Trilaminar Stage
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| Hensen's node | Serves as organizer, secreting growth factors that induce tissue type differentiation and embryogenic patterning
🗑
|
||||
| Primitive pit | Pore in center of Hensen's node
🗑
|
||||
| Primitive streak (day 15 - week 4) | Faint white trace at caudal end of embryonic disc, formed by movement of cells at onset of mesoderm formation and providing 1st evidence of embryonic axis
🗑
|
||||
| Primitive ridges | Ridge that bounds the primitive groove in early stages of embryonic development
🗑
|
||||
| Primitive groove | Lengthwise median furrow in primitive streak of the embryo
🗑
|
||||
| Situs inversus | Developmental defect when viscera in abnormal left-right orientations; probably results from defective GF genes secreted from embryonic organizer (i.e. Hensen's node)
🗑
|
||||
| Partial situs inversus | Some organs are in opposite orientations; can be fatal
🗑
|
||||
| Total situs inversus | All organs are transposed; little to no clinical consequences
🗑
|
||||
| Primitive streak expansion, regression | Begins at caudal end of germ disc; elongates towards cranial end (until day 18); extends across ~2/3 length of germ disc; streak regresses, completely disappearing by 4th week
🗑
|
||||
| Grastrulation | First movement of embryonic cell populations, serving to compartmentalize embryo into 3 germ layers - ectoderm, endoderm, mesoderm
🗑
|
||||
| How is gastrulation accomplished? | With the primitive streak
🗑
|
||||
| What cells invaginate to form the primitive groove along the caudal medial line? | Epiblastic cells
🗑
|
||||
| Endoderm (intraembryonic endoderm) | Cells that have wedged into hypoblast (from the invagination and separation of cells form the epiblast); eventually, endoderm completely replaces hypoblast by pushing it out of germ disc and into yolk sac
🗑
|
||||
| Mesoderm | Invaginating cells (from the epiblast) that do not wedge into the hypoblast
🗑
|
||||
| Ectoderm | Epiblastic cells that do not pass through the primitive streak
🗑
|
||||
| From what are all three germ layers derived? | Epiblast
🗑
|
||||
| What gives the germ disc a pear shape perimeter? | The cells that migrate into the space between the epiblast and hypoblast spread in lateral and cranial directions
🗑
|
||||
| What plate do the cells that move in the cranial direction form? | Cardiogenic (heart forming) plate
🗑
|
||||
| What else can the cranial migrating cells generate? | The notochord
🗑
|
||||
| Which cells reach the cranial extremities first? | The first cells to pass through the streak; caudual mesoderm and endoderm = younger, differentiation slightly delayed; embryos tend to develop from cranial end towards caudal
🗑
|
||||
| Sacrococcygeal teratomas | Develop when primitive streak fails to regress; most common newborn tumors; derived from pluripotent cells; consist of misture of different cell types; tumors can usually be surgically removed
🗑
|
||||
| Caudal dysgenesis | Underdevelopment of caudal features due to insufficient mesoderm in caudal-most region of embryo
🗑
|
||||
| Symptoms/abnormalities of caudal dysgenesis | Hypoplasia, fusion of lower limbs, vertebral abnormalities, renal agenesis, imperforate anus, anomalies of genital organs
🗑
|
||||
| Sirenomelia | Extreme condition of caudal dysgenesis; legs fused to produce mermaid-like fetus; common teratogenic factor = maternal diabetes
🗑
|
||||
| Notochord | Hollow, cartilaginous rod that extends through midline; phylum named after it (Chordata)
🗑
|
||||
| Notochord's role in vertebrates | Organizer
🗑
|
||||
| What is the notochord derived from? | Hensen's node
🗑
|
||||
| What differentiation does the notochord control? | Neural tube, somites
🗑
|
||||
| What happens to the notochord after it has served its purpose? | Majority of it degenerates by apoptosis; some notochordal derived cells persist in adult as nuclei pulposus of intervertebral discs
🗑
|
||||
| Formation of notochord | Epitblast cells that invaginated thru primitive pit remain contiguous, extend in cranial direction to form hollow tube (notochordal process), lumen of tube = notochordal canal
🗑
|
||||
| What region prevents the continuation of the notochordal process? | Prechordal plate (progenitor of mouth); regions contains hypoblast & epiblast celss that block further progression of process; at this point, primitive streak regression commences; occurs around day 18
🗑
|
||||
| What does the notochord fuse with? | Underlining endoderm
🗑
|
||||
| What results from the fusion of the notochord with the underlining endoderm? | Opening to yolk sac; transitory channel (via primitive pit) connects amniotic cavity & yolk sac
🗑
|
||||
| What is the connection between the amniotic cavity & yolk sac called? | Neurenteric canal
🗑
|
||||
| The tubular process that has been flattened is called ... | Notochordal plate
🗑
|
||||
| The notochordal plate folds (reforming a tube), starting at the cranial end & progressing towards the caudal end | Notochord
🗑
|
||||
| What happens when the notochord detaches from the yolk sac endoderm? | The neurenteric canal closes
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
JaneO
Popular Anatomy sets