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Embryonic Development (Organ Embryology (Sexual Organ Development…

- - - - Deveiations from the normal Ventral wrapping around to unite with Dorsal pancreatic bud
        
        rememebr the ventral does all the wrapping and migrating
        --> just like the trigger of a gun does all the work
        
        Annular Pancreas
        
        comes from abnormal migration of the ventral pancreatic bud
        
        Notes:
        
        annular pancreatis is the formation of annular ring of the ventral pancreatic bud that can constrict the duodenum
        --> reason why patients present with emesis and pancreatitis
        
        note that the pancreas is part of SAD PUCKER = retro peritoneal
        --> except the tail of the pancreas
        --> this makes sense as the dorsal bud of the pancreas is dorsal or "behind"
        --> remember counter intuitive that the tail is the only thing retro peritoneal
        --> think of a gun being pulled at your back and shooting forward to the spleen
        
        most annular pancreas are assymptomatic
        
        Case presentation:
        
        Pancreatic Divisum
        
        where the ventral pancreatic bud winds and migrates to dorsum bud
        
        but they stay divided into separate buds = DIVISUM
        
        thus the main pancreatic duct that normally comes from anterior bud can't go up to the body and tail
        
        get 2 separate ducts
  - - - Case presentation:
      - Notes:
        
        hypospadius = "below the tear"
        
        hypospadias in males refers to the non fusing of the urethral / urogenital folds that equally in female counterpart stay open to form the labia minor of the vagina oriface
        
        in men the urogenital folds close to form the penile raphe = the fold of skin that goes all the way from the anus and perineum to the glans of the penis
        
        hypospadius results in the urethra opening prematurely before the glans --> hence hypo spadius = tear or openning
    - - Male internal and external sexual Organs
        
        Leydig and Sertoli cells, and SRY gene on the Y chromosome
        
        Case presentation:
        
        Notes:
        
        note that SRY gene on the Y chromosome is what differentiates the undetermined internal gonads to become either testes or ovaries
        --> note that the default for everything is female
        --> so if there is no SRY gene on the Y chromosome then the gonads become ovaries
        
        Leydig cells produce and secrete testosterone
        --> they give men a "Leg up in competition" = testosterone
        
        Sertoli Cells "make certain the testosterone gets used" = they produce aBP = adrogen binding protein in order for DHT to bind in seminiferous tubules --> for semen
        
        note that the Leydig cells and testosterone are what are responsible for making the rest of the internal genitalia and the external genitalia
        
        internal male genitalia = testes (SRY gene Y chromosome), epididymis + vas deferens (Leydig and testosterone)
        
        DHT make the penis and the prostate
        
        note that while the external male genitalia comes from the Leydig cells and testosterone, the Mullerian develops into the female internal vagina and uterus
        
        think the Mullerian duct MUST be taken out
        
        it is the job of the sertoli cells to secrete AMH = anti Mullerian hormone to destroy it
        
        in this case with correct Leydig but Sertoli inactive --> there is no AMH so you get both male and female internal organs, ONLY male external organs
      - Mullerian and Wolfian Ducts
        
        Mullurian duct = vagina and others
        
        Wolfian duct = epidimis and vas def
        
        Mullerian Aplasia
        
        short or absent vagina
        
        no uterus
        
        all external female characteristics normal
        
        Case presentation:
        
        Notes:
        
        hypospadius = "below the tear"
        
        hypospadias in males refers to the non fusing of the urethral / urogenital folds that equally in female counterpart stay open to form the labia minor of the vagina oriface
        
        in men the urogenital folds close to form the penile raphe = the fold of skin that goes all the way from the anus and perineum to the glans of the penis
        
        hypospadius results in the urethra opening prematurely before the glans --> hence hypo spadius = tear or openning
        
        Notes:
        
        start with undifferentiated gonads
        
        note that the Wolfian duct passively dies
        --> think women are more passive and just let it die because no Testosterone
        
        in males the MUllerin duct is actively killed off by AMH = anti Mullerian hormone
        --> think males are more aggressive and want to kill things
      - *Testes Development and Descent
        
