Lecture 2 (FIRST MIDTERM)

Question 1

3 germ layers from out to in:

Answer 1

Ectoderm
Mesoderm
Endoderm

Question 2

6 main chordate features:

Answer 2

Notochord
Pharyngeal slits
Endostyle or thyroid gland
Dorsal Hollow Nerve Tube
Postanal tail
Segmented body musculature

Question 3

The concept of “a tube in a tube” (like us) is called:

Answer 3

gastrulation

Question 4

Where the ectoderm thickens, there is a specific germ layer called…

Answer 4

neural plate ectoderm

Question 5

What is neurulation?

Answer 5

Ectoderm “rolls up” and leaves a hollow core (dorsal hollow nerve tube)

Question 6

What are pharyngeal slits?

Answer 6

Piercings or almost piercings (which are pharyngeal pouches)

Probably functioned in feeding or respiration in early chordates

Question 7

Endostyle:

Thyroid gland:

Answer 7

Endostyle: a ciliated groove in the floor of the mouth - present in early chordates
Thyroid gland: present in more advanced chordates

Question 8

The central nervous system in chordates develops embryologically from…

Answer 8

ectoderm

Question 9

What is the name of the canal going down your spinal cord?

Answer 9

neurocoel

Question 10

Post-anal tail:

Answer 10

A tail extending beyond the anus

Primarily for swimming in lower chordates

Question 11

Segmented body musculature:

Answer 11

Blocks of muscle that are arranged along the length of the body

Question 12

The notochord is embryologically derived from…

Answer 12

mesoderm

Question 13

The notochord is dorsal to what?

Answer 13

The coelom (body cavity)

Question 14

The notochord is ventral to what?

Answer 14

The central nervous system

Question 15

Neural crest ectoderm turns into..

Answer 15

Peripheral nervous system, ganglia of nervous system (cranial, spinal, autonomic), dentine of teeth, head skeleton, pigment cells, covering of the brain (meninges)

Question 16

Most superficial layer in an embryo (specific germ layer):

Answer 16

epidermal ectoderm

Question 17

Specific germ layer of the dorsal hollow nerve tube:

Answer 17

neural ectoderm

Question 18

Three divisions of the mesoderm:

Answer 18

Epimere
Mesomere
Hypomere

Question 19

Epimere forms what structures?

Answer 19

Somites

Question 20

3 types of Epimere and description:

Answer 20

Dermatome: dermis
Myotome: axial, limb, and body wall musculature
Sclerotome: vertebral column and ribs

Question 21

Specific germ layer of the notochord:

Answer 21

chordamesoderm

Question 22

Specific germ layer of somites:

Answer 22

paraxial mesoderm

Question 23

Intermediate mesoderm falls under this category:

Answer 23

mesomere

Question 24

The intermediate mesoderm forms…

Answer 24

urogenital system

Question 25

Dorsal hollow nerve tube forms...

Answer 25

central nervous system

Question 26

Specific germ layer of splanchnic lateral plate mesoderm...

Answer 26

lateral plate mesoderm

Question 27

Specific germ layer of somatic lateral plate mesoderm...

Answer 27

lateral plate mesoderm

Question 28

The Splanchnic lateral plate mesoderm forms...

Answer 28

heart, blood vessels, smooth muscle of digestive system

Question 29

The Somatic lateral plate mesoderm forms...

Answer 29

limb skeletons

Question 30

Hypomere consists of...

Answer 30

Somatic lateral plate mesoderm and Splanchnic lateral plate mesoderm

Question 31

What lines the digestive tube?

Answer 31

endoderm

Question 32

Endoderm lining of the digestive tube:

Answer 32

- Abdominal foregut: stomach, liver, pancreas, beginning of small intestine - Abdominal midgut: most of small intestine, beginning of large intestine - Abdominal hindgut: terminal intestines, urinary bladder

Question 33

Segmentation is most obvious in what derivatives?

Answer 33

Mesoderm derivatives | Somites (dermatome, myotome, schlerotome)

Question 34

Transsegmental structures:

Answer 34

``` Dorsal hollow nerve tube Notochord Dorsal aorta Gut Coelom Lateral mesoderm Surface ectoderm ```

Question 35

What does transsegmental mean?

Answer 35

Continuous (longitudinal)

Question 36

Segmented structures:

Answer 36

Somites Intermediate mesoderm Segmental arteries Segmental nerves

Question 37

Inner lining of the digestive tube is _________ and the outer lining is __________

Answer 37

Inner lining of the digestive tube is _endoderm_ and the outer lining is _mesoderm_

Question 38

Parietal serosa lines... | And is associated with...

Answer 38

the inside of somatic lateral plate mesoderm | and is associated with the body wall

Question 39

Visceral serosa lines...

Answer 39

the gut wall "outside"

Question 40

Parietal serosa and visceral serosa are types of...

Answer 40

peritoneum (inside abdominal cavity)

Question 41

The "space" in between the body wall "tube" and the gut wall "tube" is called...

Answer 41

coelom

Question 42

The connection between body wall and plate mesoderm is called...

Answer 42

Somatopleure

Question 43

The connection between mesoderm and endoderm is called...

Answer 43

Splanchnopleure

Question 44

The "openings" that act as bridges for blood vessels to the gut tube are called...

Answer 44

Dorsal mesentery and ventral mesentery

Question 45

Which mesentery is closer to the aorta/notochord/DHNT?

Answer 45

Dorsal mesentery

Question 46

Explain neurulation.

Answer 46

Single layer of epidermal ectoderm with thickening in the middle (neural plate - neural ectoderm) Plate starts to fold and neural folds move toward each other and create a neural groove (just beneath the neural folds is neural crest tissue) Neural folds come together and create a tube, which separates from epidermal ectoderm Becomes Dorsal Hollow Nerve Tube (still neural ectoderm)