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Flashcards in Embryo Deck (44):
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Mutation in sonic hedghog

Holoprosencephaly

1

Mutations in homeobox genes

Appendages in the wrong location

2

What day is implantation?

Day 6

3

When does the neural tube close?

Week 4

4

When does the heart begin to beat?

Week 4

5

What is derived from surface ectoderm?

Adenohypophysis
Lens of the eye
Epi linings of oral cavity, sensory organs of the ear, olfactory epithelium
Epidermis
Anal canal below the pectinate line
Parotid, sweat and mammary glands

6

What is derived from neuroectoderm?

CNS

7

What is derived from the neural crest?

PNS
Melanocytes
Chromaffin cells of adrenal medulla
Para follicular cells of thyroid
Schwann cells
Bones of skull
Odontoblasts
Aorticopulmonary septum

8

What is derived from mesoderm?

Muscle, bone, CT, serous linings of body cavities
Spleen
CV
Lymphatics
Blood
Wall of gut tube and bladder
Urethra
Vagina
Kidneys
Adrenal cortex
Dermis
Testes
Ovaries

9

What is derived from endoderm?

Gut tube epithelium
Lungs
Liver
Gallbladder
Pancreas
Eustachian tube
Thymus
Parathyroid
Thyroid follicular cells

10

Failure of fusion of the neuropores
Increased AFP and AchE

NT defects

11

What is the urachus?

A duct between the bladder and yolk sac

12

What happens when the urachus fails to obliterate?

Urine discharge from umbilicus
Outpouching of the bladder

13

What is the vitelline duct?

Duct between yolk sac and midgut lumen

14

What comes from the 1st aortic arch?

Part of the maxillary artery (external carotid)

15

What comes from the 2nd aortic arch?

Stapedial artery and hyoid artery

16

What comes from the third aortic arch?

Common carotid artery
Proximal part if the internal carotid

17

What comes from the fourth aortic arch?

Aortic arch
Proximal part of right subclavian

18

What comes from the sixth aortic arch?

Proximal part of pulmonary arteries
Ductus arteriosus

19

What are the branching clefts derived from?

Ectoderm

20

What is derived from the 1st bronchial cleft?

External auditory meatus

21

What happens with failure of obliteration of branchial clefts?

A persistent cervical sinus in the lateral neck

22

What comes from the branchial arches?

Mesoderm and neural crest

23

What comes from the 1st branchial arch?

Meckel's cartilage: mandible, malleus, mandibular ligament
Muscles of mastication
Mylohyoid
Medial pterygoids
CN V2/3

24

What is the anomaly associated with the first branchial arch?

Treacher-Collins syndrome: first arch neural crest fails to migrate
So you get mandibular hypoplasia, facial abnormalities

25

What comes from second branchial arch?

Reichert's cartilage: stapes, stylohyoid, stapedius, facial muscles
CN VII

26

What comes from the 3rd branchial arch?

Greater horn of hyoid cartilage
Stylo pharyngeal muscle
CN IX

27

What is a congenital pharyngocutaneous fistula?

Failure of 3rd branchial arch to obliterate
Get mass in the lateral neck from fistula in the tonsillar area

28

What is derived from the 4th-6th branchial arches?

Throat cartilage
4th arch - all pharyngeal constrictors except cricothyroid and levator veli palatini, superior laryngeal branch of CN X (swallow)
6th - all intrinsic muscles of the larynx except cricothyroid, recurrent laryngeal branch of vagus (speak)

29

What is derived from the first branchial pouch?

Middle ear, Eustachian tube, mastoid air cells

30

What is derived from the second branchial pouch?

Develops into epithelial lining of palatine tonsil

31

What happens with a failure of the second pouch to regress?

A pharyngeal fistula - lateral anterior neck mass

32

What is derived from the 3rd pouch?

Inferior parathyroids
Thymus

33

What is derived from the 4th pouch?

Superior parathyroids
Parafollicular cells of the thyroid

34

What happens from incomplete fusion of the paramesonephric ducts?

Bicornuate uterus
Uterus didelphus

35

What structures are derived from the mesonephric duct?

SEED
Seminal vesicles
Ejaculatory duct
Epididymis
Ductus deferens

36

What structures come from the paramesonephric duct?

Fallopian tubes, uterus, upper portion of vagina

37

What comes from telencephalon?

Cerebral hemispheres and 4th ventricle

38

What comes from diencephalon?

Thalamus
3rd ventricle

39

Mesencephalon?

Midbrain and aqueduct

40

Metencephalon

Pons, cerebellum, and upper part of 4th ventricle

41

Myelencephalon

Medulla
Lower part of 4th ventricle

42

What does the ureteric bud give rise to?

Ureter
Calyces
Pelvises and collecting ducts

43

What does the metanephric mesenchyme do?

Interacts with the ureteric bud --> formation of glomerulus thru distal convoluted tubule