Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Reproductive System I > Embryology of Genital System Lecture (Dr. Cole) > Flashcards

Embryology of Genital System Lecture (Dr. Cole) Flashcards

1
Q

Hypospadias

A
  • Incomplete fusion go Urethral Folds

EPISPADIAS:
- Gen tube forms a UR Septum Urethral Meatus on Penis Dorsum

  • UG Sinus OPENS on top of Penis can occur with: EXSTROPHY of BLADDER (Exposed to Outside Primative Streak Mesoderm normally migrates around CLOACAL MEMBRANE to for ANTERIOR BODY WALL)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Uterine Abnormalities

A

1) Uteris Arcuatis:
- Indented Fundus

2) Atresia of Cervix:
- Closed Cervix

3) Atresia of Vagina:
- Closed Vagina, open part too

4) Persistant Septum:
a) Ut Bicornis: 2 Uteri, 1 Vagina

b) Ut Didelphys: 2 Uteri, 2 Vagina

c) Ut Bicornate Unicollis: One rudimentary Horn Abdominal Pain in FIRST Menses
- Distally, Parameso Duct DEFECT
- Mesoneph likely DEFECTIVE too, so NO KIDNEY
- Rud Horn needs to be DRAINED

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Development of the Genital System

A
  • The Genotype of the Embryo (46, XX or 46, XY) is established at Fertilization
  • Weeks 1 to 6 the Embryo remains in UNDIFFERENTIATED STATE
  • Week 7: Phenotypic SEXUAL DIFFERENTIATION Begins
  • Week 12: Male and Female EXTERNAL GENITALIA can be recognized
  • Week 20: Phenotypic DIFFERENTIATION Complete
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Primordial Germ Cells

A
  • Primordial Germ Cells from ENDODERM OF YOLK SAC invade the Dorsal Mesentery and MIGRATE to UROGENITAL RIDGES
  • Migration guided by C-KIT Receptor and STEM CELL Factor (C-Kit Ligand) expressed on PGCs
  • Failure of these cells to REACH Genital Ridges leads to GONADAL DYSGENESIS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Gonadal Dysgenesis: Nonfunctional Gonads

A
  • Several forms
  • “PURE GONADAL DYSGENESIS” (PGD) has a normal set of Sex Chromosomes (Ex 46, XX or 46, XY), as opposed to those whose Gonadal Dysgenesis results from MISSING ALL or part of the Second Sex Chromosome
  • Latter group includes those with TURNER SYNDROME (Ex 45, X) and mixed Gonadal Dysgenesis and a mixture of Cell Lines, some contains a Y Chromosome (Ex 46, XY/ 45, X)
  • SWYER SYNDROME is referred to as PGD, 46, XY and XX GONADAL DYSGENESIS as PGD, 46, XX!!!!!!!!!!!!!!!!!!!

*Patients with PGD have a NORMAL Karyotype but may have DEFECTS of a Specific Gene on a Chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Primary Sex Cords

A
  • Primary Sex Cords are aggregates of Supporting Cells (Hormone Secreting Cells). Gonad now has an OUTER CORTEX and an INNER MEDULLA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Development of Genital Ducts

A
  • Two pairs of Ducts are present in BOTH sexes
  • Both pairs are present during the Indifferent Stage
  • In the MALE, the MESONEPHRIC DUCTS play the MOST Important Role
  • IN the FEMALE, the PARAMESONEPHRIC DUCTS are the MOST Important
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Fetal Sex

A
  • Encoded on the Sex-Determing Region of the Y Chromosome (SRY)
  • Synthesis of SRY Protein (TESTIS-Determining Factor, TDF) trigger MALE Development
  • If NOT EXPRESSED (Absent or Defective), FEMALE path is Followed
  • Female: BASIC (Default) Development Pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Male Development

A

1) Activation of SRY Gene (Sex Regulating Region of the Y)

—— TDF (Testes Determining Factor) = SRY Protien ——->

2) Differentiation of Biopotential Gonad into Testis

—— ( SOX9 (Testes Differentiation of SF1!!!!!!) —————>

3) SERTOLI Cell Differentiation

————————–>

4) Müllerian INHIBITORY SUBSTACE aka Anti- Müllerian Hormone or Müllerian Inhibitory Factor

——————->

5) Regression of Paramesopnephric (Müllerian) Ducts

*****SOX9: Transcriptional Regulator for TESTES Differentiation

****SF1: A Critical Regulator of Reproduction, regulating the Transcription of Key Genes involved in SEXUAL DEVELOPMENT and Reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Campomelic Dysplasia

