Module 20: Reproductive System Flashcards
5 Anatomical features found in male
Testes Ducts Accessory sex glands Urethra Penis
6 anatomical features found in female
Ovaries Uterine tubes Uterus Cervix Accessory sex glands Vagina
Function of testes
- produce sperm
* produce testosterone
Function of ducts
• transport, store, and assist in maturation of sperm
Function of accessory sex glands in male
• secrete bulk of semen
Function of penis
- encloses urethra as passageway for excretion of urine
* + urethra used to introduce semen into female coitus and ejaculation
Function of ovaries
- produce oocytes
* produce progesterone, estrogens, inhibin, and relaxin
Function of uterine tubes
- transport oocyte to uterus
* site of fertilization
Function of uterus
• site of implantation of fertilized ovum and supports fetal development
Function of accessory sex glands in females
• secrete fluid during coitus (intercourse)
Function of vagina
• receives penis during coitus
Function of cervix and vagina
• passageway for childbirth
The specialized cells that when combined, make another, unique human being
Gametes
Gametes produced by male
Spermatozoa
A single spermatozoa
Spermatozoon
A canal enclosed by connective tissue that brings and takes rich blood supply to testes
Spermatic cord
Ducts which carry sperm
Ductus deferens (vas deferens)
Two muscles of the scrotum
Dartos
Cremaster
Surrounds the scrotal sac subcutaneously, will cause wrinkles in sac when muscle contracts
Dartos
Draws the testes higher in the scrotal sac to protect them and draw more body heat when necessary
Cremaster
Spermatozoa are made by
Spermatogenic cells
Function of sertoli (sustentacular) cells
Support spermatogensis
Function of Leydig cells
Produce androgens
Hormones which support male metabolism and secondary sex characteristics
Androgens
Inside each testis, a series of tubules(_________________) lead to a central network which then lead into the ____________.
(Seminiferous tubules), epididymis
Functions of scrotum
- support and encloses testes and spermatozoa cord
* regulates temp of testes
Carries sperm from seminiferous tubules to prostate
Ductus deferens
______ and ______ add secretions and the mixture is dumped into urethra
Prostate and seminal vesicles
_________ glands add secretions just prior to ejaculation
Bulbourethral(Cowper’s)
_________ _______ consists of sponge-like venous passages which fill up with congested blood to make penis erect
Erectile tissue
3 structures associated with erectile tissue
Corpora cavernosa (R & L) Corpus spongiosum
A midline structure that surrounds the urethras and also makes up the bulk of the glans penis
Corpus spongiosum
Uncircumcised men have _____ covering glans
Prepuce(foreskin)
Epididymis
Store and mature sperm
Protects sperm from the immune system
Blood-testes barrier
Stem cells that are found along basement membrane of seminiferous tubules, farthest from luminal surface
Spermatogonia
Sperm itinerary
- Released into lumen of seminiferous tubules of testes
- Mature in epididymis, wait for ejaculation
- Upon sexual stimulation leading to ejaculation, travel via ductus deferens
- Critical fluids from prostate and seminal vesicles are added
- Ejaculated through urethra of erect penis
Spermatogensis 1
Spermatozoon is born:
- Spermatogonia
- Primary spermatocytes
- Secondary spermatocytes
- Early spermatids
- Late spermatids
- Spermatozoa
Spermatogenesis 2
The waiting room:
- (Rete testes) after being produced in seminiferous tubules of testes, spermatozoa move to rete testes and cross imaginary border into epididymis
- (Ductus pididymis) Pass through efferent ducts to ductus epididymis
- (14 days)Ductus epididymis where sperm wait 14 days to mature
- (Contract=expel) Smooth muscle layer surrounding epididymis responds to sexual arousal by contracting = expelling sperm
The only cells in human body with flagellae
Sperm…flagellae allows them to be motile
Spermatogenesis 3
The Tubes:
- (Forced into deferens) upon leaving epididymis, spermatozoa forced into bad deferens
- (Cowper’s glands) bulbourethral glands secrete a small amt. of alkaline fluid to lubricate and buffer pH in urethra
- (Meet) vas deferens meet urethra at prostate
- secretions from seminal vesicles and prostrated added - (Semen) fluid officially semen
Spermatogenesis 4
Ejaculation:
- (Sympathetic) Sympathetic reflex coordinated by lumbar spinal cord
- (Internal closes) Internal urethral sphincter closes = prevent leakage of urine and backflow of sperm
