Spermatogenesis Flashcards
Male reproductive anatomy
Testes outlined
what they do?
Produce sperm and store it
Produce hormones which regulate spermatogenesis.
Well-vascularised, well-innervated.
Normal volume of testes approximately 15-25ml.
measured by orchidometer…
Testicular stucture
Seminiferous epithelium
what are Tight Junctions?
Exist between Sertoli cells forming blood-testis barrier.
Open to allow passage of spermatogonia prior to completion of meiosis.
Divides into basal and adluminal compartments.
Protects the spermatogonia from immune attack.
Allows specific enclosed environment for spermatogenesis which is filled with secretions from Sertoli cells.
Stages of spermatogenesis
Spermatogonia
-
Primary spermatocyte
Secondary spermatocytes
-
Spermatids
->
Spermatozoa (spermiogenesis)
Spermatogonia
Germ cell on basement membrane, capable of mitotic or meiotic division to produce primary spermatocytes or more spermatogonia by mitosis. They are diploid.
Primary Spermatocyte
Cell committed to differentiative pathway, primary spematocyctes are 46XY diploid.
They move into the adluminal compartment and duplicate their DNA to produce sister chromatids which exchange genetic material and enter meiosis I.
Secondary Spermatocytes
What have they undergone?
Secondary spermatocyctes have undergone meiosis I to give 23X + 23Y haploid number of chromosomes arranged as sister chromatids.
Spermatids
What occurs to give our spermatids?
Meiosis II occurs to give 4 haploid spermatids. Round spermatid to elongated spermatid differentiation.
Spermiogenesis
maturation of spermatids into spermatozoa
What happens at Spermatozoa?
Mature sperm extruded into the lumen.
The movement into the lumen is controlled by Sertoli cell secretions.
Factors produced by sertoli cells are required for development
Hypothalamic-Pituitary-Gonadal axis
FEMALES
(look at the feedback)
Hypothalamic-Pituitary-Gonadal axis
Males
(look at the feedback)
Androgen production in the testis
Summary (study this well)
Leydig cells contain which receptors and primarily do what?
LH receptors and primarily convert cholesterol into androgens.
After androgens are made in leydig cells, they cross over and⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
stimulate Sertoli cell function and thereby control spermatogenesis.
Sertoli cells contain which receptors? and convert androgens to?
Sertoli cells contain FSH receptors and convert androgens to oestrogen.
FSH establishes a quantitatively normal ______ _____ population, whereas androgen..
FSH establishes a quantitatively normal Sertoli cell population, whereas androgen initiates and maintains sperm production
FSH acts on sertoli cells and produces which types of proteins?
Androgen-binding proteins (ABP)
ABP binds to testosterone and concentrates the testosterone within seminiferous epithelium to aid with spermatogenesis
InhibinB is produced primarily by _____ _____ in response to ____
InhibinB is produced primarily by Sertoli cells in response to FSH
Inhibin B reduces ____ production by the _______ ______.
Inhibin B reduces FSH production by the anterior pituitary.
Seminal fluid consists of secretions from:
seminal vesicles, prostate, bulbo-urethral gland combined with epididymal fluid
Role of seminal fluid
- Transport of sperm through the male reproductive tract
- Coagulation of the ejaculate and creating a sperm deposit in the vagina
- Creation of a neutral to slightly alkaline buffered milieu in the vagina to protect spermatozoa from the acidic vaginal milieu.
- Activation and augmenting the motility of the sperm cells
- Coating the sperm cells with capacitation inhibitors
-Supplying nutrients for the sperm cells
