Reproduction

Eggs & Sperm are made in Gonads Female Gonad - Ovaries Male Gonad - Testes Sperm and Eggs are haploid- that means they have half the Number of chromosomes (add that)

Step 1: When an egg is fertilized by a sperm, it is called a zygote. = + ZYGOTE n= half of the amount of genetic material

Step 2: Zygote Divides Zygote divides by mitosis The repeated mitotic cell division is called Cleavage. Zygote divides into 2, 4, & then 8 Cells

Step 3: The zygote keeps dividing & makes a ball of cells, called a Morula

Step 4: From a Morula it becomes a Blastula When it becomes hollow it is called a Blastula **This is what a stem cell is***

Step 5: Gastrulation Differentiation of tissues occurs 3 Germ layers are made Invagination- the cells fold into each other This is called a gastrula

3 Layers have names: Ectoderm Mesoderm Endoderm

3 Germ Layers Ectoderm (outside layer) Becomes the Nervous System, skin, hair and nails Endoderm (inside layer) digestive tract and respiratory tract Mesoderm (middle Layer) Muscles, circulatory system, skeletal system, excretory system, and glands

An embryo develops in the uterus, and gets nourishment from a placenta The exchange of nutrients, respiratory gases, and waste diffuse through the placenta

Placenta

Prenatal Care/Pregnancy Environmental factors can harm the embryo/fetus EX: use of drugs, alcohol, tobacco, or other toxins

Life in the Womb Part 1

STOP

Menstrual Cycle The release of a mature egg from a follicle Occurs ~28 days, and lasts for ~7 days Starts with Puberty, and ends with menopause

4 stages of Menstrual Cycle 1. Menstruation (flow phase) 2. Follicle Stage 3. Ovulation 4. Corpus Luteum (Luteal Phase)

1. Menstruation When: Day 1- Day 6 Hormone: Increase in Follicle Stimulating Hormone Menstrual flow begins Shedding of uterine lining and blood

2. Follicle Stage When: Day 7- 14 Hormone: Follicle Stimulating Hormone stimulates an egg to become mature Follicle Stimulating Hormone thickens the uterine lining

3. Ovulation When: Day 14 Hormone: Estrogen stops the production of FSH Estrogen stimulates the release of Luteinizing hormone Mature egg is RELEASED

4. Corpus Luteum Stage “Luteal Phase” When: Day 15- Day 28 Hormones: Luteinizing and Progesterone Luteinizing hormone (LH) stimulates the Corpus Luteum to develop

Corpus Luteum is the part of the follicle that remains in the ovary It stimulates estrogen and progesterone It disintegrates and leaves a scar on the ovary

Hormones Progesterone Thickens Uterine Lining Luteinizing Stimulates the corpus luteum to develop Follicle Stimulating Hormone Stimulates an egg to become mature Estrogen Stimulates the release of Luteinizing hormone