A
  • Rare AUTOSOMAL DOMINANT Congenital Short Limber DWARFISM characterized by Congenital bowing of LONG BONES associated with Skeletal and Extra Skeletal features like HYPOPLASTIC Lungs, Malformation of Cervical Spine, Heart, and Kidneys
  • Characteristic feature is MALE to FEMALE SEX REVERSAL!!!!!!!
  • It is caused by MUTATIONS in the SRY related Gene SOX9!!!!!!
  • It has Almost FATAL Outcome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Male Hormone Production

A

1) Activation of SRY Gene (Sex Regulating Region of the Y)

—— (TDF ( Testis Determing Factor) = SRY Protien) —–>

2) Differentiation of Biopotential Gonad into Testis

——- (SOX9 (testes differentiation via SF1)) ——>

3) INTERSTITIAL (LEYDIG) Cell Differentiation

————>

4) Steroid Synthesis

———>

5) Testosterone

——— (5 Alpha Reductase) ————->

6) DIHYDROTESTOSTERONE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

DHT

A
  • Testosterone is converted to Dihydrotestosterone (DHT) by 5 Alpha Reductase 2 action!!!!!
  • DHT influences DIFFERENTIATION of External Genitalia and Development of the Prostate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

5 Alpha Reductase

A

2 Isoenzymes:
1) 5 Alpha Reductase i: Made in the LIVER and SKIN

2) 5 Alpha Reductase II: Made by parts of the Male Reproductive Tract (Epididymis, Seminal Vesicle, Prostate….)

**Second Enzyme is DEFICIENT in 5 ARD (–> INTERSEXUALITY)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Indifferent Embryo developments

A

MALE:

1) Paramesonephric Ducts:
- Regress

2) Mesonephric Ducts:
- Ductus Deferens, Epididymis

3) Urogenital Sinus:
- CLOSES: Urethra and Prostate

4) Genital Tubercle:
- Penis

5) Labioscrotal Swellings:
- CLOSURE: Scrotum

FEMALE:

1) Paramesonephric Ducts:
- Oviducts, Uterus, and Upper Vagina

2) Mesonephric Ducts:
- Regress

3) Urogenital Sinus:
- REMAINS OPEN: Lower Vagina and Vestibule

4) Genital Tubercle:
- Clitoris

5) Labioscrotal Swellings:
- REMAINS OPEN: Vulva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Development of the Ovaries

A
  • Primary (Medullary) cords degenerate by 10th Week
  • Cortical (Secondary) Cords develop and are invaded by Primordial Germ Cells
  • Cords form groups of Primordial Follicles (Oogonium + Follicular Cells)
  • All Oogonia are formed PRENATALLY
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Female Mesonephric Ducts

A
  • In the Female, the Mesonephric Ducts denigrate except for the EPOOPHORON and the PAROOPHORON found in the Mesentery of the Ovary

*** Portions of the Duct may exist as GARTNER’S DUCT!!!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Female Transcription Signals

A

1) WTN4 (Also regulates other gene that CONTROL Ovarian Development)
- ——————–>

2) Upregulates DAX1
- ——————–>

3) Inhibits SOX9 and AMH Expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Paramesonephric (Müllerian) Ducts

A
  • Develop during 6th week as Invaginations of Epithelium lateral to Mesonephros
  • CRANIAL END opens into PERITONEAL Cavity
  • DISTAL ENDS join to form UTEROVAGINAL PRIMORDIAL (Connects to Urogenital Sinus)
  • Inhibited in the Male by AMH secreted by the SERTOLI CELLS
19
Q

Paramesonephric Ducts Cont

A
  • The paired portions of the Paramesonephric Ducts become the UTERINE TUBES
  • The UTEROVAGINAL PRIMORDIAL becomes the Epithelium and Glands of the Uterus, Epithelium of the UPPER 1/3 of the Vagina, and the Muscular Wall of the Vagina

***The INFERIOR Portion of the Vagina forms from the POSTERIOR WALL of the UROGENITAL SINUS

20
Q

Anomalies of the Female Reproductive Tract

A
  • Anomalies of the Female Reproductive Tract can result from GENESIS or HYPOPLASIA, Vertical Fusion and/ or Canalization Defects, Lateral Fusion and/ or Duplication Abnormalities, or Failure of Resorption, resulting in SEPTA
21
Q

Congenital Fusion Abnormalities

A

1) Uterus Didelphys with Double Vagina
- 2 Uterus and 2 Vagina

2) Uterus Arcuatus
- Uterus with an Indentation

3) Uterus Bicornis
- One Vagina and two Uterus

4) Uterus Bicornis Unicollis
- 1 Rudimentary Horn

5) Atresia of Cervix
6) Atresia of Vagina

22
Q

Congenital Fusion Abnormalities

A

*** Vaginal Septum!!!!

  • Complete to Partial Separation of the Uterus
  • Can be associated with a Vaginal Septum
23
Q

