Exam 5: Reproductive & Development Flashcards
What originates in the yolk sac, then migrates to the embryo?
Primordial germ cells
When do the primordial germ cells migrate to the embryo?
At 5 weeks
What do the primordial germ cells give rise to?
Gonadal ridge
Hemopoietic/hematopoietic stem cells
Where does the gonadal ridge take form?
On the dorsum of the abdominopelvic cavity
What gives rise to the gonads?
Gonadal ridge
What are the male and female gonads?
Testes for male
Ovaries for female
Are primordial germ cells and primordial germ layers the same?
NO
What do hemopoietic/hematopoietic stem cells do?
Give rise to blood cells
How many chromosomes are in MOST of our cells?
46 chromosomes, or 23 pairs
What are pairs 1-22 of chromosomes called?
Autosomes
What are the two chromosomes of the 23rd pair called?
Sex chromosomes
What sex chromosomes do females have? Where do they get them from?
XX
One maternal X, one paternal X
What sex chromosomes do males have? Where do they get them from?
XY
One maternal X, one paternal Y
What chromosome can mom’s oocytes carry?
Only X
What chromosomes can dad’s sperm carry?
Either an X or Y
Does mom or dad’s chromosomal contribution determine baby’s sex?
Dads (as sperm carries either X or Y, and whichever it is will determine the sex)
Are there more genes on the X or Y chromosomes?
More on the X, very few on Y
What are characteristics determined by genes on the sex chromosomes, such as that for colorblindness?
Sex-linked traits
When primordial germ cells migrate to the gonadal ridge, what two structures are there? (In ALL embryos)
Mesonephric (Wolffian) Duct
Paramesonephric (Mullerian) Duct
Is the Mesonephric (Wolffian) Duct developed in male or female fetuses?
Male
Is the Paramesonephric (Mullerian) Duct developed in male or female fetuses?
Female
Are both Mesonephric (Wolffian) and Paramesonephric (Mullerian) Ducts present in all early fetuses?
Yes
What gene does the Y chromosome have?
Sex-Determining Region of Y (SRY gene)
What does the SRY gene code for?
The protein known as Testis-Determining Factor (TDF)
What does Testis-Determining Factor (TDF) do?
Regulates the development of the testes
What do the testes produce?
Testosterone
Anti-Mullerian Hormone (AMH)
What is testosterone responsible for?
Male hormone for primary and secondary sex characteristics
What’s the difference between primary and secondary male characteristics?
Primary: male genitalia (penis)
Secondary: hair and fat distribution, sebaceous secretions, thicker hair, larynx hypertrophy, > metabolism, >RBCs, > protein synthesis (mass)
What does Anti-Mullerian Hormone (AMH) do?
It causes the regression of female-forming Paramesonephric (Mullerian) ducts. This allows for the development of the male-forming Mesonephric (Wolffian) ducts
Which sex of fetus have to suppress the development of the opposite sex in order to develop their characteristics?
Males have to suppress the development of female reproduction
What happens if AMH doesn’t work properly?
Male fetuses would have testes that wouldn’t descend. The individual would appear female.
What happens to the Paramesonephric (Mullerian) ducts in males?
They regress, but remain as the Appendix of Epididymis and Appendix of Testis
What cells come from the Greek word for “body”?
Somatic cells
What type of cells are seen in the body in all places other than the gametes?
Somatic cells
What division do somatic cells do?
Mitosis
What are specialized cells that give rise to the gametes?
Germ cells
What nuclear division do germ cells use?
Meiosis
In mitosis, how many cells does one cell make?
One cell divides to make two cells
Are the starting and ending cells in mitosis haploid or diploid?
Both are diploid (genetic copies)
What is the cell produced by nuclear division called?
Daughter cells
What nuclear division is seen in gametogenesis?
Meiosis
What is the production of the gametes called?
Gametogenesis
How many cells do you end up with in meiosis?
One cell makes 4 daughters
Are the starting and ending cells in meiosis haploid or diploid?
One diploid cell (46 chromosomes) makes 4 haploid cells (23 chromosomes each)
What is the production of sperm or gametogenesis in the male called?
Spermatogenesis
What is the production of oocytes (eggs) or gametogenesis in the female called?
