Transcript File

Reproduction
Eggs & Sperm are made in
Gonads
Female Gonad - Ovaries
Male Gonad - Testes
Sperm and Eggs are haploidthat 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.
SPERM
EGG
n
+
n= half of the
amount
of genetic
material
n
=
2n
ZYGOTE
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
(outside layer)
Becomes the Nervous
System, skin, hair and nails
Endoderm
(inside layer)
digestive tract and
respiratory tract
Ectoderm
Muscles, circulatory system,
Mesoderm skeletal system, excretory
(middle Layer)
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