1 Flashcards
List the 2 advantages of breast milk for the mother
- The release of oxytocin, which increases the speed of uterine involution & the suppression of the menstrual cycle
List the advantages of breast milk for the development of the baby when compared to other sources of nutrition such as formula
(hint: 4 advantages)
- Better digestion & absorption of fats, iron, & amino acids
- Improved immunity
- Development of digestive system bacteria
- Decreased risk of diseases later in life
When does breast milk increase in nutrient content, mineral content, growth factors, hormones, & antibodies?
& what is included in the nutrient & mineral contents?
- After approximately the first 5 days
- Nutrient content includes: Triglyceride fat, lactose, proteins, & vitamins
- Mineral content includes: Calcium & phosphate
What is a dilute fluid that contains low concentrations of fat & lactose but high concentrations of immunoprotective factors?
- Colostrum, & is the 1st breast milk produced after the birth of the baby
What is the reflex called that induces lactation?
And, describe the events that it instigates & the hormones it releases
- Sucking of the baby (sucking reflex)
- Which instigates a series of events leading to the release of prolactin & oxytocin from the pituitary to induce lactation
During pregnancy, the mammary glands are developed due to the actions of which hormones?
Simultaneously, lactation is inhibited by the actions of which hormones?
And, when is this inhibition removed?
- Developed due to the actions of estrogens, progesterone, & human placental lactogen (hPL)
- Lactation is inhibited by the actions of estrogen, & progesterone & this inhibition is removed at parturition (the act of giving birth)
What is uterine involution?
When does it occur?
And, which type of females experience faster uterine involution?
- Uterine involution, is the return of the uterus to its pregestational size (before pregnancy)
- It occurs during that same time frame in response to decreased concentrations of estrogens & progesterone
- Females who breastfeed have increased concentrations of oxytocin, thus experiencing faster uterine involution.
Following parturition, any remaining endometrial tissue is sloughed off in a vaginal discharge called?
And, how long may it continue for following parturition?
- Lochia, which may continue for up to six weeks following parturition
What is the hormone called that binds to the uterine oxytocin receptors & stimulates contraction of the uterus?
How is it part of a positive feedback loop?
And what else does it stimulate to further the contractions of the uterus? (hint: placenta
- The posterior pituitary hormone oxytocin
- This is part of a positive feedback loop because the contractions push the uterine contents against the cervix, stretching the cervix, which results in the secretion of more oxytocin from the posterior pituitary
- Oxytocin also stimulates the placenta to secrete prostaglandins, which further stimulate the contraction of the uterus
Since Dehydroepiandrosterone (DHEA) is converted by the placenta into estrogen, where does that estrogen enter?
And, what does it stimulate & induce?
- This estrogen enters the maternal plasma & stimulates the development of gap junctions in the myometrium,
- & induces the expression of oxytocin receptors in the uterus.
What does the placental corticotrophin-releasing hormone (CRH) stimulate the secretion of?
And, what does that hormone stimulate the production of? (which 2 hormones)
& there functions
- CRH stimulates the secretion of fetal adrenal corticotrophin hormone (ACTH)
- ACTH:
Stimulates the production of fetal cortisol, which is important for fetal lung maturation,& of dehydroepiandrosterone (DHEA), which is converted by the placenta into estrogen
Which 2 things increase cytokine & prostaglandin production, triggering an inflammatory response relating to parturition?
And, what does that inflammatory response result in? (the secretion of…)
- An increase in uterine stretch (due to the growing size of the fetus) & the presence of pulmonary surfactant in the amniotic fluid (due to the maturation of the fetal lungs)
- Results in the secretion of placental corticotrophin-releasing hormone (CRH)
What is controlled by a complex series of events involving the uterus, the placenta, the developing fetus, the maternal plasma, & the endocrine system?
- The timing of parturition
Summarize the events or 3 stages of parturition
- 1st stage: Is characterized by cervical dilation and uterine contractions (labour). Uterine contractions: Begin at the superior (upper) surface of the uterus and travel downward toward the cervix. These contractions are coordinated by gap junctions throughout the myometrium. Each contraction pushes the uterine contents against the cervix, slowly wedging it open.
- 2nd stage of labour: The maximal dilation of the cervical canal allows for the baby to move through the birth canal. Voluntary & involuntary contractions of the abdominal muscles facilitate this process.
