Carlos Shared "21 Reproductive" - 161 Picmonics
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21 Reproductive
Early embryonic development (Day 0 - 10)
Early fetal development (Weeks 1 - 10)
- Within week 1
- hCG secretion begins around the time of implantation of blastocyst
- Within week 2
- Inner cell mass divides into bilaminar disc that is composed by 2 layers (Epiblast and Hypoblast). Two cavities form: the amniotic cavity and yolk sac form
- Within week 3
- Gastrulation forms trilaminar embryonic disc.
- Cells from epiblast invaginate causing primitive streak, forming the endoderm, mesoderm, ectoderm.
- Notochord arises from midline mesoderm; overlying ectoderm becomes neural plate.
- Weeks 3–8 (embryonic period)
- Neural tube formed by neuroectoderm and closes by week 4.
- Organogenesis.
- Extremely susceptible to teratogens.
- Week 4
- Heart begins to beat.
- Upper and lower limb buds begin to form.
- Week 6
- Fetal cardiac activity visible by transvaginal ultrasound.
- Week 8
- Fetal movements start.
- Week 10
- Genitalia have male/female characteristics. Baby's sex is able to be determined.
Ectoderm derivatives
- ECTODERM
- Surface ectoderm
- Epidermis
- Anterior Pituitary (Adenohypophysis) from Rathke pouch
- Lens of eye and Cornea
- Epithelial linings of nasal and oral cavity
- Sensory organs of ear
- Olfactory epithelium
- Anal canal below the pectinate line
- Parotid (salivary), sweat and mammary glands
- Neural tube (neuroectoderm)
- Brain (CNS neurons, oligodendrocytes, astrocytes, ependymal cells) and spinal cord
- Posterior Pituitary (neurohypophysis)
- Pineal gland
- Retina
- Neural Crest
- Neural Crest (see Picmonic-made Picmonic for derivatives)
Neural Crest Derivatives
- CA MOTEL ASS
- Craniofacial Structures (skull)
- Arachnoid and Pia Mater
- Melanocytes
- Odontoblasts
- Tracheal Cartilage
- Enterochromaffin (Adrenal Medulla)
- Laryngeal Cartilage
- All Ganglia
- Schwann Cells
- Spiral Septum (Aorticopulmonary Septum)
2 mins
Mesoderm derivatives
- Muscle
- Bone
- Connective tissue
- Serous linings of body cavities (eg, peritoneum)
- Spleen (derived from foregut mesentery)
- Cardiovascular structures
- Lymphatics
- Blood
- Wall of gut tube
- Upper vagina
- Kidneys
- Adrenal cortex
- Dermis
- Testes
- Ovaries
- Notochord arises from midline mesoderm. Notochord induces ectoderm to form neuroectoderm (neural plate). Its only postnatal derivative is the nucleus pulposus of the intervertebral disc.
Endoderm 563
- Gut tube epithelium (including anal canal above the pectinate line)
- Most of urethra and lower vagina (derived from urogenital sinus, the lower 2/3rds)
- Luminal epithelial derivatives (eg, lungs, liver, gallbladder, pancreas, eustachian tube, thymus, parathyroid, thyroid follicular cells)
- Parafollicular (C) Cells of Thyroid Gland which produce calcitonin
Types of errors in morphogenesis
Maternal diabetes
- TERATOGENIC
- Caudal regression syndrome (anal atresia to sirenomelia)
- Congenital Heart Defects
- Neural tube defects
- Macrosomia
- Hypoglycemia
- Insulin decreases surfactant production, leading to Neonatal Respiratory Distress Syndrome
- Also associated with polyhydramnios
Teratogens (not in other Pimonics)
- Alkylating agents
- Absence of digits, multiple anomalies
- Diethylstilbestrol (DES)
- Vaginal clear cell adenocarcinoma, congenital MĂĽllerian anomalies
- Thalidomide
- Limb defects (phocomelia, micromelia— “flipper” limbs, seal limbs)
- Methylmercury
- Neurotoxicity
- Highest in swordfish, shark, tilefish, king mackerel.
- X-rays
- Microcephaly, intellectual disability
- Minimized by lead shielding.
Fetal alcohol syndrome
- Leading cause of intellectual disability in the US.
- Newborns of alcohol-consuming mothers have increased incidence of congenital abnormalities
- Including pre- and postnatal developmental retardation, microcephaly, facial abnormalities (Pictured)
- Smooth philtrum, thin vermillion border [upper lip], small palpebral fissures, limb dislocation, heart defects
- Heart-lung fistulas and holoprosencephaly in most severe form
- Mechanism is failure of cell migration
- VSD, PDA, ASD, tetralogy of Fallot
Twinning
- Dizygotic (“fraternal”) twins arise from 2 eggs that are separately fertilized by 2 different sperm (always 2 zygotes) and will have 2 separate amniotic sacs and 2 separate placentas (chorions).
