Developmental Anatomy Block 2

Front 1

Gestational Age AKA Menstrual Age

Back 1

Age calculated since FIRST day of LAST NORMAL MENSTRUAL PERIOD (LNMP)

Length of Pregnancy = 280 Days (40 Weeks)

Front 2

Conceptual Age AKA Embryonic Age AKA Fetal Age

Back 2

Age begins at conception, about 2 weeks AFTER LNMP

Length of Pregnancy = 266 Days (38 Weeks)

Front 3

Trimesters:

Back 3

First: LNMP - 14 Weeks Gestational

Second: 14 - 26 Weeks Gestational

Third: 26 - 40 Weeks Gestational

Front 4

Nagele's Rule:

Back 4

Predicts birth date:

First Day LNMP - 3 Months + 1 Year + 7 Days

Front 5

Quickening

Back 5

When mother first feels the fetus move.

Occurs 17-20 Weeks

Front 6

When does an embryo look recognizably human, assuming the name "fetus"?

Back 6

End of 8th Week-Beginning of 9th Week

Front 7

Distinguishing Features of Week 5 Embryo:

Back 7

-Enlargement of Head
-Mesonephric Ridge =Developing Kidney
-Upper Limb Bud = Paddle-Shaped
-Lower Limb Bud = Flipper Like

Front 8

Distinguishing Features of Week 6 Embryo:

Back 8

-Elbows and Hand Plates Develop
-Digital Rays in Hand Plates
-Auricular Hillocks Develop Between First 2 Pharyngeal Arches
-Eye
-Significant Cervical Flexure

Front 9

Distinguishing Features of Week 7 Embryo:

Back 9

-Umbilical Herniation Begins
-Notches appear between digital rays in hand plates
-Bones of upper limb begin ossification

Front 10

Distinguishing Features of Week 8 Embryo:

Back 10

-Digits of hands separated, but webbed
-Notches visible in digital rays of foot plates
-Scalp vascular plexus
-Ossification of lower limbs develops
-Caudal eminence disappears
-Auricles of external ear develop
-Eyelids present, then fuse

Front 11

Measurement Types:
1) Greatest Length
2) Crown-Rump Length
3) Crown-Heel Length

Back 11

1) Unfolded, single disc, young embryos
2) Most frequently used (sitting height), good for embryonic period (folded) - end of first trimester
3) Standing height, good for fetus stage

Front 12

Changes in Fetal Size (9-38 Weeks Conceptual)

Back 12

Length Growth - Most rapid in early fetal periods

Weight Growth - Most rapid in late fetal periods

Front 13

When can you determine sex of a fetus via visual appearance?

Back 13

12-14 Weeks

Front 14

Timing of:

1) Heart Beat-
2) Detection of Heart Beat via Doppler Amplification-
3) Detection of Heart Beat via Stethoscope-

Back 14

1) 22 Days
2) 8 Weeks
3) 20 Weeks

Front 15

Ultrasonography

Back 15

Permits:

-Age Estimate
-Sex
-Many Fetal Anomalies

Front 16

When do the finger nailes/toenails reach the tips of fingers/toes?

Back 16

Finger - 32 Weeks

Toe - 36 Weeks

Front 17

What are the following derived from?

1) Pia/Arachnoid Membranes
2) Dura Matter

Back 17

1) Neural Crest Cells

2) Mesoderm

Front 18

Sym/Parasym NS Development:

Back 18

Basal Plate of Neural Tube--> Preganglionic Neurons

Neural Crest --> Postganglionic Neurons

Front 19

What determines migration patterns of Neural Crest cells?

Back 19

Combo of 2 things:

1) Intrinsic Properties
2) Features of External Environment encountered

Migration ends when they run into barriers and accumulate!

Front 20

Differentiation of Neuroblasts

Back 20

Exit cell cycle, extend processes forming bi-polar neuroblast (one process = primitive axon, the other = primitive dendrite).

Once formed, neuroblast has differentiated and can NOT divide anymore.

Front 21

Where do early migratory neural crest cells go (8 pairs of somites)?

Late migrating (12 pairs)?

Back 21

Early - Ventrally and Medially

Late - Dorsally

Front 22

Where are CNS neurons and glial cells derived from?

Back 22

All from neuroepithelium EXCEPT for Microglia which are derived from Mesenchymal cells in the bone marrow!

Front 23

Synapse Pruning Implications

Back 23

Removes select synaptic inputs

However, this actually increases the overall strength of individual synapses because they enlarge/their complexity increases

Front 24

When does myelination of CNS complete?

Back 24

Continues after birth when CNS tracts are functional

Some not complete until 30 years of age!

Front 25

Order of Cortical Layer Development:

Back 25

1 (most outer) --> 6 (most inner) --> 5 --> 4 --> 3 --> 2

Thus, with the exception of layer 1, the innermost layers develop prior to the outer layers

Front 26

What neurological disorders have been associated with altered rated or neurogenesis?

Back 26

Alzheimer's Disease
Temporal-Lobe Epilepsy
Ischemia
Depression

Front 27

What are the most active sites of neurogenesis in the adult nervous system?

Back 27

Olfactory Bulb
Olfactory Epithelium (PNS)
Hippocampus (Dentate Gyrus) --> High level of plasticity

Front 28

Sex Differences in Nervous System Development is due to what?

Back 28

Probably both hormonal (gonadal steroid hormones) AND non-hormonal (differential sex chromosome gene expression)

Front 29

When should a woman supplement with Folic Acid?

Back 29

BEFORE CONCEPTION!