- 3rd stage of labour: Is the delivery of the placenta, which is accomplished by uterine contractions shortly after the birth of the baby.
What is the event that signals the beginning of parturition?
- The rupturing of the amniotic sac
What is it called when the fetus does not position itself with its head against the cervix?
- A breech birth
Describe the significance of cervical ripening & fetal positioning prior to parturition
- Cervical ripening also occurs prior to parturition, where the cervix begins the process of ripening in which the collagen fibres in the connective tissue of the cervix begin to be broken down
- And the fetus positions itself with its head in contact with the cervix
Why does uterine contractile activity increase prior to parturition?
And what are premature uterine contractions called?
- It increases because the plasma concentrations of estrogen exceed those of progesterone & because uterine smooth muscle stretch receptors respond to the increased size of the fetus.
- Braxton-Hicks contractions
How long is a full-term pregnancy from the date of the last menstrual period (LMP)?
- It is 38 weeks in length or 40 weeks from the date of the last menstrual period (LMP).
What is the process of birth called?
- Parturition
(Maternal effects of pregnancy) Which 2 hormones secreted by the placenta play an important role in altering maternal metabolism?
And, what are their functions?
- Human placental lactogen (hPL) or human chorionic somatomammotropin (hCS): Which Promotes a maternal glucose-sparing effect, thereby ensuring that the fetus receives an adequate supply of glucose for energy production. It also promotes the growth of the fetus & stimulates maternal breast maturation
- Parathyroid hormone-related peptide (PTHrp): Which mobilizes calcium from maternal bones, thereby ensuring that the fetus receives an adequate supply of calcium for growth.
(Maternal effects of pregnancy) What is the 1st physiological change that occurs during pregnancy?
When and why does this physiological change happen (which hormones are it attributed to)?
What other body systems experience physiological changes, as a result, to accommodate the additional demands of the fetus?
- The 1st change is often morning sickness.
- This bout of nausea, which can occur at any time of the day, and is attributed to increased concentrations of human chorionic gonadotropin (hCG), estrogens, & progesterone.
- The activities of the urinary, respiratory, & cardiovascular systems all increase to accommodate the additional demands of the fetus.
(Maternal effects of pregnancy) What is 1st anatomical change that occurs during pregnancy?
And, what anatomical changes does the uterus experience?
(Hint: Eventually, the weight of the uterus increases to…)
- 1st anatomical change is the enlargement of the breasts & the darkening of the areolaes
- The uterus begins to expand with the growing fetus & comes to occupy the majority of the abdominal cavity
- Eventually, the weight of the uterus increases to more than 20 times its original weight. This increase is largely due to the presence of a growing fetus but is also due to uterine growth.
What do the maternal effects of pregnancy include?
- Includes: Anatomical, physiological, & metabolic changes
(Maintenance of pregnancy) When & how does the placenta convert cholesterol to progesterone & convert dehydroepiandrosterone (DHEA) to estrogen for secretions?
- The placenta has enzymes required to convert cholesterol into progesterone not long after implantation, but it takes 10 weeks for the placenta to become large enough to provide sufficient progesterone to meet the needs of the endometrium
- Similarly, it converts the androgen dehydroepiandrosterone (DHEA) to estrogen for secretion, but it depends on the slowly developing fetal adrenal cortex to produce DHEA.
(Maintenance of pregnancy) What are the structures called that secrete estrogen & progesterone?
And, for which periods do they take over during pregnancy?
- Corpus luteum: Secretes these hormones for the initial 2 months of pregnancy
- Placenta: Takes over the secretion of these hormones for the rest of pregnancy (2-9 months)
(Maintenance of pregnancy) What is the human chorionic gonadotropin (hCG) secreted by?
Why are its secretions important?
And, what is the hormone detected in a urine pregnancy test?
- Is secreted by the chorionic cells of the developing embryo, & is important for maintaining the corpus luteum
- hCG
List the key hormones that play a primary role in the maintenance of pregnancy
- Human chorionic gonadotropin (hCG), estrogen, & progesterone
List the functions of the placenta (all 3)
- It provides a protective barrier for the developing embryo, separating the maternal blood from the blood of the developing embryo
- It takes over the roles of the digestive, respiratory, & urinary systems
- & serves as an important endocrine gland for the duration of the pregnancy
(Placentation)
Describe the entry and exit of maternal & fetal blood (capillaries), regarding the placenta.