        Complications from patent process vaginalis
        
        Hydrocele
        
        can be either communicating = patent process vaginalis
        
        non-communicating (usually self-limiting?)
  - - - Case presentation:
      - Notes:
        
        the urachus / allantois during fetal development connect the urogenital system to the yolk sac
        --> through the umbilicus
        
        this is meant to obliterate, but if it doesn't then the child will have leakage of urine through the umbilicus
  - - - Notes:
        
        Rostral vs Caudal migration of embryology cells
        --> neural crest cells are caudal migration cells when they develop into enterocytes and the Glial cells of the periphery that make up the enteric plexus needed for peristalsis
        
        in the question above you need to knwo they migrate in a caudal fashion, so in H disease the colon is always affected
        
        depending on when the Neural crest cells stopped migrating the absence of myenteric plexus formation starts at the rectum and goes rostral direction, like in Ulcerative Colitis
        
        key presentation for Hirschprung disease is
        --> failure of infant to pass meconium in forst 48 hours
        --> since the end of the colon essentially won't move
        
        they also have symptoms of BO
        --> emesis (bilious), abdominal distension
      - Case presentation:
  - - - Case presentation:
      - Notes:
        
        note from the anatomy to the right, the Volmer is the middle bone in the septum and the maillary bones are the bones that join above the mouth
        --> failure of the intermaxillary segment predominances is what causes cleft palate
        
        Normal face development picture to the right
        
        during 5th 6th week of embryo developemtn
        
        the 1st pharyngeal pouch diveds into the 2 bone segments above and below that make up the mouth
        --> upper = maxillary
        --> lower = mandible
        
        first the 2 medial nasal prominances have to fuse to make the intermaxillary segment
        --> the intermaxillary segment becomes the ANCHOR of the upper lip
        --> note this is counterintuitive since the intermaxillary segment doesn't come from the maxillary, but from the nasal and forms the anchor or backbone for the lip to form in front of it
      - Unilateral vs Bilateral Cleft palate
        
        need the 2 medial nasal segements to fuse
        --> these form the anchor and backbone of the palate and upper lip
        
        the left and right maxillary segments then need to come to the middle and attach to the anchor
        
        if one of these fail to attach tot he intermax then you get unilateral cleft palate
        
        Cleft Lip vs. Cleft Palate
        
        note that you can get cleft lip +/- cleft palate and vice versa
        
        it can also be a cleft of the entire palate or just the anterior part
  - - - HPE = Holoproencephalon example
        
        Notes:
        
        note that HPE presents with classic signs of closely set eyes, cleft palate
        
        it is often caused by trisomy 21
        
        it can also be caused by fetal alcohol syndrome
        
        Case presentation:
      - HPE Presentation
        
        can present with cleft palate or porboscis
        
        proboscis = missing nose or a nose in the form of a proboscis (a tubular appendage) located above the eye
        
        note in animals the correct term for something like an elephants snout is a proboscis
        
        nose of a mammal, especially when it is long and mobile such as the trunk of an elephant or the snout of a tapir.
  - - - TGA = transposition of the Great Arteries
        
        failure of the normal spiralling of the pulmonary and aortic trunk in development of the heart vessels
        
        Notes:
        
        note that failure of spiralling in the aorta and pulmonary trunk results in TGA
        
        TGA = transposition of the great arteries
        
        aorta connects to the right V and pulmonary trunk connects to the left trunk
        
        TGA is not compatable with life
        --> needs surgery to switch them
        
        only way infants live for a few days is if they have a PDA that allow blood to go between the trunk and the aorta
        
        Case presentation:
    - - Notes:
        
        first = maximal = maxillary artery
        
        second = stapedus and hyoid
        
        third = C = common carotid and proximal internal carotid
        
        fourth = 4 limbs of systemic arteries
        --> the aortic arch between 2 left branch
        --> the bifurcation = proximal part of right subclavian artery
        
        6 = P upside down = pulmonary artery bifurcation + pulmonary to aorta shunt = ductus arteriosis
      - Aortic Arches case
        
        Clinical Case
        
        Notes:
        
        note that
  - - - Clinical Cases
        
        Clinical Case
        
        Notes:
        
        note that
        
        Clinical Case
        
        Embryonic development of the True Kidney example
        
        Case presentation:
        
