Topic #9 DEVELOPMENT OF THE DIGESTIVE SYSTEM

Question 1

The digestive system consists of the following : (11 parts)

Answer 1

mouth (oral cavity)
pharynx
esophagus
stomach
small intestine
colon and cecum
rectum
anal canal
liver
pancreas
salivary glands

Question 2

The oral cavity is derived from what?

Answer 2

stomodaeum

Question 3

It is a depression of surface ectoderm cranial to the pharynx. The stomodaeum is separated from the foregut (pharynx) by the oral plate or oropharyngeal membrane.

Answer 3

stomodaeum

Question 4

What separates the stomodaeum from the foregut (pharynx)?

Answer 4

Oral plate or oropharyngeal membran

Question 5

It is a thin membrane formed by the fusion of the stomodeal ectoderm and pharyngeal endoderm.

Answer 5

oral plate or oropharyngeal membrane

Question 6

How many hours of incubation of chick embryo where the stomodaeum deepens following rupture of the oral plate, to form the oral cavity that communicates w/ the pharynx?

Answer 6

72 hrs of incubation

Question 7

Where does the roof of the oral cavity come from which is supported by the hard and soft palates?

Answer 7

stomodeal ectoderm

Question 8

The oral cavity cranial floor is also from…

Answer 8

stomodeal ectoderm

Question 9

The oral cavity caudal floor is from…

Answer 9

pharyngeal endoderm and its lateral walls from neural crest cells of VA 1

Question 10

What are the 5 structures associated with the oral cavity (mouth)?

Answer 10

lips
gums
teeth
tongue
salivary glands

Question 11

It is derived from maxillary process of VA 1 and medial nasal processes that form two palatine primordia: primary palate and secondary palate.

Answer 11

Palate

Question 12

The right and left medial nasal processes fused in the midline to form a small triangular medial palatine process (primary palate) that becomes what?

Answer 12

incisive bone

Question 13

What are the two palatine primordia?

Answer 13

primary palate and secondary palate

Question 14

The right and left medial nasal processes fused in the midline to form this…

Answer 14

Medial palatine process (primary palate)

Question 15

It separates the nasal and oral cavities and is formed when rostral two-thirds of the secondary palate ossifies.

Answer 15

Hard palate

Question 16

It is a malformation of the palate and is a cleft palate caused by failure of the median palatine process (primary palate) and the lateral palatine processes (secondary palate) to close along the midline, leaving a gap or cleft. The secondary palate is affected more commonly than the primary palate. May be inherited or be the result of exposure to a teratogen. Often fatal in animals due to inability to suckle or because of aspiration of milk into the lungs (aspiration pneumonia).

Answer 16

Palatoschisis

Question 17

Failure of medial nasal processes to fuse __________ produces _________ and related defects.

Answer 17

primary cleft palate
hare lip (cheiloschisis)

Question 18

Lip and gums are derived from…

Answer 18

stomodeal ectoderm

Question 19

Tissue external to the groove forms what?

Answer 19

Lip

Question 20

Tissue medial to the groove forms what? .

Answer 20

Gingiva (gum)

Question 21

Fusion of upper and lower lips caudally forms what?

Answer 21

Cheeks

Question 22

The tooth is composed of what?

Answer 22

enamel
dentin
dental pulp
cementum

Question 23

Teeth are derived from…

Answer 23

stomodeal ectoderm and ectomesenchyme (neural crest) of VA1

Question 24

An arc of periodically thickened ectoderm, situated inside of the labiogingival lamina, constitutes the ________. Dental lamina invaginates to form ________.

Answer 24

dental lamina
dental bud

Question 25

Each bud assumes a cup-shaped configuration becoming an _________.

Answer 25

enamel organ

Question 26

The inner concave epithelium of the enamel organ differentiates into _________ that secrete the tooth enamel.

Answer 26

columnar ameloblasts

Question 27

It is a loose aggregation of stomodeal ectodermal cells.

Answer 27

stellate reticulum

Question 28

The right and left maxillary processes give off bilateral medial extensions, the ___________, which meet at the midline, merging dorsally with the nasal septum and rostrally with the primary palate.

