Phys 83 Pregnancy and Lactation
Terms in this set (99)
Where is the ovum in the primary oocyte stage?
Where is it in the second oocyte stage?
Secondary: Ovary, just before release
what causes the cilia of the fibria to begin to beat towards the uterus?
What two substances help aid the movement of sperm by causing contractions of the uterus?
Prostaglandins in the seminal fluid
Oxytocin from pituitary gland from orgasm
Of the billion sperm that are released, how many actually succeed in reaching the ampulla?
a few 1000
how long does it take for the fertilized ovum to reach the uterus?
What are the two physiologic hinderances of the ovum reaching the uterus?
Ruggest Cryptoid surface in uterine tubes
Spastic contraction of the Isthmus 3 days after ovulation
What causes the spastic isthmus to relax after ovulation, thus allowing the fertilized ovum to reach the uterus?
Progesterone increases progesterone receptors on the isthmus, which then activates the receptors causing the muscles to relax.
when does implantation occur?
5-7 days after ovulation
What are the cells called in the uterus when they are stimulated by progesterone and they begin to swell and contain extra glycogen, proteins and lipids?
Describe when and where the developing fetus obtains its nutrients from week one to birth?
1-8 weeks: Decidua (decidual Cells)
8-40 weeks: Placenta
how many umbilical arteries does the fetus have?
How many umbilical veins does the fetus have?
what artery does the maternal blood come from going to the placenta?
how does the fetal and maternal blood come into close enough contact to share nutrients?
Fetal Capillaries are completely surrounded by maternal blood in the intervillous space
What two factors normally cause the permeability not to occur in the placenta very well during the early months of pregnancy?
Placental membrane is thick and permeability is low
Low surface area of the placenta
What is the partial pressure of O2 in the mother's blood at the placenta?
What is the partial pressure of O2 in the fetal blood at the placenta?
What is the mean pressure gradient for diffusion of O2 through the placental membrane?
How is the fetal hemoglobin curve compared to the maternal hemoglobin curve?
Shifted to the Left
What three factors cause the fetus to obtain enough oxygen from the maternal blood?
1. HbF shifts curve to the left (greater affinity)
2. 50% more Hb in Fetus
3. Double Bohr Effect: HbF gives off CO2 to the maternal Hb causing the maternal Hb to give off more O2
What is the difference in PCO2 from the fetus to the mother?
2-3 mmHg higher
How does glucose get into the fetus through the placenta?
What produces hCG?
When is the peak of hCG secretion?
When does the corpus luteum naturally involute?
What are the three functions of hCG?
Prevents involution of corpus luteum (makes it bigger)
Causes the corpus luteum to produce more sex hormones
Stimulates male fetus to produce testosterone
How is estrogen produced in the placenta?
Dehydroepiandrosterone and 16-hydroxydehydroepiandorsterone (mainly the first one) are secreted by the mother and fetus (mainly the fetuses adrenal glands).
These steroids are converted to Estradiol, estrone, and estriol in the placenta.
What are the four functions of estrogen during pregnancy?
(Making a woman more like a woman)
Enlargement of Uterus
Enlargement of breasts
Enlargement of female external genitalia
Relaxes Pelvic Ligaments
What are the four functions of progesterone during pregnancy?
(making a woman more pregnant)
Development of Decidual cells
Decreases Contractility of Uterus
Secretion of Nutritive substances in Uterine tubes
Prepare Breasts for Lactation
What hormone during pregnancy is produced in the greatest quantity?
Somatomammotropin (several time greater than all other hormones combined)
What are the 4 functions of Human Chorionic Somatomammotropin?
Partial development of the breasts (lower animals only)
Formation of Protein Tissues (like growth hormone)
Decrease insulin sensitivity in the mother making more glucose for the baby.
Increases Free Fatty Acid release for energy to the mother
What are the 3 hormones secreted by the 50% increased anterior pituitary during pregnancy?
