1.2 - Embryology + Anamolies Flashcards Preview

ECU Craniofacial Anomalies + Laryngeal Rehab > 1.2 - Embryology + Anamolies > Flashcards

Flashcards in 1.2 - Embryology + Anamolies Deck (68)
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1

What is an Embryo?

(2)

The first stage of development in utero

Between fertilization and 8 weeks

2

What is a Fetus?

How does it differ from an embryo? (2)

In utero - between 8 weeks gestation to birth

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Organs begin functioning

Genitalia are visible on ultrasound

3

How large is an embryo at 4 weeks?

2.5 mm

4

What are Somites on an embryo?

(2)

Bilaterally paired blocks of mesoderm

Gives rise to the vertebrae, rib cage, and part of the occipital bone; skeletal muscle, cartilage, tendons, and skin (of the back).

5

How big is a fetus at 6 weeks?

8 mm

6

What are the 3 Germ Layers? on an embryo

Ectoderm

Mesoderm

Endoderm

7

What is the Ectoderm on an embryo?

(2)

Outer layer

Forms central nervous system, peripheral nervous system, + epidermis

8

What is the Mesoderm on an embryo?

(2)

Middle layer

Forms connective tissue, cartilage, bone, striated + smooth muscles, heart, blood + lymph vessels, kidneys, gonads, and other organs

9

What is the Endoderm on an embryo?

(2)

Inner layer

Forms epithelial lining of organs, parenchyma of the tonsils + other organs, epithelial lining of tympanic cavity, auditory tube, and other organs

10

What is the Neural Tube on an embryo?

(3)

Tube located in middle of embryo

Precursor to Central Nervous System

Rostral end will become brain

11

What structures can we see on an Embryo between 3-4 weeks?

(7)

Frontonasal Prominence

Heart

Umbilical Cord

Pharyngeal Arches 1 + 2

Mandibular Arch already formed

Lungs

Limb Buds

12

What is the Frontonasal Prominence of an embryo?

When does it appear?

Two areas of thickened ectoderm under the fore-brain, one on either side

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3rd week

13

What is contained in the Frontonasal Prominence of an embryo?

(3)

Olfactory pits

Nasal pits (will become nostrils)

Upper lip

14

How do the nasal pits/nostrils form (Frontonasal Prominence) on an embryo?

When does it appear?

Fusion of median + lateral nasal prominences

4th week

15

How is the upper lip formed (Frontonasal Prominence) on an embryo? (2)

When does it appear?

Fusion of maxillary + median

Merging of median nasal

//

7th week

16

What is the Maxillary Processes on an embryo?

When does it appear

Embryological structure which gives rise to the upper jaw elements (e.g., maxillary bone) of the developing face

4th week

17

How is the Maxillary Processes formed on an embryo?

(3)

They enlarge and grow ventrally and medially, surrounding the future oral cavity.

Grow rapidly, first meeting the lateral nasal processes, and then the lower extension of the medial nasal processes.

The lower extension will give rise to the midstructure (philtrum) of the upper lip.

18

What are the Mandibular Process on an embryo? (2)

What are they the first to do?

When do they appear?

Forms the lateral wall and base of the primitive mouth

Give rise to the mandible and the lower part of the face and tongue.

//

First to merge with each other at the mid line

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7th week

19

How do ears appear on an embryo?

Ears appear lateral + posteriorly as low set ears

20

What is the Hyoid Arch on an embryo?

When does it appear?

Almost complete ring of tissue around the external auditory meatus

4th week

21

What comes together to form the Hard Palate on an embryo?

(2)

Premaxillae

2 Palatine processes (vertical orientation)

22

Are the Oral and Nasal Cavities separated in a embryo at 7 weeks?

(2)

No

Tongue is in both cavities

23

What are the Pharyngeal Arches on an embryo?

When do they appear?

Series of externally visible anterior tissue bands lying under the early brain that give rise to the structures of the head and neck

4th week

24

What is the Mandibular Arch?

When does it form?

First of the bronchial arches

4th week

25

What happens if there is an interruption to fetal development during week 6?

Cleft lip (+/- palate) will remain

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26

What forms the Nasal Prominence in an embryo?

Fusion of the maxillary prominence

27

What forms the Philtrum in an embryo?

Merging of median nasal prominence along with inferior movement

28

What is Fusion?

Two separate processes unite and become one

29

What is Merging?

Underlayers "push" up epithelium to "fill in" structures

(not a combining of two structures)

30

What important structure develops during the 9th week of fetal development?

How does this occur? (3)

Palate

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Fusion of shelves (palatine processes)

Starts anteriorly to posterior

Last thing to fuse is uvula (bifid uvula)