Reproductive system Flashcards
Where are the male and female gonads derived from embryologically?
Urogenital/gonadal ridge
What is present in the undifferentiated reproductive tract? (3)
Wolffian ducts
Mullerian ducts
Cloaca
What causes male reproductive organs to form?
Presence of the Y chromosome and thus the absence of SRY gene
What does the Y chromosome do?
SRY gene causes primordial gonads to differentiate into testes.
Sertoli cells –> produce MIF –> Mullerian ducts regress
Leydig cells –> produce testosterone –> Wolffian ducts develop
How does male external genitalia develop?
Testosterone in target tissue –> converted into DIH.
DIH stimulates development of scrotum, penis and prostate
What causes testes to descend into the scrotum?
Testosterone
What forms the glans penis?
Genital tubercle
What forms the corpus spongiosum?
Urethral folds (fuse)
What forms the scrotum, penis and prostate?
Labioscrotal folds
What does the X chromosome do?
Absence of SRY gene causes primordial cells to differentiate into ovaries
No MIF –> Mullerian ducts persist
No testosterone –> Wolffian ducts regress
What forms the clitoris?
Glands tubercle
What forms the labia minora?
Urethral folds (fuse)
What forms the labia majora?
Labioscrotal folds
What are germ cells?
Specialised cells that develop into gametes (sperm & ova)
What are the two stages of gametogenesis?
- Mitosis of primordial germ cells
1 Meiosis
When does mitosis happen in the germ cells?
Males: some during fetal development, but mainly after puberty and throughout life
Females: during fetal development
What does mitosis of the primordial germ cells produce?
Males: primary spermatocytes
Females: perimary oocytes
When does meiosis 1 compete in the germ cells?
Males: During puberty
Females: After puberty
When does meiosis 2 complete in the germ cells?
Males: During puberty
Females: After fertilisation
What does meiosis 1 of the germ cells produce?
Males: Secondary spermatocyte (2)
Females: Secondary oocyte (1) + primary polar body
What does meiosis 2 of the germ cells produce?
Males: Spermatids
Females: Ovum + secondary polar body
Where does meiosis occur in the male?
Seminiferous tubules
Where does meiosis occur in the female?
Meiosis 1 = ovaries
Meiosis 2 = fallopian tube
What is the path of sperm from inside to outside? (8)
[SREEVEN UP] Seminiferous tubules Rete testes Efferent ductules Epididymis Vas deferens Ejaculatory duct Nothing
Urethra
Penile urethra
What is the unfertilised egg that’s lost during menarche?
Secondary oocyte (arrested @ metaphase 2)
What is needed for normal sperm production and how is this achieved?
Temp. of 35 degrees
- air circulating around scrotum
- heat exchange mechanism via pampiniform plexus
What forms the blood-testes barrier?
Sertoli cells (around circumference of seminiferous tubules) connected by tight junctions
What are type A spermatogonia?
Remain outside the BTB, and produce more spermatogonia until death
What does the epididymis do?
Site for sperm maturation and storage
What forms the ejaculatory duct?
Seminal vesicles
Vad deferens
Where does the ejaculatory duct join the urethra?
In the prostate gland
What does ejaculate consist of?
Fluid from prostate gland and seminal vesicle (90%)
Sperm (10%)
What do fluid from prostate and seminal vesicles contain?
- Buffers (acidic vaginal secretions & residual urine in M urethra)
- Fructose (provide energy for motility)
- Prostaglandins (stimulate female peristaltic contractions)
What is the need for a blood-testes barrier?
To separate sperm from the immune system
What are type B spermatogonia?
Enter BTB and differentiate into primary spermatocytes
What is spermiogenesis?
Spermatids –> spermatozoa (by discarding cytoplasm and growing a tail)
Describe the HPG axis of male reproductive function (6)
HT: secretes GnRH
AP: secretes LH and FSH
LH: Leydig cells –> testosterone
FSH: Sertoli cells –> spermatogenesis + inhibin
Testosterone inhibits HP and LH release at AP
Inhibin inhibits FSH release at AP
Name the parts of the fallopian tube in the direction of travel of the egg
Fimbriae
Infundibulum
Ampulla (fertilisation)
Isthmus (narrow)
Define primary amenorrhoea
Haven’t stated menarche
Define secondary amenorrhoea
Started period, but it has since stopped for > 3 months
Define oligomenorrhoea
Infrequent periods
Define menorrhagia
Painful/ heavy periods
