Reproductive system Flashcards
The female reproductive system includes what internal organs?
The ovaries, oviducts (fallopian and uterine tubes), uterus, and vagina as well as the external genitalia collectively called the vulva
What does the female reproductive system need to do?
It must produce eggs and estrogen as well as maintain the development of the fetus after fertilization of an egg occurs
ovaries
are the main reproductive organ in females
the ovaries are two almond shaped glands
One ovary is on each side of the uterus below the uterine tubes
ovarian follicles
inside each ovary are ovarian follicles which each hold an immature egg.
ovulation
or release of a mature egg. Occurs approximately every 28 days
ovarian cycle
an egg is released from the ovarian follicle, which becomes the corpus luteum after ovulation
corpus luteum
after an egg is released from the ovarian follicle - it becomes the corpus luteum after ovulation
it helps maintain a pregnancy if an egg is fertilized - if not it disintegrates
what are the ducts in the female reproductive system?
oviducts, uterus, and vaginal canal
oviducts
also called uterine or fallopian tubes
extend from the ovaries to the uterus
each tube has three sections:
infundibulum, ampulla, and isthmus (closest to the uterus)
what are the three coats of the oviducts?
the outer serosa coat, the middle muscular coat, and inner mucosa coat
fimbriae
the oviducts are not physically touching the ovaries but instead have fingerlike projections on the infundibulum end of the tube
The fimbrae capture the egg from the ovary at the time ovulation
when the oocyte bursts from the follicle within the ovary during ovulation
It is swept into the oviduct by the combined action of the fimbriae and the beating of cillia that line the oviducts
ampulla
the middle section of the oviducts
the egg is quickly moved into the ampulla where is ir most ofter fertilized
this region nourishes the fertilized egg during early cell division
the mucosa layer of the ampulla provides nourishing fluid that allows repeated cellular divisions.
isthmus
after being in the ampulla for several days it moves to the isthmus through muscle contractions and cilia moving it towards the uterus.
the isthmus opens into the uterus - delivering the developing embryo into the uterine cavity when it is time for implantation
uterus
is a hollow, thick walled muscular organ shaped like an inverted pear connecting the uterine tubes and vagina
it is in a forward tilted position between the bladder and the rectum
What are the three layers of the uterus
the outer serous perimetrium, middle muscular myometrium, and inner glandular endometrium
muscular myometiurm
expands during pregnancy to hold the growing fetus and contracts during labor to push the baby out of the uterus
inner endometrium layer
this is where the embryo completes its development
the inner layer is shed monthly (approx, even 28 days) if the female is not pregnant which is known as menstruation or menses
three regions of the uterus
the fundus (superior region), the body, and the cervix (posterior part)
the fundus
the fundus height can be measured from the top of the pubic bone during pregnancy to provide growth rates and a crude indication of an abnormality (breach presentation or twins)
the body of the uterus
receives the fertilized ovum where it becomes implanted in the endometrium to receive nourishment and develop from an ovum to an embryo to fetus and gestate until childbirth
cervix
the lower portion of the uterus is called the cervix
it connects the uterus to the vagina and changes in size and texture.
what happens to the cervix prior to ovulation?
It swells and softens and secretes muscus allowing sperm better access to and viability within the uterus
what does the cervix do during pregnancy?
a mucus plug develops in the cervix and prevents bacteria and pathogens from entering the uterus thus protecting the health of the fetus
a firm, closed cervix also holds the developing fetus in the uterus until it reaches full term.
vaginal canal
a small opening in the cervix leads to the vaginal canal
the vagina is a muscular tube the leads from the cervix of the uterus to the outside of body
what does the vaginal wall consist of?
inner tissue layer, intermediate muscle layer, and outer tissue layer
what causes the wetness and moistness of the vagina
this is achieved by the mucus from the cervix
what does the outer layer of the vagina consist of?
elastic fibers, blood vessels, lymph vessels, and nerves.
