Repro Embryogenisis Of Pituitary Gland Flashcards
Importance of reproductive system embryogenesis
Limitation of reproductive performance - sterility
Process whereby a primitive group of un specialized cells develop into a functional, recognizable group of cells that have a common function
Differentiation
Cells form
Organs
3 types of embryonic germ layers
Endoderm, mesoderm, ectoderm
Digestive system, respiratory system, most glands
Endoderm
Muscle, blood vessels, urinary system, skeletal system, reproductive system
Mesoderm
Skin, hair, nails, sweat glands, oral cavity, nasal cavity
ectoderm
Ectoderm nervous system
Hypothalamus, anterior and posterior pituitary
Ectoderm reproductive tract
Portions of vagina and vestibule, penis, clitoris
Neurohypophysis - neural tissue
Neural tissue of brain
Posterior lobe of pituitary gland
Adenohypophysis - glandular tissue - hormone secreting
Tissue in roof of embryonic mouth
Anterior love is pituitary gland
A sad or pouch diverting from a main tube, channel or cavity
Diverticulum
Posterior diverticulum
Infundibulum
Anterior diverticulum
Rathke’s pouch
Protective cavity around pituitary
Sella turcica
Develop in yolk sac inner lining
Ameboid movement
Still can’t determine sex
Primordial germ cells
Primordial germ cells functions
Colonize genital ridge
Stimulate connective tissue proliferation
Form compact strands of tissue
Cause femoral ridges to enlarge
Develop at same time and in close proximity to urogenital system
Reproductive and renal systems
3 types of renal system in embryo
Pronephros, mesonephros, metanephros
Non- function, remnant of lower animals
Pronephros
Functional, bilateral, produces urine, drain into ducts or urogenital sinus
Mesonephros
Final renal form - adult
Both male and female ducts present - still can’t determine sex
Metanephros
Pair of ducts beside mesonephric ducts
Paramesonephric ducts
Sex determining region
Y (SRY) gene
Acts on sex cords of primitive gonad
Simulate male reproductive system
Testis development
TDF
Secret anti-mullerian hormone (AMH) and dihydrotestosterone
Sertoli cells
Causes fetal leydig cells to differentiate and produce
Desert hedgehog gene (DHH)
Secondary sex characteristics, penis, scrotum
Dihydrotestosterone
Causes paramesonephric ducts to degenerate
Anti-mullerian hormone (AMH) and testosterone
Rete tubules —>
Rete testis
Mesonephric tubules —>
Efferent ducts
Mesonephric duct —>
Epididymis and ductus deferens
Sex cords —>
Seminiferous tubules
Testis descent — must get from level of ____ to _______
Ribs to scrotum
Testis descent — must travel from _______ position in _____ _______ to _________
Retroperitoneal, body cavity, scrotum
3 phases of testis descent
Growth and elongation of fetal body away from testis
Rapid growth of extra abdominal gubernaculum
Shrinkage of gubernaculum within scrotum
Factor produced by testis that promotes growth of gubernaculum
Descendin
2 layers of peritoneum cover testis and descend with it
Visceral vaginal tunic
Parietal vaginal tunic
Layers of peritoneum are separated by
Vaginal cavity
Incomplete closure of inguinal canal
Inguinal hernia
Hidden testis - testis don’t descend
Cryptorchidism
Results in sterility but still produce testosterone
Bilateral cryptorchidism
Female differentiation
No TDF
No AMH
Sex cords
No tubular outlet for gametes
Female differentiation: no TDF
Cells form primitive follicle cells (not Sertoli cells)
Female differentiation: No AMH
Leydig cells can’t produce testosterone
No male development
Mesonephric duct and tubules regress
Paramesonephric ducts develop
Fragment into cellular clusters
Each enclose primitive germ cell
Close to surface of ovary
Form primordial follicles and correct of ovary
Sex cords
female differentiation: follicles
Follicle number reaches maximum before birth
Paramesonephric duct —>
Oviduct and uterus
Regression of sex cords —>
Primordial follicles of ovary
Coelomic epithelium —>
Cortex of ovary
Fused Paramesonephric ducts —>
Cervix, uterine body and anterior vagina
Urogenital sinus —>
Posterior vagina and vestibule
Genital fold —>
Broad ligament
Chromosomal sex : XXY
Klinefelter’s syndrome
Chromosomal sex : XO
Turner’s syndrome
Congenital adrenal hyperplasia
Hermaphrodite
Testicular descent in horses can take up to ___ years after birth
Two