Oogenesis
What are the 3 main phases in somatic cell division?
Interphase
Nuclear division (mitosis/meiosis)
Cytokinesis
What phase is preparation for cell division?
Interphase
What subphase of interphase has biosynthesis of proteins and organelle duplication?
G1
What subphase of interphase has DNA replication?
S
What subphase of interphase has cell growth and enzyme production?
G2
What subphase of interphase has cells no longer dividing?
G0
What is the division of the nucleus called?
Mitosis
In what phase do chromosomes condense and become visible as individual chromosomes?
Prophase
In what phase does the nuclear membrane and nucleoli disappear?
Prophase
In what phase do the spindle fibers and asters appear?
Prophase
What are specialized microtubules that connect chromatids to their respective poles?
Spindles
What are specialized microtubules that anchor the centrosomes or centrioles in place?
Asters
In what phase do centromeres of chromosomes line up on the metaphase plate?
Metaphase II
In what phase do centromeres divide and migration happens to the poles?
Anaphase
What migrates in anaphase?
Sister chromatids
How is the migration in anaphase powered?
The motor proteins of the kinetochores
What phase is essentially the opposite of prophase?
Telophase
What is the division of cytoplasm called?
Cytokinesis
How many base pairs are there in 46 chromosomes?
About 3 billion base pairs
When does spermatogenesis begin/end?
Begins in puberty, lasts throughout life
When does oogenesis begin/end?
Begins in the fetus, stops at first meiotic arrest.
Resumes at puberty, stops at second meiotic arrest
What ends the first meiotic arrest?
Puberty
What ends the second meiotic arrest?
Fertilization
Which gametogenesis is this:
a single diploid cells gives rise to 4 functional haploid cells
Spermatogenesis
Which gametogenesis is this:
a single diploid cell gives rise to 1 functional haploid cell and 3 chromosomal dumps (polar bodies and ootids)
Oogenesis
What phase does first meiotic arrest happen?
Prophase I
What phase does second meiotic arrest happen?
Metaphase II
When does meiosis stop permanently for females?
Once all the follicles and their oocytes are lost, after menopause
What is another name for first meiotic division?
Reduction division
What happens to the number of chromosomes and cells in first meiotic division/reduction division?
The number of chromosomes is cut from 1 cell with 46 to 2 cells with 23
Are the chromosomes in the 2 cells with 23 chromosomes in first meiotic division/reduction division still replicated?
YES
What is it called when homologous pairs pair up? (#1 from mom pairs with #1 from dad)
Synapsis
What is it called when some paternal genes swap over to the maternal chromosomes and vice versa to mix up the traits?
Crossing over
Why is crossing over important?
Increases genetic variability
What happens to the number of chromosomes and cells in second meiotic division?
The number of chromosomes is maintained from 2 haploid cells with 23 chromosomes to 2 more haploid cells with 23 chromosomes (a total of 4)
In what phase do homologous pairs line up on the metaphase plate?
Metaphase I
What are two chromatids still attached at the centromere called?
Dyad
What is a tetrad?
A homologous pair that is lined up together (a total of 4 chromatids and 2 centromeres)
What is the “pinch” in the cell membrane demonstrating the cytoplasm’s division?
Cleavage furrow
When are chromatids counted as separate chromosomes?
After they divide in anaphase II
What is intermeiotic interphase?
Interphase II, also known as interkinesis
Between meiosis I and meiosis II
How long does spermatogenesis take in days?
70-75 days
What is the miotic development of diploid spermatogonia called?
Spermatocytogenesis
What is the release of sperm into the seminiferous tubules called?
Spermiation
What part of the spermatozoan is filled with hydrolytic/proteolytic enzymes?
Acrosome
What do the hydrolytic/proteolytic enzymes do?
Digest the sperms way into the oocyte
Where is the DNA contained in the spermatozoan?
Nucleus
What does the head of the spermatozoan consist of?
Nucleus + acrosome
What is another name for the midpiece in the spermatozoan?
Mitochondria
What does the mitochondria/midpiece do?
Make ATP
What is another name for the sperm’s tail?
Flagellum
What produces spermatozoa?