What is inhibited by the enlarged anterior pituitary during pregnancy?
What two corticosteroid hormones are increased in production from pregnancy?
Glucocorticoids (possible for increased aa in blood)
Aldosterone (2 fold increase)
What pathologic condition can the two fold increase in aldosterone during pregnancy lead to?
What is released from the placenta that increases the secretion rate of thyroxin from the thyroid?
hCT (hC Thyrotropin)
Why does parathyroid hormone increase during pregnancy and increase even more after birth?
Pregnant: Fetus requires calcium for bone growth
After Birth: Lactation
the newborn baby needs more calcium than the fetus
why is relaxin released during pregnancy?
No one knows
what is the average weight gain in a pregnant woman?
when does the weight gain normally occur?
Last 2 trimesters
What is the breakdown of weight gain in a pregnant woman?
Amnionic Fluid, Placenta, Membrane: 4
Blood/Extracellular Fluid: 5
Fat Accumulation: 3-13
When does metabolism increase occur during pregnancy?
What are side-effects of this increased metabolism?
Latter Half of Pregnancy
When does the Fetus grow the most?
When does the weight almost double?
How is the mother able to provide this much nutrition in such a short time?
Last 2 months
She stores the nutrient before hand in the placenta and normal storage deposits
What is a common problem in women during the last 2 months of pregnancy?
Not consuming enough iron in the diet
What are three nutrients that are necessary in high quantities for the mother during the last 2 months of pregnancy?
Vitamin D: Calcium Absorption
Vitamin K: Prothrombin
How much does the cardiac output increase in a pregnant woman?
What are the reasons for this increase?
When does this increase usually occur?
Increased (625 mL) flow to placenta and increased metabolism
occurs around 27th week of pregnancy
Why does the cardiac output decrease to around normal around the last 8 weeks of pregnancy?
No one knows
when does an increase in blood volume during pregnancy normally occur?
What causes this occurrence?
Why does this increase occur?
Latter half of pregnancy
Safety factor for bleeding during deliver
What happens to the maternal respiratory rate during pregenancy?
respiratory rate Increases 20%
Increased metabolic rate, greater size, and Uterus pressing against diaphragm
Why does the renal glomerular filtration rate increase 50% during pregnancy?
Increased renal vasodilation
how often is the amnionic fluid replaced?
What is another name for preeclampsia?
Toxemia of Pregnancy
What are three effects of preeclampsia?
Decreased Filtration Rate
What causes preeclampsia?
Decreased blood flow to the placenta causing the placenta to release substances in to the maternal blood that decreases renal glomerular filtration rate, increased Na and Water retention, and impaired vascular endothelial function
Name 6 symptoms of eclampsia
Vascular Spasms throughout the body
Decreased Kidney Output
when does eclampsia usually occur?
Shortly before birth
What does progesterone do for labor?
Inhibits Uterine contractility
What does estrogen do for labor?
Increases number of gap junctions between adjacent uterine smooth muscle cells
what ratio increases sufficiently towards the end of pregnancy to be partially responsible for the increased contractility of the uterus?
What are the four reasons that oxytocin is believed to be important in increasing contractility of the uterus?
Uterine muscles increase oxytocin receptors during the latter few months
Oxytocin secretions are considerably higher during time of labor
Labor is prolonged in an hypophysectomized animal
Stretching of the cervix causes a neurogenic reflex causing the neurohypophysis to secrete oxytocin
What three substances from the fetus increase uterine contractions and where are they released from?
Adrenal Gland: Cortisol
Fetal Membrane: Prostaglandins
What 4 (5) hormones increase uterine contractility?
Cortisol from fetus
Oxytocin from fetus
Prostaglandins from fetus
What two mechanical factors increase uterine contractility?
Cervical Stretching or Irritation
Why are twins usually born 19 days earlier than a single child?
Overly stretched uterus which increases contractility
Baby girl Bethany is sitting in the uterus at 32 weeks gestation and every now and then the uterus gets a little tight and cramped but it only lasts for a few seconds to minutes then it goes away. What causes this?