Paramesonephric Ducts role in Atresias

A
  • Partial or Total Atresia of the Distal Portion of BOTH Ducts ca result in Cervical or Vaginal Atresia
  • 46, XY can have persistence of Paramesonephric Ducts if the Circulating levels of AMH are LOW or there is an ABNORMAL response to the Normal AMH
24
Q

Müllerian (Paramesonephric) Agenesis

A
  • FAILURE of the Paramesonpehric Ducts to DEVELOP
  • Results in missing UTERINE TUBES, UTERUS and variable Malformations of the UPPER PORTION of the Vagina
  • Also called MRKH or MAYER- ROKITANSKY- KÜSTER- HAUSER SYNDROME
25
Q

Scientists use Women’s Own Cells to create Lab-Grown Vaginas

A
  • Vaginal organs created using muscle and Epithelial Cells taken from the Patient’s External Genitals.
  • Cells are cultured, then placed on a Biodegradable Scaffold that was Hand-Sewn into a Vagina- like shape
  • A week later the scaffold is sutured to Patient’s Existing Internal Reproductive Organs. After Implantation, nerves and Blood Vessels form, and the cells on the Scaffold “Expand and Form Tissue.” While the body begins to absorb the Biodegradable Scaffold., “The Cells lay down materials to form a Permanent Support Structure, gradually replacing the Engineered Scaffold with a New Organ”
26
Q

Recanalization Abnormalities

A
  • The Majority of adolescents will present with CYCLIC or PERSISTENT PELVIC PAIN and Primary AMENORRHEA (Absence of Menses).
  • If significant HEMATOMETRA is present, an Abdominal Mass also may be palpated.
  • RETROGRADE pass of Blood into the Uterine Tubes can cause HEMATOSALPINX, which can lead to ENDOMETRIOSIS and ADHESION FORMATION.
  • Blood also may pass Freely into the Peritoneal Cavity, forming Hemoperitoneum
27
Q

Development of External Genitalia

A
  • In Both sexes, a Genital Tubercle develops near CLOACAL MEMBRANE
  • URORECTAL SEPTUM divides local Membrane into Urogenital and Anal Membranes (Cloaca divides into Urogenital Sinus and Rectum)
  • Forms SPHINCTER URETHRAE and EXTERNAL ANAL SPHINCTER
  • Also forms URETHRAL FOLDS ANTERIORLY and ANAL FOLDS POSTERIORLY
28
Q

Development of Male External Genitalia

A

1) Enlargement of Genital Tubercle forms the Phallus
2) Urethral Folds —> Urethral Groove, then fuse to form PENILE URETHRA
3) LABIOSCROTAL SWELLINGS become the SCROTUM

29
Q

Genital Tubercle in Females

A
  • Genital Tubercle ELONGATES and bends INFERIORLY to become the Clitoris
  • Urethral Folds become the LABIA MINORA; Labioscrotal swellings become the LABIA MAJORA
  • Urethra and Vagina open into the Vestibule
30
Q

Female External Genitalia

A
  • ESTROGENS influence the Development of both Internal (Paramesonephric) Female Duct system as well as the External Genitalia
  • Errors in the production of or Sensitivity to Androgenic Hormones in a Male fetus leads to Predominantly Female Characteristics of the External Genitalia due to the Influence of Maternal/ Placental Estrogens
31
Q

Cryptorchidism

A
  • Unilateral or Bilateral AGENESIS
  • UNDESCENDED TESTES (Cryptorchidism). Testes usually descend within the First Year. Associated with INCREASED incidence of Testicular Cancer (20 - 40%)
  • ECTOPIC Testes or Ovary (Rare)
32
Q

Molecular Basis for Cryptochidism

A
  • Shortly before birth (B) ANDROGENS cause an INVOLUTION of the CRANIAL SUSPENSORY LIGAMENT (CSL), allowing the thickening GUBERNACULUM, under the influence of Insulin‐like Factor‐3/Relaxin‐like Factor (INSL3/RLF), to retain the testis in the inguinal region while the embryo grows
  •  MÜLLERIAN INHIBITING SUBSTANCE (MIS=AMH) from developing SERTOLI CELLS, causes the Involution of the Mullerian/Paramesonephric duct, while ANDROGENS continue to stimulate the development of Wolffian/Mesonephric derivatives
  •  Finally, the GUBERNACULUM facilitates the passage of the testis into the scrotum with the development of an INGUINAL CANAL.
  •  In the FEMALE, the CSL is retained holding the OVARY close to the KIDNEY, as the remaining abdomen grows ventrally. The Paramesonephric Müllerian duct is retained later to form the Uterine Tubes and Uterus, while the Mesonephric/Wolffian derivatives and gubernaculum involute.
33
Q

HYPOSPADIAS

A

***HYPOSPADIAS: Incomplete Fusion of the Urethral Fodls

  • Urethra opens onto the VENTRAL aspect of the Penis
  • Can result from Inadequate Androgen production or Inadequate receptor sites for DHT!!!!!

