Lecture 2 Flashcards
Testes
Oval in shape and are suspended
inside a sac (scrotum) by the spermatic cord
The spermatic cords
- vas (ductus) deferens
- arteries
- veins
- lymphatics
- nerves
All are bound together by connective tissue.
Testes
exocrine and endocrine
Produces:
• sperm (exocrine function) – seminiferous tubules
• testosterone (endocrine function) – interstitial cells
tunica albuginea.
Tough, white, fibrous tissue that encapsulates each testis
Seminiferous tubules
- The interior of the testis is divided into 250 lobules (small lobes).
- Each lobule contains 1 to 4 highly coiled, convoluted tubules
= seminiferous tubules - Interstitial cells are found in the connective tissue surrounding the
seminiferous tubules - The tubules (seminiferous) unite to form a complex network of
channels called the rete testis.
The __________ are involved in sperm cell production - _______
seminiferous tubules
spermatogenesis
Spermatogenesis involves 5 stages:
- Spermatogonia – mitosis
- Primary spermatocyte - meiosis I
- Secondary spermatocyte - meiosis II
- Spermatid - maturation of sperm
- Sperm cell
Sperm production begins at ______ and continues _______
puberty
throughout life
The entire development process from spermatogonium division until sperm release—
takes about 64 days.
The staggering of developmental stages allows sperm production to remain nearly constant at a rate of
200 million sperm per day.
Once sperm form they
move into the epididymis for maturation and storage
Stored in epididymis for
12 days and later destroyed by macrophages
Spermiogenesis
The spermatids produced are interconnected
• To produces separate mature spermatozoa requires the
participation of the Sertoli cells
• This process is called spermiogenesis
• Sertoli cells secrete factors that regulate spermatogenesis and
spermiogenesis
• Spermatids remain embedded in the apical membrane of Sertoli
cells while they complete the transformation into sperm cells
Functions of Sertoli Cells
Supportive: nutrients, waste materials from spermiogenesis to blood and lymp
Phagocytotic: residual bodies shed by spermatids, effete cellular material
Secretory: 8th week – Mullerian inhibitory substance: suppress further development of duct.
Prepubertal: prevent meiotic division of germinal epithelial cells
Sexual maturation: Androgen binding protein (FSH dependent) – high testosterone levels in sem tubes
Protective: Blood-testis barrier- Occluding junctions
Sperm in epididymis
Sperm stored as non-motile within lumen of seminiferous tubules, epididymis, vas deferens
• Movespassivelyintesticularfluidtoepididymis
• After 12 days in 7 m tubes of epididymis sperm mature
biochemically = capacitation
• In cauda epididymis the sperm are capable of fertilizing the egg
Sperm pathway
Functions of Testosterone
- Spermatogenesis
- Growth and maintenance of reproductive system
• Penis
• Prostate
• Seminal vesicles
• Burbo-urethral glands
• Testes - Secondary sexual characteristics
• Posture
• Hair growth and distribution
• Growth
• Acne
• Vocal cords - Sexual behavior
- Feedback with Hypothalamus
What cell type is number 7, and what is their function?
- Leydig cells
- are the primary source of testosterone
Control of the Testicular function