the elastic fibers give the vagina wall strength and elasticity
mucousal lining of the vagiana
lies in the folds and can extend, which is important when the vagina serves as a birth canal and it also facilitates intercourse
vulva
part of the female reproductive system
external genitalia consisting of the mons pubis, vestibule, labia minora, labia majora, clitoris, urethral, and vaginal orifises
mons pubis
is a fat pad located in front of the pubic symphysis and is covered with hair after puberty
vestibule
surrounds the urethral and orifices
labia majora and labia minora
labia major - is the outer fold of skin that is located posterior to the mons pubis
labia minora- second set of skin folds surrounded by the labia majora
clitoris
anterior to the labia minora
orifices
or openings for the urethra and vagina are located inside the labia minora
mammary glands
female breast tissue
contains one to two dozen lobules- each with their own mammary duct
ducts begin at the nipple and divides into numerous ducts ending in blind sacs called alveoli
non lactating breasts
the ducts far out number the alveoli since alveoli are made up of cells that can produce milk
milk is not produced during pregnancy because prolactin is needed for lactation - milk production - to begin
prolactin is suppressed by estrogen and progesterone until a few days after the baby is delivered.
colostrum
prior to milk production the breasts produce a watery, yellowish white substance, which has a similar composition but contains a higher concentration of protein
Oogenesis
is the production of eggs in the ovaries that occurs during development of the fetus in the womb and is complete by the time of birth
therefore at the time of birth, a female has all the immature eggs that she can later ovulate during her reproductive lifetime which extends from puberty to about 50 years of age.
menopause
the end of female reproductive lifetime is known as menopause
oogonia
female stem cells, known as oogonia, undergo mitotic division into two daughter cells known as PRIMARY OOCYTES
the primary oocytes are covered by follicles known as PRIMARY FOLLICLES
this process is complete at birth
FSH
the anterior pituitary gland starts secreting follicle stimulating hormone when a female reaches puberty.
FSH causes a few follicles to mature each month
the primary oocyte in the follicle undergoes its first meiotic division into two daughter cells: the secondary oocyte and first polar body
polar body
a polar body is produced so that the chromosomes divide properly
But all the cytoplasm is “donated” from the polar body to the secondary oocyte in case of fertilization.
It takes a tremendous amount of cellular energy to sustain life during the first several cell divisions - so the secondary oocyte needs to maintain as much of the cell contents as possible
What happens if secondary oocyte is united with a sperm after ovulation?
the second meiotic division occurs which produces a second polar body and ovum with 23 chromosomes
the ovum and sperm combine their chromosomes to form a fertilized egg with 46 chromosomes
First polar body
may or may not undergo a second meiotic division
therefore a females produce two or three polar bodies and one viable gamete or ovum with 23 chromosomes.
If the secondary oocyte does not unite with a sperm, it dies and menstruation occurs.
Lutenizing hormone (LH)
around the time of ovulation, the anterior pituitary secretes a second hormone (LH)
LH causes the follicle to become the corpus luteum which is necessary for maintaining a pregnancy
What hormones do the ovaries produce?
Estrogen -Is important for the production of eggs and the menstrual cycle
It is responsible for secondary sex characteristics
progesterone- is necessary for the maintenance of pregnancy but does not promote secondary sex characteristics
secondary characteristics in females
are not directly involved in the sexual reproductive process but develop changes that occur throughout puberty
These include: enlarged breasts, widening pelvis, and fat deposits in the breasts, hips, and buttocks
ovarian cycle
is closely integrated with the menstrual cycle (uterine cycle)
Every month, the ovaries release hormones estrogen and progesterone that causes changes to the endometrium of the uterus preparing for implantation for fertilization to occur
if fertilization does not occur the endometrium is shed approx. every 28 days
menstrual cycle
divided into three phases - the menstrual phase, proliferative phase, and secretory phase
menstral phase
begins on day 1 when all the but the innermost basal layer of the endometrium is shed and continues through day 5.
