Reproductive System Flashcards
Where do germ cells arise? How do they get to the gonads?
- Epithelium of yolk sac near base of allantois
- They travel along dorsal mesentary to primordial gonads
What drives the development of male gonads?
SRY gene found on Y chromosome
How do the gonads influence the formation of male and female reproductive tracts?
- Testis secrete androgens which:
- Supports mesonephric duct which forms internal duct system (epididymis, vas deferens, urethra)
- Supports male external genitalia
- Testis also secrete Mullerian Inhibiting Substance causing degeneration of paramesonephric duct
- Ovaries don’t secrete androgens so:
- Mesonephric ducts regress
- Female external genitalia occur
- There no Mullerian Inhibiting Substance so paramesonephric ducts persist
Describe the descent of the testes
- Start in upper lumbar regions
- They are tethered to labioscrotal folds by gubernaculum
- As the body the relative position becomes more caudal
- Musculo-fascial layer envaginates into scrotum to form processus vaginalis
What is the remanant of the gubernaculum in males and females?
Males - scrotal ligament
Females - ovarian ligament and round ligament
Describe the descent of the ovaries
- Develop high on posterior abdominal wall - mesonephric ridge
- Tethered to labioscrotal folds by gubernaculum
- Descend through the abdomen and stop at pelvis due to presence of uterus
Describe development of uterus
- Paramesonephric ducts fuse together in the midline
What is the arterial supply, venous drainage and lymphatic drainage of the ovaries?
- Ovarian artery
- Ovarian vein
- Para-aortic nodes
What is the difference in the route of the right and left ovarian venous drainage?
Right - straight into IVC
Left - left renal vein
What are the segments of the fallopian tubes?
- Fimbriae
- Infundibulum
- Ampulla
- Isthmus
What is the arterial supply, venous drainage and lymphatic drainage of the fallopian tubes?
Same as ovary except lymphatics
- Ovarian artery
- Ovarian vein
- Iliac, sacral and aortic lymph nodes
What is the arterial supply, venous drainage and lymphatic drainage of the uterus?
- Uterine arteries
- Uterine veins
- Iliac, sacral, aortic, inguinal lymph nodes
What is the position of the uterus?
- Anteverted with respect to vagina
- Anteflexed with respect to the cervix
What are the two regions of the cervix? What type of epithelium covers them?
- Ectocervix - portion that projects into vagina, opening is external os
- Stratified squamous non-keratinised epithelium
- Endocervix - Between vagina and uterus, boundaries are external and internal os
- Mucus-secreting simple columnar epithelium
What is the arterial supply, venous drainage and lymphatic drainage of the cervix?
Same as uterus
- Uterine artery
- Uterine vein
- Iliac, sacral, aortic and inguinal lymph nodes
What is the innervation of the vagina?
- Inferior 1/5th recieves somatic innervation from pudendal nerve
- Superior 4/5th recieves innervation from uterovaginal plexus (parasympathetic, sympathetic and visceral afferents)
Which ligments support the pelvic viscera?
- Transverse cervical ligament
- Uterosacral ligament
Describe the route from the testis to urethra
Seminferous tubules > rete testis > efferent ductules > epididymis > vas deferens (ductus deferents)
What surrounds the testes?
Tunica vaginalis then tunica albuginea (capsule) - Superficial to deep
What is the function of Serolti cells and Leydig cells?
- Sertoli cells are nurse cells, they help in the process of spermatogenesis - stimulated by FSH
- Leydig cells secrete testosterone
What are the contents of the spermatic cord?
- Testicular artery, cremasteric artery, artery to vas deferens
- Pampiniform plexus
- Genital branch of genitofemoral nerve
- Lymphatics
- Vas deferens
- Processus vaginalis
What are the coverings of the spermatic cord?
- Internal spermatic fascia
- Cremasteric fascia
- External spermatic fascia
Deep to superficial
Which part of the prostate does benign prostatic hyperplasia affect?
Central zone
What is different about the gynaecoid pelvis?
- Round inlet
- Sub-pubic arch >90o
- Ischial spinces not too prominent
- Well curved sacrum
- Well-rounded greater sciatic notch
- Straight side walls
What are the muscles of the pelvic floor?
- Pubococcygeus
- Puborectalis
- Iliococcygeus
- Coccygeus
What is the purpose of the perineal body?
- Fibromuscular node at junction between anterior and posterior perineum
- Point of attachment for anal sphincter, bulbospongiosus, superficial transverse perineal muscles and fibres of levator ani
- Joints pelvic floor to perineum
What is the difference between spermatogenic wave and spermatogenic cycle?
- Cycle = describes the days it takes for consecutive cell divisions of spermatogonia to produce spermatocytes
- Wave = describes how the production sweeps along the length of the seminferous tubule
What is the role of testosterone in adults?
- Causes spermatogenesis
- Maintains internal genitalia
- Metabolic effects
- Behavioural effects
What do Sertoli cells cause/release?
- Spermatogenesis
- Inhibin
What is the difference between determinative effects and regulatory effects of sex hormones?
Determinative effects - qualitative and only partly reversible, mostly to do with sexondary sexual characteristics
Regulatory effects - highly reversible and rely on continous hormonal stimulation
What are the determinative effects and regulatory effects of testosterone in males?
Determinative effects:
- Increase size and mass of muscles, vocal cords, bones
- Deepening of voice
- Facial and body hair
- Growth of penis
Regulatory effects:
- Maintainence of male internal genitalia
- Metabolic action
- Behavioural effects - aggression, sexual activity
At what stage is an ovum arrested at birth?
Prophase I