- (Peristaltic waves) Peristaltic waves occur in epididymis, vas deferens, seminal vesicles, ejaculatory ducts, and prostate
- (Contractions) Contractions of muscles at root of penis
- bulbosponglosus
- ischiocavernosa
- superficial transverse perineus
- Emission and ejaculation
Is ejaculation sympathetic or parasympathetic
Sympathetic
Semen =
Sperm + fluid secretions
Seminal vesicles contribution to semen
pH, fructose, prostaglandins
The major unit which powers sperm motility
Fructose
Contribution to semen from prostate
Zinc, citrate, and enzyme acid phosphatase
______ give semen a milky quality
Prostatic secretion
One of the anti-clotting agents found in semen
Prostatic-specific antigen (PSA)
How much semen in average ejaculate
2.5-5mL
How much spermatozoa per mL
100 million
How much spermatozoa in semen to be defined as infertility
pH of semen
7.2-7.7 = neutralizes acidity of urethra and vagina
T/F: semen clots 5 minutes after ejaculation
True
Where are female gametes produced
Ovaries
If no fertilization occurs, or for some reason the embryo is unable to implant, then the uterine linings do ovum/embryo are flushed out of the uterus
Menstruation
Serves as an outlet for menstrual tissue, a channel for childbirth, and location of coitus
Vagina
The externally visible parts of the female reproductive system are collectively called
Vulva or pudendum
In younger women, a membranous structure that may partially or completely cover vaginal orifice
Hymen
3 parts of the vulva
External urethral orifice
Labia minora
Labia majora
Convey the female gamete from the ovaries to the uterus
Uterine tubes
T/F: there is no firm connection between the ovaries and uterine tubes
True
Condition where an oocyte may slip out of reproductive system and fertilize in peritoneum or other locations
Ectopic pregnancy
The removal of ovaries
Oophorsalpingohysterectomy
Or hysterectosalpingoopherectomy
- stores and matures eggs
* secreted estrogens and progesterone
Ovaries
- conduct egg from ovary to uterus
* usual site of conception
Uterine tubes
• site for embryo implantation
Uterus
- muscular tube to permit insertion of penis
* flexible channel for childbirth
Vagina
- external opening(introitus) for reproduction
* external urethral orifice allows urination
Vulva
The structure that encloses an oocyte and promotes its maturation is a
Follicle
The female reproductive years lie between
Menarche and menopause
First menstruation
Menarche
Last menstruation
Menopause
Precursors to the ova that undergo their last cell division before birth and remain in a quiescent state as ________ _______ until after menarche
Primary oocytes
What, in several concentric layers, surround a primary oocyte
Granulosa cells
What’s the follicle called when granulosa cells surround the primary oocyte
Primary follicle
What’s the follicle called when a fluid-filled pocket develops
Secondary follicle
What’s the follicle called when the fluid predominates
Mature/graafian follicle
When a mature/Graafian follicle ruptures
Ovulation
Stimulates development of a follicle in the ovary
Follicle-stimulating hormone (FSH)
What releases FSH and LG
Anterior pituitary
Average female reproductive cycle
28 days
What’s the oocyte called when the mature follicle ruptures releasing the oocyte
Secondary oocyte
In response to a surge of LH released from the pituitary once each month, the mature follicle ruptures and releases a secondary oocyte
Ovulation
The follicular cells of secondary and mature follicles secrete
Estrogens
after the follicle ruptures and the secondary oocyte is released, the follicle becomes filled with a yellowish, waxy substance called
Corpus luteum
The corpus luteum secretes ________ and ________ whose job it is to maintain the lining of the uterus and prepare woman’s body for implantation
Progesterone & estrogens
After 14 days, the corpus luteum no longer secretes hormone and becomes a _______ ________, a knot of scar tissue with no endocrine function
Corpus albicans
a knot of scar tissue with no endocrine function
Corpus albicans
Follicular development in the ovary
- Primordial follicle
- Primary follicle
- Secondary follicle
- Mature follicle
- about 2 cm in diameter
- Ovulation ➡️ secondary oocyte expelled
- Corpus luteum
- Degenerating corpus luteum
- Corpus albicans (scar tissue)
Which part of menstrual cycle secondary and mature follicles secrete estrogens
Days 1-14
What part of menstrual cycle corpus luteum secreted progesterone and estrogens
15-28
Path of secondary oocyte
