Flashcards in Repro 1.1 Deck (50)
Approximately how long are ova viable?
What does the female internal genitalia accommodate?
travel (ova and sperm)
development of the embryo
delivery of the foetus
When do secondary sexual characteristics develop?
WHat are the principle female secondary sexual characteristics?
Growth of body hair
Widening of hips
More subcutaneous fat (buttocks, hips and thighs)
What are the male secondary sexual characteristics?
Body and facial hair
Enlargement of larynx and deepening of the voice
Increased muscle mass and stature
Broadening of shoulders
What do reproductive hormones influence?
Production of gametes
Mechanism of gestation and parturition
Where are reproductive hormones produced?
Posterior pituitary (oxytocin through neural control from hypothalamus)
Anterior pituitary gland
What hormones are produced in the hypothalamus?
Peptide releasing factors:
GnRH - gonadotrophin releasing hormone
PRH - prolactin releasing hormone
PIH - prolactin inhibiting hormone
What is produced in the anterior pituitary gland?
What hormones are produced in the male gonads?
androgens eg testosterone (leydig interstitial cells)
What hormones are produced in the female gonads?
Oestrogen (mainly oestrodiol but also oestrogen and oestriol)
What is the urogenital ridge?
A region of mesoderm giving rise to both the embryonic kidney and gonad. Gonad derived from intermediate mesoderm and primordial germ cells (migrate into mesoderm)
From where do the germ cells arise?
Epithelium of the yolk sac near the base of the allantois
To where do the germ cells migrate and at what stage?
Primordial gonad, 6 weeks post conception
Where do the primordial gonads lie?
superficial and medial to the mesonephric tissue
What does the mesonephros form?
Primitive medullary cords
What does the coelomic epithelium form?
What happens to the sex cords if the germ cells are male?
Vigorous growth of the sex cords into the medullary region of the gonad to meet the mesonephric cords and form the definitive testis cords (precursors to rate testes)
How do the seminiferous tubules arise?
Germ cells enter the definitive testis cords
What type of cells do mesodermal cells give rise to in males?
What gene do sertoli cells express and what does it do?
SRY determines formation of the testes. In its absence, ovaries form
What happens to mesonephric cords in females?
Do not develop - regress
What happens to female germ cells?
They become surrounded by mesenchymal cells to form primordial follicles (oogonia). Germ cells are now surrounded by a single layer of granulosa cells.
What happens if there is no germ cell?
Development of primitive cords is not initiated therefore no gonadal ridges form and consequently mature gonads do not develop.
From where and how does the male internal genitalia evolve?
Wolffian or mesonephric ducts.
Interstitial cells secrete testosterone causing the Wolffian ducts to develop. The seminiferous cords join the ducts at the rete testis and the remainder forms the epidydimus, vas deferens and seminal vesicles.
What happens to the Mullerian ducts in males?
Regress due to the influence of Mullerian inhibiting hormone (MIH) secreted by the sertoli cells
From where and how does the female genitalia evolve?
Mullerian or paramesonephric ducts. These develop into oviducts, uterus, cervix and upper vagina in the absence of MIH
What happens to the Wolffian ducts in the female?
Regress due to insufficient testosterone
If there are no gonads, what develops?