the blastocyst

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18
Q

What are the 3 stages of implantation?

A
  1. Apposition - the blastocyst contacts the implantation site of the endometrium
  2. Adhesion - trophoblast cells of the blastocyst attach to the receptive endometrial epithelium
  3. Invasion - Invasive trophoblast cells cross the endometrial epithelial basement membrane and invade the endometrial storms
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19
Q

What happen during apposition?

A

2 to 4 days after the arrival of morula in the uterine cavity,

The blastocyst differentiates into an inner cell mass (embryo) and trophectoderm (trophoblast)(forms placenta)

Stromal cells surrounding the implanting blastocyst undergo decidualisation (cell differentiation) to form decidual cells.

20
Q

What happen during cell adhesion?

A

Trophectoderm (trophoblast) of the blastocyst adhere to the endometrium (endometrial luminal epithelial cells)

This process is mediated by cell adhesion molecules, which are expressed on the surface of invasive trophoblast

21
Q

What happens during cell invasion?

A

Foetal trophoblast invade and migrate into the endometrium (maternal decidua) and penetrate the basement membrane

Trophoblasts form masses of cytotrophoblasts and syncytiotrophoblasts.

22
Q

Which parts of the trophoblast invades the uterine wall?

A

Syncytiotrophoblast

Originated from trophoblast

23
Q

What are the structure found on the surface of the endometrium which connects the zygote and endometrium?

A

Pinodopodes

24
Q

What is ectopic implantation?

A

Attachment of foetus/embryo out of the uterus

Normally Fallopian tube (93-97%)

25
Q

In which days the subsequent event to occur (after ovulation), taking ovulation as day 0

  1. Fertilisation
  2. Entrance of blastocyst into uterine cavity
  3. Implantation
  4. Formation of trophoblast and attachment of endometrium
  5. Onset of trophoblast secretion of hCG
  6. hCG “rescue” of corpus luteum
A
  1. Fertilisation
  2. Entrance of blastocyst into uterine cavity
  3. Implantation
  4. Formation of trophoblast and attachment of endometrium
  5. Onset of trophoblast secretion of hCG
  6. hCG “rescue” of corpus luteum
  7. Day 1
  8. Day 4
  9. Day 5
  10. Day 6
  11. Day 8
  12. Day 10
26
Q

What happens after the embryo settles in the endometrium?

A

Trophoblast becomes syncytiotrophoblast

Cytotrophoblast forms placenta

Inner cell mass will develop into epiblast and hypoblast, which eventually will form the foetus

Fluid starts to accumulate within the extraembryonic mesoderm, which is known as amniotic fluid

The cavity where amniotic fluid is called amniotic cavity

27
Q

What is found in the placenta (cross section of the placental wall)?

A

Starting from mother side to the foetus side

Maternal blood in intervillous space, syncytiotrophoblast cell, cytotrophoblast, basement membrane, connective tissue, foetal capillary

28
Q

During foetal stage, what is formed in the placenta?

A

Decidua basalis (forms maternal part of placenta)

Chorion frondosum - consist of layers of trophoblast and extraembryonic mesoderm, surrounded by numerous villi
(Frondosum means bushy)

29
Q

What happens to the uterine cavity during late pregnancy?

A

The uterine cavity is being compressed due to the foetus occupying most of the cavity

30
Q

What is decidua capsularis?

A

A layer of tissue that envelops the embryo

31
Q

What is chorion laeve?

A

The part of the chorion that is in contact with the decidua capsularis undergoes atrophy, so that by the fourth month scarcely a trace of the villi is left.

Laeve means smooth

32
Q

What is the functional unit of placenta?

A

Chorionic villus

33
Q

Umbilical artery contains O2/deO2 blood?

Umbilical vein contains O2/deO2 blood?

A
  1. DeO2

2. O2

34
Q

What are the layer found in chorionic villus?