        Notes:
        
        note that the true kidney comes from the metanephric part of the embryo
        
        the ureteric bud develops everything distal in the kidney to the COLLECTING DUCTS
      - Fetal Hydronephrosis and Ureter Pelvic Junction = UPJ
        
        UPJ is the last thing in the kideny ureter bladder to cannulize
        
        can obstruct the ureter and give hydronephrosis
  - - - *Embryo Blood Vessel Derivatives
        
        umbilical vein = degenerate into --> round ligment
        
        vitilline veins --> portal system
        --> recall vitilline duct with the allantois forms the umbilical cord and degenerates after
        
        cardinal veins --> system veins
- - - - *Neural Crest Cell Derivatives
        
        Neural Crest GAMES
        
        Neural Crest Cell Derivatives
        example
        
        Notes:
        
        note that cummulative incidence is over a specified time period like a year in this example
        
        it does NOT count the people in the population who already have the disease so you have to subtract them from the total population first
        
        you don't subtract anything else, even deaths since these people may have gotten the disease in the time period
        
        Example:
        
        Wear your home team CREST to the GAMES
        ... (AM go together)
        
        think neural crest cells from 2 sides of nural tube
        
        2 letters for each
        G = glial cells (peripheral) / ganglia
        A = Arachnoid and pia layers / Adrenal Medulla
        M = medulla / melanocytes
        E = enterocytes / endocardial cushions
        --> End Cushions = (bed GAMES) --> rest of Heart = (MEANS = Meso for living)
        S = Schwann Cells / Skull bones
      - *Neural Tube of the Attractoderm
        
        "NEURETINAL TUBE"
        
        "NEURETINAL" = retinas
        
        "TUBE " = brain
        --> behind the SURFACE Attractoderm (lens and cornea of eyes)
        
        the TUBE is BEHIND the surface attractoderm
        --> has the post pituitary gland also
        
        think of the brain as a TUBE behind the SURFACE Attractoderm
        
        tube = brain and spinal chord
        
        behind the SURFACE attractoderm
        = retina of the eyes and posterior pituitary gland
      - *Surface Ectoderm = Attractoderm
        
        SURFACE of the eyes = lens + cornea
        
        SURFACE of the pituitary gland = anterior pituitary gland
        
        SURFACE of attractoderm
        
        SURFACE of the eyes = lens + cornea
        
        SURFACE of the pituitary gland = anterior pituitary gland
        
        Clinical Cases
        
        Clinical Case
        
        Clinical Case
        
        Notes:
        
        note that
    - - - Heart derived from
        --> End Cushions = (bed GAMES)
        --> rest of Heart = (MEANS = Meso for living)
      - MEANS to hear
        
        tympanic membrane = ear drum
        --> comes from ALL three layers
        
        but the malleus, incus and stapes are bones
        --> thus come from the MEANSoderm
        --> Malleus = max arch = arch1
        --> stapes = secondar arch of mesoderm
- - - - Clinical Cases
        
        Clinical Case
        
        Clinical Case
        
        Notes:
        
        note that
        
        Pharyngeal and Aortic Arches
        
        Mnemonic for Embryological aortic arches:
        
        First is MAXIMAL
        
        Second is Stapedius artery
        
        Third is 3rd in the alphabet = C = common carotid arteries
  - - - Clinical Cases
        
        Clinical Case
        
        Clinical Case
        
        Notes:
        
        note that
        
        Pharyngeal Pouches
        
        Notes:
        for pharyngeal pouches
        
        Third 3 = pharyngeal pouch
        --> Thymus and P thyroid (inferior and closest)
        --> note the THYROID gland does not come from the pharyngeal pouches, it comes from the GI pouches
        
        the inferior parathyroid and thymus come from the THIRD pharyngeal pouch
        
        AP TIPS at the sPUB
        --> pharyngeal pouches give tips on ordering APPS at the PUB
        1st pouch = A
        --> auditory tube
        2nd pouch = P
        --> palantine
        Third pouch = TIP
        --> thymus / inferior parathyroid
        1st pouch = sPUB
        --> superior parathyroid / Ultimobranchial body
- - - - Day 8
        