Braxton Hicks Contractions
Once the Braxton Hicks Contractions become strong enough to start forcing the stretch of the cervix. at this point they are then known as what?
Describe the positive feedback loop of labor
Baby's head stretches cervix
This causes the Uterus to contract even stronger
This also causes the pituitary gland to secrete oxytocin which increases uterine contractility
These two factors increase cervical dilation
What is necessary for a positive feedback mechanism to continue
Each new cycle of the positive feedback must be stronger than the previous one
What causes the abdominal muscles to contract during labor?
Pain signals from the uterus and birth canal
Where do contractions of the uterus start?
Where are the strongest contractions of the uterus?
Top of the Uterine Fundus
Top of uterine fundus
how much force is generated by the uterus and abdominal muscles during labor?
Why do contractions happen intermittently instead of one strong long contraction?
contractions impede or stop blood flow to the placenta and can kill the baby
What is it called when the baby is butt first?
what consists of the first stage of labor?
Progressive cervical dilation
how long can the first stage of labor last for the first pregnancy?
What consists of the second stage of labor?
Fetal membrane ruptures
The head of the fetus moves rapidly into the birth canal
The baby continues to wedge its way through the canal until delivery
How long can the second stage of labor last?
What causes the release of the placenta from the uterus?
How long can list last?
A shearing effect of the uterus continually contracting to a smaller and smaller size
What is the mechanism of cutting off the blood supply to the uterus after birth so as not to continually bleed when the placenta is removed?
Smooth muscle fibers surrounding the blood vessels contract after the baby is born
Prostaglandins formed at the placental separation site cause additional blood vessel spasms
What causes the initial labor pains?
Hypoxia of the uterine muscles resulting from the compression of the blood vessels in the uterus
What nerves can be cut to stop the initial labor pains?
(visceral) Hypogastric Nerves
What causes the pain of the second stage of labor?
Stretching/tearing of vaginal canal
What nerves transmit pain signals during the second stage of labor?
If the mother does this, the uterus will return to prepregnancy size in 4 weeks
What part of lactation causes the uterus to return to normal?
Suppression of pituitary gonadotropin and ovarian hormone secretion
What is the term for vaginal discharge after birth from the autolyzing of the endometrium?
How long is Lochia produced after birth?
What 5 hormones are important for the growth of the ductal system of the breasts?
What hormone is required, besides the 5 main hormones used for breast development, for the budding and development of secretory characteristics of the breasts?
What two hormones inhibit the actual secretion of milk?
Which hormone promotes milk production?
Inhibits: Estrogen, Progesterone
What is the term for the fluid that is secreted by the breasts during the first few days before and first few days after parturition?
What is similar about colostrum to normal breast milk?
What is lacking in colostrum to normal breast milk?
Similar: Proteins, Lactose
Lacking: Fat, rate is only 1/100 of normal
What 4 hormones are the most important for providing adequate AA's, fatty acids, glucose, and calcium for formation of milk?
when does prolactin return to nonpregnant levels after birth?
a few weeks after parturition
How is milk continually made if prolactin is removed from the mother after birth?
Nursing causes nervous signals to hypothalamus causing a 10-20 fold increase in prolactin secretions that last for an hour
within this amount of time of not nursing, the mother can loss the prolactin-milk producing reflex.
What is released from the hypothalamus to inhibit prolactin secretion?
Dopamin (prolactin inhibitory hormone)
What are two possible reasons for the decreased production of LH and FSH during nursing?
Nervous signals from nursing
increased prolactin-inhibit secretion
What causes the ejection of milk from the breasts?
how does milk ejection occur?
nerve impulses from the nipples cause oxytocin release which causes the contraction of myoepithelial cells which causes milk ejection
What are the two names for milk being ejected from the nipples?
how many liters of milk is formed per day in the breasts
What 3 immune factors are secreted in the milk?