the detached tissue of the endometrium and blood flow from the uterus into the vagina and exit the body via the vaginal orifice as menstrual flow
proliferative phase
occurs on days 6-14 as the endometrium rebuilds in response to increasing estrogen levels
ovulation of an egg typically occurs in the ovaries on day 14
ovulation is triggered when the anterior pituitary (in the brain) releases the luteinizing hormone (LH) as a response to high levels of estrogen
secretory phase
the final phase of the menstrual cycle
occurs days 15-28
during this phase the corpus luteum begins to secrete progesterone
what does progesterone do in the secretory phase
progesterone causes an increased blood supply
progesterone causes an increased blood supply in the uterus and secretion of nutrients, preparing the uterus for implantation
if fertilization has not occurred, the corpus luteum dies and the endometrium blood supply decreases because of decreased progesterone which begins the menstrual phase again.
male reproductive system
includes the testes, epididymis, vas deferens, seminal vesicles, prostate gland, bulburethral glands, urethra, and penis
gonads
paired testes which are suspended within fascia sacs of the scrotum
testes
the testes and the penis are the main organs of the reproductive system
the testes have the function of sperm and testosterone production
begin their development in the abdominal cavity, but they descend into scrotal sacs as development proceeds
Testosterone
is a hormone produced by the interstitial cells inside the connective tissues
seminiferous tubules
each testes has hundreds of lobules, and each lobule contains several seminiferous tubules where the site of sperm production takes place
epididymus
where sperm travel to after they are produced to mature and remain until they are expelled outside the body
sterility
is the inability to produce gametes which occurs if the testes do not descend into the scrotum
sterility occurs because sperm production requires a cooler environment than body temperature.
duct system
contains the accessory organs of the male reproductive system, the epididymus, vas deferens, and the uretha
the duct system provides a place for sperm to mature and then sperm expelled from the body at the appropriate time
sperm matures in the epididymis
epididymis
tightly coiled tubules that start at the superior end of the testes and then travel inferiorly along the posterior lateral sides of the testes
where sperm matures
maturation for about 20 days is required for sperm to gain the ability to swim
vas deferens
once sperm are fully matured they are propelled into the vas deferens by muscular contractions
vas defrenes is contained in the spermatic cord and held in place by the spermatic facia which surrounds the vas deferns as well as bood vessels and nerves
spermatic cord
this surrounds the vas deferens as well as other nerves and blood vessels
the vas deferens travels inside the spermatic cord superiorly through the inguinal canal
inguinal canal
in males the inguinal canal is the location in the anterior abdominal wall for the spermatic cord to enter
after entering the abdominal wall the vas deferens continues to rise and approximately follow the pelvis until it turns posteriorly over the bladder
then it descends inferiorly to the base of the prostate gland where it connects with the duct of the seminal vesicle to form the ejaculatory duct
ejaculatory duct
connects with the urethra to provide a means for the sperm to exit the body
during arousal, the smooth muscles of the vas deferens contract and sperm enter the urethra, part of which is inside the penis
vasectomy
can be performed to lead to permanent sterility
in this procedure the vas deferens is cut and tied which permanently prevents sperm from exiting the body to fertilize an egg.
it does not effect testosterone, therefore male secondary characteristics remain intact
male urethra
travels from the bladder to the penis carrying urine.
it is part of both the urinary system and reproductive systems because it functions to transport both sperm and urine outside the body
only reproductive or urinary function can occur at a given time (not at the same time)
three regions of the male urethra
prostatic urethra, membranous urethra, and spongy urethra
prostatic urethra
is surrounded by the prostate gland
membraneous urethra
begins at the end of the prostatic urethra and travels to the penis
spongy urethra
runs through the penis and opens to the outside at the external orifice
external genitalia (male)
the penis and scrotum
penis
a cylindrical organ that hangs in front of the scrotum
spongy erectile tissue containing distensible blood spaces extends through the shaft of the penis
penis has two parts - the shaft and glans penis
shaft of penis
long cylindrical part of the penis made up of left and right corpus cavernosum and one corpus spongiosum
glans penis
is the enlarged tip of the penis.
