Male Reproductive System

Question 1

Anatomy of scrotum

Answer 1

Outer layer Dartos muscles
Inner Cremaster muscles
Scrotal septum in the middle
3 layers Tunica vagina lips (outer layer formed from peritoneum) Tunica albuginea (fibrous covering forms septa dividing tested) Tunica vasculosa (network of capillaries)

Internal of Testis
Seminiferous tubules, convoluted loops of epithelium (large SA) produce spermatozoa
Leydig cells produce testosterone after puberty
Epididymis single highly convoluted tubule contains immature sperm
Vas Deferens duct formed from epididymis leaving scrotum in spermatic cord. 2 fibromuscular pouches at posterior of bladder join vas deferens by duct to form ejaculatory duct and secrete seminal fluid (alkaline to neutralise acidity of vagina). Assists coagulation of sperm after sex.

Question 2

Anatomy of penis

Answer 2

Prostate: doughnut shaped gland inferior to bladder produces milky coloured prostatic fluid 30% semen.
Bulbourethral glands: pea sized glands inferior to prostate produce alkaline fluid to protect semen secrete mucous lubricating penis

Penis composed of 3 columns erectile tissue
Corpora cavernous: 2 lateral columns
Corpus spogiosum: midventral column containing urethra
Glans penis: expanded triangular distal end covered with foreskin (prepuce).

Question 3

Explain what happens during intercourse

Answer 3

Erection, caused by parasympathetic stimulus resulting in increase of blood to fill corpus cavernous and spongiosum.
Ejaculation, sympathetic bladder sphincter closes, vas deferens contraction to squeeze sperm forward (peristalsis) 2nd phase muscles at base of penis contract every 0.8 secs 5spurts.

Question 4

Male puberty

Answer 4

12-13 years induced by body mass, triggered by gonadotrophin releasing hormone (GnRH) and FSH and LH.
Growth of muscle
Enlargement of larynx deeper voice voice breaks
Growth of hair pubic facial axillary
Enlarged penis scrotum prostate gland
Mature seminiferous tubules production of spermatozoa
Thick skin oilier.

Question 5

Describe a mature spermatozoon

Answer 5

Head: filled by nucleus contains DNA has enzymes on acrosome (outer layer) to penetrate oocyte.
Midpiece contains mitochondria to supply energy to tail
Tail: flagellum to transport sperm

Question 6

Process of fertilisation

Answer 6

1. Sperm makes contact with ovum (capacitation)
2. Acrosome reacts and penetrates corona radiate then zona pellucida
3. Acrosome reacts with pervitelline space
4. Fusion of sperm cell membrane and oocyte cell membrane
   Oocyte completes meiosis 2 becomes ovum and sperm nucleus enters egg
5. Cortical granules fuse with egg plasma membrane renders Vitellius layer impenetrable to sperm. Becomes zygote.

Question 7

Describe spermatogenisis

Answer 7

In seminiferous tubules the tubules are lined with serotonin cells (somatic cells that support and provide nutrients to sperm cells),these contain germ cells (spermatagonium) they enter mitosis and become primary spermatocytes, then they double and become secondary spermatocytes.
After meiosis They’re now haploid spermatids then they begin differentiation into sperm.