1 Menstruation or Pregnancy Human Reproduction II.
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Transcript of 1 Menstruation or Pregnancy Human Reproduction II.
1
Menstruation or PregnancyHuman Reproduction II
S1-1-09 Describe the structure and function of the male and female reproductive systems.
S1-1-10 Outline human development from conception through birth.
Vocabulary & People Ovulation Menstruation FertilizationZygote Embryo Fetus
Ovulation: Release of ovum from a follicle in the ovary as a response to a hormonal signal (brain - LH).
• Follicle – cells surrounding the egg inside (becomes corpus luteum)
Menstruation:Monthly cycle of changes that occur in the ovaries and uterus - including ovulation.• Ovulation occurs around the 13-15 day of cycle
The “egg(s)” is also know as an oocyte(s) or an ovum (ova)
Endometrium: the inside of the uterus
– the part that prepares for the
baby – also called endometrial lining
Menstruation
Ovulation
Menstrual Cycle consists for four steps:approximately 28 days before repeating
STEP Key Hormone DAY
• Brain triggers development of a follicle • Building up endometrium
• FSH• Estrogen
1 - 13
• Follicle releases ova (egg) – ovulation • LH 13 - 15
• Corpus Luteum forms • Endometrium is maintained • Progesterone
15 - 21
• No fertilization – menstruation• Endometrial lining and ova are expelled
All hormones at low levels
21 - 28
Notice: two hormones made by the “shell ”– estrogen and progesterone – work to prepare the uterus for a fertilized egg
14 21
14 21 28 days
0 7 14 21
Regression
Pituitarygland
Progesterone
Estrogen
28 days
28 days
FSH FSH
LH
0 7
0 7
Female Menstrual Cycle
Brain Hormone Levels
Ovarian Cycle
Sex Hormone Levels
Endometrial changes
Notice: the shedding of the endometrium ends and begins the
diagram - it’s a continuous CYCLE
Fetal Development
Egg and sperm meet in the oviduct - Fertilization.
Remember: the sex is determined by the male - X or Y sex
chromosome in the sperm
• Nuclei join to produce a single diploid cell called a zygote
• Zygote implants into the endometrium and releases hormones to maintain the lining
MEIOSIS– MALES
46 ChromosomesDIPLOID 2n
HAPLOID 1n
x y
xx yyxx yy
Female sperm Male sperm
MEIOSIS– FEMALES
46 ChromosomesDIPLOID 2n
HAPLOID 1n
x x
xx xxxx xx
Female egg
x xx
y
Female zygote Male zygote
x xx
y
There are 2 stages of “baby” development:
1. Embryo Stage (the first 8 weeks)Zygote implants in endometrial lining and begins togrow (divide) by mitosis.
Once implanted – called an embryo
Cleavage: the process of mitotic divisions that
change zygote into a multicellular embryo.
Congrats! You are now officially pregnant
2. Fetus Stage (after 8 weeks till birth)
Developing embryo forms bone cells around the ninth week of pregnancy.
Once bone forms - called a fetus (until born)
Placenta - exchanges waste and nutrients through umbilical cord.
Amnion – protective sac filled with fluid.
Pregnancy can also be divided in 3 trimesters:
1st trimester – conception to 3rd month• development of all body systems and organs• fetus is particularly sensitive to alcohol/drugs• sex can be determined
1st trimester
2nd trimester – 4th to 6th months• period of rapid and continuous growth• Only brain and lungs still developing• embryo movements can be felt
2nd trimester
3rd trimester – 7th to 9th (birth) month• fetus kicks, stretches and moves freely• Eyes sense light, fingerprints have formed• At end – fetus weighs 3300 grams, 35 cm long
3rd trimester
And then, before you know it...
CAN YOU ANSWER THESE QUESTIONS?S1-1-09:What parts make up the male and female sex systems and what is the function of each part?
S1-1-10:How does a fertilized egg turn into a baby and what determines the gender?
Vocabulary & People Ovulation Menstruation FertilizationZygote Embryo Fetus