development of the human embryo mr. nichols phhs

Development of the Human Embryo

Mr. Nichols PHHS

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Breaking News!!!• Outside the Diner at 9pm last night, James Scott and Dr.

Ainsworth were in a verbal and physical altercation. This ended with James Scott being struck in the face and knocked out cold. Dr. Ainsworth then promptly got into his BMW and drove away.

• Neither party is going to press charges but James was later treated by nurses for a mild concussion as well as a nasal fracture.

• AJ and Goldie were witness to this event. And agreed, that the altercation was because James accused Dr. Ainsworth of killing his brother and all the other people.

Breaking News!!!• AJ went on to say that “Dr. Ainsworth did not say anything to

deny the allegations but was adamant that he not cause a scene and arouse panic. “

-Note AJ was the one to break up the fight and said he smelt alcohol on the Dr’s breath.

• Goldie said “All the things James was saying made sense, and if he was the one responsible for my sister’s death, I don’t know what I’d do!!!!”

Developmental History of a Human

1. Fertilization

2. Cleavage

2. Cleavage

1. Begins ~ 12 hours post-fertilization2. Zygote divides into 2 cells (mitosis)3. 46 chromosomes in zygote = 46

chromosomes in both daughter cells4. 2 cell into 4 cell stage (24 – 36 hours)5. 4 cell into 8 cell stage (36 – 72 hours)6. 16 cell stage -- Morula

3. Morula

Morula

3. Morula

• ~ 16 cell stage• Develops ~ 72 hours (3 days) from

fertilization• Morula enters the uterus ~ after 3 days in

oviduct

3. Morula

72 hours post-fertilizationentering uterus

Gestational Sac

4. Blastocyst

4. Blastocyst

• Morula, once entering the uterine cavity, floats freely

• Morula begins to accumulate fluid and forms a cavity between its cells

• Once cavity appears, it is now called ablastocyst.

4. Blastocyst

4. Blastocyst• Blastocyst has fluid-filled inner cavity• Evolves from morula on day 5

Implantation

Two Distinct Cell Types

Inner cell mass

trophoblasts

Two Distinct Cell Types

1. Trophoblasts – will form the invading placenta

2. Inner cell mass cells – will form the embryo

hCG is produced• hCG is human chorionic gonadotropin• Large amounts are produced by the trophoblasts

starting on day 6• hCG is a hormone• hCG causes endometrium of uterus to grow and

proliferate• hCG prevents the menstrual cycle from occuring• This is why a female misses her periods when she

is pregnant

Week 2

• Implantation continues• Erosion of maternal bloodvessels• Complete emersion intoendometrium of uterus

Weeks 3-4• Development of CV and nervous systems

Weeks 3-4

Weeks 5-8• Embryo will develop all structures that an adult has by the end

of week 8

Embryo/Fetus• Embryonic period is weeks 1-8• Fetal period begins on week 9 and goes until

birth at 38 weeks.• Embryonic period is characterized by

development of structures (organs).• Fetal period is characterized by growth of

those structures.

Fetal Period

9-12

13-16

17-20

21-38

Placenta

• The placenta is a structure that develops in your uterus during pregnancy. The placenta provides oxygen and nutrients to your growing baby and removes waste products from your baby's blood.

• It attaches to the wall of your uterus, and your baby's umbilical cord arises from it. In most pregnancies, the placenta attaches at the top or side of the uterus.

Placenta

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Background

• Hepatitis B Acute Disease• 1% mortality rate• 85-90% complete resolution• 10-15% chronically infected

• Hepatitis B Chronic Disease• Persistent e antigen• Active viral DNA synthesis

• 4,000 to 5,000 die annually secondary to chronic liver disease

Background

• Hepatitis B• Horizontal transmission

• Parenteral contact (IV drug use)• Sexual contact (25% regular contacts will

convert)• Vertical transmission

• Transmission to neonate• World-wide #1 transmission

Frequency in Pregnancy

• In the United States• Acute Hepatitis B

• 1-2/1,000 pregnancies• Chronic carrier

• 5-15/1,000 pregnancies

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Breaking News!!!!• The new church went through its last structure inspection

yesterday. Daniel Anderson was the man responsible for commissioning the new property.

• Mr. Anderson reached out to our Chief yesterday to report some weird findings.

• He said: “While the structure was safe and passed code, there were some out of the ordinary aspects, not typically found in a church. All I know is there is three hollow columns into the tabernacle that are surrounded by heating coils. There has also been digging specialized crews on site for a while now.”

Church Tabernacle