Unit 11 - Reproductive Physiology Flashcards
Achievement of Pregnancy
Sperm, Ovum, Healthy environment, normally functioning hormone pathways
Sperm
head (consists primarily of the nucleusDNA)
acrsome (enzyme-filled vesicle that caps tip of the head, used to penetrate ovum)
Midpiece (area where mitochondria are concentrated)
Tail (provides mobility for spermatozoan)
Male reproductive functions
Production of sperm
delivery of sperm to female
female reproductive functions
production of ova
reception of sperm
transport of sperm and ovum to common site for union (fertilization or conception)
maintenance of the developing fetus until it can survive in outside world (pregnancy)
Giving birth to the baby (parturition)
nourishing infant after birth by milk production (lactation)
Female reproductive organs
Ovaries, oviducts, uterus
Ovaries
primary female reproductive organs
produce ova
secrete female sex hormones
oviducts
pick up ova ovulation
serve as site for fertilization
uterus
maintenance of fetus during development
expelling fetus at end of pregnancy
Ovarian cycle two phases
follicular phase and luteal phase
Follicular phase
first half of cycle
increased amounts of estrogen
rapid follicular growth (mature about 14 days)
follicle ruptures to release oocyte from ovary (ovulation)
oocyte enters oviducts (it may or may not be fertilized)
Luteal phase
last 14 days of ovarian cycle
old follicular cells transform to corpus luteum
secretes progesterone along with smaller amounts of estrogen
converts endometrium to highly vascularized, glycogen filled tissue
1. If released ovum is not fertilized corpus luteum degenerates within about 14 days
2. if ovum -> corpus luteum becomes corpus luteum of pregnancy
oviduct
ovum transport to oviduct (must within 24 after ovulation)
sperm deposited in vagina travel through cervical canal, uterus, and to upper third of oviduct (female reproductive tract aids in sperm migration) contractions of myometrium, upward contractions of oviduct smooth muscle, allurin released by mature eggs
Accessory Sex Glands
seminal vesicles, prostate gland, bulbourethral gland
Seminal Vesicles
supply fructose for energy
supply prostaglandins (promote smooth muscle movement (enhances sperm transport)
secrete fibrinogen
Prostate gland
contributes alkaline fluid that neutralizes acidic vaginal secretions
provides clotting enzymes and fibrinolysin
Bulbourethral glands
release lubricating mucus
Fertilization
First sperm to reach ovum
Fuses with plasma membrane of ovum
triggers chemical change in ovum’s surrounding membrane that makes outer layer impermeable to entry of more sperm
Head of sperm gradually pulled into ovum’s cytoplasm
within hour, sperm and egg nuclei fuse fertilized ovum now called a zygote
ovum and sperm transport to the site of fertilization
complication : ectopic pregnancy
Blastocyst
fertilized ovum divides mitotically (within week grows and differentiates into blastocyst capable of implantation)
blastocyst implants in endometrial lining with the help of enzymes released by trophoblasts (enzymes digest endometrial tissue, carve hole in endometrium for implantation of blastocyst, release nutrients from endometrial cells for use by developing embryo)
Formation of the Placenta and amniotic sac
finger-like projections of chorionic tissue extend into the pools of maternal blood
the developing embryo sends out cappillaries into these chorionic projections to form placental villi
inner cell mass forms a fluid-filled amniotic cavity (amniotic sac or amnion, amniotic fluid)
Placenta
organ of exchange between maternal and fetal blood
Performs the functions of the digestive system, the respiratory system, and the kidneys for the fetus
nutrients and oxygen diffuse from the maternal blood across the thin placental barrier into the fetal blood
carbon dioxide and other metabolic wastes diffuse from the fetal blood into the maternal blood
acts as an endocrine organ that secretes pregnancy hormones
Stage of Fetus developmemt
product of fertilization is known as an embryo (ovum, zygoyt [cleavage,morula] blastocyst)
after first two months of intrauterine development, embryo is known as a fetus
Changes During pregnancy
cardiovascular ( raise cardiac output 40%, raise blood volume 5-6L 30%, HR raise BP raise)
Hematological ( raise RBC, anemia; lower iron)
Respiratory (raise function 20%)
Genitourinary ( raise frequency of urination and output)
Gastrointestinal (raise in saliva, nausea, vomiting, heartburn, lowers GI mobility, constipation, gallstones)
Breast (raise size and vascularity)
musculoskeletal (waddling, ache, posture change, relaxtion of pelvic joints)
Endocrine (raise thyroid and parathyroid function)
skin (raise pogmentation, stretch of the abdominal wall)
raise in weight 20-35 lb
raise in nutritional requirements
put it all together
normal physiologic changes can lead to normal symptoms like…
