Human Human ReproductionReproduction

Influenced by gene expression, Influenced by gene expression, hormones, and the environmenthormones, and the environment

Male Reproductive SystemMale Reproductive SystemTestesTestes produce sperm cells and produce sperm cells and testosteronetestosterone – the hormone associated with – the hormone associated with male secondary sex characteristics and the male secondary sex characteristics and the production of sperm ex: body hair, deep production of sperm ex: body hair, deep voice, increased muscle massvoice, increased muscle mass

Structures that produce fluid and nutrients Structures that produce fluid and nutrients needed for proper function and delivery of needed for proper function and delivery of gametes (sperm) to the male reproductive gametes (sperm) to the male reproductive systemsystem

Male AnatomyMale Anatomy2 paired testes hang outside the body in a 2 paired testes hang outside the body in a sac of skin called the sac of skin called the scrotumscrotum (this keeps (this keeps the temperature slightly lower than inside the the temperature slightly lower than inside the body and allows for the survival of sperm.)body and allows for the survival of sperm.)

Testes initially develop inside the body Testes initially develop inside the body and descend about 1 month before birth – and descend about 1 month before birth – failure to descend can lead to an failure to descend can lead to an increased risk of cancer so it must be increased risk of cancer so it must be surgically brought downsurgically brought down

Each testis is composed of hundreds of Each testis is composed of hundreds of small tubules where the sperm are madesmall tubules where the sperm are made

Sperm are made continually throughout life Sperm are made continually throughout life though the number of healthy sperm though the number of healthy sperm decreases as one agesdecreases as one ages

From the testes the sperm move into an From the testes the sperm move into an epididymisepididymis – storage tubule – where they – storage tubule – where they maturemature

Next they move into the Next they move into the Vas DeferensVas Deferens – – long tube that goes up into the bodylong tube that goes up into the body

Empties into the Empties into the urethraurethra which passes which passes through the penis and delivers sperm to through the penis and delivers sperm to the femalethe female

3 structures that secrete fluid to nourish 3 structures that secrete fluid to nourish and transport sperm. This fluid + sperm and transport sperm. This fluid + sperm = = SemenSemen

Involuntary contractions force semen Involuntary contractions force semen through the urethra and outside the through the urethra and outside the body = ejaculationbody = ejaculation

Muscle closes bladder to urethra so Muscle closes bladder to urethra so urine does not exit with semenurine does not exit with semen

Female Reproductive SystemFemale Reproductive System

Internal fertilization in oviductInternal fertilization in oviduct

Internal development in uterusInternal development in uterus

Production of sex cells in ovariesProduction of sex cells in ovaries

Provide essential nutrients to embryo Provide essential nutrients to embryo and fetus through the placentaand fetus through the placenta

Provide nutrition through milk to the Provide nutrition through milk to the newbornnewborn

Gonads are ovaries Gonads are ovaries produce eggs, produce eggs, hormones (estrogen and progesterone)hormones (estrogen and progesterone)

ESTROGENESTROGEN – determines female sex – determines female sex characteristics: breasts, fat distribution, characteristics: breasts, fat distribution, regulate menstrual cycleregulate menstrual cycle

PROGESTERONEPROGESTERONE – maintains uterus – maintains uterus during pregnancyduring pregnancy

Female AnatomyFemale AnatomyOvaries (2) 4cm X 2cm in lower abdomen – Ovaries (2) 4cm X 2cm in lower abdomen – each contains small sacs known as follicles each contains small sacs known as follicles that hold an egg (~500 in mature ovary)that hold an egg (~500 in mature ovary)

When egg matures follicle ruptures (1 each When egg matures follicle ruptures (1 each month) and egg pops out (month) and egg pops out (ovulationovulation))

Egg enters tubes known as oviducts (egg Egg enters tubes known as oviducts (egg ducts) or fallopian tubes – it lives ~24-48 ducts) or fallopian tubes – it lives ~24-48 hours and this is where is can be fertilizedhours and this is where is can be fertilized

Leads to Leads to uterusuterus – muscular organ where – muscular organ where embryo develops into fetus. Where embryo embryo develops into fetus. Where embryo sinks into wall – sinks into wall – PlacentaPlacenta forms which forms which provides nutrients to fetusprovides nutrients to fetus

DeliveryDelivery – Uterus – Uterus contracts and pushes contracts and pushes through through cervixcervix opening of uterus opening of uterus to to the vagina (birth canal)the vagina (birth canal)

Urinary system is totally Urinary system is totally separate – urethra separate – urethra opens anterior to the opens anterior to the vaginavagina

At sexual maturity (puberty) females begin At sexual maturity (puberty) females begin menstrual cyclemenstrual cycle

~ 28 days with ~ 28 days with ovulationovulation occurring at occurring at day 14 day 14 timing controlled by 2 hormones timing controlled by 2 hormones from the from the pituitary pituitary and 2 hormones from and 2 hormones from ovariesovaries

