TOPIC: Reproduction AIM: How does reproduction occur?

TOPIC: Reproduction AIM: How does a human being develop before birth TOPIC: Reproduction AIM: How does a human being develop before birth? DO NOW: Where does fertilization occur in the female reproductive system?

In-Vitro Fertilization

MENSTRUAL CYCLE The word "menstruation" comes from menses, the Latin word for "month." That gives you a big clue to what it's all about. Or if you've heard friends talk about "that time of the month," you can probably guess that women menstruate about every month.

Monthly cycle of change that occurs in the female reproductive system (28 days) Regulated by ______. Menstrual Cycle

Hormones involved: LH & FSH (from pituitary) Estrogen & progesterone (ovaries)

Menstrual Cycle Follicle Stage: FSH is released from Pituitary and Egg develops in follicle in ovary. OVULATION – egg released from ovary (Day 14)

3. Corpus Leutum: Broken follicle secretes Hormone Progesterone - Lining of uterus thickens with blood vessels

4. If no fertilization occurs: menstruation (lining & egg shed from body)

OR 4. Fertilization occurs

5. Zygote attaches to uterus  develops into baby

Development Before Birth

Gestation 9 months of pregnancy

Zygote Fertilized egg

(30-45 hours after fertilization) zygote (30-45 hours after fertilization)

(8-9 days)

Embryo Zygote that is developing (dividing) and growing (8 weeks)

Fetus Embryo after 8 weeks

Amniotic Sac Filled with amniotic fluid that surrounds fetus Cushions and protects

Blood vessels of mother and fetus Exchange of materials (food and wastes) 2.Placenta

3. Umbilical Cord Made of fetal blood vessels Connects fetus to the placenta

What occurs at the end of gestation? Labor = muscular contractions of the uterus

Amniotic sac breaks Contractions cause cervix to widen

Baby is pushed out through the vagina

By the time the baby is born, the infant normally weighs 6 to 9 pounds, and his or her heart is pumping 300 gallons of blood per day.

TOPIC: Reproduction 3/21/11 AIM: Review DO NOW: Take out HW # 16 & 17

REVIEW If fertilization does not occur in the female reproductive system, what process will occur? What is a zygote? What is the difference between an embryo and fetus? Which structure provides the fetus with nutrients from the mother? Which structure cushions the fetus? What is the umbilical cord made of?

oviduct placenta Amniotic sac Umbilical cord cervix

By day 20 foundations of the brain, spinal cord and nervous system are already established. By day 21 the heart begins to beat.

1 month (4 weeks): The embryo is 10,000x larger than the original fertilized egg and is developing rapidly. The backbone and muscles are forming. Arms, legs, eyes, and ears have begun to show.

At 5 weeks five fingers can be seen in the hand At 5 weeks five fingers can be seen in the hand. The eyes darken as pigment is produced. Brain waves can be detected and recorded. At 6 weeks the liver is now taking over production of blood cells and the brain begins to control muscle movements and organs.

7 weeks: The embryo begins to move spontaneously 7 weeks: The embryo begins to move spontaneously. The jaw forms, including teeth buds in the gums. Soon the eyelids will seal to protect the embryo’s developing light-sensitive eyes, and will reopen at about the seventh month.

8 weeks Discovery Health :: Fetal Development Video 8 weeks: The fetus is a little more than 1 inch long and now has everything found in a fully developed adult. The heart has been beating for more than a month, the kidneys are functioning, the stomach is producing digestive juices and the baby responds to touch.

9 weeks: The fetus has fingerprints and will curve its hand around an object placed in its palm. By Week 10 the fetus can squint, swallow, and wrinkle its forehead. At the 11th week, the fetus is now about 2 inches long. Urination occurs. Muscle movements are becoming more coordinated.

3m 3 months (12 weeks): The fetus sleeps, awakens, exercises its muscles, and “breathes” amniotic fluid to help develop its respiratory system. Fine hair is growing on the head. The fetus is more flexible with ability to move head, mouth, lips, arms, wrists, hands, legs, feet, and toes.

