Human Reproduction and Female Pregnancy Flashcards
what is the primary reproductive organ in males
testes
what is the primary reproductive organ in females
ovaries
reproductive tract
the system of specialized ducts that house or transport gametes after they are produced
accessory sex glands
empty supportive secretions into the reproductive tract
external genitalia
externally visable portions of the reproductive system
Secondary sexual characteristics
- external characteristics NOT directly involved in reproductions
- body configuration and hair distribution
function of the male reproductive systme
- spermatogenesis (production of sperm)
- delivery of sperm to the female
what are the male accessory sex organs
- seminal vessicles
- proastate gland
- bulbourethral gland
penis
the organ that deposits semen in the female
male reproductive tract
epididymis –> vas deferens –> ejactulatory duct –> urethra
function of testes
- produce sperm (seminiferous tubules)
- secrete testosterone (leydig / interstitial cells)
effects of testosterone before birth
- masculaizes the reproductive tract and external genital
- promotes decent of testes into the scrotum
effects of testosterone on sex specific tissues after birth
- promotes growth and maturation of the reproductive system at puberty
- is essential for spermatogenesis
effects of testosterone on other reproduction-related events
- developes sex drive at puberty
- control ganadotropin hormone secretion
testosterone effects on secondary sexual characteristics
- induces the male pattern of hair growth
- causes the deepening of the voive because it thicken the vocal cords
- promotes muscular growth responsible for the male body pattern configuration
effect of testosterone on nonreproductive actions
- exerts protein anabolic effect
- promotes bone growth at puberty
- closes the epiphyseal plates after being converted to estrogen by aromatase
- may induce aggressive behavior
spermatogenesis results
highly specialized, mobile sperm
spermatogenesis
- the complex process by which undifferentiated diploid primordial germ cells (spermatogonia) are converted to haploid spermatozoa (sperm)
what are the 3 stages of spermatogenesis
- mitotic proliferation
- meisos
- packing
Mitotic proliferation
- sperm forming daughter cells divides miotically twice more to form four identical primary spermocytes
meiosis
- each spermatocyte forms two secondary spermatocytes yeilding four spermatids after the second meiotic division
- theoretically, sixteen spermatozoa results from each spermatogonium that goes through the process
Spermatozoan remains closely associated with _________ throughout the development
Sertoli cells
what are the 4 parts of sperm
- head
- acrosomes
- midpeice
- tail
head
consists primarily of the nucleus
- contains DNA
Acrosomes
- enzyme filled vessicle in the head
- used to penetrate the ovum
Acrosomes are formed by
the endoplasmic reticulum and golgi complex
midpiece
the area where mitochondria are concentrated
tail
provides moility for spermatozoan
semen average volume
2.75ml
semen volume range
2-6ml
higher volumes of sperm follow period of
abstinence
what is the average sperm count
180million
- some ejactulation can contain as many as 400million
what is the sperm count to be considered infertile
under 20million
functions of sertoli cells
- form blood testes barrier
- provide nurishment
- phagocytic function (destroy defective sperm)
- secrete seminiferous tubule fluid (flushes released sperm into epeidydimus for storage)
- secrete androgen-binding protein (testosterone)
- site and control of spermatogenesis
- releases inhibin
- acts in a negative feedback fashion to regulate FSH secretion
epididymus and ductus deferens
- store and concentrate sperm
- increase sperm motility and fertilily prior to ejactualtion
seminal vesicles
- supply fructose (energy)
- supply prostaglandin’s (promote smooth muscle motility in both male and femal reproductive tracts–> enhances sperm transportation)
- provides more than half of the semen
- secrete fibrinogen (make sperm clot)
prostate gland
- secretes alkaline fluid that neutralizes the acidic vaginal secretions
- provides clotting enzyme fibrinolysin
Bulbourthral glands
- release lubricating mucus
purpose of sexual intercourse
- a union of male and female gametes to produce offspring
two compontents of the male sexual act
- erection
- ejaculation
erection relies on ____ nervous stimulation
parasympathetic
ejaculation relies on _____ nervous stimulation
sympathetic
erection
hardening of the normally flaccid penis to premit entry into the vagina
two components of ejaculation
- emission phase
- expulsion phase
emission phase
empting of sperm and accesory sex gland secretions (semen) into the urethra
expulsion phase
forceful expulsion of semen from the penis
what are the 4 phases of sexual intercourse
- excitement phase
- plateau phase
- orgasmic phase
- resolution phase
in which phase does steadily increasing heart rate, blood pressure, respiratory rate, and muscle tension