The rise and fall of hormones regulates the The rise and fall of hormones regulates the cycle (variable lengths) Menstrual cycle cycle (variable lengths) Menstrual cycle starts around 10-14 years and ends by ~ 50-starts around 10-14 years and ends by ~ 50-55 at 55 at MenopauseMenopause

4 Stages of the Menstrual Cycle4 Stages of the Menstrual Cycle

1.1. Follicle StageFollicle Stage – Pituitary – Pituitary makes makes FSHFSH (follicle stimulating hormone) (follicle stimulating hormone) stimulates stimulates follicle in ovary to get egg readyfollicle in ovary to get egg ready

- Follicle makes estrogen- Follicle makes estrogen starts to starts to get uterine wall thicker in case of get uterine wall thicker in case of pregnancy (lasts till day 14)pregnancy (lasts till day 14)

2. 2. OvulationOvulation – Pituitary – Pituitary LHLH (lutenizing (lutenizing hormone) hormone) Ruptures follicle (ovulation) Ruptures follicle (ovulation) egg is out of follicleegg is out of follicle

4 Stages of the Menstrual Cycle4 Stages of the Menstrual Cycle

3. 3. Corpus Luteum StageCorpus Luteum Stage – Follicle turns yellow – Follicle turns yellow corpus luteum produces progesterone – corpus luteum produces progesterone – develops in uterusdevelops in uterus

4. 4. MenstruationMenstruation – If fertilization does not occur – If fertilization does not occur – corpus luteum disappears – corpus luteum disappears no no progesterone progesterone lining of the uterine walls lining of the uterine walls sheds – blood and wall is shed and known as sheds – blood and wall is shed and known as menstruation (~5 days)menstruation (~5 days)

Human DevelopmentHuman DevelopmentPregnancy = gestation Pregnancy = gestation

continues in the uterus continues in the uterus (lasts ~9 months or 40 (lasts ~9 months or 40 weeks)weeks)

embryo embryo 2 2 months “Fetus”months “Fetus”

11stst part of pregnancy = part of pregnancy = development of organs development of organs occurs in the first 3 occurs in the first 3 monthsmonths

Things can go wrong that affect the development Things can go wrong that affect the development of the fetusof the fetus

- Faults in the genes or DNAFaults in the genes or DNA- XraysXrays- STD’sSTD’s- Environmental factors:Environmental factors:

a) alcohol – FAS (fetal alcohol a) alcohol – FAS (fetal alcohol syndrome)syndrome)

b) drugs – drug addicted babiesb) drugs – drug addicted babies

c) smoking – low birth weight babiesc) smoking – low birth weight babies

d) poor diet in motherd) poor diet in mother

e) infections – especially German e) infections – especially German Measles and AIDS can cause defectsMeasles and AIDS can cause defects

Mother needs Pre-Natal care and should Mother needs Pre-Natal care and should avoid harmful things that can cause birth avoid harmful things that can cause birth defectsdefects

- After birth – development and - After birth – development and differentiation and growth continue until differentiation and growth continue until adulthood when organs are age, weaken, adulthood when organs are age, weaken, and dieand die

Process of BirthProcess of Birth

Labor = rhythmic contractions of Labor = rhythmic contractions of uterusuterus

1. cervix opens (.1-10 cm)1. cervix opens (.1-10 cm)

2. head delivered first2. head delivered first

3. amniotic fluid comes out3. amniotic fluid comes out

4. umbilical cord cut4. umbilical cord cut

5. Placenta delivered5. Placenta delivered

Reproductive TechnologyReproductive Technology

Birth Control = Contraception Birth Control = Contraception methods of methods of preventing pregnancypreventing pregnancy

1. pill – disrupts hormones1. pill – disrupts hormones

2. diaphragm or condom – barrier 2. diaphragm or condom – barrier method and prevents STD’smethod and prevents STD’s

3. surgical vasectomy or hysterectomy3. surgical vasectomy or hysterectomy

4. 4. ABSTINENCEABSTINENCE – only 100% affective – only 100% affective form of birth controlform of birth control

Reproductive TechnologyReproductive Technology

Ecology – Ecology –

1. Build up endangered species – transplant 1. Build up endangered species – transplant embryos into different animalsembryos into different animals

Medicine – Medicine –

1. Hormone prescription to help women who can’t 1. Hormone prescription to help women who can’t get get pregnant (fertility drugs)pregnant (fertility drugs)

2. Artificial insemination2. Artificial insemination

3. In-vitro fertilization – test tube embryos 3. In-vitro fertilization – test tube embryos implantedimplanted

4. Ultrasound and mini camera – view reproductive 4. Ultrasound and mini camera – view reproductive organsorgans

5. Amniocentesis – needle to remove cells from fluid 5. Amniocentesis – needle to remove cells from fluid around baby – analyze cells for genetic problemsaround baby – analyze cells for genetic problems