Essentials of Human Anatomy & Physiology

Mr. Hildebrandt

The Reproductive SystemAnatomy & Physiology

Reproductive System FunctionsReproductive System Functions Ensure the continuation

of the human species

Designed to produce, store & transport gametes

(sex cells).

Gonads (sex organs) carry out meiosis to produce gametes:

Testis – Male gonads produce sperm Ovaries – Female gonads that produce

eggs

Reproductive System DevelopmentReproductive System Development Sexual Dimorphism (differentiation)

begins soon after fertilization

Dependant upon the development of endocrine & urinary systems

Puberty marks reproductive maturity

Gamete production slows when there is a reduction in sex hormones:

Males – Andropause Females - Menopause

Male External GenitaliaMale External Genitalia Scrotum: divided sac that maintains testes

at 3°C lower than normal body temperature to protect sperm viability

Penis: Shaft: contains three

areas of erectile tissue Glans penis (enlarged tip) Prepuce (foreskin)

Folded cuff of skin around proximal end Often removed by circumcision

Male Gamete ProductionMale Gamete Production Spermatogenesis

(sperm production) begins in the testis and takes 64-72 days

Each lobule of the testis contains 1-4 seminiferous tubules

Interstitial cells in testis produce androgens such as testosterone

Sperm Cell – The male gameteSperm Cell – The male gamete

The only human flagellated cell

DNA is found in the head

Are produced from puberty until death

Male Reproductive SystemMale Reproductive System Testis – male gonad

Epididymis

Ductus (vas) deferens

Seminal vesicles

Prostate gland

Bulbourethral (Cowper’s) gland

Urethra

SemenSemen – designed to survive the – designed to survive the female reproductive tractfemale reproductive tract

Mixture of sperm and accessory gland secretions

Advantages of additive secretions: Fructose provides energy for sperm cells

Alkalinity of semen helps neutralize the acidic environment of vagina

Semen inhibits bacterial multiplication

Elements of semen enhance sperm motility

Male Reproductive SystemMale Reproductive System

Female External GenitaliaFemale External Genitalia

Vaginal orifice

Vestibule

Clitoris

Labia majora

Labia minora

Female Gamete ProductionFemale Gamete Production Oogenesis (egg production) takes place

in the ovaries The total supply of eggs

are present at birth Ability to release eggs

begins at puberty Reproductive ability

ends at menopause Oocytes (female gamete) are matured

in developing ovarian follicles

Ovarian Follicle StagesOvarian Follicle Stages Primary follicle – contains an immature

oocyte

Graafian (vesicular) follicle – growing follicle with a maturing oocyte

Ovulation – when the egg is mature the follicle ruptures Occurs about every 28

days Ruptured follicle transforms

into corpus luteum

Female Reproductive SystemFemale Reproductive System

Ovaries

Fallopian tubes

Uterus

Cervix

Vaginal canal

Female Reproductive SystemFemale Reproductive System

Menstrual (Uterine) CycleMenstrual (Uterine) Cycle Pituitary gland secretes follicle stimulating

hormone (FSH) into bloodstream.

Ovaries recognize FSH & produce a follicle (egg & supportive cells).

Follicle secretes estrogen into bloodstream.

Estrogen leads is recognized by: Pituitary gland which stops secreting FSH Uterus which begins to thicken its lining

Pituitary gland now secretes lutenizing hormone (LH) into bloodstream.

More of the Menstrual CycleMore of the Menstrual Cycle The ovary recognizes LH and releases an

ovum – ovulation.

Supportive cells left behind in the ovary (now called the corpus luteum) secrete

progesterone into the bloodstream.

Progesterone is recognized by: Pituitary gland which stops secreting LH Uterus which rapidly thickens its lining

If no fertilization occurs, corpus luteum breaks down & stops making progesterone

Without progesterone, the extra uterine lining is shed - menstruation

Hormonal Control of the Ovarian and Uterine Hormonal Control of the Ovarian and Uterine CyclesCycles

Sexual ReproductionSexual Reproduction Requires sexual dimorphism A certain amount of arousal is necessary Copulation is the transfer of sperm to

the female reproductive tract Fertilization takes place in the female

fallopian tubes Embryo implants in the female uterus Embryogenesis is comprised of the 23

Carnegie stages of development

Human FertilizationHuman Fertilization The oocyte is viable for 12 to

24 hours after ovulation Sperm are viable for 12 to 48

hours after ejaculation Sperm cells must make their

way to the uterine tube for fertilization to be possible

The membrane of the oocyte does not permit a second sperm head to enter

Human FertilizationHuman Fertilization

Childbirth (Partition)Childbirth (Partition) Labor – the series of events that expel

the infant from the uterus

Initiation of labor: Estrogen levels rise Uterine contractions begin The placenta releases

prostaglandins Oxytocin is released by the

pituitary These hormones produce

contractions

Human Mammary GlandsHuman Mammary Glands Modified sweat glands:

Alveolar glands – clusters of milk producing glands within lobules

Lactiferous ducts – connect alveolar glands to nipple

Present in both sexes, but only function in

females Stimulated by sex

hormones (mostly estrogens) to increase

in size