Ch 27: Reproductive System

• General organization

• Anatomy of male reproductive system

• Anatomy of female reproductive system

General Organization

• Gonads gametes & hormones

• Ducts transport of . . . ?

• Glands secrete fluid

• Perineal structures = external genitalia

Anatomy of Male Repro System

• Primary reproductive organs produce gametes

• Secondary reproductive organs . . . .

• Male reproductive and urinary tracts are partially shared

Fig 27-1

Testes (paired glands)

• Develop adjacent to kidneys

• Descend into scrotum through inguinal canal

• Peritoneal lining is carried along lining of scrotum

• Cryptorchidism (in 3% of full-term and 30% of premature deliveries) – Significance?– Treatment?

Fig 27-2

4 month

Scrotum

Function: supports and protects testes

Structure: Skin & underlying superficial fascia– Dartos muscle in subcutis– Cremaster muscle deep to dermis

(continuation of ___________)

Involuntary contraction (cremasteric reflex) in response to ________

Scrotal sac forms 2 separate chambers

Cremaster muscle

Structure of Testes

• Two tissue layers cover testes:

– Tunica albuginea

– Tunica vaginalis

• 200-300 lobules

• 3 seminiferous tubules

Fig 27-4/5

From Spermatocyte to Spermatozoon

• Spermatogenesis: Meiosis of primary spermatocytes spermatids

• Spermiogenesis: Spermatid maturation into spermatozoa within Sertoli cells

• Spermiation: Spermatozoon released into lumen

Sustentacular (Sertoli) Cells• Maintenance of blood testis barrier

» special lumen fluid» sperm specific ag

• Support of spermatogenesis» FSH and Testosterone work via Sertoli cells

• Support of spermiogenesis

• Secretion of inhibin

• Secretion of androgen-binding protein (ABP)

Anatomy of Spermatozoon

Mature sperm has 3 portions

1. Head with acrosome

2. Midpiece with lots of ?

3. Flagellum (rotating in corkscrew fashion)

See fig 27-6

Epididymis

~ 7 m long

1. Sperm-maturation

2. Recycling of damaged spermatozoa

3. Adjusting composition of tubular fluid (stereocilia!!)

Functions:

Path of Spermatozoa from tail of epididymis:

ductus (vas) deferens

ampulla

ejaculatory duct

urethra

Capacitation

Activation of spermatozoa

Occurs after spermatozoa leave epididymis and come in contact with seminal fluid.

Seminal fluid + Sperm = Semen

Final capacitation when exposed to conditions inside female reproductive tract

The Accessory Glands.

Provide for 95% of the seminal fluid

1. Seminal vesicles

2. Prostate gland

3. Bulbourethral glands

Seminal Vesicles

Produce 60% of seminal fluid

Tubular glands (~ 15 cm)

Secretionis rich in fructose

leads to sperm motility

Prostate Gland

• 25% of seminal fluid

• Single, doughnut-shaped

• Secretion contains:– citrate – seminal plasmin– prostate specific antigen

(PSA)

Bulbourethral glands (Cowper’s glands)

Pea size

Alkaline secretion containing lots of mucus. function??

Erectile TissuePenis has 3 cylindrical columns:

One corpus spongiosum

Two corpora cavernosa

Corpora cavernosa

Corpus spongiosum

??