Male Reproductive system

Reproductive system

**only system not essential to life of individual

• produces, stores, nourishes, & transports gametes (reproductive cells) to ensure continued existence of human species

Scrotum

• flesh pouch that covers the testes

• Tests are suspended inside this

• Small pockets are part of the peritoneal cavity

Descent of testes

• as a fetus the testes form inside the body next to the kidneys & gradually move

Cryptorchidism

• abdominal testes/ testes do not descend & need to be surgically repaired

  • 3% male births; 30% premature male births

Spermatic cords

• extends from the pelvic cavity to testes

• Contains vas deferens, blood & nerve supply

Inguinal canal

• passageway thru abdominal musculature for spermatic cords

  • Causes a weak area that can lead to an inguinal hernia in males (very rare in females)

Cremaster & dartos muscles

• 2 degrees F cooler tan body temp (pulls testes closer to body)

Tunica vaginali & tunica albuginea

• connective tissues covering the testes

Seminiferous tubules

• Tightly coiled tubes, place of sperm production

Interstitial cells

• Found in spaces between seminiferous tubules

• production of sex hormones

  • Androgens (mostly testosterone)

Rete testes

• Passageway that leads from seminiferous tubules

Efferent ductules

• connect rete testes to epididymis

Epididymis

• Beginning of male reproductive track, coiled tube contains head, body, and tail

What makes up the male reproductive tract?

1. Epididymis

2. Vas deferens

3. Ejaculatory duct

4. Urethra

3 functions of the epididymis

1. Monitors and adjust the fluid produced by the seminiferous tubules

2. recycles damaged spermatozoa

3. stores, protects, & matures spermatozoa after detaching from Sertoli Cells

Vas deferens (ductus deferens)

• begins at tail of epididymis

• Part of spermatic cord

• Ascends thru inguinal canal

Ejaculatory duct

• Empties vas deferens & seminal vesicles into urethra near prostate gland

Urethra

• passageway from the bladder to the tip of the penis,

  • used by both the urinary and reproductive systems

Accessory glands functions

1. Activating spermatozoa

2. provides nutrients needed for motility

3. propels spermatozoa & fluids along reproductive tract

4. produces buffers against vaginal acidity

Seminal vesicles

• drains into ejaculator duct

• contributes 60% to total volume

• contains:

  • fructose (energy)

  • prostaglandins (contracts smooth muscle)

  • fibrinogen (forms clot inside vagina)

Prostate gland

• Encircles urethra as it leaves the bladder

• contains antibiotic to prevent urinary infection

• common area for male cancer

Bulbourethral gland is also known as

Cowper’s gland

Bulbourethral gland

• 2 small round glands found at the base of the penis

• Empties into urethra

  • Helps make semen alkaline

Semen

Ejaculate

• 2-5 mL

• Regenerates in 36 hours

Spermatozoa

• 20-100 million per mL

• Only 60% are NORMAL (actively swimming)

Seminal fluid

• mixture of fluids from accessory glands (95%)

Enzymes

• dissolve vaginal secretions (antibiotic to kill bacteria- E. Coli)

• Coagulates semen by fibrinogen→ fibrin dissolves clot after 15-30 minutes

Penis

External organ containing the urethra

Root

Attaches penis to body wall

Body (shaft)

Middle part of penis

Glans of penis

• expanded distal end

• Surrounds external orifice

Prepuce

• Foreskin

  • Attaches to neck & extends over the glans

circumcision

Surgical removal of the foreskin

• done to prevent infection or religious beliefs

• Mostly done in America 2nd day after birth

Erectile tissue

• maze of vascular tissue, when dilated w/ blood causes ERECTION

Corpora cavernosum

• paired structures, extends length of shaft

• Each surrounds a central artery

Corpus spongiosum

• surrounds urethra, extends tip of penis

• Expands the glans

Spermatogenesis length

• 9 weeks

Mitosis

• cell division

• 2 daughter cells

• 46 chromosomes

• Diploid

Meiosis

• involves I & II

• 4 gametes

• 23 chromosomes

• Haploid

Spermiogenesis

• development from spermatic to sperm cell

• Rids itself of cytoplasm & organelles

• Grows flagellum

Sertoli (sustentacular cells) Functions

1. Blood- testis barrier (prevents immune system from attacking sperm cells)

2. Support mitosis & meiosis ( by circulating FSH & testosterone)

3. Provide nutrients & chemical stimuli that promote cell development

4. Secretes inhibin (regulates production)

5. Secretes androgen-binding protein (attracts testosterone)

6. Helps in fetal development of testes

Sperm cell

• mobile carrier of genetic material

  • Lacks glycogen & organelles (reduces weight)

  • Absorbs energy (fructose) from surroundings

Acrosomal cap

• front tip of sperm

• Helps enter egg

Nucleus

• contains genetic material

Neck

• contains mitochondria to provide energy for tail

Tail

• flagellum

• Provides movement

• Swimming action

Male reproductive hormones:

1. GnRH

2. FSH

3. Inhibin

4. LH

Male reproductive hormones (GnRH)

• FSH & LH

Male reproductive hormones (FSH)

1. Promote spermatogenesis

2. Secrete androgen-binding protein (ABP)

Male reproductive hormones (Inhibin)

• inhibits FSH production

  • Increase in FSH causes release

• Negative feed back loop

Male reproductive hormone (LH)

Secretion of testosterone which:

1. Stimulates spermatogenesis & maturation

2. Affects CNS including sex drive

3. Stimulates protein synthesis & muscle growth

4. Establishes & maintains secondary sex characteristics

5. Maintains accessory glands