plateau phase
excitement phase
erection and heightened sexual awareness
in which phase does return the genitalia and body ssytems to the prearousal state
resolution phase
in which phase does ejaculation and other responses that are collectively experienced as intense physical pleasure and heightened emotions
orgasmic phase
In which phase does tactile stimulation of the clitoris and perineal
excitement phase
in which phase does heightened tactile stimulation in both females and males
plateau phase
in which phase does
initiated by physical or psychological stimuli
excitement phase
in which phase does contraction occurs mostly intensely engorged lower third of the vaginal canal
orgasmic phase
In which phase does
swelling of the labia and erection of the clitoris due to parasympathetically induced vasocongestion; nipples and breasts enlarge
excitment phase
in which phase does
release of mucus (bartholin’s gland) during sexual arousal from glands surronding the vagina causes lubrication
Sex flush
excitment phase
in which phase does pelvic vasocongestion and systemic manifestations gradually subside
resolution phase
in which phase does ballooning effect occurs in which phase
plateau
ballooning effect
the uterus raises upwards, lifting the cervix and enlarging the upper 2/3 of the vagina
- creates a space for ejaculate deposition
in which phase is the
time of great physical relaxarion
resolution phase
orgasmic experience in females is similar to that in males, except
- no female counter part for ejaculation
- do not become refractory following an orgasm
-females can experience 12 successive orgasms
functions of estrogen
- essential for ovum maturation and release
- establishment of female secondary sexual characteristics
- essential for transport of sperm from the vagina to the fertilization site in the oviduct
- contributed to breast development in anticipation of lactation
progesterone functionsin pregnancy
- essential to prepare a suitable environment for nourishing a developing embryo/fetus
- contributes to the breast ability to produce milk
oogonia
- undifferntiated primordial germ cells in fetal ovaries
oogonia divide mitotically to give rise to ___________ oogonia by fifth month of gestation
6-7 million
primary oocytes
- contain diploid number of 46 replicated chromosomes
- remain in meiotic arrest for years until they are prepared for ovulation
primary oocyte is surrounded by
- surrounded by a single layer of granulosa cells
primary follicle
oocyte + granulosa cell
if the primary follicle is not developed
degenerates to form scar tissue (atresia)
What happens to follicles between puberty and menopause
follicles develop into secondary (antral) follicles on a cyclic basis
under the influence of local paracrines, gransusosa cells proliferate to form
zona pellucida
thecal cells respond to which hormone
LH
granulosa cells respond to which hormone
FSH
how long does the average ovarian cycle last
28 days
ovarian cycle is interrupted by
pregnancy
the ovarian cycle consists of what two alternating phases
- follicular
- luteal
follicular phase is dominated by the presence of
maturing follicles
luteal phase is dominated by the presence of
corpus luteum
follicular phase takes part in
the first half of the cycle
theca cells in follicular phase
secrete increased amounts of estrogen
ovulation
during the follicular phase the folicle ruptures to release oocytes from the ovary
- enters the oviduct where it may or may not be fertalized
how long does the luteal phase last
14 days
luteal phase characteristics
- old follicular cells undergo a structural transfermation to form the corpus luteum
- becomes highly vascularized
- becomes fully functional after 4-5 days
during the follicular phases FSH signals the ovarian follicle to secrete
estrogen
- negative feedback (inhibits FSH secretion)
when LH rises in the follcular phase it triggers
ovulation
the corpus luteum secretes what hormone during the luteal phase
- estorgen
- progesterone
progesterone secretion inhibits
FSH and LH secretion
thecal cells convert
closterol to androgen to estrogen
what are the 3 phases of the menstral cycle
- menstral phase
- proliferative phase
- secretory or progestational phase
menstral phase is characterized by
the discharge of blood and endometrium from the vagina
the start of a new cycle begins
on the first day of menstration
menstral phases causes the release of what hormone
prostaglandin
prostaglandin functions in the menstral phase
- causes vasoconstriction of endometrial vessels (disrupts blood supply–> causes death)
- stimulates mild rhythmic contractions of the unterine myometrium (helps expell blood
proliferative Phase
LH surge
- endothelium starts to repair itself and proliferate under the influence of estrogen
- lasts from the end of menstration to ovulation
Secretory or progestational phase
- enters phase after ovulation when a new corpus luteum is formed
what does the corpus leteum serete in the secretory phase of menstration
progesterone
