Histology of the Male Reproductive System Flashcards
What are the two major responsibilities of the male repro system?
Production and storage of spermatozoa
Synthesis and secretion of male sex hormones
What are the four major components of the male repro system?
testes
efferent duct system (epididymis, ductus deferens, ejaculatory duct, urethra)
Three accessory glands (seminal vesicle, prostate, bulbourethral glands)
Penis
What is the general organization of the seminiferous tubules?
1-4 in each lobule
40-70 cm long
Walls composed of three layers: tunica propria, basal lamina, seminiferous epithelium
What is the location and function of leydig cells?
occur in clusters between the tubules
secrete testosterone on stimulation by LH
What are the characteristics of sertoli cells?
tall, branched columnar cells that rest on basement membrane
pale oval nucleus with a prominent nucleolus
respond to FSH
margins poorly defined yet bound tightly (occluding)
Forms continuous sheeat around the lumen
Forms blood-testis barrier
What are the functions of sertoli cells?
Protect developing spermatids
Physical support - extensive cytoplasmic ramifications of sertoli cells
Phagocytosis of residual bodies
secretion - fluid for sperm transport, ABP, inhibin, AMH and activin (positive feedback on FSH secretion)
Nutritional regulation
How doe spermatogenic cells receive nutrients?
Isolation of developing spermatozoa from blood so sertoli cell exchange nutrients
What is the purpose of the blood-testis barrier?
sexual maturity occurs after development of immunocompetence
Prevents developing spermatozoa from being recognized as foreign
Separates seminiferous tubule into two functional compartments
How is the blood-testis barrier formed?
Continuous belt of occluding junctions joining lateral surfaces of adjacent Sertoli cells
What are the three phases of spermatogenesis?
Spermatocytogenesis
Meiosis
spermiogenesis
Describe spermatocytogenesis
Division of spermatogonia to form primary spermatocytes via mitosis
Describe meiosis of primary spermatocyte
Primary spermatocytes (46, 4n) -> Secondary spermatocytes (23, 2n) -> Spermatids (23, n)
What stage of the sperm is found in the lumen of seminiferous tubules?
final products of spermiogenesis are spermatozoa
Dark, flattened nuclei
have long flagella
Also called late spermatids
What are the 4 major events of spermiogenesis?
Development of the flagellum
Development of the acrosome
Development of the manchette
Nuclear condensation
Describe the cap phase of spermiogenesis
Specialized lysosome
Contains a variety of hydrolygic enzymes
Aids in penetrating the ovum during fertilization
Describe the acrosomal phase of spermiogenesis
Flagellum emerges from axonemal complex of one centriole forms fibrous rings (9) that surround axoneme
Band of microtubules surrounds nucleus (manchette)
Describe the maturation phase of spermiogenesis
Nuclear shaping and condensation Nucleus flattens and elongates Somatic histones replaced by sperm-specific histones (protamines) Mitochondria migrate in Residual body phagocytozed Sperm released into the lumen
Describe the structure and function of the head component of the sperm
Sperm cell membrane: egg receptors
Acrosome: digests ECM and ZP
Nucleus DNA
Describe the structure and function of the tail component of the sperm
The midpiece: many mitochondria to make ATP for flagellar movement
Tail: axoneme
What is primary ciliary dyskinesia?
Also called immobile cilia syndrome
It’s a rare ciliopathic autosomal recessive disorder
Defects sin action of cilia lining respiratory tract, Fallopian tube and flagella of sperm cells
No dynein arms
What is the temperature maintained in the scrotum?
34-35 C
What is cryptochidism?
undescended testes
Issues for fertility and increased risk of testicular cancer
What is acute orchitis?
inflammation on the testicle that accompanies mumps 20-30% of the time
What is varicocele?
Dilation of veins in spermatic cord
Causes a decrease in sperm production