And, how the fetal blood leaves the placenta. (Fetal placental capillaries & how fetal blood leaves the placenta)
- Maternal blood enters the placenta: Through the maternal arterioles & moves through a pool of blood in the intervillus spaces
- Maternal blood leaves the placenta: Through the maternal venules
- Fetal placental capillaries: Branch off the umbilical artery & project into the placental villi where exchanges are made between the fetal & maternal blood
- Fetal blood leaves the placenta: Through the umbilical vein
(Placenta development) What occurs after 9 weeks of prenatal development?
And, what is that embryo then referred to as?
- All the essential internal & external structures are present in the embryo
- Embryo is referred to as a fetus
(Placenta development) The outer layer of trophoblast cells divides and develops into the….?
Where does it project, and what does it form?
And, what forms within the inner cell mass?
- The Chorion cells, which project into the blood-filled cavities of the endometrium & form the chorionic villi of the placenta
- Additionally, a fluid-filled amniotic cavity forms within the inner cell mass
(Processes of implantation) What is the blastocyst referred to as upon successful implantation?
- Embryo
What is it called when implantation occurs in a location other than the uterine cavity?
- Ectopic pregnancy
(Processes of implantation) What do trophoblast cells of the blastocyte also secrete to initiate the decidual response?
And, what is the decidual response?
- Also, secrete paracrines, which initiate the decidual response,
- Decidual response is a set of changes (e.g., vascularization) in the endometrial tissue
(Processes of implantation)
What is the physiological significance of the enzymes secreted by the trophoblast cells of the blastocyst?
- Trophoblast cells secrete enzymes that digest the endometrial cell layer to provide a physical space for the blastocyst to embed itself
- The digestion & breakdown of the endometrial tissue by the trophoblasts provides nutrients for the dividing cells of the blastocyst
(Processes of implantation) What results from the actions of the trophoblast cells?
- Implantation
(Processes of implantation) What occurs following the movement of the blastocyst into the uterine cavity?
- Implantation usually occurs
(Processes of fertilization) What do the outer & inner layers of the blastocyst cells become?
And describe the significance of said layers
- Outer layer = trophoblast, which is a layer of cells important both for implantation & for the development of the fetal placenta
- Inner layer = inner cell mass, which will develop into the embryo
(Processes of fertilization) What are the cells called that are not differentiated in any way from one another, and each has the ability to develop into a separate embryo?
What occurs if the division of the morula occurs?
And, with continued cell division, the totipotent cells of the morula begin to differentiate & form a…?
- Totipotent cells
- Identical or monozygotic twins will be produced
- Forming a blastocyst
(Processes of fertilization) What occurs over the next three to four days to the zygote following sperm-oocyte fusion? (hint: mitotic division…)
- The zygote mitotically divides to form a morula, which consists of totipotent cells
(Processes of fertilization) What is a fertilized ovum called?
And what is the sequence of events that occurs within the 1st hour of the sperm-oocyte fusion? (hint: The sperm plasma membrane…)
- Zygote
- The sperm plasma membrane disintegrates, the chromosomes from both the spermatozoon & the ovum migrate to the centre of the zygote, & the DNA is replicated in preparation for the 1st mitotic division
(Processes of fertilization) What must a spermatozoon do to be transported into the oocyte cytoplasm?
What does the sperm-oocyte fusion process trigger?
What does it prevent as a result?
Also stimulates the…
- Must be the 1st spermatozoon that successfully fuses with the oocyte
- It triggers the inactivation of sperm-binding proteins & the hardening of the zona pellucida, both of which prevent polyspermy (fertilization by more than one spermatozoon).
- Sperm-oocyte fusion stimulates the 2nd meiotic division of the oocyte to produce an ovum
(Processes of fertilization) What do oocytes release to facilitate the process of fertilization?
What does that chemical messenger stimulate?
How does the process of penetration through the corona radiata & zona pellucida begin?
And, what must the spermatozoa do to be able to fuse with the oocyte plasma membrane?
