Reproductive System 2- Male Flashcards
When does sexual differentiation occur?
Occurs early in development= 7th week of development
How is male sexual differentiation determined?
SRY gene= produces protein which is testis determining= Initiates production of multiple proteins that causes gonad medulla to differentiate into testis
Leads to:
Leydig cells= Secrete testosterone= controls development of Wolffian duct into accessory structures _ Development of male external genetalia via DHT
Sertoli cells: secrete anti-Mullerian hormone=Causes regression of Mullein duct
What does the human reproductive anatomy consist of in general?
1) Gonads
Male: Pair of testes
Female: Ovaries
Function of mature gonads= Produce gametes (eggs and sperm, gametogenesis) + Sex hormones= Testosterone and oestrogen
2) Reproductive tract
System of specialised ducts for transporting or housing gametes
3) Accessory sex glands
Produce supporting secretions into tract
What are the different parts of male reproductive system,?
1) Gonads: Pair of testes
2) Reproductive tract: Penis= method of delivery of sperm, epididymis= becomes the vas deferent which poses into the abdomen
3) Accessory sex glands:
Seminal vesicles , prostate gland and bulbourethral glands = Semen= Liquid medium for delivering the sperm + help protect male reproductive tract from pathogens
What is gametogenesis?
Production of gametes is under complex endocrine control= Both male and female
Sex steroid hormones are derived from cholesterol
3 glands are involved in production of hormones needed for gametogenesis
1) Hypothalamus: Hormone produced here
2) Pituitary: Connected to rest of body via blood vessels= Transports the hormones
3) Gonads
What is the hypothalamopituitarygonadal axis?
Pathway of the hormonal control of reproduction in both sexes
1) GnRN is released from hypothalamus
2) Causes the secretion of LH and FSH from pituitary
3) FSH and LH act on the gonads (testes) by getting it to release testosterone and ultimate causes spermatogenesis
What are some of the effects of testosterone?
1) Acts on reproductive system before birth= Masculinises tract, promotes descent of testes into scrotum
2) Has effects in sex-specific tissues after birth
Promotes growth and maturation of system at puberty
Needed for spermatogenesis and maintenance of tract as adult
3) Development of secondary sexual characteristics
Effects in male pattern hair growth, deep voice, muscle growth
4) Other reproductive related effects
Sex drive, gonadotrophin hormone secretion
5) Non-productive effects
Protein anabolic effect, promotes bone growth + aggressive behaviour
What is spermatogenesis? What are the stages?
Process in which spermatozoa are produced from male primordial germ cells by way of mitosis and meiosis.
3 major steps:
Spermatogonia= Germ cells found clustered near basal ends of Steroli cells
1) Mitotic division= Germ cells undergo mitosis= Create additional germ cells
2) Meiotic division= Spermatogonia —> Primary spermatocytes, halve number of chromosomes
3) Cytodifferentiation= Differentiate them so that it is the right kind of cell, differentiate into sperm= move inward toward the tubule lumen
What are some features of sperm?
1) Cells formed are highly specialised to carry genetic material a considerable distance
2) Have tails + mitochondria + Nucleus + Acrosomal vesicle= Stick to egg and have enzymes to digest the cell wall of egg
What is the function of sertoli cells?
Spermatozoan keep close association with them during development
They regulate sperm development + provide sustenance (nourishment)
1 Spermatogonium =4 spermatoza
Where is sperm stored and what are the different stages of its release?
Stored: In epididymis and ductus deferenens Stages: 1) excitement phase 2) plateau phase 3) Orgasmic phase 4) Resolution phase
During ejaculation phase: Sperm is mixed with secretions from accessory glands= produce mucus to make sperm swim
What is the reproductive system like for elephants?
Around 2m long
Testes of elephants situated within the body
Male produce sperm from 10-15
Musth= Episodes of elevated testosterone and heightened aggressive states with linked behaviours
