Embryology

Question 1

What is a blastula?

Answer 1

Embryonic ball of cells

Question 2

What is a bilaminar disc?

Answer 2

Flattened plate of cells with amniotic cavity dorsally and yolk sac ventrally

Question 3

What does the bilaminar disc form?

Answer 3

Trilaminar disc- ectoderm, mesoderm and endoderm

Question 4

Why is there no mesoderm at 2 point in the embryo?

Answer 4

Areas that will form the mouth and anus

Question 5

What causes axis formation in the embryo?

Answer 5

Notochord formation

Question 6

What germ layer forms the neural tube?

Answer 6

Ectoderm

Question 7

What forms the neural crest cells?

Answer 7

Some cells at the crest of the neural fold that seperate

Question 8

When do neural crest cells mix with the mesoderm?

Answer 8

In the head and neck region

Question 9

What is the cavity at the superior of the embryo?

Answer 9

Amniotic

Question 10

What cavity is at the inferior of the embryo?

Answer 10

Yolk sac

Question 11

What are somites?

Answer 11

Cells derived from the paraxial mesoderm and form structures like the axial skeleton and muscles

Question 12

How many somites are there?

Answer 12

33 in total

Question 13

What do somites in the head region of the embryo form?

Answer 13

Help in development of cranial skeleton

Question 14

What are the branchial arches?

Answer 14

Series of arches which develop around the future mouth and pharynx

Question 15

What is the function of the branchial arches?

Answer 15

Support primitive pharynx

Face and neck development

Question 16

Hw many branchial arches are there in humans?

Answer 16

5

Question 17

What does the ectoderm form in the branchial arches?

Answer 17

Clefts between arches

Question 18

What does the mesoderm form in the branchial arches?

Answer 18

Cartilage

Muscles

Question 19

What does the endoderm form in the branchial arches?

Answer 19

Pouched between arches

Question 20

What nerve supplies the 1st branchial arch?

Answer 20

Mandibular branch of trigeminal nerve

Question 21

What does the 1st branchial arch form?

Answer 21

Anterior belly of digastric muscle

Mandible, males, incus

Question 22

What nerve supplies the 2nd branchial arch?

Answer 22

Facial nerve

Question 23

What does the 2nd branchial arch form?

Answer 23

Muscles of the face and posterior belly of the digastric muscle
Hyoid, styloid, stapes

Question 24

What nerve supplies the 3rd brcnhail arch?

Answer 24

Glossopharyngeal

Question 25

What nerve supplies the 4th branchial arch?

Answer 25

Superior laryngeal branch of vagus

Question 26

What does the 4th branchial arch form?

Answer 26

Striated muscle of oesophagus and cricoid cartilage | Thyroid cartilage

Question 27

What nerve supplies the 6th branchial arch?

Answer 27

Recurrent laryngeal branch of vagus

Question 28

What does the 6th branchial arch form?

Answer 28

Striated muscle of oesophagus and cricoid cartilage

Question 29

What does the 3rd branchia; arch form?

Answer 29

Hyoid

Question 30

What glandular structures develop from the branchial arches?

Answer 30

Thyroid Parathyroid Part of pituitary

Question 31

What does the face develop from?

Answer 31

5 processes

Question 32

What are the 5 processes that the face will develop from?

Answer 32

Frontonasal process Two maxillary processes Two mandibular processes

Question 33

How are the nasal placodes formed?

Answer 33

Rapid downward growth of the frontonasal process

Question 34

What happens to the nasal placodes?

Answer 34

Invaginate to form the nasal pit, which will form the nostrils

Question 35

How are the nostrils and mouth separated?

Answer 35

Formation of 2 medial processes which fuse and 2 lateral nasal processes

Question 36

What do to medial processed form?

Answer 36

Philtrum and septum

Question 37

What are the 2 maxillary processes formed from?

Answer 37

Maxillary part of 1st branchial arch

Question 38

What do the mandibular processes form from?

Answer 38

1st brachial arch mesoderm

Question 39

What do the mandibular processes do?

Answer 39

Fuse in the middle to separate oral and nasal cavities

Question 40

What forms the flat bones of the skull?

Answer 40

Membranous ossification

Question 41

What forms the irregular bones of the skull?

Answer 41

Endochondral ossification

Question 42

What forms the skeleton of the face?

Answer 42

Branchial arches and sensory capsules

Question 43

What is the process of membranous ossification?

Answer 43

Mesenchyme directly above the surface of the brain ossifies

Question 44

What forms the mesenchyme around the notochord?

Answer 44

Mainly neural crest cells

Question 45

What is the process of endochrondral ossification?

Answer 45

Preform in cartilage, then ossify

Question 46

What are the sensory capsules derived from?

Answer 46

Mesoderm of somites in head and neck