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Development Study Guide

Histology

Human Development Lab Assignment

Human Development

Lab Component

http://www.tokyo-med.ac.jp/genet/mfi-e.htm

I). Gametes

A). Structure of sperm

1). Head

acromere

2). Midpiece

3). Tail

 

  http://www.ivf-infertility.com/infertility/investigations/

primary oocyte

http://www.ouhsc.edu/histology/text%20sections/female%20reprodcutive.html

         http://www.drmalpani.com/embryos2.htm

PRIMARY OOCYTE

     SECONDARY OOCYTE

B). Oocyte

1). Primary oocyte:

2). Secondary oocyte:

offspring inherit  mitochondrial DNA from their mothers.

 

After meiosis only one cell contains almost all of the cytoplasm and organelles.

The sperm does not bring in any cytoplasm or organelles

Thus offspring inherit mitochondria (& mitochondrial DNA) from their mothers.

Penetration of the Sperm Sperm Entering the Oocyte

II). How does the sperm penetrate the secondary oocyte?

1.  Oocyte encapsulated

corna radiata

zona pellucida

2.
The sperm becomes capacitated (readied)

3.  The enzymes of one acromere are not enough to break through the capsule.

4. Connect to the sperm receptors

5. Sperm and oocyte membranes merge 

III). Immediately after fertilization occurs

Fertilization occurs

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sperm loses tail

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secondary oocyte undergoes meiosis II

(meiosis I occurred during the female’s fetal development)

eject polar body

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female pronuclei & male pronuclei

form a mitotic spindle

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 produce a diploid zygote.

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undergoes cleavage

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trophoblast

 

Penetration of the sperm until the formation of 2 duaghter cells
IV). Stages of Development

Primary oocyte

Secondary oocyte

Ovum

Zygote

Embryo

Fetus

 
V).  Zygote Development

Zygote formation

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cleavage

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4 cells

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Morula

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Blastocyst

 

Stages of Zygote Development
Blastocysts differentiates into the:

Inner cell mass

Trophoblast cells

 

Embryo Implants

VI). Embryonic Membranes

 develop during gastrula

1). Embryonic (Disc) Germ Layers

Ectoderm

Mesoderm

Endoderm

2).  Amnion:

3). Yolk Sac:

  •  part of the gut
  •  early blood cells
  • forms  gonads

4). Allantios:

5). Chorion:

 
VII). Placenta

A). What prevents the normal sloughing off of the uterine wall?

The  embryo must maintain the corpus luteum until the placenta can take over its endocrine functions.

 human chorionic gonadotropin (hCG) acts like luteinizing hormone.

B). Formation

Trophoblast

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Chorion & chronic villi form:

(Amnion forms around the embryo)

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new vessels form, which extend to the embryo

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 The endometrium the villi forms the placenta.

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Fetal side is flat and smooth and slick

     Maternal side is bumpy

VII). Fetal Circulation  

Blood cells arise in the yolk sac

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spaces appear in mesoderm

(middle germ layer)

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become network

heart, blood vessels, etc.

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by 3.5 weeks heart is formed and beating

1. Umbilical vein (to the heart) transports oxygen rich blood from the placenta to the fetus

 

2. Blood enters the liver and the ductus venous that shunts blood to the vena cava

 

3. Most of the blood is than shunted from the right atrium to the left atrium bypassing the pulmonary arteries and lungs.

 

4. The opening between the atriums of the heart is called the foramen ovale

 

5. Blood in the pulmonary trunk enters the aorta-bypassing lungs at the ductus arteriosus

 

6. Blood in the descending aorta branches off into the umbilical arteries and to the placenta

 

  http://nursingcrib.com/nursing-notes-reviewer/fetal-circulation/