Released from follicle, from ovary @ ovulation ➡️ fimbriae ➡️ uterine tubes(encounters sperm) ➡️ undergoes cell division = ovum ➡️ fertilize = zygote ➡️ embryo ➡️ out tubes to uterus & implantation
Female gamete
Ovum
Inner lining of the uterus
Endometrium
Muscular layer of uterus
Myometrium
Serosa layer of uterus(nearest pelvic cavity)
Perimetrium
What is sloughed off during menstrual cycle
Epithelium & stratum functionalis
More than 90% of the thickness of the uterus is the
Myometriun
Blood flow in uterus
Internal iliac arteries ➡️ uterine arteries ➡️ arcuate arteries ➡️ radial arteries ➡️ branch into spiral arteries (shed with stratum functionalis) and straight Arterioles (stratum basalis not shed) ➡️ uterine veins ➡️ internal iliac veins
(IUARSSUI)
Muscular layer of uterus
Myometrium
Serosa layer of uterus(nearest pelvic cavity)
Perimetrium
What is sloughed off during menstrual cycle
Epithelium & stratum functionalis
More than 90% of the thickness of the uterus is the
Myometriun
Blood flow in uterus
Internal iliac arteries ➡️ uterine arteries ➡️ arcuate arteries ➡️ radial arteries ➡️ branch into spiral arteries (shed with stratum functionalis) and straight Arterioles (stratum basalis not shed) ➡️ uterine veins ➡️ internal iliac veins
(IUARSSUI)
3 layers of endometrium
- simple columnar epithelium
- stratum functionalis
- stratum basalis
T/F: stratum functionalis is shed during menstrual cycle
True
T/F: Arterioles and venules of stratum functionalis are shed with endometrium during menstruation, then regrow from stratum basalis during proliferative phase
True
Menorrhagia
> 80 mL blood
How long does the ideal menstruation last of a 28 day cycle
7 days
Is there a complete or incomplete loss of stratum functionalis during menstruation
Complete
Stratum functionalis rebuilt during which phase
Proliferative
Which phase do glands of endometrium proliferate and endometrium becomes a secretory organ as well as “potting soil” for embryo
Secretory phase
2 phases of uterine cycle
Proliferative
Secretory
Average menstrual flow
37 mL per cycle
T/F: ovarian and uterine cycles are in sync
True
What is Gonadotropin releasing hormone (GnRH) from hypothalamus used for
To coordinate release of FSH and LH from anterior pituitary
What secretes estrogens to help maintain the growth and development of stratum functionalis of endometrium
Mature follicle
At the midpoint of the cycle, day 14, a burst of ___ and ___ triggers ovulation
FSH and LH
4 structures that secrete hormones used to coordinate ovarian and uterine cycles
Pituitary, follicle, corpus luteum, endometrial glands
A temporary endocrine organ that secretes progesterone and estrogens
Corpus luteum
Hormone that promotes development and maintenance of female reproductive structures, feminine secondary sex characteristics, & breasts
Estrogen
Hormone that ⬆️ protein anabolism
Estrogen
Hormone that ⬇️ blood cholesterol
Estrogen
Hormone that moderate levels inhibit release of GnRH, FSH, & LH
Estrogen
Hormone that works with estrogens to prepare endometrium for implantation
Progesterone
Hormone that prepares mammary glands to secrete milks
Progesterone
Hormone that inhibits release of GnRH & LH
Progesterone
Hormone that inhibits contractions of uterine smooth muscle
Relaxin
Hormone that during labor, increased flexibility of pubic symphysis and dilates uterine cervix
Relaxin
Hormone that inhibits release of FSH and, to a lesser extent, LH
Inhibin
Predominate estrogen in nonpregnant females
17B-estradiol
What is 17B-estradiol made from
Testosterone
Main estrogen form during menopause and later
Estrone
Main estrogen during pregnancy
Estriol
What makes estriol
Fetal liver
How long is normal gestation
40 weeks
All ___ week embryos start out as an indifferent gender(male and female appear exactly the same)
5
what gene on Y chromosome -> development of male gonads and genitalia
Sex-determining region Y (SRY)
Generic designation for female
XX
Genetic designation for Male
XY
If there is no ___ chromosome there is no SRY gene
Y
If SRY is not present ______ gonads develop
Female
Intersex/hermaphrodites
Development of gonads is somewhere between SRY-on and SRY-off
Estimate of intersex incidence
Range 0.02-1.7%
Analogous gonads
Male: testes
Female: ovaries
Analogous paramesoneohric ducts
Male: [degenerate]
Female: uterine tubes, uterus, vagina
Analogous glans area of genital tubercle
Male: glans penis & corpora cavernosum
Female: clitoris
Analogous urethral folds of genital tubercle
Male: penile urethra
Female: labia minora