at birth a fold of skin called foreskin is located on the glans penis
erection
during arousal, nervous system reflexes cause an increase in arterial blood flow to the penis
in an erection, the spaces fill with blood in the erectile tissue and penis, which is normally limp, stiffens and increases in size
an erection functions to enable the penis to be inserted into the vagina when sexually aroused to deposit sperm into the female reproductive tract
scrotum
a pouch of skin that holds the testes outside the body just posterior to the penis, held in place by the spermatic fascia
the testes must be held outside for sperm production
the skin of the scrotum and adjust to outside temperature, contracting when outside temp is cold -getting heat from the body
they expand away from the body in warmer temperature to keep sperm away from higher body temp
semen
male reproductive system also contains accessory glands that produce semen - a thick whitish fluid that contains sperm and accessory gland secretions-
some components are fructose (sugar for fuel) , prostaglandins (facilitates movement), relaxin (enhances motility), alkaline pH (protective), and antibiotic (to kill any bacteria in the male urethra or female reproductive system that would kill sperm.
three semen glands
seminal vesicles, prostate, and bulbourethral glands
seminal vesicles
paired seminal vesicles lie at the base of the bladder where they each join with a vas deferens to form an ejaculatory duct that enters the urethra
as sperm pass from the vas deferens to the urethra, the seminal vesicles secrete a think, viscous fluid containing nutrients (fructose, vitamin C, and prostaglandins) for use by sperm
prostate gland
just below the bladder
it secretes a milky alkaline fluid helping to increase the motility of sperm
in older men the prostate can become enlarged, constricting the urethra and making urination slow or difficult
bulbourethral gland
slightly below the prostate and on either side of the urethra is a small pair of glands - bulbourethral glands
these secrete alkaline fluid- the first fluid to be released during ejaculation
the acidity in urine is harmful to sperm - so this secreted fluid neutralizes the acidity of any urine remaining inside the urethra
urine and ejaculaiton can not occur at the same time.
spermatogenesis
production of testosterone (male reproductive systems two jobs are sperm and testosterone production)
can take 64-72 days to complete
at the onset of puberty males start producing sperm
unlike females who have all their eggs at birth, men produce sperm throughout their lifetime
spermatogonia
sperm are formed from spermatogonia in the seminiferous tubules located in the testes
these are stem cells that go through mitotic divisions (46 chromosomes each beginning at birth until puberty.
once puberty begins the anterior pituitary glands begins to secrete FSH
once FSH is released the spermatogonia undergo one cell division - one of the cells continues the stem cell line
the other cell becomes the primary spermatocyte that undergoes meiosis
primary spermatocyte
after FSH is released, the spermatogonia undergoes one cell division making one cell that continues the stem line and one that becomes the primary spermatocyte that undergoes meiosis
meiosis produces four gametes with 23 chromosomes each known as spermatids
all four spermatids are viable gametes
spermiogenesis
spermatids are not mature sperm yet and undergo spermiogenesis
this is the final stage of spermatogenesis - where the surplus of cytoplasm is stripped away forming the mature sperm cell
three parts of mature sperm
head, midpeice, tail
head of sperm
is almost entirely nucleus containing the cell DNA with a crown called the acrosome, which contains enzymes that break down the membrane of the egg to allow the sperm to penetrate.
