ReviewBoth males and females produce specialized sex cells called “gametes.”Each gamete contains ½ of the genetic information to form a new individual.The role of the male reproductive system is to produce sperm and deliver them to the female gamete, the egg.
The Male Reproductive SystemA sexually mature human male, produces millions of sperm cells each day.Sperm are produced in the testes by meiosis (spermatogenesis).Review (meiosis)
Structure of Sperm Tail- used for locomotion. Midsection- contains mitochondria. Why? Head- holds chromosomes and digestive enzymes which allow sperm to penetrate into the egg.
Male Testicle- Produces fluid that nourishes sperm
The “Pathway” of Sperm Seminal Vesicle Prostate Gland Penis Urethra Testes Bulbourethral Vas Epididymis Gland Deferens
The “Pathway” of SpermIn order for fertilization to occur, sperm must be released (ejaculated) from the penis.During ejaculation: 1.) Muscles in vas deferens push sperm toward urethra. 2.) Tube to bladder is blocked off by a valve. 3.) Glands add fluid to sperm. - Seminal vesicles provide fluid that “nourishes” sperm. - Bulbourethral gland and prostate gland create a fluid that makes sperm resistant to acid. - Sperm + Glandular secretions = SEMEN.
HormonesChemical messengers sent from one area of the body to another.In males and females, different hormones help to control sperm production and the menstrual cycle.
“The Menstrual Cycle”Eggs begin to mature in the ovaries before a female is born.Growth of the eggs stop before they are completely developed.All the eggs remain immature until puberty.After puberty, several eggs begin to mature each month.Each egg develops inside a “follicle.”
“The Menstrual Cycle”Usually only one egg makes it to maturity.This egg will burst out of the follicle (ovulation) and move down the oviduct.Fertilization may or may not occur.The uterus must be ready to accept a fertilized egg.
Female HormonesThe females reproductive role is to: 1.) Make and release eggs. 2.) Nourish the developing fetus.A mix of hormones controls these events during the “menstrual cycle.”
Female Hormones1.) FSH (Follicle stimulating hormone) - Causes follicles to mature. - As follicles grow they release estrogen.2.) Estrogen - As estrogen levels rise, another hormone (LH) begins to rise.3.) LH (Leutinizing hormone) - Around day 14, LH levels shoot up. This causes at least one follicle to burst open. - Once the egg is released it begins to produce progesterone.4.) Progesterone - If egg becomes fertilized, progesterone levels stay high. - If egg begins to disintegrate, progesterone levels fall. - Role of progesterone is to prepare the uterus for possible pregnancy.
Birth Control1.) Physical forms - Condoms and diaphragms block the sperm from getting to the egg.2.) Chemical forms - “The pill.” Works by preventing FSH and LH to be released. - Result = No ovulation. Normal menstrual cycle proceeds.
Fertilization and DevelopmentZygote- Newly fertilized egg.Once it begins to divide, it is called an embryo.Embryo continues to release progesterone. Why?Embryo must “implant” itself into the uterine wall.
The PlacentaTransports materials back and forth to the embryo.Oxygen – Carbon dioxideNutrients (carbo’s, protein, fat)Urea (liquid, cellular waste)AntibodiesTeratogens
Maternal HealthThe health of the baby depends on the health and activities of the mother.Smoking, drugs, alcohol, radiation, and pathogens can all harm the fetus.Pregnancy is divided into three month segments called “trimesters.”
First TrimesterImplantation of zygote.All vital organs are formedHeart is formed.Brain and spinal cord.Sex organs.Limbs.Eyes and ears.
Second TrimesterCirculatory system is functioning.Hair formation.Major body changes in the mother.
Third TrimesterEyes open.Fat begins to form under the skin.Fetus gains lots of weight.If fetus spends a full three trimesters inside the uterus, survival outside the mother is very likely.
BirthAt nine months, the baby will position itself with its head against the cervix.Oxotycin (hormone) causes uterine muscles to push baby outwards (labor).Cervix opens up and baby is forced into vagina.“Afterbirth” is expelled.
Stopping of the Menstrual CycleBetween ages 45 – 55 ovulation and menstruation stop.The shut down of ovarian and uterine cycles is known as menopause.