- Monozygotic (“identical”) twins arise from 1 fertilized egg (1 egg + 1 sperm) that splits in early pregnancy.
- The timing of cleavage determines chorionicity (number of chorions) and amnionicity (number of amnions).
Placenta
- 1Âş site of nutrient and gas exchange between mother and fetus.
- Fetal component
- Cytotrophoblast
- Inner layer of chorionic villi.
- Syncytiotrophoblast
- Outer layer of chorionic villi
- Synthesizes and secretes hormones, eg, hCG (structurally similar to LH; stimulates corpus luteum to secrete progesterone during first trimester).
- Lacks MHC-I expression causing a decreased chance of attack by maternal immune system.
- Maternal component
- Decidua basalis
- Derived from endometrium.
- Maternal blood in lacunae.
Umbilical cord
- Umbilical arteries (2)—return deoxygenated blood from fetal internal iliac arteries to placenta
- Umbilical vein (1)—supplies oxygenated blood from placenta to fetus; drains into IVC via liver or via ductus venosus.
- Single umbilical artery (2-vessel cord) is associated with congenital and chromosomal anomalies.
- Umbilical arteries and vein are derived from allantois.
Urachus
- In the 3rd week the yolk sac forms the allantois, which extends into urogenital sinus.
- Allantois becomes the urachus, a duct between fetal bladder and umbilicus.
- Patent urachus
- Total failure of urachus to obliterate leads to urine discharge from umbilicus.
- Urachal cyst
- Partial failure of urachus to obliterate; fluid-filled cavity lined with uroepithelium, between umbilicus and bladder.
- Can lead to infection, adenocarcinoma.
- Vesicourachal diverticulum
- Slight failure of urachus to obliterate leads to outpouching of bladder.
Vitelline duct
- 7th week—obliteration of vitelline duct (omphalomesenteric duct), which connects yolk sac to midgut lumen.
- Vitelline fistula
- Vitelline duct fails to close causing meconium discharge from umbilicus.
- Meckel diverticulum
- Details in other Picmonic
- VItelline Sinus
- Results from a partial closure of the vitelline duct, with the patent portion open at the umbilicus
- vitelline duct cyst
- Forms if peripheral portions of the vitelline duct (connected to the ileum and umbilicus) obliterate, but the central part remains
- This cyst is connected with the ileum and abdominal wall by fibrous bands
Aortic arch derivatives
- Develop into arterial system
- 1st
- Part of maxillary artery (branch of external carotid).
- 2nd
- Stapedial artery and hyoid artery
- 3rd
- Common Carotid artery and proximal part of internal Carotid artery.
- 4th
- On left, aortic arch; on right, proximal part of right subclavian artery.
- 6th
- Proximal part of pulmonary arteries and (on left only) ductus arteriosus.
- recurrent laryngeal nerve
- Right recurrent laryngeal nerve loops around right subclavian artery
- Left recurrent laryngeal nerve loops around aortic arch distal to ductus arteriosus
568 Branchial (Pharyngeal) Apparatus and Branchial Cleft Derivatives
- Branchial (pharyngeal) apparatus
- Composed of branchial clefts, arches, pouches
- Branchial clefts—derived from ectoderm. Also called branchial grooves
- Branchial arches—derived from mesoderm (muscles, arteries) and neural crest (bones, cartilage)
- Branchial pouches—derived from endoderm
- Clefts = ectoderm
- Arches = mesoderm + neural crest
- Pouches = endoderm
- Branchial cleft derivatives
- 1st cleft develops into external auditory meatus
- 2nd through 4th clefts form temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme
- Persistent cervical sinus leading to branchial cleft cyst within lateral neck, anterior to sternocleidomastoid muscle. Immobile during swallowing
Pharyngeal Arch Derivatives: 1st Arch
- Cartilage
- Meckel's Cartilage
- Mandible
- Malleus
- Incus
- Sphenomandibular Ligament
- Muscles
- Muscles of Mastication
- Tensor Tympani
- Tensor Veli Palatini
- Anterior Belly of the Digastric
- Mylohyoid
- Nerves
- CN V2
- CN V3
- Conditions
- Treacher Collins Syndrome
3 mins
Pharyngeal Arch Derivatives: 2nd Arch
- Cartilage
- Reichert's Cartilage
- Stapes
- Styloid Process
- Lesser Horn of Hyoid
- Stylohyoid Ligament
- Muscles
- Muscles of Facial Expression
- Stapedius
- Stylohyoid
- Platysma
- Posterior Belly of Digastric
- Nerves
- CN VII
- Conditions
- Congenital Pharyngocutaneous Fistula
2 mins
Pharyngeal Arch Derivatives: 3rd Arch
- Cartilage
- Greater Horn of Hyoid
- Muscles
- Stylopharyngeus
- Nerves
- CN IX (Glossopharyngeal)
- Arteries
- Common Carotid
- Internal Carotid
1 min
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