nausea, constipation, weight gain, breast tenderness, leaking, light headedness, dizziness, hypotension
Parturition
Labour &delivery, birth
Requires - dilation of cervical canal to accommodate passage of fetus from uterus through vagina and to the outside, contractions of uterine myometrium that are sufficiently strong to expel fetus
Three hormones and Parturition
- Corticotropin-releasing hormone CRH (placenta clock)
- Estrogen
- Oxytocin
CRH
maturating the fetal lungs
drives the production of estrogen
Estrogen
Promote synthesis of connexons within the uterine smooth muscle (higher gap junction)
myometrial contract as coordinating unit
Promotes production of prostaglandins -> cervical softening
increase oxytocin receptors in myometrim -> uterine responsiveness to oxytocin
Oxytocin
uterine muscle stimulant
causes stronger contractions
key role in progression of labour
Cervical dilation first stage
longest stage
lasts from several hours to as long as 24 hours in a first pregnancy
cervix changes from a long thick structure to one that is tissue-paper thin
moves from posterior to anterior
dilates from closed to fully 10cm
for the primip, effacement usually occurs before dilatation whereas in multip, effacement and dilatation occur simultaneously
Cervical changes
thinning/effacement and position
dilatation
Cervical changes
A-cervix not effaed. lengthof cervical canal 4cm
B- cervix partly effaced. length of cervical canal= 2cm
C- cervix fully effaced
D- cervix dilated 3cm
E- cervix dilated 8cm
Effacement
0=50%-80%-fully and posterior to anterior
Dilatation
0-10cm/fully
Contractions
primary and secondary forces work in coordinated fashion to achieve birth of fetus, membranes and placenta
Primary contractions: uterine contractions
cause the complete effacement and dilatation of cervix
During labour uterine contractions are rhythmic but intermittent with a period of relaxation
Secondary contractions: use of abdominal muscles
engaged only once cervix fully dilated and allow pushing or bearing down which aids in expulsion of fetus and placenta
2nd stage (Birth)
when cervix is fully dilated increased bloody show bulging of the perineum uncontrollable urge to bear down for some women, contractions become less frequent (3-5 mins) but more intense. Usually lasts 30-90 minutes
3rd stage (Birth of placenta)
shortest stage: usually completed within 15 to 30 min after baby is born
uterine contractions separates placenta from uterine
membranes are last to separate-peel off the uterine wall as placenta descends into the vagina
signs of placental separation usually appear within 5 minutes after birth of infant (globular-shaped uterus, rise of the fundus in abdomen, increased blood flow)
after delivery, uterus shrinks to pre-gestational size involution
Breasts Tissues
secretory gland composed of all things necessary to make and deliver milk to the infant
Glandular tissue to make and transport the milk
Connective tissue to support the breast
Blood to nourish the breast and provide nutrients to make milk
Lymph to remove waste
Nerves to stimulate the release of hormones for milk production and ejection
Adipose tissue to protect the breast from injury
Preparation of the Breasts for lactation
Estrogen
Progesterone
Prolactin
Secretion of milk depends on drop in estrogen and progesterone with delivery
Estrogen
stimulates ducts development in the breasts
Inhibits milk-secreting actions of prolactin
estrogen levels drop at delivery
Progesterone
stimulates the growth in size of alveoli and lobes
inhibits milk-secreting actions of prolactin
Prolactin
contributes to the accelerated growth of the alveoli
with suckling, prolactin is released from the anterior pituitary allowing milk to be produced (prolactin main hormone of lactation)
Oxytocin
hormone responsible for milk ejection reflex
acts to contract the myoepithelial cells to squeeze milk into the ducts
mothers may experience a let down even by hearing a baby cry
inhibition of letdown generally due to: pain, stress hormones, nicotine, alcohol
Stimulation of Lactation via suckling
Oxytocin: causes milk ejection by stimulating cells surrounding alveoli to squeeze secreted milk out through ducts
Prolactin: stimulates secretion of more milk to replace milk ejected as baby nurses
Advantages of breastfeeding for the infant
promote development of digestive organs
enhances development of the immune system
immune cells: produce antibodies
IgA: fight against microbes
Mucus: attaches to microorganism -> can’t attach to intestinal mucose
Lactoferrin: decrease the availability of iron and mineral -> decrease multiplication of pathogens
Bidifus factor: increase multiplication of non apthogens
Advantages of breastfeeding for the mother
oxytocin-uterine involution
suppress the menstrual cycle and ovulation (inhibiting LH and FSH)
weight loss
