The master switch gene
SRY region on the Y chromosome.
Role of SRY
Allows testes to develop.
Mullerian ducts are found in
Wolffian ducts are found in
Before sex differentiation we all have
Urethral folds, urethral groove, genital tubercle, and labioscrotal swelling.
development of urethra, prostate, and external genitals.
Sertoli cells secrete an
Anti-mullerian hormone, regression of mullerian ducts.
Leydig cells secrete
Testosterone, supports development of wolffian ducts.
Glans area in males form into
Labioscrotal swelling in males form into
Urethral folds in males form into
The shalt of the penis.
What is the first sign of puberty?
Increased LH levels at night.
First characteristic of the male to develop in puberty
Second characteristic of the male to develop in puberty
Pubic hair development.
Third characteristic of the male to develop in puberty
Fourth characteristic of the male to develop in puberty
Sperm production occurs in
The seminiferous tubules within the testes.
Sertoli cell role in spermatogenesis
Support and provide nutrients to dividing cells.
Sperm stem cells that are 2(n).
Spermatogonia cells divide by mitosis to give
Two daughter cells, one will remain in the basement membrane as a spermatogonium and the other will become a primary spermatocyte.
The primary spermatocyte divides by
Meiosis I into a secondary spermatocyte with (n).
The secondary spermatocyte divides by
Meiosis II into an early spermatid.
Role of duct system in males
Transports and stores sperm, assists in maturation and coveys them into the exterior.
Parts of the scrotum
Scrotal septem, dartos muscle, and cremaster muscle.
Divides the two sacs.
Bundles of smooth muscle in subcutaneous layer of scrotum.
skeletal muscle, surrounds the testes and is extension of internal oblique muscle.
Parts of the testes
Tunica vaginalis, lobules, seminiferous tublues, and sertolicells.
A serous membrane that partially covers the testes.
Contain seminiferous tubles.
A cap like resicle filled with enzymes to penetrate the oocyte to bring about fertilization.
The tail consists of
The neck, middle piece (contains mitochondria), principle piece (longest part of the tail) and the end piece.
What is the basis of how males get secondary sexual characteristics?
HPG axis - hypothalamus, (anterior) pituitary and gonads.
What is the role of the hypothalamus in the development of secondary sexual characteristics?
Releases GnRH onto the anterior pituitary gland.
What is the role of the anterior pituitary gland in the development of secondary sexual characteristics?
Releases FSH and LH once stimulated by the hypothalamus.
What is the role of LH in the development of secondary sexual characteristics?
Acts on the leydig cells which produce and release testosterone.
enzyme 5 alpha reductase converts..
Testosterone into DHT.
Role of inhibin?
Inhibits FSH when FSH levels reach too high.
Role of FSH in a male
Acts as an androgen binding protein. This protein carries lipid-soluble hormones around the blood.
What is in place to stop testosterone levels reaching too high?
A negative feed back system, when the level reaches too high it inhibits the amount of GnRH released in the hypothalamus acting on the anterior pituitary. This in turn reduces the amount of LH and FSH produced.