Analogous labioscrotal swellings of genital tubercle
Male:
•penis, scrotum
•Corpus spongiosum
Female:
• labia majora
•Vestibular bulb, pubocervical fascia
Analogous to prostate
Paraurethral
Analogous to bulbourethral glands
Greater vestibular glands
The region surrounding the genitals and anus
Perineum
Two triangular regions or the perineum
Urogenital triangle
Anal triangle
Are the vestibular bulb and greater vestibular glands present in male or female
Female only
“Sitz bones” where our weight rests if we sit on a flat bench
Ischial tuberosities
Primary sex organs
Gonads
In both males and females, _____ from the hypothalamus directs the secretion of ____ or ____ from the anterior pituitary
GnRH, FSH, LH
T/F: males have follicles and a corpora lutea
FALSE! Instead, FSH acts as a stimulant to the spermatogenic cells and sustentacular(Sertoli) cells of the testes
What does FSH do in males
Act as a stimulant to the spermatogenic cells and Sertoli cells of testes
In males what does LH do
Acts on Leydig cells of testes
What can testosterone be converted to
Dihydrotestosterone
A hormone that alters and maintains secondary sexual characteristics in males
Dihydrotestosterone
A negative feedback loop controlled by __________ levels ensures that sperm are not over-produced
Inhibin
Most body cells are
Somatic cells
A process where the DNA content is doubles as and then divided equally between two daughter cells
Mitosis
The chromosome content of somatic cells
Ploidy
Somatic cells have 2 copies of every chromosome which makes them…..
Diploid
Are gametes haploid or diploid
Haploid
Meiosis is a ________ ________
Reduction division
Where DNA content is reduced
Reduction division
In meiosis are cells diploid or haploid
Both: start off diploid then are haploid after division
During what phase of mitosis is DNA content doubled
S phase
Where the two alleles from homologous chromosomes “swap places” on chromosomes during meiosis
Cross over
And important feature unique to meiosis is
Crossing over
What phase of meiosis does genetic recombination occur
Prophase of Meiosis 1
Mitosis or Meiosis: a cell division where the DNA of the daughter cells is exactly the same sequence in the same order as that of the parent cell
Mitosis
Mitosis or Meiosis: involves tetrad formation and crossing over
Meiosis
Mitosis or Meiosis: a reduction division
Meiosis
Mitosis or Meiosis: preserves the ploidy and n number of the cell.
Mitosis
Multiplication of the n number in mitosis occurs during what phase
S phase
Diploid or haploid: precursors of gametes
Diploid
Resulting cell = haploid
Diploid or haploid: When 2 haploid gametes meet, and the Nucleu combine, the resulting cell is
Diploid
Fertilized ovum
Zygote
Zygo turns into…
Divided mitotically into an embryo, then fetus
T/F: mitosis is a cyclical process
True
Mitosis or Meiosis: once cells become gametes, they can’t ever produce new cells except by joining another gamer in fertilization
Meiosis
All cells of the body except germ cells
Somatic cells
Do spermatogonia undergo mitosis or meiosis
Mitosis
As long as spermatogonia stay near the basement membrane, they remain a ________________ and divide by ___________
Stem cell, mitosis
If spermatogonia leave the basement membrane that begin a process of ____________
Differentiation
What happens when spermatogonia go through differentiation
They become a primary spermatocyte (diploid)
Primary spermatocytes undergo _____________ to become ____________
Meiosis 1, secondary spermatocyte(haploid)
What happens when secondary spermatocytes undergo meiosis 2
They split up their DNA into individual chromatids = haploid spermatids
T/F: spermatids undergo further differentiation after meiosis 2, but have no further changes in DNA content
True….so they end up haploid (1n spermatozoa)
Which are euploid
• haploid
• diploid
• polyploid
All
Euploid: 23 X 1 =
Haploid
Euploid: 23 X 2 =
Diploid
Euploid: 23 X anything > 2 =
Polyploid
When does meiosis 1 begin in female gametes
After oogonia undergo their last mitotic division in female fetus
Female gametes undergo meiosis 1 =
Primary oocyte
How long do oocytes stay suspended halfway through meiosis 1
10-50 years
How many primary oocytes respond to the hormonal signals from the pituitary after menarche
5-12
How many of the 5-12 primary oocytes generally progress all the way meiosis 1 and to form what
1 to form secondary oocyte
Remaining genetic material, of primary oocyte after changing into secondary oocyte, is disposed of by the body forming….
