Week 2 Flashcards
What does Oestrogen do in pregnancy?
Growth and development of breasts;
Hyperplasia of the endometrium - building up the lining of the uterus;
Hypertrophy of the uterus - growth in size;
Increased vascularisation of the uterus;
Promotes growth of myometrial muscle;
Increases blood flow.
What is the role of progesterone in pregnancy?
Relaxes smooth muscle;
Reduces uterine muscle excitability, to prevent uterine contraction;
Suppresses immune system;
Relaxation of blood vessels.
What is the role of Human Chorionic Gonadotropin (hCG)?
Maintains the corpus luteum so that it continues to produce Oestrogen and Progesterone until the placenta takes over at 3 months.
Which hormone is detected by pregnancy tests?
Human Chorionic Gonadotropin (hCG).
What is the role of Human Placental Lactogen (hPL)?
It facilitates growth, changing maternal metabolism to maximise the nutrients available to the fetus in utero.
What is the function of the Corpus Luteum?
Maintain the endometrium for implantation and embryonic development;
Suppress ovulation;
Achieves this through release of Oestrogen and Progesterone.
Which hormone is released 5 days after fertilisation?
Human Chorionic Gonadotropin (hCG).
The corpus luteum produces which hormones?
Oestrogen and Progesterone
Oestrogen and progesterone are supress what during pregnancy?
Production of Follicle Stimulating Hormone (FSH) and Lutenising Hormone (LH) and therefore Ovulation and Menstruation.
When does the placenta take over from the corpus luteum in producing Oestrogen and Progesterone?
At around 3 months.
What occurs during Lactogenesis?
Initiation of production of colostrum and milk.
When are the three phases of breast development during the lifespan of the woman?
Inutero; first two years of life, and puberty.
When does the primitive milk streak develop?
During embryogenesis - 4th week after fertilisation.
When does the mammary ridge develop?
During embryogenesis - 5th week after fertilsation.
How is the immune system impacted by pregnancy?
White blood cells increase in number and responsiveness;
Phagocytic activity is supressed (phagocytes attach to foriegn bodies such as bacteria and break them down);
Prostaglandins supress NK cell activity (cells that respond to viral infection.
How is the cardiovascular system impacted by pregnancy?
The heart is displaced upward by the diaphragm;
The heart enlarges and cardiac volume increases by 10-20%;
Cardiac output increases;
Heart rate increases from the 4th week;
Increase in plasma volume and red cell mass, but relativity of increases results in dilute of Hb resulting in anaemia;
Diastolic BP decreases in 1st/2nd trimester, returning to normal in 3rd trimester (drop is due to decrease in total peripheral resistance thanks to progesterone);
Little to no change to systolic BP.
How is the respiratory system impacted by pregnancy?
Diaphragm moves upward;
No change to lung capacity due to increase in diameters of the thoracic cavity;
Tidal volume increases with an offset in residual volume;
02 consumption increases to accomodate the needs of the growing fetus.
How is the renal system impacted by pregnancy?
Kidneys enlarge by 1 - 1.5cm;
Increased blood flow to the kidneys;
Progestoerone dilates the calycesm pelves and ureters (slower passage of urine);
Bladder is displaced up and forward, with reduced capacity meaning frequent urination;
Glomerular filtration increases by about 50%;
Reabsorption of electrolytes is increased as activity of the renin-angiotensis-aldosterone system increases (due to in increased progesterone/oestrogen).
How is the gastrointestinal system impacted by pregnancy?
Displaced by the uterus;
Tone and motility decreased due to progesterone - decreased peristalsis (symptoms include constipation, haemorrhoids, nausea and vomiting and indigestion);
Liver - size and blood volume unchanged;
Gall bladder - increased risk of gall stones; hypotonic, distended, slow emptying;
NVP;
Indigestion due to pressure of uterus and relaxation of sphincters.
What is a teratogen?
Any agent that can disturb the development of an embryo or fetus. Examples include alcohol, medication, cigarettes, bacteria/viruses.
What is the corona radiata?
Outer layer of the oocyte after released from the ovary.
What is the zona pellucida?
The inner layer of the oocyte, inside the corona radiata.
What is the “acrosome reaction”?
Where the acrosome of the sperm releases digestive enzymes after the sperm has attached to receptors on the surface of the zona pellucida. This is stimulated by progesterone.
What is the cell called immediately after fertilisation?
Zygote.
What is meant by cleavage?
The repeated mitotic divisions of the zygote.
What is a morula?
This is the developed zygote at day 4 - 5 that enters the uterus for implantation.
What are the cells of the zygote called?
Blastomeres
How is the blastocyst cavity formed?
Once the morula enters the uterus, uterine secretions pass through the zona pellucida creating a fluid filled space called the blastocyst cavity.
When the zona pellucida disintergrates, what is the fertilised ovum called?
Blastocyst
When does implantation normally occur?