Testes
What are the tubules within testes where sperm develops?
Seminiferous tubules
What cells surround and maintain the developing sperm?
Sertoli cells (sustentacular or nurse cells)
What do the sertoli cells make up?
The blood-testes barrier
What happens if the blood-testes barrier is compromised?
The immune system will attack the sperm as “non-self” resulting in sterility
What cells are in the connective tissue just outside the seminiferous tubules?
Leydig cells (interstitial cells)
What do Leydig cells produce?
Testosterone and other androgens
What is a term for male hormones?
Androgens
What do accessory sex glands make?
Semen
What accessory sex gland produces 60% of the semen?
Seminal vesicles
What accessory sex gland makes the other 40% of semen?
Prostate gland
What accessory sex gland produces a lubricating fluid to protect and support sperm?
Bulbourethral gland
What is semen made out of?
Fructose, bicarb ions, enzymes
What % of total ejaculate is actually sperm cells (as opposed to semen)?
2-5%
What hormone causes the release of gonadotropins from the anterior pituitary gland?
Gonadotropin releasing hormone (GnRH)
What are examples of gonadotropins that are released from the anterior pituitary?
FSH and LH
What does the LH do in males?
Causes Leydig cells to make testosterone
What does FSH do in males?
Up-regulates testosterone receptors (make the sperm sensitive to testosterone)
Which hormone stimulates spermatogenesis?
FSH
What hormone triggers spermatogenesis directly?
Testosterone
What is another term for sex drive?
Libido
What is the single erectile structure surrounding the urethra?
Corpus spongiosum
What are the two structures of erectile tissue?
Corpus cavernosum (singular: corpora cavernosa)
What drains the erectile tissues?
Dorsal vein of the penis
What is the head of the penis?
Glans
What is the foreskin called?
Prepuce
Once spermatozoa are released from seminiferous tubules, where are they stored?
The epididymis
When does sperm become mobile?
In the epididymis
What transports sperm to the prostatic urethra?
Vas deferens/ductus deferens
What is the swollen portion of the vas deferens just prior to the prostatic urethra?
Ampulla
What is the “heat exchanger” that allows cooler venous blood from the scrotum cool hot arterial blood prior to entering the testes?
Pampiniform plexus
How much cooler does sperm need to be than body temperature?
4 degrees cooler
What muscle is in the spermatic cord allowing testes to drop/rise to regulate temperature?
Cremaster
What muscle in the walls of the scrotum contract when cold to hold heat and relax when hot to release heat?
Dartos muscle
What allows the testes to remain cooler than the body temperature?
Scrotum
What happens to sperm at body temperature?
They are unable to mature
What gene do females NOT have, thanks to XX (missing the Y)?
SRY gene
What hormone is NOT present in females, thus allowing the Mullerian ducts to develop?
Anti-Mullerian Hormone (AMH)
What structures do the paramesonephric/mullerian ducts form?
Fallopian tubes, uterus, upper 1/3 of vagina
What is the shell that surrounds the oocyte?
Zona pellucida
What does the ovarian follicle contain?
The oocyte
What is the fluid-filled space in the follicle called?
Antrum
What cells are the inner wall of ovarian follicles made of?
Granluosa cells
What do granulosa cells contain?
The enzyme aromatase
What does aromatase do?
Convert testosterone into estrogen
What in females makes testosterone?
Thecal cells
What cells are the outer wall of the ovarian follicle made of?
Thecal cells
What is the degeneration of oocyte called?
Atresia
When does atresia happen?
Throughout reproductive life
How many oocytes are there at:
20 weeks of fetal development
6-7 million
How many oocytes are there at:
Birth
1.5 million
How many oocytes are there at:
Puberty
400,000
How many oocytes are there at:
After menopause
0
What cells are gone after menopause?
Granluolsa cells
What is the serous layer of the uterus?
Perimetrium
What layer of the uterus has interlacing smooth muscle?
Myometrium
What is the mucosal lining of the uterus?
Endometrium
Which layer of the endometrium is lost during menses?
Functional layer
Which layer of the endometrium remains during menses?
Basal layer
Which is deeper, functional or basal layer?
Basal
What tissue are the functional layer of the endometrium made of?