        Blastocyst starts producing Beta hCG
        
        think of Beta = 8 hCG
        
        Week 2 Gestation
        
        blastocyst embedding into the endometrium
        --> 2 weeks = Bi = Blast
        
        Blastocyst
        
        Blastocyst made of 2 parts: TROPH EEEE blast
        --> winning a TROPH EEEE is a BLAST
        
        outer ring = trophoblast
        
        inner line = embryoblast
        
        Trophoblast
        
        outer trophy of Blastocyst
        
        Embryoblast
        
        inner line = embryoblast
        --> becomes the embryo and fetus
        
        Amnion and Yolk Sac
        
        EMBRYONIC DISK
        
        Trophoblast --> Chorion Formation
        
        Week 3 Gestation = Yolk Sac splits into Vitiline --> Gut Tube + Allantois
        
        Allantois = fake urethra
        
        gut tube = looks like shrimp with amniotic sac
        --> starting to elongate like a fetus now
        
        Weeks 4 -8 =
        1 = Chorion + Amnion --> form Amniotic Sac
        2 = Umbillicus Formation = from Vitilline duct + allantois + body stalk
        
        Amniotic Sac = main job is to insulate and protect fetus
        
        2nd Trimester
        -
        
        2 more items...
        
        1 = Amnioric Sac
        
        formed from chorion and Amnion
        
        1 more item...
        
        2 = Umbillicus Formation = from Vitilline duct + allantois + body stalk
        
        Umbullicus = AV Body
        --> allantois + Vitlline + body stalk
        
        2 more items...
        
        Gut Tube
        
        Vitelline duct
        
        Gut tube
        
        Allantois
        
        Chorion
        
        Weeks 2 - 8 Overview = 4 main membranes formed
        
        Embryo body + Gut tube
        
        Amniotic Sac
        --> Chorion makes both the placenta (fetal part) plus combines with amnion = Amniotic Sac
        
        Placenta
        --> Chorion makes both the placenta (fetal part) plus combines with amnion = Amniotic Sac
        
        Umbilical Cord
        
        hCG Production
        
        hCG Production case
        
        Clinical Case
        
        Notes:
        
        note that the egg enters the uterus by day 3-4
- - - - WEEK 7 = GONAD differentiation (M / F)
        
        SRY gene = sex determining region gene on Y chromosome
        
        if NO SRY gene --> default = female gonad production
        
        Week 7 Gonad Differentiation = Male
        
        Week 7 Gonad Differentiation = Male = testes formation
        
        Seminiferus tubules
        
        Week 8 = Sertoli and Leydig Cells
        
        Leydig make testosterone
        --> active destruction of the Mullerian Duct
        
        Sertoli cells make AMH
        --> AMH = anti-Mullerian Hormone
        
        Mesonephric Duct = Wolffian Duc
        
        also active degeneration of the paramesonephric = Mullerian Duct = female
        
        done by Sertoli cells --> AMH
        
        2 more items...
        
        Mesonephric Duct = Undifferentiated
        --> SRY ==> Wolffian Duct
        
        mesonephric
        --> meso = main = man /
        --> parameso = beside/lesser than meso = women
        --> nephric = because the gonads come from NEPHRO genic mart of meansoderm
        
        1 more item...
        
        Sertoli and Leydig Cells
        
        Leydig make testosterone
        --> testosterone makes the rest of internal reproductive tract
        = epidydimis + vas deferens
        
        think of the Leydig as LA DIGS = ALWAYS CREATING
        --> Leydig cells make testosterone
        --> in reproductive development testost MAKES Wolfian duct
        --> in adult life testost makes sperm cells
        
        Sertoli cells make AMH
        --> note that testost already negative feeds back on LH
        
        Sertoli cells in contrast to Leydigs that CREATE, Sertoli cells DESTROY
        --> in development they make AMH
        --> destroys the Mullerian duct
        --> in adult life the Sertoli cells make inhibin
        --> inhibin negative feeds back on FSH
        