The first polar body
Does the secondary oocyte complete meiosis 2
No, unless sperm penetrates
When secondary oocyte completes meiosis 2 it becomes an
Ovum
After becoming an ovum, the genetic material is again disposed to form
Second polar body
For a time, female DNA and male DNA remain separate, as female and male _____
Pronuclei
After male and female DNA pronuclei they eventually fuse to form ______________
The diploid zygote (2n)
The fusion of pronuclei to form a zygote is _____________ of embryonic development
Time zero
Primary sex characteristics in males
Penis, scrotum, and associated glands
Primary Sex characteristics in females
Vulva, ovaries, uterine tubes, uterus, and associated glands
Male secondary sex characteristics
- Body hair in pubic region, arms, and legs
- deeper voice
- more prominent Adam’s apple
- more muscular and skeletal growth
Female secondary sex characteristics
- body hair in public region, arms, and legs
- larger breasts
- wider hips
__________ ands _________ change structure of the embryonic and newborn brain
Androgens and estrogens
During puberty, a burst of ____ from the hypothalamus leads to _ ____ and _ ___ which in turn _ ___ and _ ___
GnRH, ⬆️ LH, ⬆️ FSH, ⬆️ androgens, ⬆️ estrogens
Puberty is triggered by _________ _________
Complex interactions
T/F: ⬆️ obesity does not affect onset of puberty
False: it is a factor responsible for change. It acts on and endocrine organ and may alter the developmental clock
Which is a gradual process…menarche or menopause
Menopause
Average age of menarche
Just over 12
Relatively sudden….menarche or menopause
Menarche
Theories of ongoing decline in average age of menarche:
- decline over last few centuries due to better nutrition, health
- decline in last few decades due to childhood obesity? Other factors?
🙂
An instrument for measuring penile erection
Penile plesmythograph
An instrument for measuring penile erection
Penile plesmythograph
Sexual response is easier to study in males or females
Males
Incoming sensory information from structures which produce sexual arousal comes into spinal cord at ________
S2-S4
Nerves of sexual arousal:
Outgoing striated motor and parasympathetic autonomic
S2-S4
Nerves of Sexual Arousal:
Outgoing sympathetic autonomic (motor) at
T10-L2
T/F: the brain does not influence the basic sexual arousal reflex pathway
False! It does influence!!
Penile erection results from
Congestion in the corpora cavernosa
The processes that work together to cause penile erection
- Relaxation of smooth muscle in corpora cavernosa
- Vasodilation ⬆️ arterial blood flow to penis
- Restricted flow of blood out of the penis due to compression of dorsal veins
What promotes dilation of blood vessels throughout the body
Nitric oxide
Increased ___ promotes penile erection by stimulating all of the the processes
NO (nitric oxide)
_____ ______ is a neurotransmitter that causes vasodilation
Nitric oxide
Mouse eNOS mutants:
Unable to make NO = ⬆️ arterial blood pressure than “normal” mice
Why is nitroglycerine used in angina(heart pain from decreases blood flow to heart)
Because NO causes vasodilation
As blood vessels dilate in corpora cavernosa….