Simple columnar epi
What follicles develop in the fetus?
Premordial
What follicle is an oocyte surrounded by a single layer of simple squamous epi?
Premordial follicle
What follicles begin development at puberty in small numbers?
Primary follicles
What follicles are surrounded by a single layer of cuboidal cells?
Primary follicles
What follicles have multiple layers of cuboidal cells and the beginning formation of spaces?
Secondary follicles
What follicles have a fully formed antrum?
Tertiary/mature/Graafian follicles
What is the release of the oocyte from the tertiary follicles called?
Ovulation
Which follicle does ovulation occur from?
Tertiary follicle
What is it called when the antrum is filled with blood (just after ovulation)?
Corpus hemorrhagicum
What is it called when progesterone is produced to maintain the uterus for pregnancy?
Corpus luteum
If fertilized, how long will the corpus luteum last producing hormones?
8 weeks
What takes over after 8 weeks producing hormones to maintain the uterus for pregnancy?
The placenta
What is the scar tissue made from the corpus luteum called?
Corpus albicans
After puberty, how many oocytes will resume meiosis each month?
5-9
How many oocytes will survive to be ovulated?
Usually only 1
At metaphase II and the second meiotic arrest…What happens if there’s no fertilization?
The oocyte will enter the uterus and be lost during menses
At metaphase II and the second meiotic arrest…What happens if there IS fertilization?
Meiosis will resume
Where does fertilization occur?
In the swollen upper 1/3 of the fallopian tubes (ampulla)
How many days does it take the embryo to reach the uterus?
3 days
At what phase, in females, is there a brief period with 69 chromosomes (before the second polar body is dumped)?
Anaphase II
Once telophase II and cytokinesis II occur, what will the division switch to?
Mitosis
Is the normal relationship between steroids and gonadotropins (for most of the cycle) positive or negative feedback?
Negative feedback
When is the relationship between steroids and gonadotropins positive feedback?
After 30-50 hours of elevated estrogen during the follicular phase
What does the positive feedback in the follicular phase cause?
LH surge causing ovulation
What hormone causes ovulation on day 14?
LH
What causes the LH (or gonadotropin) surge?
The elevated estrogen levels
How many hours/month is the oocyte able to be fertilized?
~15 hours/month
If fertilized, what does the corpus luteum become?
Pregnancy
If not fertilized, what does the corpus luteum become?
Corpus albicans
What produces Human Chorionic Gonadotropin (HCG) for the first 8 weeks?
Trophoblasts
What does HCG do for the ovary in the first 8 weeks of pregnancy?
Keeps it producing estrogen and progesterone (via corpus luteum)
What does the morning after pill (emergency contraceptive) contain?
High levels of progesterone or estrogen
How does high levels of progesterone prevent pregnancy?
Prevents sperm from reaching the egg and keeps the embryo from implanting
How does high levels of estrogen prevent pregnancy?
Prevents ovulation
What is the “abortion pill” called?
RU486
What does RU486 do?
Inhibits progesterone by blocking its receptors, thus causing menses
What hormone causes granulosa cells to use aromatase to convert T to E?
FSH
What’s another name for estrogen?
Estradiol
What up-regulates progesterone receptors in the uterus, making it more sensitive?
Estrogen
What does a drop in progesterone cause in the uterine arteries?
Vasoconstriction, and menses
What does progesterone down-regulate?
Oxytocin receptors and gap junctions, making the uterus less sensitive to oxy
What does down-regulating oxytocin mean for the uterus?
Less risk of pre-term contractions
What days are the follicular phase in the ovary?
Day 0-13
What days are the luteal phase in the ovary?
Day 15-28
What days are menses in the uterus?
Day 0-5
What days are the proliferative phase in the uterus?
Day 6-14
What days are the secretory phase in the uterus?
Days 15-28
What phase does LH cause thecal cells produce T, FSH causes resumption of meiosis in the ovary?
Follicular phase
What phase does the corpus hemorrhagicum become the corpus luteum and then albicans in the ovary?
Luteal phase
In what phase does the functional endometrium get lost in the uterus?
Menses
In what phase is there an increase of progesterone receptors and a thinning of the uterine mucus in the uterus?
