KEY CONCEPT Female and male reproductive organs fully develop during puberty.
Human Reproductive Systems and Offspring Development
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 Structures The female reproductive system contains two ovaries, two fallopian tubes, and a uterus.
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
Human reproductive processes depend on cycles of hormones. Estrogen is a hormone that serves three main functions. (in females) - develop female sexual characteristics - develop eggs - prepare uterus for pregnancy Testosterone is the main hormone that serves two main functions. (in males) developing male sexual characteristics producing sperm
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 in the ovaries of females. Hormones FSH and LH are secreted from the pituitary gland in the brain. meiosis produces eggs and polar bodies (small eggs that disintegrate) each egg has 23 chromosomes meiosis is completed at fertilization
FSH, LH, and estrogen stimulate the release of eggs. follicle ruptures at ovulation egg travels into fallopian tube Ovulation video clip fallopian tube egg cell egg released corpus luteum uterine wall ovary follicle uterus 5 to 7 days to uterus
Female Reproductive System
Eggs mature and are released according to hormonal cycles. The menstrual cycle has three phases. flow phase: endometrium sheds follicular phase: ovulation occurs luteal phase: corpus luteum forms
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 is also controlled by hormones. Testosterone, FSH, and LH stimulate sperm production in the testes of males. one sex cell divides into four sperm each sperm has 23 chromosomes potential sperm 4 sperm cells Meiosis I Meiosis II Spermatogenesis animation
Sperm cells fully mature in the epididymis. acrosome head midpiece tail mitochondria nucleus with 23 chromosomes head contains acrosome (enzyme to break through wall of ovum) midpiece contains ATP tail allows mobility
Male Reproductive System
Fertilization occurs when a sperm cell joins an egg cell. Sperm penetrates an egg. Chemical reaction releases a membrane barrier that keeps out other sperm nucleus of sperm joins with egg zygote formed Multiple zygotes can result from fertilization. - identical twins: splitting apart from the same egg - fraternal twins: fertilization of two separate eggs Fertilization of Sea Urchin Eggs
KEY CONCEPT Development progresses in stages from zygote to fetus.
ectoderm develops into skin and nervous system The fertilized egg implants into the uterus and is nourished by the placenta and umbilical cord. The zygote becomes a blastocyst (mass of cells through mitosis) 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
Early Zygote Development
Embryonic membranes protect and nourish the embryo. Once implanted in the female's uterus, the blastocyst becomes an embryo. Embryonic membranes protect and nourish the embryo. amniotic sac (membrane surrounding fetus with amniotic fluid) 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.
A surge of oxytocin hormone causes uterine muscle contractions to begin the birthing process.
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 (prescription for prenatal vitamins) mother must avoid toxic chemicals (alcohol, caffeine)
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
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
STDs attack reproductive organs. can cause infertility 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 with medicine to regulate symptoms, but there is no cure for these diseases. STDs attack reproductive organs. can cause infertility untreated, some can be fatal Most STDs can be avoided and prevented.