4 months: The fetus is 8-10 inches long and weighs half a pound 4 months: The fetus is 8-10 inches long and weighs half a pound. The mother starts to “show.” The baby’s ears are functional. It can hear its mother.

5 months (20 weeks): The fetus is now about 12 inches long and weighs about 1 ½ lbs. There is movement felt by the mother. The baby may react to startling or loud noises. The fetus may suck on it’s thumb. There is very fast brain growth, the eyebrows and scalp hair become more visible and the fetus blinks more often.

6 months: Oil and sweat glands are now working 6 months: Oil and sweat glands are now working. The skin is protected by a special ointment called “vernix.” If the baby were born now and given proper care, he/she would survive.

7 months: The baby is 16 in. long, weighs about 2½ - 3 lbs, and now uses the four senses of hearing, vision, taste, and touch. The child can respond to his or her mother’s voice.

8 months: The skin begins to thicken with a layer of fat stored underneath for insulation and nourishment. Antibodies increasingly build up.

EGGS!!!! A woman is born with all the eggs she’ll ever have! Over her lifetime, she will release about 500 mature eggs. The number of eggs that she has depends on her age. The highest number is actually found before she is born! Here's how it happens: A 20-week-old female fetus (still in the mother's uterus) has approximately 7 million eggs. At birth, the number decreases to about 2 million. By the time puberty begins, there will be between 300,000 and 500,000 eggs. Only between 400 and 500 will ripen into mature eggs during the average lifetime.

PREGNANCY… Despite the widespread rumors that say pregnant women need to gain all the weight they can in order to birth a healthy baby, the truth is that most women will only need an extra 300 calories per day. That's equivalent to about one serving of yogurt and half a bagel. Most women only need to gain about 25 pounds throughout their entire pregnancy. Your teeth start growing 6 months before you are born. While few babies are born with teeth in place, the teeth that will eventually push through the gums of young children are formed long before the child even leaves the womb. At 9 to 12 weeks the fetus starts to form the teeth buds that will turn into baby teeth. A fetus acquires fingerprints at the age of three months. At only 6-13 weeks of development, the whorls of what will be fingerprints have already developed. Oddly enough, those fingerprints will not change throughout the person’s life and will be one of the last things to disappear after death. The average woman's uterus expands up to five hundred times its normal size during pregnancy. It only takes 6-8 weeks for it to return to its original size.

BABIES… Babies are born without kneecaps. The largest surviving baby was born in October 2009 in Sumatra, Indonesia and weighed an astounding 19.2 pounds at birth. Babies are, pound for pound, stronger than an ox. While a baby certainly couldn’t pull a covered wagon at its present size, if the child were the size of an oxen it just might very well be able to. Babies have especially strong and powerful legs for such tiny creatures, so watch out for those kicks. A newborn baby’s heart beats about twice as fast of a normal adult (between 130 and 160 times a minute). Babies breathe much faster than adults - 30 to 50 times a minute compared to an adult's 15 to 20 times a minute. Babies have very small stomachs. An 8lb baby can get 3 ounces of milk into its stomach. The average stomach in the average baby is no bigger than the size of his fist!

Did you know… The only mammals to undergo menopause are elephants, humpback whales, and human females. Smoking cigarettes can kill a woman’s eggs and cause menstrual periods to stop prematurely. Smoking and alcohol can lead to changes in sperm shape and sperm count. A healthy couple in their 20's has only 25 percent chances of conceiving each month. SPERM: Sperm needs to travel about 3 to 4 inches to fertilize the egg, which could take from half an hour to several days. This journey, however, is quite difficult to undertake. Several factors can affect how fast sperm can reach the egg. First of all, not all sperm are good swimmers. Secondly, those who do swim may not travel in the right direction, because only one of the fallopian tubes will release the egg.  Also it depends on the time of female cycle, because sperm is able to travel easier and faster during the woman's most fertile period, when the cervical mucus creates a favorable environment. While at least 40 million sperm are released from the male, only a few hundred will get close to the egg overcoming all the obstacles in its way.