Proliferative phase
In what phase is there an increase of endometrium glucose, making uterine milk in the uterus?
Secretory phase
What is glucose made from in uterine milk?
Glycogen
What phases are before ovulation in the ovary and uterus?
Follicular
Menses, Proliferative
What phases are after ovulation in the ovary and uterus?
Luteal
Secretory
What is the body temperature maintained at during the luteal phase of the menstrual cycle and during pregnancy?
0.5 degrees F hotter
What term means tending to produce heat?
Thermogenic
What makes the body hotter during the luteal phase and pregnancy?
Progesterone
When does the placenta produce HCG from?
Week 8 to the 4th month
When does the placenta produce estrogen and progesterone?
From 4 months on
What is the development of the placenta called?
Placentation
What is the fetal contribution to the placenta?
Chorion
What is the maternal contribution to the placenta called?
Decidua
What guides fetal vessels into the uterus?
Chorionic villi
What part of the placenta participates in nutrient/waste exchange?
Decidua
What part of the placenta protects the fetus from maternal immune attack?
Decidua
What is the failure of testes to descend called?
Cryptorchidism
What causes cryptorchidism?
Failure of the testes to mature
Does cryptorchidism cause infertility and reduced sexual maturity?
Yes
What % of term babies have cryptorchidism?
3%
What % of premature babies have cryptorchidism?
20%
Is testicular cancer treatment successful?
Relatively successful, if diagnosed early enough
What plasma protein when elevated indicates prostate cancer?
Prostate specific antigen (PSA)
What is prostate enlargement called?
Benign prostatic hypertrophy (BPH)
What are symptoms of BPH?
Increased urgency, frequency, and delay
Decreased force and urinary retention
What are treatments for BPH?
Surgery, indwelling catheter, alpha-adrenergic blockers, hormones
What % of cancer deaths does prostatic cancer cause?
13%
What % of cancers in men is prostatic cancer?
28%
What is the only cancer that causes more deaths than prostate (according to him)?
Lung
What is persistent, painful erection without sexual stimulation?
Priapism
What causes priaprism?
Neurological factors
Spinal or pelvic trauma
Reduced venous outflow
Sickle cell anemia
Tumors
What is an absence of menstruation called?
Amenorrhea
What causes amenorrhea?
Hormones, genetics, excessive exercise, weight loss, malnutrition, diseases
What is painful menstruation with successful ovulation?
Dysmenorrhea
What % of women between 15-25 experience some form of dysmenorrhea?
50%
What causes dysmenhorrhea?
Prostaglandins
What do prostaglandins cause?
Uterine contractions and meningeal vasodilation (headaches)
What is excessive amounts of androgens with conversion to estradiol called?
Polycystic ovarian syndrome (POS)
In what phase does premenstrual syndrome (PMS) occur?
Luteal
What % of women have severe PMS symptoms?
5-10%
What % of women have moderately distressing symptoms of PMS?
50%
What is a severe and disabling form of PMS?
Premenstrual dysphoric disorder (PMDD)
What % of women suffer from PMDD?
3-8%
What are symptoms of PMDD?
Severe depression, anxiety, fatigue, edema
What exacerbates PMDD symptoms?
Alcohol, thyroid disorders, familial history, overweight, lack of exercise
What is acute inflammation of upper genital tract?
Pelvic inflammatory disease
What causes pelvic inflammatory disease?
Syphilis, gonorrhea, chlamydia, infertility, ectopic pregnancy, chronic pelvic pain, pelvic adhesions, abcesses
What can pelvic inflammatory disease cause?
Septic shock
What can uterine prolapse be treated with?
Pessary, or surgery
What’s another name for fibroids?
Leiomyomas
What are the most common benign tumors of the uterus’s smooth muscle?
Leiomyomas
What does fibroids cause?
Abnormal bleeding due to increase of uterine cavity surface area
What % of women over 50 get fibroids?
70-80%
What is it called when there is a functioning endometrium outside of the uterus?
Endometriosis
Where do the living endometrial cells regurgitate through in endometriosis?
The fallopian tube back into the abdominopelvic cavity
What happens during menses to the endometrial cells in the abdomen due endometriosis?