        SRY gene
        
        makes testes determining factor
        
        Seminiferous tubules
        
        note the seminiferous tubules contain spermatagonia
        
        the spermatagonia though lay dormant until puberty
        
        during puberty they then make sperm
        
        Week 7 Gonad Differentiation = Female
        
        Week 7 Gonad Differentiation = Female = primordial follicles
        
        primordial follicles = means the follicle germ cells make oocytes that dont complete meiosis 1 (stay in prophaase till puberty)
        
        Paramesonephric Duct = Mullerian Duc
        
        also passive degeneration of the mesonephric = Wolffian Duct = male
        
        Paramesonephric Duct = Undifferentiated
        --> NO SRY ==> Mullerian Duct
        
        paramesonephric
        --> parameso = beside/lesser than meso = women
        --> nephric = because the gonads come from NEPHRO genic mart of meansoderm
        
        Oogenesis in Ovaries
        
        see notes above
        
        2 more items...
        
        Primary / Secondary OOcytes / Meiosis 1 and 2 Arresting stages
        
        meiosis arrest #1 - begins at puberty
        --> PUBERTY = prophase of Meiosis 1
        
        meiosis arrest #2 - begins at ovulation and fertilization
        --> ends at fertilization
        --> fertilization needs a MALE = metaphase of Meiosis 1
        
        6 more items...
        
        Mullerian and Wolfian Ducts Case examples
        
        Mullurian duct = vagina and others
        
        Wolfian duct = epidimis and vas def
        
        Mullerian Aplasia
        
        short or absent vagina
        
        no uterus
        
        all external female characteristics normal
        
        4 more items...
        
        Lateral and Vertical Fusion of the Mullerian Ducts = Paramesonephric Ducts
        
        can be seen on a HSG = hysterosalpingogram
        
        7 more items...
        
        Primordial follicles
        
        Undifferentiated Mesonephric and Paramesonephric Ducts
        
        Mesonephric Ducts
        --> matures into male Wolffian Duct
        
        Paramesonephric Ducts
        --> matures into f emale Mullerian Duct
        
        Notes:
        
        start with undifferentiated gonads
        
        note that the Wolfian duct passively dies
        --> think women are more passive and just let it die because no Testosterone
        
        in males the MUllerin duct is actively killed off by AMH = anti Mullerian hormone
        --> think males are more aggressive and want to kill things
        
        .
        
        Mesonephric Duct = Undifferentiated
        --> SRY ==> Wolffian Duct
        
        mesonephric
        --> meso = main = man /
        --> parameso = beside/lesser than meso = women
        --> nephric = because the gonads come from NEPHRO genic mart of meansoderm
        
        Paramesonephric Duct = Undifferentiated
        --> NO SRY ==> Mullerian Duct
        
        paramesonephric
        --> parameso = beside/lesser than meso = women
        --> nephric = because the gonads come from NEPHRO genic mart of meansoderm
        
        WEEK 9 = External Genitalia Differentiation
        
        External Genitalia Differentiation
        
        WEEK 9 = External Genitalia Differentiation
        
        either by testosterone or estrogen
        
        Week 7 External Genitalia Differentiation = Male
        
        Testosterone --> 5-alpha - reductase --> DHT
        
        DHT responsible for male external genitals
        
        2 more items...
        
        Week 7 External Genitalia Differentiation = Female
        
        ABSENCE of Testosterone
        
        2 more items...
        
        Undifferentiated External Genitalia
        
        .
        
        1 more item...
        
        SUMMARY = External Genitalia Differentiation
        
        1 more item...
      - Gonads
        
        come from the mesoderm
        
        meoderm = MEANS O DERM
        --> MEANS for GENES
        
        gonads come from nephrogenic cord of the mesoderm
      - GREAT Gonad MIGRATION
        
        week 5-6 of gestation
        
        germ cells actually first start in the yolk sac
        
        they migrate along the vitilline duct to the nephrogenic part of the mesoderm
        --> form the gonads from here
    - - 3 Priumary Germ Layers
        
        Ectoderm
        --> Attractoderm
        
        Mesoderm
        --> MEANS O DERM
        
        Endoderm
        --> Endernal organ