Penile erection occurs
Mechanism of Action of Viagra:
Normally, the signaling molecule involved is inactivates by an enzyme called ____
PDE5
________ block PDE5 and prolongs smooth muscle relaxation
Sildenafil (Viagra)
Can NO cause erection of the clitoris
Yes, because it’s still a dilation of vasculature
Is the erection of the clitoris enough to cause a sexual response in females
No
____ and _____ _____ are the only structure which demonstrate ⬆️ blood flow during sexual arousal
Clitoris & vaginal bulb
An area surrounding the female introitus
Vestibular bulb
Entrance to the vagina
Introitus
The _______ ____, the _______ ______, and the ______ ______ embedded in nearby tissue, are also homologous to the corpus spongiosum penis in males, so that embryonic origin is consistent with a similar role in female sexual arousal
Vestibular bulb, pubocervical fascia (Halban’s fascia), paraurethral glands(skenes glands)
A location in the vaginal wall near the position of the pubocervical fascia
Grafenberg spot (G-spot)
The vestibular glands have been implicated in providing the _______ that accompanies sexual arousal in females
Lubrication
Is the lubrication from the vestibular glands in females sufficient for sex purposes
No
Four stages of sexual arousal in the Masters and Johnson Model of female response
- Excitement
- Plateau
- Orgasm
- Resolution
What kind of response is the focus in the Masters and Johnson Model
Physiological
Stages of the Kaplan model of female sexual arousal
- Desire (psychological)
- Excitement
- Orgasm (physiological)
Basson model of female sexual response posits that _________________________________ is the primary motivator for sexual activity
Emotional intimacy
Model of female sexual response that is based on “male”, hydraulic model of sexual arousal
Masters and Johnson
Model of female sexual arousal that is a motivation model
Kaplan
Model of female sexual arousal that states women engage in sexual intercourse because of desire for emotional closeness (sexual neutrality)
Basson
How long can some survive after ejaculation
3 days
How long does an unfertilized secondary oocyte survive
2 days after ovulation
Where does conception(fertilization) take place
Uterine tubes
What is the name of the head of sperm
Acrosome
What is the unpolymerized actin in the acrosome of the spermatozoon
Profilacin
Profilactin is converted to actin in the _______ ________
Acrosomal reaction
This process helps the spermatozoon penetrate the secondary oocyte
Acrosomal reaction
About how many sperm are released to begin journey in the female reproductive tract
300 Million
T/F: thousands of spermatozoa reach the uterine tube
False! Only a few hundred
T/F: some sperm can complete the journey to the uterine tubes within a few minutes
True
Occurs when a single spermatozoon penetrates the secondary oocyte, causing it to develop an ovum
Fertilization
What kind of twins occur when two oocytes are shed
Dizygotic (fraternal)
What kind of twins occur when the zygote splits into two embryos in an early division
Monozygotic (identical)
Can fertilization occur if > 1 spermatozoon penetrates a single oocyte
No
2 block to polyspermy
Fast
&
Slow
What forms when granulosa cells from the follicle partially surround the ovulated secondary oocyte
Corona radiata (radiant crown)
A thick, clear layer, that also surrounds the oocyte
Zona pellucida
In what reaction does the penetration of oocyte by the first spermatozoon cause calcium ions to be released from cortical granules in the oocyte
Cortical reaction
In the cortical reaction, the penetration of the oocyte by the first spermatozoon causes calcium ions to be released from what in the oocyte
Cortical granules
Two layers that surround occyte
Corona radiata
Zona pellucida
What is lifted in result of the cortical reaction
Zona pellucida
Can sperm penetrate the oocyte membrane when contact between Zona pellucida and oocyte is lost
No
Where do sperm undergo capacitation
Uterine tubes
- flagella beat more vigorously
- plasma membrane of spermatozoa prepared to fuse with plasma membrane of secondary oocyte
~ cholesterol, glycoproteins, and proteins scrubbed off spermatozoon’s membrane
Sperm capacitation
A two symmetrical, equal cell
Two-cell embryo
A two symmetrical, equal cell
Two-cell embryo
5 steps of fertilization to implantation in first week