They are shed, but remain in the cavity and cause acute inflammation
What are symptoms of endometriosis?
Pelvic pain, infertility, pelvic masses, pain with intercourse and defecation
What % of women with pelvic pain, infertility, and masses have endometriosis?
50%
What % of women have infertility with endometriosis?
40%
What is treatment for endometriosis?
Hormonal suppression of ovulation, surgical removal, presacral neurectomy
What is presacral neurectomy?
Permanent removal of certain nerves
What is the 3rd most common cancer in women?
Cervical carcinoma
What % of female cancers is cervical carcinoma?
20%
What percent of cervical carcinoma is caused by HPV, thus causing it to be considered an STD?
99%
What is the “precancer” stage of cervical carcinoma?
Dysplasia
What cells are in cervical dysplasia?
Replacement of some epithelial cells with atypical neoplastic cells
What chance of malignancy is dysplasia?
Mild, 15%
Dysplasia treatment?
Cyrosurgery, laser, conization
What is the cure rate for dysplasia?
100%
What is it called when all/most of the cervical epithelium has features of cervical carcinoma?
Cervical carcinoma in situ
Are the underlying tissues affected in cervical carcinoma in situ?
NO
Where is cervical carcinoma in situ especially at?
The squamo-columnar junction (transformation zone)
What stage of cervical carcinoma has columnar epithelium constantly replaced by stratified squamous epithelium?
Metaplasia
What phase of cervical carcinoma has invasion of adjacent tissues (metastasis)?
Invasive carcinoma
What are symptoms of invasive carcinoma?
Vaginal bleeding and discharge
What is the prognosis for invasive carcinoma with early detection vs regular detection?
Early: 88+% 5 year survival rate
Regular: 66% 5 year survival rate
What % of female neoplasms is ovarian cancer?
3%
What cancer has the most deaths of females?
Ovarian cancer
What reduces the risk of ovarian cancer?
Oral contraceptives
What breast disease is benign, but has pain or tenderness (especially near menses)?
Fibrocystic breast disease
What is the treatment for fibrocystic breast disease?
Cyst drainage, reduce caffeine, fats, and carbs
What is the most common cancer in women?
Breast cancer
What is the most common cancer for all sexes?
Lung
What proportion of women get breast cancer?
1/8
What age of having their first baby increases risk of breast cancer?
Over the age of 30
Who has greater risk of breast cancer?
Women with 0 children
Does early menarche and early menopause increase or decrease breast cancer risk?
Increase
What causes syphillis?
Treponema pallidum
How long has syphilis been an epidemic?
Since 1986
How far in ancient history does syphilis date back to?
10,000 BCE
What is the first stage of syphilis?
Chancre
In what stage of syphilis is there local inflammation that soon disappears? (After 4-6 weeks all external signs are gone)
Chancre
What phase of syphilis is chronic symptoms over 5 years with pustular skin rashes, painful mucus patches on tongue/cheeks/gums?
Secondary stage
What stage of syphilis is where symptoms may or may not reappear?
Latent stage
What stage of syphilis has permanent systemic damage to heart, kidneys, brain (dementia)?
Tertiary stage
What does syphilis do to the heart?
Metastatic calcium deposition on heart valves, and coronary artery damage
What % of patients in mental hospitals priors to antibiotics were due to syphilitic dementia?
20%
What is it called when syphilis crosses the placenta and infects the fetus?
Congenital syphilis
What does congenital syphilis cause?
Damaged teeth and palate (notched incisors)
Saber shins
Saddle-nose with discharge
What STD is “flow of seed”, or pus resembling semen discovered in 130 AD Greece?
Neisseria gonorrhoeae
How long can you be a carrier for Neisseria gonorrhoeae?
Up to 15 years
How long can Neisseria gonorrhoeae be viable on fomites (laundry, surfaces)?
Several hours
How long can Neisseria gonorrhoeae be viable in dried pus?
Several weeks
What is the only natural host for Neisseria gonorrhoeae?
Humans
What type of STD is a corneal infection?
Chlamydia trachomatis (trachoma)
How many cases of Chlamydia trachomatis are there yearly?
