Male reproductive physiology Flashcards
what are the testes?
male reproductive gland- functions to produce sperm
what is the epididymis?
- a structure attached to the back of the testes
- contains ducts that allow storage of spermatozoa while they mature and then transports the spermatozoa to the vas deferans
what is the vas deferans?
- important part of the male reproductive system
- a thick walled tube that transports sperm from the epididymis to the ejaculatory ducts in preparation for ejaculation
what is the seminal vesicle?
- 2 tubular glands that lie behind the bladder of males
- they secrete fluid that contributes to semen
what is the prostate gland?
- an accessory male reproductive gland
- secretes fluid that is a component of semen- adds sugars eg glucose and ATP to the sperm to make more mobile
what are the bulbourethral glands?
- glands of the male reproductive system
- secrete alkaline fluid because the vagina is acidic
what is spermatogenesis?
the formation of sperm
where does spermatogenesis occur?
in the seminiferous tubules of the testes
what are the functions of testosterone?
- spermatogenesis
- sexual maturation - puberty
- sexual differentiation
what is the function of inhibin?
- negative feedback of FSH
what is the function of anti-mullerian hormone?
- sexual differentiation
what are the 2 main types of cells in the testis & what is their function?
- leydig cells - testosterone
- sertoli cells - AMH, inhibin and estrogen
what are the effects of testosterone before birth?
- masculinizes the reproductive tract and external genitalia
what are the effects of testerone on secondary sexual characteristics?
- induces the male pattern of hair growth - eg beard
- causes the voice to deepen - thickening of vocal cords
- promotes muscle growth
what are the effects of testosterone on the male sex organs after birth?
- promotes growth and maturation of the reproductive system at puberty
- its essential for spermatogenesis
- maintains the preproductive tract throughout childhood
what are the non reproductive actions of testosterone?
- exerts a protein anabolic effect
- promotes bone growth at puberty
- closes the epiphyseal plate after being
what are the effects of testosterone administration?
- descrease on testicular size
- impairs fertility
- increased aggresive behaviour
- used in theraby of lacking libido
what hormone is testosterone synthesis regulated by?
LH acts on the leydig cells
what hormone acts on the sertoli cells?
FSH
Describe the male hypothalamic - pituitary - gonadal axis
- hypothalamus produces GnRH
- GnRh stimulates FSH and LH release from pituitary gland
- FSH acts on sertoli cells
- LH acts on the leydig cells to produce testosterone
- testosterone has a negative feedback effect on LH and inhibin produced by the sertoli cells has a negative feedback effect on FSH
what are myoid cells?
smooth muscle cells that surrond the seminiforous tubules
what enzyme produces testosterone?
alpha reductase
Describe the steps of spermatogenesis
- undifferentiated germ cells - **spermatogonia **
- through mitosis differentitaion - they become **primary spermatocytes **
- 1st meiotic division - they become** secondary spermatocytes**
- 2nd meotic division they become** spermatids**
- spermatids differentiate into spermatozoa
what is the andropause?
- the male menopause
- the decline of testosterone with age due to decline in leydig and sertoli cells
what is an alpha 5a reductase deficiency?
- autosommal recessive disorder - only effects males
- characteristics include - cyptorchidism - when one testes hasnt moved to its proper position after birth
- can be born with external female genitalia
- their bodies do not produce enough DHT - dihydrotestosterone
what is secondary hypogonadism?
- ie hypogonadotrophic hypogonadism
- GnRH insufficiency
- hypopituitarism - may be caused by tumours , surgical trauma, kallman syndrome etc
- there is a reduction in testosterone and GnRH levels
what is Kallmans syndrome?
and what is an essential distinguishing feature?
* inherited disorder of deficient GnRH production
* mutations in KAL1 gene inteferes with GnRH secreting neurons to hypothalamus during development
* characterised by infertility, absent/incomplete or partial puberty maturation, also hypogonadotrophic hypogonadism
* 50% of cases have anosmia (loss of smell) - distinguishes KALLMANS SYNDROME from other HH syndromes
what is hyperprolactinemia?
what is it? what are potential causes? what does it cause in males vs females?
- presence of abnormally high levels of prolactin in the blood
- causes include benign functioning pituitary adenomas (that are secreting prolactin)
- other tumours that lower dopamine levels can also cause hyperprolactinemia
- in males it causes infertility and loss of libido
- in females it causes galactorrhea (secretion of milk from breast that is not associated with child birth) and amenorrhea
what is androgen insensitivity syndrome?
- x linked recessive
- 3 types - complete, mild or partial
- characteristics include failure of male genital development and impaired secondary sexual development, female internal organs never present
- gender assignment is very challenging
