What are the 4 important genes of embryogenesis?
Sonic hedgehog - A/P & CNS
Wnt-7 - D/V
FGF - Lengthen limbs
Homeobox (Hox) - Craniocaudal
What genes are produces at apical ectodermal ridge (thickened ectoderm at distal end of developing limbs)?
Wnt-7 - D/V
FGF - length
Forms trilaminar embryonic disc (3rd week)
Epiblast invaginating to form primitive streak
What structures are formed by the surface ectoderm?
Adenohypophysis (Rathke's pouch)
Lens & Sensory organ of ear
Olfactory and oral cavity epithelium
Parotid, sweat, and mammary glands
What does the neuroectoderm form?
CNS: Brain, retina/optic nerve, spinal cord
What do neural crest cells form?
PNS (dorsal root ganglia, CN, celiac ganglion, ANS)
Chromaffin cells of adrenal medulla
Parafollicular cells of thyroid
Pia and arachnoid
Bones of skull
What do mesodermal defects cause?
What structures are formed from endoderm?
Gut tube epithelium
Luminal epithelial derivatives
What is the difference between agenesis and aplasia?
Agenesis: Absent organ due to absent primordial tissue
Aplasia: Absent organ depsite presence or primordial tissue
Incomplete organ development
Primordial tissue present
What is the difference between Deformation, Disruption, and Malformation?
Deformation: Extrinsic disruption, post embryonic period
Disruption: 2˚ breakdown of previously normal tissue
Malformation: Intrinsic disruption, occurs during embryonic period
What is an example of a sequence error?
Oligohydramnios → Potter Sequence
When is a developing fetus most susceptible to teratogens?
Embryonic Period (Weeks 3-8)
What 3 structures are found in the umbilical cord?
Umbilical arteries (2) - deoxygenated blood from fetal iliac arteries
Umbilical vein - Oxygenated blood
Duct between fetal bladder and yolk sac
Yolk sac → Allantois (extends to UG sinus) → Urachus
What 3 things can result if the urachus fails to obliterate?
Patent urachus - urine discharge from umbilicus
Urachal cyst - fluid-filled cavity lined w/ uroepithelium between umbilicus and bladder
Vesicourachal diverticulum - outpouching of bladder
Connects yolk sac to midgut lumen
If the vitelline duct doesn't completely obliterate (7th week) what can occur?
Vitelline fistula - meconium discharge from umbilicus
Meckel diverticulum - melana, periumbilical pain, ulcers
1st aoritc arch forms the ____________.
2nd aortic arch forms what 2 arteries?
Stapedial and hyoid
3rd aortic arch forms what 2 arteries?
Proxiaml part of Internal Carotid
4th aortic arch forms what 2 arteries
L: aortic arch
R: proximal R subclavian
6th aortic arch forms what what structures?
Proximal pulmonary arteries
What are the brachial clefts, arches and pouches formed from?
CAP covers outside to insdie
What does the 1st brachial cleft form?
External auditory meatus
What do the 2nd-4th brachial clefts form?
Temporary cervical sinuses
**which are obliterated by proliferation of 2nd arch mesenchyme**
What does a persistant cervical sinus form?
Brachial cleft cyst - lateral neck
What are the symptoms of DiGeorge?
22q11 - aberrant development of 3rd and 4th pouches
T-cell deficiency (thymic aplasia)
Hypocalcemia (failure of parathyroid)
RET germline mutation - neural crest
Parafollicular cells (medullary thyroid cancer)
Failure of fusion of the maxillary and medial nasal sinus
Formation of 1˚ palate
Failure of fusion of 2 lateral palatine processes
Failulre of fusion of Lateral palatine process w/ nasal septum and/or median palatine process
Formation of the 2˚ palate
What 3 things are necessary for male development?
SRY gene (Y chromosome)
Mullerian Inhibitory Factor (Sertoli cells)
Androgens (Leydig cells)
Mullerian duct - Develops on default
Fallopian tubes, uterus, and upper 2/3 of vagina
Wolffian duct (SEED)
Seminal vesicles, Epididymis, Ejaculatory duct, and Ductus deferens
What results from an incomplete fusion of the paramesonephric ducts?