3-5 million
What % of Chlamydia trachomatis cases are from pregnant women?
11%
What % of Chlamydia trachomatis cases are from pediatric pneumonia?
30%
What % male and what % female have asymptomatic Chlamydia trachomatis?
10% male
80% female
What 2 widespread STDs can be a primary cause of infertility in women?
Gonorrhea and chlamydia
What is human papilloma virus (HPV) also called?
Condylomata Acuminata
What does HPV cause?
Venereal warts
What does HPV cause in males vs females?
Males: bump on penis skin
Females: cervical carcinoma
What STD is caused by a flagellated protozoan that causes acute vaginitis?
Trichomonas vaginalis
What STD may cause liver failure or cancer?
Hepatitis B
What STD is known as a yeast infection?
Candida albicans
What is Candida albicans called if oral?
Thrush
What is the developing embryo or fetus called?
Conceptus
What is the time of development within the uterus called?
Gestation
What is the pre-human called from day 1 to week 8?
Embryo
What is the pre-human called from the 8th week till birth (40 weeks)?
Fetus
What is a fertilized oocyte?
Zygote
When does a two-celled embryo exist?
30 hours after fertilization
What is each cell in the embryo called?When does a two-celled embryo exist?
Blastomere
When does a four-celled embryo exist?
48 hours gestation
When does an eight-celled embryo exist?
60 hours
When does a morula (solid ball of cells) exist?
Day 3
What are blastomeres called, meaning they have the potential to develop into a complete individual (twins, or clones)?
Totipotent
In what meiosis phase does fertilization occur?
In metaphase II
What is a hollow ball of cells called?
Blastula/blastocyst
When does a blastula exist?
Day 4
In what early developmental form does the uterus reach the uterus as?
Blastula
What must the embryo “hatch” out of in order to nidate?
Zona pellucida
What is the zona pellucida made of?
Glycoprotein shell
What does nidation mean?
Implant
What will the inner cell mass become?
Embryo proper
What cells are on the outer wall of the embryo and will contribute to the placenta?
Trophoblasts
What do trophoblasts produce to make the uterus ready for pregnancy (and is used to detect pregnancy)?
HCG
What is a fluid filled space called?
Blastocoel
When does nidation occur?
Day 6-9 after fertilization as a blastula
What do trophoblasts give rise to?
Cytotrphoblasts
What do cytotrophoblasts give rise to?
Syncytiotrophoblasts
What do syncytiotrophoblasts give rise to?
The chorion portion of the placenta
At what day does the blastula become bilaminar?
Day 7
Does the epiblast give rise to the embryo proper or the extraembryonic endoderm?
Embryo proper
Does the hypoblast give rise to the embryo proper or the extraembryonic endoderm?
Extraembryonic endoderm
What does the embryo proper consist of?
3 primary/primordial germ layers (endoderm, mesoderm, ectoderm) or trilaminar embryo
What does do the extraembryonic structures consist of?
Yolk sac
What does the extraembryonic endoderm make?
Extraembryonic structures
What does “syncytio” mean?
Multinucleated
What cells are aggressively invasive and digest into the uterus?
Syncytiotrophoblasts
What are spaces that form within the syncytiotrophoblasts and are eventually filled with maternal blood that bathes the chorionic villi?
Lacunae
What surrounds the embryo/fetus to protect it?
Amnion
What surrounds the amnion?
Chorion
How much amniotic fluid fills the amnion and is replaced daily?
1000 ml
What does the chorion line?
The inside surface of cytotrophoblasts
By what day does the lacunae fuse and maternal blood seeps in?
Day 12
What fills the lacunae in addition to maternal blood?
Embryonic blood vessels (within the chorionic villi)
What arteries does the embryonic blood vessels receive nutrients from?
Spiral arteries
What are CO2 and other wastes picked up by in the uterus?
Uterine veins
Where does the secondary yolk sac push down from?
The hypoblast
What does the connecting stalk become?
The umbilical cord
What is the appearance of the 3 primordial germ layers called?
Gastrulation
What becomes the cephalic (head) region of the embryo?
Prochordal plate
What is the trilaminar embryonic disc or trilaminar embryo referred to in “lower animals”?