Four Types:

1) Glandular
2) Penile
3) Penoscrotal
4) Perineal (Bifid Scrotum)

34
Q

Epispadias

A
  • Urethral Meatus OPENS on the Dorsum of the Penis

- Often occurs with BLADDER EXSTROPHY

35
Q

Previos Terminology and Revised Nomenclature of Disorders of Sexual Developemtn

A

1) Female Pseudohermaphrodite:
- 46, XX DSD

2) Male Pseudohermaphrodite:
- 46, XY DSD

3) True Hermaphrodite:
- Ovotesticular DSD

4) XX Male:
- 46, XX Testicular DSD

5) XY Sex Reversal:
- 46, XY Complete Gonadal Dysgenesis

36
Q

Sex Chromosome DSD

KLINEFELTER SYNDROME

A
  • 47, XXY
  • 1/ 1000 Births
  • SMALL TESTES, LOW levels of Testosterone
  • Poorly developed Secondary Sexual Characteristics and Gynecomastia (40%)
  • Elongated Limbs
  • TESTOSTERONE REPLACEMENT THERAPY!!!!!!
37
Q

Sex Chromosome DSD

TURNER’S SYNDROME

A
  • 45, X
  • 1/ 5000 Births
  • Short Stature, No adolescent Growth Spurt, Broad Chest, Webbed Neck, Congenital Heart Disease
  • Ovary Development is ABORTIVE
  • Secondary Sex characteristics DO NOT DEVELOP
  • ESTROGEN REPLEACEMENT THERAPY!!!!!!!!
38
Q

Pseudointersexuality of 46 XX DSD or 46 XY DSD

A
  • External Genitalia of one Sex accompanies the Gonads of the Other Sex
  • Can be caused by ABNORMAL LEVELS of Sex Hormones or Abnormalities in the Receptors for these Hormones
  • Old Term: Pseudphermaphroditism
39
Q

46, XX DSD

A
  • Induced by PRENATAL EXPOSURE to ANDROGENS
  • Exposure after the 12th Fetal Week leads only to CLITORAL HYPERTROPHY
  • Exposure at Progressively Earlier stages of Differentiation leads to RETENTION of the UROGENITAL SINUS and LABIOSCROTAL FUSION
  • If Exposure occurs sufficiently early, the Labia will fuse to form a PENILE URETHRA
40
Q

Classical Virilizing Adrenal Hyperplasia (46, XX DSD)

A
  • FEMAL INTERSEX
  • Female (46, XX) with Severe forms of Adrenal Hyperplasia have AMBIGUOUS GENITALIA at Birth due to Excess Adrenal Androgen production IN UTERO
  • Ambiguous genitalia ranges from COMPLETE FUSION of the LABIOSCROTAL folds and a PHALLIC URETHRA to only CLITOROMEGALY, partial Fusion of the Labioscrotal Folds, or Both
  • No Abnormalities of Ovaries
41
Q

Androgen Insensitivity Syndrome (AIS)

Complete 46, XY DSD

A
  • An X-LINKED disorder in which receptors remain Unresponsive to Androgens
  • Despite normal levels of Testosterone, the Male fails to Masculinise
  • The External Genitalia are FEMININE. Internally they possess non-functioning UNDESCENDED TESTES
  • At Puberty, Secondary FEMALE Sexual Characteristics may appear due to ESTRADIOL from Testosterone Aromatization
  • It is common to Perform GONADECTOMIES at Puberty and for them to receive Hormone Therapy, to be reared as Female

***Degree of Feminization depends upon AFFECTED ANDROGENS and the AMOUNT of Residual Receptor Function

42
Q

5 Alpha Reductase Deficiency (5- ARD)

A
  • AUTOSOMAL RECESSIVE Condition resulting in the Inability to convert TESTOSTERONE to the more physiologically active DIHYDROTESTOSTERONE (DHT)
  • Because DHT is required for the Normal Masculinization of the External Genitalia in Utero, Genetic Males with 5- ARD are down with AMBIGUOUS GENITALIA (Underdevelopment of Penis and Scrotum or Pseudovaginal Perineoscrotal Hypospadias)
  • Derivatives of Mesonephric Duct are Normal
  • Often misdiagnosed as AIS!!!!!!
  • ‘Guevedoche’ or ‘Machihembras’ (First Women then Man) THIRD GENDER
  • Also a 46, XY DSD
43
Q

True Intersex or Ovotesticular DSD

A
  • VERY RARE
  • Have BOTH OVARIAN and TESTICULAR Tissue or OVOTESTES!!!!!!!!
  • Causes are Poorly Udnerstoof
  • Ambiguous External Genitalia
  • Traditionally, most raised as Female

Reproductive System I (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions