Reproductive system: collection of specialized organs, glands and hormones that help to produce a new human being. Puberty: hypothalamus and pituitary gland release hormones that begin the process of developing your sexual characteristics and reproductive system
The female reproductive system produces ova. There are two main functions of the female reproductive system. produce ova, or egg cells provide a place where a zygote develops uterus cervix rectum vagina urethra urinary bladder pubic bone ovary fallopian tube
Female reproductive organs are all INTERNAL To protect a fertilized egg while it develops Eggs (ova) are produced in the ovaries Uterus (womb)– in between the 2 ovaries When a female is born- she already has about 2 million potential egg cells stored in her ovaries!! uterus cervix rectum vagina urethra urinary bladder pubic bone ovary fallopian tube
In the ovaries: Follicle stimulating hormone (FSH) and luteinizng hormone (LH) stimulate the release of estrogen Estrogen – steroid hormone - has three main functions: develop female sexual characteristics -widening of the pelvis -increasing fat deposits and bone mass -enlarging breasts develop eggs prepare uterus for pregnancy every month and maintain a pregnancy when it occurs
When an egg cells matures each month… Released from ovary Enters fallopian tube-10 cm long, connects ovary to uterus Egg takes several days to travel through Can only be fertilized by sperm in the fallopian tube Fertilized egg: will attach to wall of uterus Unfertilized egg: will be broken down and discarded
Lower end of uterus = cervix: opens into vagina Size and shape of a pear 3 layers: thin layer of epithelial cells thick middle layer of muscle outer layer of connective tissue Lower end of uterus = cervix: opens into vagina
The male reproductive system produces sperm. There are two main functions of the male reproductive system. produce sperm cells deliver sperm to the female reproductive system urinary bladder vas deferens pubic bone prostate gland penis urethra testis scrotum epididymis bulbourethral gland rectum seminal vesicle
Males do not produce sperm cells until puberty- but then can produce them their entire lives Sperm production occurs in the testicles (testes) Luteinizing hormone (LH) stimulates release of testosterone Testosterone has two main functions. developing male sexual characteristics (deeper voice, more body hair, greater bone density, increased muscle mass) producing sperm
Sperm production in the testes is controlled by hormones. Testosterone, FSH, and LH stimulate sperm production. one sex cell divides into four sperm each sperm has 23 chromosomes potential sperm 4 sperm cells Meiosis I Meiosis II
Testes are enclosed in a pouch called the scrotum Hangs below the pelvis on the outside of body Keeps testes 2-3 degrees cooler than the core body temp. Allows sperm to develop Immature sperm leave testes through epididymis (long, coiled tube)- place where sperm mature and stay until expelled or reabsorbed.
Sperm cells fully mature in the epididymis. head contains acrosome midpiece contains ATP tail allows mobility acrosome head midpiece tail mitochondria nucleus with 23 chromosomes
During sexual stimulation- Sperm travel into another long duct= vas deferens Other sex glands secrete fluids into the vas deferens to nourish and protect the sperm Prostate gland (surround urethra) produces a fluid that helps sperm move more easily Bulbourethral gland & seminal vesicle- secrete basic fluids to help neutralize the acidity in urethra and in female’s vagina Semen= fluid from these 3 glands together with sperm
During sexual arousal- Blood flows into penis (makes it rigid) Semen moves from vas deferens into urethra Ejaculation is when semen exits urethra and leaves penis - when this occurs- a muscle closes off the bladder to prevent urine from mixing with the semen in the urethra -smooth muscle contractions propel the semen along the urethra
Fertilization occurs when a sperm cell joins an egg cell. Sperm penetrates an egg. membrane keeps out other sperm nucleus of sperm joins with egg zygote formed
Multiple zygotes can result from fertilization. identical twins from the same egg fraternal twins from two separate eggs Infertility makes reproduction difficult or impossible.
Eggs mature and are released according to hormonal cycles. potential egg first polar body second polar ovum (egg) Meiosis I Completed Meiosis II only after sperm enters Follicle-stimulating hormone (FSH) and lutenizing hormone (LH) regulate egg production. meiosis produces eggs and polar bodies each egg has 23 chromosomes meiosis is completed at fertilization
Female Reproductive Cycle Controlled by hormones released by the: Feedback Loops among hormones ensure that each process occurs at the right time and in the right order Female Reproductive Cycle Controlled by hormones released by the: Hypothalamus Pituitary gland Ovaries Feedback loops each month cause the hormone levels to rise and fall
Production of eggs begins before a female is born Meiosis begins: Meiosis I begins and then the potential eggs enter a resting phase that last until puberty @birth- about 2 million partially developed eggs in ovaries Many break down before puberty- ~400,000 left A monthly hormone cycle begins the 2nd stage: Every 28 days or so FSH increases Stimulates a potential egg to complete meiosis I Divides unevenly = 1 gets most of cytoplasm, nutrients, and organelles This one will complete meiosis II only after a sperm enters it Cell divides again to produce an ovum (egg) w/ 23 chromosomes
FSH, LH, and estrogen stimulate the release of eggs. Each developing sex cell is surrounded by group of cells called follicle that help egg to mature follicle ruptures and egg is released from ovary =ovulation egg travels into fallopian tube fallopian tube egg cell egg released corpus luteum uterine wall ovary follicle uterus 5 to 7 days to uterus
Over the next 5-7 days egg moves through fallopian tube to uterus Unfertilized eggs are discarded during menstruation Most women: only one egg released/month Which ovary it comes from is random About 400-500 eggs released in a female’s repro. life Menstrual Cycle Producing and releasing an egg and preparing uterus Length of cycle is different for each female (~28 days) 3 main phases: Flow phase -endometrium sheds Follicular phase-ovulation occurs Luteal phase-corpus luteum forms
Day 1: 1st day of menstrual flow FLOW PHASE: Day 1: 1st day of menstrual flow Uterus lining (endometrium) detaches from wall and passes through vagina to outside Blood, mucus and tissue fluid are also expelled Muscles help to expel it (cramping) FSH starts to rise another follicle starts to mature
Eggs mature and are released according to hormonal cycles.
Follicular Phase: about day 6day 14 Estrogen is low at start Pituitary gland is stimulated to release more FSH and LH Causes egg and follicle to mature Ovulation occurs around day 14 As egg develops, follicle releases estrogen Causes endometrium to thicken AND Stimulates production of LH- causes follicle to rupture, releasing egg
Eggs mature and are released according to hormonal cycles.
Luteal Phase: Hormones released to stop egg production Develop endometrium Empty follicle turns yellow and is called corpus luteum Releases estrogen and progesterone - increase blood vessels in endometrium - limits production of LH - if not fertilized, these high levels will signal the stop of FSH and LH release -then corpus luteum breaks down and stops releasing hormones - as a result: uterus lining breaks down and is shed back to FLOW Phase again
Eggs mature and are released according to hormonal cycles.
The menstrual cycle stops at menopause. cycle continues until a woman’s mid-40’s or 50’s decline in hormone levels make cycles irregular eventually, cycle stops altogether
Sperm production in the testes is controlled by hormones. Testosterone, FSH, and LH stimulate sperm production. one sex cell divides into four sperm each sperm has 23 chromosomes potential sperm 4 sperm cells Meiosis I Meiosis II
Pituitary gland receives message to release FSH and LH Circulate to testes Testes release testosterone Causes specialized cells to go through meiosis to develop mature sperm As testosterone increases, FSH and LH decrease (feedback loop to control amount of sperm produced) Sperm divide into 4 equal sperm cells
Sperm cells fully mature in the epididymis. head contains acrosome Has enzymes that help sperm to penetrate egg’s membrane midpiece contains ATP tail allows mobility acrosome head midpiece tail mitochondria nucleus with 23 chromosomes -After sperm released through penis, testosterone levels decline -stimulates hypothalamus and sperm production begins again
Fertilization… During sexual intercourse, the penis is inserted into the vagina until the tip comes close to the opening of the uterus. Semen is ejaculated through the penis Sperm released into vagina One ejaculation can contain 50-500 million sperm cells Sperm must swim up through uterus into fallopian tubes
Fertilization occurs when a sperm cell joins an egg cell. Sperm penetrates an egg. membrane keeps out other sperm Egg completes meiosis II nucleus of sperm joins with nucleus of egg zygote formed
Multiple zygotes can result from fertilization. identical twins from the same egg fraternal twins from two separate eggs Infertility – any condition that makes reproduction difficult or impossible Vas deferens too narrow, blocked Sperm count too low or sperm weakened or deformed Illnesses can destroy testes ability to produce sperm Illnesses can damage ovaries or fallopian tubes Fallopian tubes deformed or blocked Eggs can have defects
Sexually transmitted diseases affect fertility and overall health. Sexually transmitted diseases (STDs) are passed from one person to another during sexual contact. bacterial STDs include chlamydia, syphilis, gonorrhea viral STDs include hepatitis B, genital herpes, human papillomavirus, and HIV HIV
Viral STDs can be treated, but there is no cure for these diseases. Bacterial STDs can be treated, and in many cases, cured with antibiotics A parasite causes trichomoniasis, which can affect fertility. Viral STDs can be treated, but there is no cure for these diseases. STDs attack reproductive organs. can cause infertility untreated, some can be fatal STDs can be avoided by abstinence or by using a condom.
The zygote becomes a blastocyst and implants in the uterus. The fertilized egg implants into the uterus and is nourished by the placenta and umbilical cord. The zygote becomes a blastocyst and implants in the uterus. ectoderm develops into skin and nervous system mesoderm develops into Internal tissues and organs endoderm develops into digestive organs and their lining blastocyst uterine wall Implantation of blastocyst
The blastocyst becomes an embryo. Embryonic membranes protect and nourish the embryo. amniotic sac cushions embryo. placenta connects mother and embryo. umbilical cord connects embryo to placenta. placenta umbilical cord uterus amniotic sac
A zygote develops into a fully formed fetus in about 38 weeks. Human pregnancies are divided into trimesters. 1st trimester: body plan and early development
2nd trimester: fetus more active, developed
3rd trimester: all organs fully formed After about 38 weeks, fetus is ready to be born.
The mother affects the fetus, and pregnancy affects the mother. The fetus depends on the mother for all its nutrition. mother's diet must support fetal health mother must avoid toxic chemicals
The mother’s health is affected by pregnancy in a number of ways. increase in Calories and body weight pregnancy hormones affecting homeostasis regular medical checkups needed
Birth occurs in three stages. Stage one of birth is the dilation of the cervix. contractions push cervix open if cervix dilates too little, C-section done STAGE 1 As regular, strong contractions occur, the cervix dilates and the baby turns.
Stage two is the emergence of the baby. baby usually born headfirst oxytocin stimulates milk production STAGE 2 The baby is pushed through the cervix and out of the vaginal canal.
Stage three is the expulsion of the placenta. placenta detaches from uterine wall contractions helps control bleeding STAGE 3 Contractions continue, expelling the placenta and helping to control bleeding.
Human growth and aging also occur in stages. Genetics, hormones, lifestyle, environment affect all stages. during infancy, growth is rapid during childhood, motor and language skills develop
Genetics, hormones, lifestyle, environment affect all stages. during puberty, sexually maturity begins during adolescence, growth is rapid and the brain rewired adulthood marks the peak of skills and independence
Aging is also affected by genetics, hormones, lifestyle, environment. Effects of aging can be reduced with good diet, exercise, and continued learning. Jerry Peel at age 1 1/2 Jerry Peel at age 17 Jerry Peel at age 71