What lymph nodes do the ovaries/testes drain to?
What lymph nodes do the distal vagina/vulva/scrotum drain to?
What lymph nodes do the proximal vagina/uterus drain to?
Obturator, external iliac, and hypogastric
What ligament contains the ovarian vessels?
Infundibulopelvic - suspensory ligament of the ovaries
What ligament contains the uterine vessels?
Cardinal ligament (cervix to side of pelvis)
What ligament is a derivative of gubernaculum?
Round ligament of the uterus
Uterine fundus to labia majora
What structures are contained in the broad ligament?
Ovaries, fallopian tubes, and round ligament of the uterus
Ovarian ligament connects what two structures?
Medial pole of ovary to lateral uterus
What is the histology of the fallopian tube?
Simple columnar epithelium - many ciliated cells
Few secretory (peg) cells
What is the histology of the outer surface of the ovary?
Simple cuboidal epithelium (germinal epithelium covering surface of ovary)
What is the pathway of sperm during ejaculation?
Which cells in the testes does increase in temperature affect?
↓sperm production and inhibin
Which of the male non-germ cells secrete androgen-binding protein?
Sertoli - maintain local level of testosterone
Support sperm synthesis
What is the order of estrogens in terms of potency?
Estradiol > Estrone > Estriol
What 3 places is estrogen synthesized?
Ovary - 17β-estradiol
Placenta - Estriol
Adipose - Estrone
What 3 things does estrogen promote the development of?
Female genetalia and breast
Female fat distribution
Estrogen induces the upregulation of what 3 receptors? And provides feedback inhibition for what 2 hormones?
ER, PR, and LH receptor
FSH and LH
What effect does estrogen have on SHBG, HDL and LDL?
The fall in _____________ after delivery disinhibits prolactin.
What 4 structures can produce progesterone?
What is tanner stage 2?
Pubic hair appears and breast buds from (thelarche)
What is tanner stage 3?
Pubic hair darkens and becomes curly
↑ Penis size/length
Tanner stage 4
Darker scrotal skin
Development of glans
What is Tanner stage 5?
Adult - areolae are no longer raised
What is the differnece between metorrhagia, menorrhagia, and menometrorrhagia?
Metorrhagia: Frequent, irregular bleeding
Menorrhagia: Heavy bleeding
Menometrorrhagia: Heavy irregularly, irregular
1˚ oocytes begin meiosis I during _________ and complete meiosis I just prior to ____________.
Meiosis I is arrested in ___________ for years.
Meiosis II is arrested in _________ until fertilization.
If fertilization does not occur within ______ the 2˚ oocyte degenerates.
↑ estrogen, and ↑GnRH receptors on the anterior pituitary
What stimulates the LH surge?
Transient mid-cycle ovulatory pain
Peritoneal irritaiton, follicular swelling/rupture, fallopian tube contraction
Implantation within the wall of hte uterus occurs ______ after fertilization.
What cells secrete hCG into the blood? How early is this detectable?
1 week after conception - blood
2 weeks after conception - urine
What is the role of prolactin and oxytocin in lactation?
Prolactin: induces and maintains lactation - ↓repro fx
Oxytocin: milk letdown and promotes uterine contractions
What benefits does breastmilk have for infants?
Maternal IgA, Mφ, lymphocytes
↓ risk for child to develop asthma, allergies, diabetes mellitus, and obesity
What must be supplemented in exclusively breast fed infants?
What hormonal changes are seen in menopause?
↑↑FSH & ↑LH
What are the symptoms seen with menopause?
Atrophy of the Vagina
Spermatogenesis begins at _______ with spermatogonia
Where does spermatogenesis occur? How long does it take?
What 2 things must happen to a spermatid for them to form a mature spermatozoon?
Loss of cytoplasmic contents
What two organs synthesize androgens?
Testis: DHT and testosterone
What is the order of potency of androgens?
DHT > testosterone > androstenedione
What are the functions of testosterone? (5)
Differentiation of epididymis, vas deferens, seminal vesicles
Deepending of voice
Closing of epiphyseal plates