A

Starting from maternal blood

Placental membrane (barrier)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
Syncytiotrophoblast 
Cytotrophoblast 
Basement membrane
Connective tissue
Foetal capillary basement membrane
Foetal capillary endothelial layer
—————————————
Foetal blood
35
Q

What is the process of Oxygen transport in placenta

A
  1. Haemoglobin-oxygen dissociation in erythrocytes
  2. Diffusion if oxygen through erythrocyte membrane
  3. Diffusion across the syncytiotrophoblast
  4. Diffusion across basement membrane and villus stroma
  5. Diffusion across endothelium of foetal blood vessel
  6. Diffusion through foetal erythrocyte membrane
  7. Foetal haemoglobin-oxygen binding
36
Q

What are the factors that increase maternal O2 transfer to foetus?

A
  1. Increased maternal blood supply to placenta (20 fold increase)
  2. Increased foetal blood supply to placenta
  3. Higher O2 affinity of foetal haemoglobin than maternal haemoglobin
  4. Foetal haemoglobin is 40% higher in concentration than adults
  5. Double Bohr effect (ability of mother to give away O2 at low partial O2 pressure and ability of foetus to keep O2 at low partial pressure)
37
Q

How does Double Bohr effect occur at placenta?

A

Partial pressure of CO2 in foetus is high

Causes a right shift in O2 dissociation curve (first Bohr effect)

Besides, partial pressure of pCO2 at placenta in mother is also high

Causes a right shift in O2 dissociation curve
(2nd Bohr effect)

Hence, the high pCO2 causes Hb in mother to release its O2 readily

38
Q

State the metabolite that do and do not cross the placenta

A
Mother      Placenta     Foetus
Glucose ————-> Glucose
Amino acid ———> Amino acid
Ketones ————-> Ketones
Oxygen
H2O
Electrolytes
Carbohydrates
Lipids
Polypeptide
Vitamins
Hormone
Some drug
Some pathogen
Almost all viruses

Triglyceride ———> Fatty acid

Insulin —————X
Glucagon ———-X
RBC —————-X

39
Q

What are the types of hormones released by placenta?

A

Placenta plays a central role in endocrinology of pregnancy by producing hormones which are essential for maintenance of pregnancy and preparation for lactation

The types of placental hormones are

  1. Placental protein and peptide hormones
  2. Placental steroid hormones
  3. Other placental hormones
40
Q

What hormones belongs to the placental protein and peptide hormones?

A
  1. Human Chorionic Gonadotropin (hCG) -helps corpus luteum to survive which secretes progesterone to remain thickening of placenta
  2. Human Chorionic Somatonam-motrophin (hCS)
  3. Placental lactogen - helps in giving glucose to the foetus
41
Q

What hormones belong to the placental steroid hormone?

A

Oestrogen and Progesterone

Androgens

42
Q

What belongs in the “Other Placental Hormones”?

A

Prostaglandin

43
Q

Describe the hormones level during pregnancy

A
  1. Human Chorionic Gonadotrophin (hCG) peaks at Week 12 while remain low till end of pregnancy
  2. Human placenta lactogen (hPL), Prostaglandin (P) and Oestrogen (E3) are low during the first trimester of pregnancy but increases steadily and peaks at the last 4 weeks of pregnancy
44
Q

Describe hCG in terms of

  1. Component
  2. Location of synthesis
  3. Subunits
A
  1. Glycoproteins
  2. Syncytiotrophoblast
  3. 2 subunits

Alpha subunit
-Rises throughout pregnancy

Beta subunit

  • Basis for diagnosis of pregnancy and monitoring trophoblast is disease
  • Peak plasma levels at 60-90 days of gestation
45
Q

Action and detection of hCG

A

Action
Acting on Luteinising hormone/chorionogonadotropin receptor (LHCG) on the ovaries to maintain the corpus luteum during first few months of pregnancy

Detection of hCG
6 days after conception
9 days after mid cycle peak
8 days after ovulation
1 day after implantation

Urine level
As early as 14 days