midpiece of sperm
contains numerous mitochondria that generate the locomotive energy needed by the sperm
tremendous amounts of energy are needed to swim all the way through the female reproductive tract to contact the ovum
tail of sperm
is a typical flagellum, which is used to propel the sperm through the female reproductive tract
testosterone
producing testosterone is one of the two jobs of the male reproductive system
the production of it starts in puberty in a male when the anterior pituitary secretes LH and FSH together
testosterone stimulates growth in males. It also stimulates secondary sex characteristics, such as broad shoulders, deep voice, increased muscle size and bone density, and increased hair
gametes
humans reproduce through sexual reproduction which involves sex cells called gametes
gametes are specialized eggs (oocytes) in females or sperm (spermatocytes) in males
copulation
is the sexual union to facilitate the reception of sperm by a female
in reproduction the offspring inherits half their genes from one parent and half from the other
therefore an offspring has a different combination of genes than either parent
in this way variation is introduces and maintained
variation is advantageous to a species if the environment is changing because an offspring may be better adapted than either of the parent
diploid
human cells throughout the body contain 46 chromosomes
these are called diploid because they contain 2n or the full number of chromosomes
diploid cells undergo mitosis during cell division
mitosis
during mitosis as a cell grows, it divides into two cells each containing 46 chromosomes
haploid
gamete cells are haploid cells (n) because they contain 23 chromosomes instead of 46
when gametes mature the cell divides two times
the first division of the gametes is a mitotic division and the second division is known as meiosis, which only occurs in reproductive cells
meiosis
only occurs in reproductive cells
during meiosis, gametes divide to form 4 gametes, each with only half the chromosomes needed (23)
zygote
when a sperm gamete and egg gamete combine they form a zygote, a fertilized egg
it has a total of 46 chromosomes again
after fertilization the zygote continues to divide by mitosis, developing into a baby
what do the 46 chromosomes of a zygote determine?
it determines the entirety of the genetic characteristics of the offspring, such as eye color and skin color.
also sex is determined by chromosomes
males have one X chromosome and one Y, and female are XX
therefore sex is determined by the father’s sperm cell (whether they receive and X or Y)
pregnancy
begins with fertilization of an egg by sperm to form a zygote
sperm is viable for 3-5 days after ejaculaiton depending on the environment and an egg can survive for 24 hours after ovulation
in oder for fertilization to occur it must happen within 1 day of ovulation to up to 2 days prior to ovulation
fertilization normally happens in the oviducts where the egg releases chemicals to attract the sperm
cornea radiata
sperm cells release an enzymes that break apart the cornea radiata, follicle surrounding the egg
once that is accomplished more sperm release acrosomal enzymes that make a hole in the membrane of an egg allowing one sperm to combine with the egg
once the sperm and egg unite, the membrane of the egg instantly chemically changes preventing other sperm from penetrating the egg
morula
the zygote begins frequent mitotic divisions as it travels through the oviducts
the zygote spends 3-4 days undergoing mitosis in the oviducts forming the morula
blastocyst
after the morula is formed, it spends another 3-4 days undergoing mitosis while unattached to the uterus, forming the blastocyst as the endometrium prepares for implantation
what sustains the blastocyst
progesterone is released from the corpus luteum, the endometrium increases its blood supply and secretes glycogen
both of these actions help sustain the blastocyst before it implants in the endometrium
human chorionic gonadotropin (HCG)
the corpus luteum is stimulated to release progesterone because the blastocyst releases HCG
the presence of HCG in the urine will result in a positive pregnancy test taken at home
when does the blastocyst implant?
it implants in the endometrium around day 7.