functions of progesterone in the secretory phase
- converts endothelium into highly vascularized, glycogen filled tissue
- actively secretes glycogen
what is the site of fertilization
oviduct/uterine/fallopian tibe
fertilization usually occurs with in ____ of ovulation
24 hours
how long can sperm last in the female vagina
48 hours
factors that assure the successful transportation of sperm to the egg
- contractions of myometrium
- upward contractions of oviduct smooth muscle
- allurin is released by the egg
fertilin
- produced by the plasma membrane of sperm
- binds with the ovum cell membrane protein ZP3, causing the fusion of both
what is the ovums cell membrane protein
ZP3
what is the sperms cell membrane protein
fetilin
a fertilized ovum is now called a
zygote
how does the fertilized ovum divide
mitotically
- change into blastocytes
how do blastocyst implant
in the endometrial lining using enzymes released by trophoblasts
how do the enzymes released by trophoblasts digest endometrial tissue
- carve holes in the endometrium for implantation of blastocyst
- release nutrients from endometrial cells for use by developing embryo
trophoblast
accomplished implantation and develops into fetal portions of the placenta
inner cell mass
desinated to become fetus
how long after implantation does it take for the placenta to develop
5 weeks
placenta functions
- organ of exchange between maternal and fetal blood
- acts as transient, complex endocrine organ that secretes essential pregnancy hormones
what hormones are secreted by the placenta
- human chorionic gonadotrpin
- estrogen
- progesterone
human chorioonic gonadotropin
- maintain corpus luteum until th eplacenta takes over function in the last 2 trimesters
estrogen and progesterone pregnancy
essential for maintaining a normal pregnancy
Placentation
- relationship between the developing fetus and uterus as pregnancy progesses
- Schematic representation of interlocking maternal and fetal structures that forn the placenta
how long does pregnancy last
about 38 weeks
what are the physical changes in the mother while pregnat
- uterine enlargement
- breat enlargement and the ability to produce milk
- blood volume increases by 30%
- weight gain
- respitory activity increases by 20%
- kidneys excrete additional wastes from the fetus
- nutritional requirements increase
parturition is also know as
- labour
- delivery
- birth
parturition requires
- dilalation of the cervical canal
- contraction of the uterine myometrium
- factors that increase contractilitly of the uterus
where is relaxin produced
corpus luteum of pregnancy and placenta
relaxin
relaxes pelvic ligaments for paturation
prostiglandin effecton paturation
- promotes cervical enzyme production (softens cervix)
how is estrogen made during pregnancy
androgen –> DHEA –> estrogen
why is estrogen not made by the placenta
placenta lacks enzymes to synthesize estrogen
functions of estrogen in pregnancy
- growth of the myometrium (uterus enlargement)
- development of the ammary ducts within th ebreasts
- stimulates the enlargement of the external genitalia
functions of progesterone during pregnancy
- promotes the growth and maintence of the endometrium
- suppresses uterine contractions to prevent miscarriage
- promotes mucus plug formation of the cervix
- promotes the development of milk glands in the breasts for lactation
oxytocin role in pregnancy
- powerful uterine contractions
- icreases uterine responsiveness x100 greater
- increases oxytocin receptors in the myometrium for a strong myometrial contraction s(critical threshold)
CRH fucntions
- determine the onset of labour
- promotes fetal lung maturation
CRH is secreted from
the fetal placenta
CRH stimulates the pituitary gland to secrete
ACTH
functions of cortisol in pregnancy
- synthesize pulmonary surfactant
- lung expansion and reduces work of breathing
what is stage 1 of labour
cervical dialation
what is stage 2 of labour
delivery of the baby
what is stage 3 of labour
delivery of the placenta
stage 1 of labour is characterized by
the dialation of the cervix to accommodate the diameter of the babys head
what enhances dialation
fetus head pushing against the cervix
how long does stage 1 of labour last
longest
- up to 24 hours
stage 2 of labour is characterized by
an actual birth of the baby and cervical dialation is complete
how long does stage 2 of labour last
30-90 mins
stage 3 of labour is characterised by
- the delivery of the placenta
how long does the 3 stage of labur last
15-30 mins
lactation
- stimulates the synthesis of enzymes essential for milk production by alveolar epithelial cells
- withdrawl of the placental steriods at paturation initiates lactation sustained by suckeling
- triggers release of oxytocin and prolactin
- stimulates secretion of more milk to replace milk ejected as babay suckles
oxytocin role in lactation
- caused milk EJECTION by stimulating cells surrounding alveoli to squeeze secreted milk out though ducts
prolactin role in lactation
increases milk SECRETION