- Fertilization (12-34 hrs after ovulation)
- Cleavage (30 hrs after fertilization)
- Morula (3-4 days)
- Blastocyst (4.5-5 days)
- Implantation (6 days)
When sperm and egg unite it forms a
Diploid zygote
And starts our developmental “clock”
Stages of embryo in first week of fertilization and implantation
- two-cell
- four-cell
- morula
- blastocyst
Occurs within uterine tube within 12-24 hrs after ovulation
Fertilization
First one is completed about 30 ha after fertilization
Cleavage
3-4 days after fertilization
Morula
4.5-5 days after fertilization
Blastocyst
Occurs about 6 days after fertilization
Implantation
The point of contact between the blastocyst and the endometrium, under the influence of chemical factors released by the uterus, begins to develop into what
Inner cell mass
- blastocyst makes contact with the endometrial wall
- inner cell mass develops
- problem: embryo is “foreign” tissue
- implantation involved evading mother’s defense mechanism
Day 6: implantation
Three layers that the blastocyst develop
- Trophoblast
- Inner cell mass -> embryonic disc
- yolk sac
- upon implantation, the blastocyst divides into three parts
* the endometrial lining becomes the decidua
Days 8-12: implantation
A folding process that creates three germ layers in the embryo
Gastrulation
Three germ layers created from gastrulation
- Ectoderm
- Mesoderm
- Endoderm
Becomes skin and nervous system
Ectoderm
Becomes connective tissue, muscles, and bones
Mesoderm
Becomes gut tube
Endoderm
_________ is necessary for organogenesis to begin
Gastrulation
Cancer coming from ectoderm
Carcinomata
Cancer coming from the mesoderm
Sarcomata
3 things the placenta provides
- food to embryo
- oxygenated blood to embryo
- protection for the embryo from invaders with antibodies
Placenta =
1/2 embryonic tissue
1/2 maternal tissue
Embryonic tissue formed loops of blood vessels
Chorionic villi
Circular “wall” around the entire embryonic project area
Chorion
One of the most common abnormalities detected by chorionic villus biopsy
Down syndrome (Trisomy 21)
What does development of extraembryonic membrane begin with
Lacunae (open spaces)
When can chorionic villus sampling(biopsy) be done
As early as 8 weeks
Researchers estimate 50% of spontaneous abortions are from what
Nondisjuction syndromes (like Down syndrome)
Trisomy 21 or other chromosomal abnormalities result from what
Nondisjunction
Failure to separate chromosomes
Nondisjunction
In meiosis, all four chromatids of 21 are supposed to arrive where
In different gametes
How heavy is the placenta by the time of birth
500g
Oxygenated blood flowing from mother to child flows through what
Umbilical vein
Blood flow through structure of placenta
- Maternal circulation
- Maternal endometrial arteriole
- Fetal blood vessels is chorionic villi
- Umbilical vein
- Embryo
- Umbilical artery
- Fetal blood vessels in chorionic villi
- Maternal endometrial Venule
(more mothers fight until embryo unties father & mother)
What’s the tissue of the mother that form around the embryo
Decidua
When does embryonic folding organogenesis begin
Days 20-28
A prominent feature of the dorsal surface of the Embryo, forming a distinct groove
Neural folds
The fetal brain form from what
Neural tube
Substances which cause birth defects can strongly influence development
Teratogens
The time when systems are sensitive
Critical period
Rubella, cytomegalovirus, toxoplasma, radiation, and some other chemicals are examples of what
Teratogens
A fertilization to 8 weeks
Embryonic period
9 weeks to birth
Fetal period
Which period is there growth and development of fetus, but most involved the organs carrying out a development plan set out during the embryonic period
Fetal period
Normal gestation is
40 wks
Four hormones released by placenta
- human chorionic gonadotropin (hCG)
- relaxin
- human chorionic somatomammotropin (hCS)
- corticotropin-releasing hormone (CRH)
- maintains corpus luteum
- corpus luteum continues to secrete progesterone, estrogens
- basis for home pregnancy testing
Human chorionic gonadotropin (hCG)
- increases flexibility of pubic symphysis and AIDS in cervical dilation
Relaxin
- alters maternal metabolism
Human chorionic somatomammotropin (hCS)
- control timing of birth
- ⬆️ secretion of cortisol
Corticotropin-releasing hormon (CRH)
Spike of hCG is earliest
Peak between 8-10 wks