upon implantation the blastocyst develops three layers which become the embryo - the ectoderm, mesoderm, and endoderm
other cells of the blastocysts form supportive cells for embryonic function - amnion, placenta, and umbilical cord
placenta
a temporary organ that carries out the nutritive, respiroty, excretory, and endocrine functions for the embryo
the fetus continues to grow in the uterus with nutrition provided by the placenta for nine months until it is time for delivery
amnion
the amnion form a sac filled with fluid to cushion and protect the fetus
umbilical cord
attaches the embryo the placenta
ectoderm layer
the skin and nervous tissue develop from the outer ectoderm layer of the blastocyst
endoderm layer
the inner endoderm layer forms the glands (thyroid, parathyroid, and thymus)
solid organs the pancreas and liver
lining of hollow organs of the digestive and respitory systems
mesoderm layer
all other tissues, including the cardiovascular system, red blood cells, and muscles develop from the middle mesoderm layer of the blastocyst
three trimesters
1st - 1-3 months
2nd - 4-6 moths
3rd- 7-9 months
key body systems develop in the first trimester including nervous and cardiovascular systems
just after implantation, the heart begins to beat around week 3
by week 6 it can be detected by an ultrasound
the head shape is developed by the end of 1st trimester but is disproportionately large
neurulation
by week 5 nearulation occurs- this is the formation of the neural tube that form the outer folds of the ectoderm
see diagram
the blue portions on the lateral sides of the diagram move together (convergence) forming the epidermis superficially
the neural fold in green forms underneath the epidermis, becoming the neural crest
the neural plate in purple becomes the neural groove and then finally the neural tube once convergence is complete
the anterior portion of the neural tube becomes the brain and the rest of the neural tube became the brainstem and spinal cord
spina bifida
if neurulation does not completely close the neural tube, a disorder called spinal bifida occurs
people with spina bifida have varying levels of sensory and or motor disabilities, depending on the region or extent of the neural tube dysfunction
pregnant mothers are recommended to take folic acid supplements to prevent neural tube defects
fetus
by the end of week 8, the embryo is now considered a fetus and begins to move but is still to small during the first trimester to fell fetal movement by the mother
arms and legs being to form and by week 13 the fetus has all moveable joints, fingers, and toes
the ears, nose, and eyes begin to form but are not in the correct position yet
second trimester
the eyes, nose and ears move to the correct location on the face
the head and body form to proper proportions
by 16 weeks the eyes are developed enough to detect light and dark
unique fingerprints develop on the hands
the mother begins to feel fetal movement (around 18-21 weeks)
lanugo (fetal hair develops to keep fetus warm
fetus develops sleep/wake cycles, and heart begins to beat in regular patterns
third trimester
characterized by continual development of the systems already in place
for males, testes descend into the scrotum
the baby increases in weight and begins to develop fat under the skin
sucking reflex which is vital for feeding begin to develop around 32 weeks
two development milestone for survival outside the uterus include lung maturation and temperature self-regulation
by end of pregnancy a baby is typically between 19-22 inches and 6-10 pounds
labor and delivery
pregnancy ends with this phase which typically occurs at 40 weeks but varies from 38-42 weeks
can be divided into three phases - dilation of cervix, delivery of the baby, delivery of the placenta
dilation of cervix
is the time it takes for the cervix to dilate to 10 cm
during this stage the uterus contracts which pushes the baby against the cervix causing it to dilate/widen
this stage of labor is the longest lasting an average of 6-10 hours
oxytocin is released by the posterior pituitary gland to stimulate contractions in the myometrium of the uterus
as contractions continue oxytocin is increasingly released until the baby is born
delivery of baby
this second stage is the time it takes for the baby to be pushed out of the birth canal after full dilation has occurred
the mother uses abdominal muscles to push the baby with the help of uterine contractions, through the cervix and out the vagina
this stage is shorter on average lasting 50 mins in first delivery and 20 mins in later deliveries
after the baby is born the umbilical cord is cut and tied
breech
babies are typically born head first, but is the baby is in a different position (like buttock first they are breech
this can cause complications for a mother and Child
in breech and other long and difficult deliveries a cesarean section is preformed which is delivery through surgical incision made through the abdominal and uterine wall
delivery of placenta
third and final stage is when the placenta is pushed out of the birth canal
the placenta is referred to as after birth
this should occur within 15 mins of the birth of the child
the entire placenta needs to delivered or removed or the uterine bleeding with continue
menarche
first menstruation
beginning of reproductive life of female at first menstruation