Day 6.
What is gastrulation?
The reorganisation of cells of the bilaminar disc to form the trilaminar disc.
What are the three primary germ layers?
Ectoderm, mesoderm and endoderm.
What is the embryo called after gastrulation?
The gastrula.
The trophoblast differentiates into ?
Syncytiotrophoblast (maternal side); and
Cytotrophoblast (fetal side).
What does the syncytiotrophoblast do?
releases enzymes that break down maternal tissue to allow implantation.
What is the endometrium referred to as after implantation?
The decidua.
What is the decidua basalis?
The region beneath the site of implantation.
What is the decidua capsularis?
Area covering implantation site.
What is the decidua parietalis?
The remaining uterine lining excluding the decidua basalis and the decidua capsularis.
When is the embryonic period?
Weeks 3 - 8.
What is the embryo known as after week 8?
Fetus.
When does the neural tube close?
Week 4.
Which hormone is secreted by the trophoblast?
Human Chorionic Gonadotropin (hCG).
When is hCG detectable in blood and urine?
Blood: 7 days after fertilisation;
Urine: 26 - 29 days after fertilisation.
Which hormone is secreted by the syncytiotrophoblast?
Human Placental Lactogen (hPL) and progesterone.
When does the synthesis of hPL begin?
5 - 10 days after implantation.
What are the three main metabolic changes facilitated by hPL?
- Reduces maternal utilisation of glucose by reducing the response to insulin (an insulin antagonist). This raises the maternal BGL making more available to the fetus;
- Mobilises maternal lipid stores, releasing fatty acids for use by the mother, reserving glucose for the fetus;
- Accelerates amino acid transfer to the fetus.
What is the common precursor for production of steroids such as oestrogen and progesterone?
Cholesterol.
What are the three types of oestrogen?
- Oestriol: the weaker form, and the most common. It increases most significantly during pregnancy.
- beta oestradtiol;
- Oestrone.
What pregnancy symptoms are associated with the progesterone-induced relaxation of smooth muscle?
- Oesophageal reflux (heartburn) due to relaxation of oesophageal sphincter;
- NVP;
- UTIs which increase due to stasis of urine caused by relaxation of the smooth muscle in the ureters and bladder;
- varicose veins and haemorrhoids due to dilation of the veins in the legs and rectal region;
- postural hypotension due to venous pooling resulting from reduced peripheral resistance in blood vessels in the lower limbs.
What neurohormones does the placenta produce?
Corticotrophic-releasing hormone (CRH);
Thyrotrophin-releasing hormone (TRH);
Adrenocorticotrophic hormone (ACTH);
Beta endorphin.
True or False: The release of cortisol by the adrenal glands increases two to three times during pregnancy?
TRUE
True or False: Glucocorticoids such as cortisol stimulate the release of glucose stores into the plasma.
TRUE
What is the operculum and what is it’s function?
The mucous plug of the cervix, that prevents ascending infection.
What is Jacquemier’s sign?
A bluish-purplish colour in the vagina/cervix that occurs due to the increased blood supply in the region during pregnancy. This is related to the increase in oestrogen.
What is Osiander’s sign?
The pulsation of the uterine arteries that can be palpated in the lateral fornices of the vagina.
What is leucorrhoea?
A whitsh/yellowish discharge from the vagina caused by an increase in shedding of superficial mucosal cells.
What causes haemodilution?
Blood volume increases during pregnancy. However, the plasma increases as a faster rate than the cellular components, resulting in lower haemoglobin per blood volume.
What stimulates erythropoeisis?
The production of red blood cells is stimluated by increased O2 demand and increased metabolism.
True or False: Haemodilution decreases blood viscosity, which decreases the workload on the heart.
TRUE
What are the impacts on the musculoskeletal system during pregnancy?
Symphysis pubis, sacroiliac and sacrococcygeal joints soften and facilitate widening of the pelvis;
Relaxation of ligaments due to relaxin and oestrogen.
Which hormone is stimulated during pregnancy and results in deeper pigmentation of the skin?
Melanocyte-stimulating hormone.
Name four hormones of pregnancy.
hPL;
hCG;
Oestrogen;
Progesterone.
Which is the main hormone produced by the placenta?
Human Placental Lactogen (hPL)
Which hormones are produced by the corpus luteum?
Oestrogen & Progesterone.
Name three signs of early pregnancy.
- Amenorrhoea;
- Increased urination;
- Breast tenderness;
- hCG detected in urine.
How much does cardiac output increase by during pregnancy?
30 - 50%
True or False: Blood volume increases in pregnancy to accomodate the growing the fetus.
True
True or False: Lung capacity increases during pregnancy.
False - Tidal volume increaes, with an offseting decrease to residual volume.
True or False: Respiratory rate decreases during pregnancy
False
True or False: The bladder is displaced up and forward with reduced capacity.
True.
