Topic 2 - Stages of Development Flashcards
(93 cards)
A time period known as __________ that starts with fertilization. The cells divide continuously over the course of 2 weeks.
Conception
When the sperm unites with the ovum and produces a zygote.
Fertilization
A mass of 12 to 16 cells that form within 72 hours of conception. It travels down the fallopian tube with peristaltic movements.
Morula (aka. Mulberry)
The morula enters the uterus and divides into a __________ within 3 to 6 days of conception.
Blastocyst
What are the 2 parts of a blastocyst?
1) Trophoblast
2) Embryoblast
Make up the outer border of a blastocyst and this will form the placenta.
Trophoblast
Make up the inner mass of a blastocyst and this will form the embryo.
Embryoblast
The _________ period occurs from 2 to 8 weeks. There is an increase in cell numbers and elaboration of cell product.
Embryonic
What are the 3 germ layers that develop during the embryonic period that all organs and structures of the body will be derived from?
1) Ectoderm
2) Mesoderm
3) Endoderm
Development of form and massive cell movement.
Morphogenesis
A period of _____ development occurring at 3 weeks of the embryonic period. There is development of the _________/axial skeleton arising from the mesoderm layer.
Rapid
Notochord
Primitive heart development starts at this stage, arising from the mesoderm layer, occurring at ____ weeks. Neural plates & folds, which arise from a thickened portion of the ectoderm layer, form a closed neural tube which will house the ____________. Limb buds and optic pits also form.
4
Spinal Cord
A condition where a portion of the neural tube fails to develop or close properly, causing defects in the spinal cord and in the bones of the spine. It can range from mild to severe and when early treatment is necessary, it is done surgically but doesn’t always resolve the issue.
Spina Bifida
When does Spina Bifida occur?
24th-27th day closure of the spine
A congenital heart defect when a valve doesn’t close properly
Heart Murmur
The time period when upper limbs form is ____ weeks
6
The time period when digits form and intestines enter the umbilical cord and start developing from there is ____ weeks
7
Occurs when part of the intestine sticks out through the opening in the embryo’s abdominal muscles through which the umbilical cord passes. It is very common and typically harmless
Umbilical Herniation
The time period when the fetus is considered “human-like” and eyes open and eyelids/ears are present is ____ weeks
8
Time period from 9 weeks until birth (38-40 weeks)
Fetal Period
When centres of the skull and long bones undergo ________, external genitalia forms, liver becomes the site of RBC production, and kidneys become functional by turning urine into amniotic fluid. Growth and differentiation of the body and organ systems occurs at ____ weeks. Fetal head growth ________ and body length growth ________.
Ossification
12
Slows
Accelerates
Ossification of the skeleton, scalp hair patterning, and differentiation of ovaries occurs during the ______ week
13-16th
Fine hair called ________ and creamy biofilm called ____________ is produced during the ______ week. Eyebrows, hair, and ________ fat is also present during this time period.
Lanugo
Vernix Caseosa
17-20th
Brown
The first hair to be produced by the fetal hair follicles and is very soft and usually unpigmented. It is normally shed before birth (around ______ months of gestation), but is sometimes present at birth and will disappear on its own within a few days/weeks.
Lanugo
7-8
