Spermatogenesis and Testes Endocrine Function Flashcards
What is the counter current exchange in the testes?
Heat transfer in the counter current flow causes hot blood to be shunted away from the testes keeping them cool for sperm production
How does testosterone work in the counter current exchange?
Testosterone is shunted in a manner that keeps it within the testes to keep T levels high
What is spermatogenesis?
Proces of sperm production and includes spermiogenesis and spermeation.
What is spermiogenesis?
Cellular remodeling of spermatids into spermatozoa
What is spermeation?
Extrusion of flagellated spermatozoa into the lumen of the tubule
Where are the most mature sperm found in the semniferous tubule?
Towards the center
What happens to the majority of cells undergoing spermatogenesis?
Undergo continuous mitotic division with the minority undergoing meiosis
What is the acrosome?
A cap of membranes containing digestive enzymes
What are the functions of the epididymus?
- Sperm maturation: gain motility, lose cytoplasm
- Reservoir for sperm
- Stabilize acrosome
What is the function of the prostate?
- Secretions are alkaline – neutralize vaginal secretions
* Prostatic specific antigen (diagnostic value)
What is the function of the seminal vesicle?
•Secretions of prostaglandins – contractions of uterus and fallopian tubes considered important in sperm movement
What is the function of inhibin?
It will inhibit pituitary release of FSH/LH
What is the function of activin?
It will activate pituitary release of FSH.LH
What are Leydig cells activated by?
They are stimulated by LH
What is the function of the Leydig cells?
They secrete T via a GPCR -> PKA pathway that will increase T synthesis and increase sterol carrier protein
What are Sertoli cells activated by?
FSH
What is the function of Sertoli cells?
Facilitate sperm development via a GPCR path to increase androgen binding protein and increase aromatase synthesis as well as androgen receptor and inhibit synthesis
What is the function of androgen binding protein (ABP)?
It will keep T levels high as it absorbs T and it will release it as T levels drop and keep the levels consistently high
What are the paracrine functions of inhibin?
Stimulates T secretion
What are the paracrine functions of activin?
Inhibits T secretion
What NS control is erection under?
Parasympathetic via ACh and NO activation of guanylyl cyclase which makes cGMP and leads to vasodilation
What NS control is ejaculation under?
Sympathetic control via a spinal reflex
What is emission?
It is the movement of ejaculate into the prostatic/proximal part of urethra
What endocrine disorder type is hypergonadotropic hypogonadism?
Primary
What endocrine disorder type is hypogonadotropic hypogonadism?
Secondary/Tertiary
What are the effects of hypergonadotropic hypogonadism?
Increased LH, FSH with decreased testosterone, DHT
What are the effects of hypogonadotropic hypogonadism?
Decreased LH, FSH and decreased testosterone, DHT
What are the examples of diseases that cause hypergonadotropic hypogonadism?
Klinfelter’s
17alpha-hydroxylase deficiency
5alpha-reductase deficiency
What are the examples of diseases that cause hypogonadotropic hypogonadism?
Kallman’s
Hyperprolactinemia
Hypothalamic Syndromes
What phase are the oocytes arrested in until ovulation?
Prophase of meiosis
What are the primordial follicles?
Inactive with 90-95% found in this state
What are the primary follicles?
Follicular cells differentiate into granulosa cells and the oocyte enlarges
What are the secondary follicles?
Under FSH influence a group of primary follicle will become secondary with one of the follicles eventually becoming dominant
What is the Graafian follicle?
It is the secondary follicle that is dominant.
It will have the cumulus oophorus appear and the antrum will enlarge with the granulosa cells beginning to loosen
What is ovulation?
Rupture of the follicle - release of oocyte to peritoneal cavity
What is the function of the corpus luteum?
Corpus luteum provides progesterone and gonadal steroids that optimize implantation and maintain zygote until placenta is formed
What is the dominant estrogen?
Estradiol (E2)
What is most estradiol transported by?
Albumin most and the SHBG next
What are the major progestin hormones?
Progesterone and 17alpha-hydroxyprogesterone
What is the function of follistatin?
Inhibits the release of FSH by pituitary gonadotrophs