Gastrula
What is the development of the embryo from zygote to trilaminar embryo called?
Embryogenesis
What primary germ layer gives rise to the nervous system, epidermis, pituitary gland, and adrenal medulla?
Ectoderm
What primary germ layer gives rise to connective tissue and mesenchyme?
Mesoderm
What is mesenchyme?
Embryonic form of connective tissue
What primary germ layer gives rise to the viscera?
Endoderm
At how many weeks does the heart begin to pump blood?
4 weeks
What is the development of organs and their systems called?
Organogenesis
At 28 days, how big is the pre-human?
5 mm long
What are mesodermal masses that lie on either side of the notocord, giving the embryo a “segmented” appearance?
Somites
What can somites be used for?
Dating the embryo’s progress
What do somites develop into?
Parts of the skeleton, skin, muscles
What is the median cylindrical structure eventually replaced by the vertebral column
Notochord
How many pairs of somites?
40
How many functional parts do somites have?
3
What cells in somites produce the vertebra and rib at each level?
Sclerotome
What cells in somites form the dermis of the skin on the dorsal part of the body?
Dermatome
What cells in somites produce skeletal muscles of the neck, trunk, and limbs?
Myotome
What do myotome cells form muscles with?
Limb buds
What gives rise to auditory ossicles, parts of the mandible, nerves, hyoid bone, thymus, and other neck structures?
Pharyngeal arches
When does the chorion start to thin?
28 days
What originates in the yolk sac and then moves to the embryo proper to form the gonads?
Primordial germ cells
What role does the placenta have in immunity?
It allows passage of the maternal IgG’s to the fetus
As the fetus is a combination of maternal and paternal genes, it is similar to what?
An allograft
What keeps the corpus luteum functioning so it can continue to release progesterone?
HCG
What is the embryonic process where rudiments of the future CNS and skeleton are established?
Neurulation
What is it called when a flat sheet of cells is turned into a hollow, tube-like structure?
Embryonic folding
What is sampling the amniotic fluid to examine fetal chromosomes found in sloughed skin cells for genetic disease?
Amniocentesis
When is amniocentesis usually done?
10-12 weeks
What is biopsy of villus cells to examine fetal chromosomes for potential diseases?
Chorionic villus sampling (CVS)
When is CVS usually done?
15-18 weeks old
What structure will become part of the umbilical cord and urinary bladder, important for development of extraembryonic membranes?
Allantois
What will the allantois become?
Urachis
When does the neural groove form in the dorsum of the embryo?
Day 18
When does the anterior portion of the neural tube close?
Day 25
When does the posterior portion of the neural tube close?
Day 27
What does the anterior portion of the neural tube become?
Forebrain or cerebral cortex
What does the posterior portion of the neural tube become?
Spinal cord
What deficiency is seen with neural tube defects (NTD)?
Folic acid
Is anencephaly anterior or posterior NTD?
Anterior
Is Spina Bifida anterior or posterior NTD?
Posterior
What are NTD indicated by?
Increased alpha fetal protein
What is the process of birth called?
Partuition
The fetus releases what in response to stress?
Cortisol
What does the fetal release of cortisol cause the mother to release?
Oxytocin
Where is oxytocin released from the mother?
Posterior pituitary gland
What does oxytocin cause?
Uterine contractions, pushing the fetus, stretching the cervix, thus signaling for more oxytocin release
Is the oxytocin feedback positive or negative?
Positive
Where is oxytocin MADE?
Hypothalamus
What is the first stage of labor?
Dilation
What will the cervix dilate to?
10 cm
What is it called when the fetal head pushes down into the cervix, and the cervix thins and softens?
Effacement
What is the middle stage of labor from dilation to delivery?
Expulsion stage
What is it called when the fetal head begins to push through the vaginal orifice?
Crowning
What is the stage of delivery where the placenta separates from the uterine wall and is delivered with the fetal membranes?
Placental stage
When does the placental stage happen?
Usually within 30 minutes of delivery
What does the ductus venosus bypass?
Liver
What is the opening in the interatrial septum where the ductus arteriosus is?
Foramen ovale
What does the ductus arteriosus bypass?
Pulmonary circulation
