Male Reproductive System Flashcards
First Page
What is the epithelium of seminiferous tubules?
4-8 layers of germinal epithelium with spermatogneic cells and sertoli cells
Where are leydig cells located in the seminiferous tubules? What are their defining characteristics? What do they produce?
Located in the interstitial areas between seminiferous tubules. They are acidophilic with large central nuclei and abundant smooth ER and lipid droplets. Produce and secrete testosterone from cholesterol esters
What stimulates testosterone secretion? What method of secretion? (endocrine or exocrine?)
Stimulated by lutenizing hormone from the pituitary gland. Endocrine secretion
What is a sertoli cell? What is is its key features?
Sertoli cell is a support cell for spermatogenic cells. Tall columnar cell, pale, oval, indented nucleus with large nucleolus. Prominant organelles
Why do sertoli cells form junctions, and what do they form junction with?
Forms junctions (zona occludens) with other sertoli cells for dividing seminiferous tubule into a basal and adluminal compartment - blood testes barrier
What can a sertoli cell do?
Phagocytose excess cytoplasm of maturing spermatids,
secrete fructose rich fluid that transports speratozoa through sem. tubules.
Synthesize and secrete Androgen-binding protein which concentrates testosterone
Synthesize and secrete inhibin - inhibits synthesis and release of FSH by anterior pituitary
Synth. and secrete testicular transferrin - accepts iron from serum transferrin and gives to maturing gamates
What kind of receptors do sertoli cells have?
FSH receptors on plasma membrane
What is the purpose of the blood-testis barrier?
Protecting developing sperm from immune system
When does sperm production begin? what is present before?
Puberty, spermategonia present before
What are the three phases of sperm development?
Spermatogonial (spermatogenesis), spermatocyte (meiosis), and spermatid (spermiogenesis)
Intercellular bridges
What are the wave-like sequences
Are spermatogonia diploid or haploid? How many chromosomes?
Diploid, 46 chromosomes
What is the difference between pale and dark type A spermatogonia
Pale type are mitotically active and give rise to more Ap or B cells. Dark cells are mitotically inactive and are essentially stored in the G0 phase - can resume mitosis to produce pale A cells.
What is special about Dark type A cells in terms of cancer?
They are chemo/radiation resistant
What is a Type B spermatogonia?
Type B undergo mitosis and are precursor to primary spermatocyte.
What is characteristic of type B spermatogonia in terms of chromatin?
Stays in large clumps arlong nuclear envolope with a central nucleolus
List in order the cell development of sperm from Ad to Spermatozoa
Ad -> Ap - >B - > Secondary spermotocyte - > spermatids - > spermatozoa
When do primary spermatocytes migrate to adluminal compartment?
Once they have formed duplicate chromosomes and have 2x 2n DNA
What forms while primary spermatocytes migrate?
Form zonula occludens with sertoli cells
How many sperm does each spermatogonia form?
4 sperm
How many cells divisions are in spermatogenesis? How many DNA replications?
2 cell divisions, 1 DNA replication
Describe the meiosis phase of spermatogenesis (I and II)
Primary spermatocytes reduce from diploid to haploid as one chromosome with 2 chromatids divides into each 2 degree spermatocyte.
2nd division results in 2 spermatids with no replication, such that each spermatid contains a single stranded chromatid