Physiological changes of pregnancy in cardiovascular system (7)
- ⬆️ blood flow to placenta
- ⬆️ stroke volume
- ⬆️ cardiac output
- heart rate
- blood volume
- compression of inferior vena cava = edema in legs and varicose veins
- compression of renal artery = renal hypertension
Physiological changes of pregnancy in respiratory system (5)
- ⬆️ tidal volume
- ⬆️ ventilation
- ⬆️ total oxygen consumption
- ⬇️ expiratory reserve volume (ERV)
- dyspnea possible
Physiological changes of pregnancy in GI system
- ⬆️ appetite
* ⬇️ bowel motility
Physiological changes of pregnancy in Urinary system
- pressure on urinary bladder
* ⬆️ Glomerular Filtration Rate (GFR)
Three stages of labor
Dilation
Expulsion
Placental
- onset of labor to dilation of cervix
- about 6-12 hrs
- regular contractions
- usually rupturing of amniotic sac (breaking water)
- ends with complex dilation of cervix
Dilation stage
- 10 minutes to several hrs
- ends with delivery of the baby
Expulsion stage
- 5-30 min
- ends with expulsion of placenta
- powerful uterine contractions expel placenta and help control bleeding
Placental stage
Is labor (parturition) a neg or pos feedback loop
Positive
Homeostatic control of labor:
Input: stretching of cervix sends sensory info to brain
Processing and output: brain interprets signal, releases OXYTOCIN from POSTERIOR PITUITARY
• oxytocin causes uterus to contract more forcefully
• delivery of baby stops pos feedback loop
• synthetic oxytocin can be used to stimulate this homeostatic loop
🙂
Is milk let-down reflex a pos or neg feedback loop
Positive
Suckling
Input: baby sucks nipple
Processing and output: hypothalamus and posterior pituitary
- releases oxytocin which stimulates “Milk let-down reflex”
• cycle continues until baby stops suckling
🙂
What kind of glands are mammary glands
Modified suderiferous (sweat) glands
Embedded in adipose tissue of mammary glands is a set of
Alveolar glands
The alveolar glands in mammary glands are surrounded by
Myoepithelial cells
Contract in response to oxytocin in mammary glands
Myoepithelial cells
The nipple is surrounded by a pigmented tissue
Areola
Structure of breast is maintained by ligaments
Suspensory ligaments
Lobes separated by adipose tissue have (2)
Lobules & alveoli
Travel of milk in mammary glands
- Alveoli
- Mammary ducts
- Lactiferous sinuses
- Lactiferous ducts
- Nipple
Probability of pregnancy from a single, unprotected act of intercourse
2-4%
Peak of probability of pregnancy from a single, unprotected act of coitus
8% (days 12-14)
Lowest probability of pregnancy from a single unprotected act of coitus
0% (days 1-2)
Ductus deferens is isolated and resected
- sometimes causes nerve damage
- may not be reversible
Vasectomy
Uterine tubes cut and tied off
- complicated, invasive, expensive surgery
- not reversible
Tubal ligation
Only true reliable method of birth control
Abstinence
2nd best in terms of efficient birth control
Surgical methods
- vasectomy
- tubal ligation
Are female hormonal control methods of birth control highly effective
Yes, if used properly
Purpose of Intrauterine device (IUD)
Prevent implantation of embryo
Failure rate of male condom used properly
6%
Failure rate of an improperly used condom
14%
What type of birth control? Protection rate(high, middle, low)
- oral contraceptive
- non-oral contraceptives
Hormonal methods, middle-high
What type of birth control? Protection rate(high, middle, low)
• intrauterine devices
Intrauterine device, middle
What type of birth control? Protection rate(high, middle, low)
• spermicides (alone)
Spermicides (alone), middle-low
What type of birth control? Protection rate(high, middle, low)
- male condom
- vaginal pouch
- diaphragm
- cervical cap
Barrier methods, low
What type of birth control? Protection rate(high, middle, low)
- rhythm method
- sympto-thermal method (STM)
Periodic abstinence, lower
What type of birth control? Protection rate(high, middle, low)
• no method
No method, lowest
What type of birth control? Protection rate(high, middle, low)
•complete abstinence
Complete abstinence, highest
What type of birth control? Protection rate(high, middle, low)
- vasectomy
- tubal ligation
Surgical sterilization, higher
What type of birth control? Protection rate(high, middle, low)
• non-incisional sterilization
Non-incisional sterilization, high
