Reproductive

FINAL WEEk 

Reproductive System

Male Reproductive System

Gonads= primary sex organs 

• Produce gametes and secrete hormones 

• Are both endocrine and exocrine organs 

• Male gonad are testes 

  • Produce male gametes = sperm 

• Female gonads are ovaries 

  • Produce female gametes = eggs (oocytes)

Male Reproductive System (numbers = order of sperm flow)

1. Testis 

2. Epididymis

3. Vas Deferens 

4. Ejaculatory duct 

5. Prostatic urethra 

6. Membrane urethra 

Testes

• Sperm form in seminiferous tubules, then travel into epididymis thru ducts = exocrine function 

• Interstitial cells between seminiferous tubules produce androgens (i.e., testosterone)

  • Hormones secreted into bloodstream = endocrine 

Epididymis 

• Holding site for sperm 

• During ejaculation, smooth muscles in the walls of the epididymis tubule contract to push sperm into vas deferens

Ducts Transport Sperm 

Vas deferens (ductus deferens) 

• Propels sperm from epididymis to ejaculatory duct 

• Ejaculation = peristalsis= smooth muscles in walls of vas deferens contract in waves to push sperm thru 

• Vasectomy = birth control method

  • Vas deferens cut near testes = stops sperm travel 

  • Sperm still form but they die in epididymis 

  • Blood vessels not cut, so hormones still flow 

Urethra

• From urinary bladder thru penis 

• Carries urine during urination (micturition)

• Propels semen during ejaculation 

• Sperm enter urethra from ejaculatory duct 

• 3 sections, in order

  • Prostatic urethra: thru prostate 

  • Membranous urethra: short section thru urogenital diaphragm

  • Spongy urethra (penile urethra): thru penis  

Accessory Glands Produce Semen

Semen = fluid that carries sperm during ejaculation 

Like: semen = river, sperm = fish

Semen = secretions from 3 different glands:

1. Seminal vesicles (2)

2. Bulbourethral glands (2)

3. Prostate gland (1)

   1. Inflammation of the prostate common in older males 

   2. Prostate cancer = 3rd most common male cancer 

Semen

Helps sperm because:

1. It contains fructose = sperm use it to make ATP

2. It’s alkaline (high pH) = neutralizes acid in vagina 

   1. Vaginal acid stops infections (yeast) but kills sperm

3. Alkaline in semen also show bacterial growth 

4. Contains substances that help sperm swim 

Male Genitalia = external structures 

Scrotum

• Sac that holds testes outside body 

  • Below body temperature—keeps sperm alive 

  • Sperm die at normal body temp (37C) 

  • Seems hazardous…but shows how human evolution forms a structure that is not perfect but works well enough
    
    

Penis

• Deposits sperm into female vagina 

• Regions

  • Body (shaft)

  • Glans (tip)

  • Prepuce (foreskin)

    • Removed by circumcision

• Erection = during sexual stimulation, blood from 2 arteries fills spongy erectile tissue around spongy urethra 

Testosterone 

• Stimulates development of reproductive organs 

• Causes sex drive 

• Causes secondary sex characteristics:

  • Deepens voice

  • Increases: Hair growth, skeletal muscle mass, bone growth and density 

Testosterone Production 

During puberty: 

• Luteinizing hormone (LH) from anterior pituitary

• Stimulates interstitial cells in testes to produce and secrete testosterone

Hormonal, humoral or neural stimulus ??????

FEMALE REPRODUCTIVE SYSTEM

Ovaries

• Contain many ovarian follicles

• Each follicle consists of:

  • Oocyte = maturing egg

  • Follicular cells = cell layers surrounding oocyte 

• Primary follicle has immature primary oocyte 

• Mature (vesicular) follicle contains mature egg = secondary oocyte 

• Ovulation = follicle ruptures, ejects mature egg

  • Occurs about every 28 days

• If no fertilization….ruptured follicle becomes corpus luteum and eventually degenerates 

Duct System 

• Uterine tubes ( Fallopian tubes)

  • Receive oocyte ejected from ovary at ovulation

  • Sites of fertilization = joining of sperm and egg

  • Lead into uterus 

  • Supported and enclosed by broad ligament and other ligaments 

  • Broad ligaments on right and left sides… like mesentery = keep structures in place (no tangling) 

Ducts

• Uterine (fallopian) tubes 

  • Fimbriae = fingers extending from uterine tube over ovary. ( make a fist then cover with fingers)

  • No direct passageway from ovaries to uterine tubes 

  • Not “perfect” but shows human evolution forms a structure that works well enough

  • Cilia on mucosa of tube move to create current to carry oocyte slowly to uterus

    • Takes three to four days = window of time to fertilize egg 

Uterus

• Site of growth and development of embryo/fetus 

• Regions: 

  • Fundus = rounded region superior to uterine tube entrances (like fundus of stomach)

  • Body = main part (as in stomach)

  • Cervix = outlet passageway 

    • Like pylorus of stomach 

    • Extends into vagina 

    • Dilates to 10 cm diameter during childbirth 

Layers of Uterine wall:

• Endometrium = inner lining = mucous membrane 

  • Thickens before/after ovulation 

  • For implantation of fertilized egg

• Myometrium = middle of smooth muscle layer that contracts involuntarily during labor/birth 

Vagina 

• Tube from cervix to exterior 

• Mucosa = non-keratinized stratified squamous ET (why)

• Functions:

Vulva = female external genitalia 

• Mons pubis

  • Fatty tissue anterior to pubic symphysis 

  • Skin grows pubic hair at puberty 

  • Vestibule 

• Labia majora

• Labia minora

• Clitoiis 

Greater vestibular glands 

• On both sides of vagina 

• Secrete lubricant thru ducts due to sexual stimulation (like male bulbourethral glands)

Clitoris 

Oogenesis and Ovarian cycle 

• Oogenesis = egg formation 

• Ovarian cycle = monthly changes in ovary 

• Primary oocytes inactive until puberty 

Follicle stimulating hormone (FSH) released from anterior pituitary causes some primary follicles to mature each month

• Follicular maturation takes 14 days

Release of luteinizing hormone (LH) from anterior pituitary stimulates ovulation 

Menstrual (uterine) cycle 

• Cyclic changes of endometrium approximately every 28 days 

• Regulated by cyclic production/release of estrogens and progesterone by ovaries 

• FSH and LH from anterior pituitary, regulate levels of estrogen and progesterone

• Ovulation usually occurs mid-cycle: on or about day 14

Phases of Menstrual (Uterine) Cycle 

• Menstrual phase = shedding 

• Proliferative phase = rebuilding 

• Secretory phase = preparing