- Oocytes release a chemical messenger called allurin, which stimulates spermatozoa to move toward the oocyte
- Several sperm usually reach the oocyte & release their acrosomal enzymes to begin the process of penetration…
- Spermatozoa must also bind to sperm-binding proteins in the zona pellucida before being able to fuse…
What is the number of sperm that is deposited in the vagina? How many successfully arrive at the oocyte?
How long does the oocyte remain viable for following ovulation?
And, how long are spermatozoa able to survive in the female reproductive tract?
- Millions of sperm are deposited in the vagina, however only a few hundred successfully arrive at the oocyte
- Oocyte: Remains viable for only 12 to 24 hours following ovulation
- Spermatozoa: Survive for up to five days in the female reproductive tract
What is the process called that increases spermatozoan motility & is characterized by a set of functional changes occurring over a period of hours after the arrival of the spermatozoa in the female reproductive tract?
And, what is the purpose of the changes this process triggers to the plasma membrane of the spermatozoa?
- Process of capacitation
- To help prepare the spermatozoa for fusion with the oocyte plasma membrane
What does the sperm movement through the cervical canal, uterus, & uterine depend on?
- Depends on the contractile activity of the smooth muscle of these structures & the motility of the spermatozoa.
As ovulation approaches, what occurs to the cervical mucus?
Also, what occurs around the time of ovulation?
- The cervical mucus becomes more profuse & less viscous,
- Eventually becoming penetrable by sperm for a short period of a few days around the time of ovulation.
In the initial stages of pregnancy, where does fertilization occur in?
Also, upon deposition in the vagina, where must the spermatozoa travel through to reach the oocyte?
- Fertilization usually occurs in the uterine tubes
- Spermatozoa must travel through the female reproductive tract
What do the initial stages of pregnancy consist of?
- Fertilization, implantation, & placentation
What is not involved in the maintenance of homeostasis but is important for the continuation of the species?
- The reproductive system
In females, what signals the end of their fertile period?
And, what are the symptoms or effects of said event?
- Menopause
- Ovulation ceases, estrogen levels decrease, & maintenance of the secondary sex characteristics & reproductive structures is discontinued.
What causes males to remain fertile their entire life?
- Due to plasma testosterone concentrations that may decrease slightly with aging, but remain in concentrations sufficient for continued spermatogenesis
Throughout which period of life are plasma concentrations of reproductive hormones typically remained high & are responsible for the maintenance of the reproductive organs & the secondary sex characteristics ?
- Throughout early adulthood (approximately ages 18 to 39)
Full reproductive maturity (fertility) is achieved by the end of which period of life?
- Puberty
During puberty, an increased concentration of which hormones in males & females are responsible for the development of the secondary sex characteristics?
- Testosterone & estrogen
Which period of life are the levels of reproductive hormones in both males & females are low ?
- Throughout childhood
What accounts for the decrease in estrogen & progesterone concentrations at the end of the luteal phase?
And what is responsible for triggering menstruation & the start of a new menstrual cycle? (The removal of what…)
- The degeneration of the corpus luteum
- The removal of the negative feedback (the inhibitory effects of estrogen & progesterone), which causes a small increase in FSH & LH levels
Following ovulation, in particular, the progesterone secreted from the newly formed corpus luteum is important for what exactly?
(hint: maintaining & developing ….)
- Is important in maintaining the secretory-phase conditions of the uterus & the development of the breasts
Following ovulation, what takes over the secretion of estrogen & progesterone?
What do estrogen & progesterone act on?
And why do they act on said structures?
(hint: which 2 structures & to decrease what)
- The newly formed corpus luteum
- Both estrogen & progesterone act on the hypothalamus & anterior pituitary to decrease the secretion of FSH & LH
What occurs with the expression of LH receptors on the granulosa cells?
And, how is it exerted in the late follicular phase?
This is called the _____, and is the primary factor in stimulating ___,____, & ___ of the ___ into the ___ ____
- With the expression of LH receptors on the granulosa cells, the granulosa cells become directly responsive to LH & secrete estrogen, which, in the late follicular phase, exerts positive feedback on the hypothalamus & anterior pituitary to increase the secretion of LH.
- This is called the LH surge, and is the primary factor in stimulating Meiosis I, ovulation, and transformation of the follicle into the corpus luteum.