Answer 28

lateral palatine processes

Question 29

Caudal third of the secondary palate does not ossify and become the _________ that divides the pharynx into dorsal nasopharynx and ventral oropharynx.  

Answer 29

Soft palate

Question 30

In the ectoderm lining the stomodeal cavity, an arc of the thickened ectoderm, the  _______, forms along the upper and lower jaws.

Answer 30

labiogingival lamina

Question 31

The lamina invaginates into underlying ectomesenchyme, forming a ________.

Answer 31

labiogingival groove

Question 32

The groove forms the future _______ (space between the lip and the gum).

Answer 32

vestibule

Question 33

Each bud assumes a cup-shaped configuration becoming an __________.

Answer 33

enamel organ

Question 34

The inner concave epithelium of the enamel organ differentiates into ________that secrete the tooth enamel.

Answer 34

columnar ameloblasts

Question 35

Between the inner concave and outer convex epithelia of enamel organ is the _________, a loose aggregation of stomodeal ectodermal cells.

Answer 35

stellate reticulum

Question 36

________ within the concavity of the enamel organ forms a ________.

Answer 36

ectomesenchyme dental papilla

Question 37

The concave epithelial layer of the enamel organ induces ectomesenchyme of the dental papilla to form an epithelial layer of _______ that deposit the dentin of the tooth.

Answer 37

odontoblasts

Question 38

The outer cells of the dental papilla differentiate into ________ (induced by ameloblasts) that secrete _______.

Answer 38

columnar odontoblasts dentin

Question 39

It surrounded the enamel organ which condenses into a dental sac that gives rise to three layers:

Answer 39

Ectomesenchyme

Question 40

What are the three layers of ectomesenchyme or dental sac?

Answer 40

Outer cells of dental sac Middle layer of dental sac Inner cells of the sac

Question 41

Outer cells of dental sac differentiates into _______ that deposit bone of the    alveolus (socket receiving the tooth).

Answer 41

osteoblasts

Question 42

It deposits bone from the alveolus (socket receiving the tooth).

Answer 42

Osteoblasts

Question 43

Middle layer of dental sac differentiates into ________, that secrete collagen fibers to form the periodontal ligament that anchors the tooth within the alveolar socket.

Answer 43

fibroblasts

Question 44

It secrete collagen fibers to form the periodontal ligament that anchors the tooth within the alveolar socket.

Answer 44

Fibroblasts

Question 45

Middle layer of dental sac differentiates into fibroblasts, that secrete collagen fibers to form __________ that anchors the tooth within the alveolar socket.

Answer 45

periodontal ligament

Question 46

It anchors the tooth within the                  alveolar socket.

Answer 46

Periodontal ligament

Question 47

Inner cells of the sac become ______ that secrete _______ (modified bone) that adheres to the surface of the tooth, particularly the dentin surface of the root of the tooth.

Answer 47

cementoblasts cementum

Question 48

It adheres to the surface of the tooth, particularly the dentin surface of the root of the tooth.

Answer 48

Cementum

Question 49

Tongue develops from four swellings. What are the swellings?

Answer 49

2 distal 1 median 1 proximal tongue swelling

Question 50

General sensation is from....

Answer 50

trigeminal nerve (V)

Question 51

Taste sensation is from...

Answer 51

facial nerve (VII)

Question 52

The root of the tongue is formed by...

Answer 52

proximal swelling or copula

Question 53

These are derived from stomodeal ectoderm (parotid, zygomatic, labial and buccal accessory salivary glands) or pharyngeal endoderm (mandibular and sublingual glands).

Answer 53

Salivary glands

Question 54

It is derived from the cranial part of the foregut.

Answer 54

pharynx

Question 55

What are the 5 parts formed by foregut?

Answer 55

pharynx esophagus stomach cranial duodenum liver and pancreas

Question 56

What are the 7 parts formed by midgut?

Answer 56

remaining small intestines (caudal duodenum, jejunum, and ileum), cecum ascending colon part of the transvers colon

Question 57

What are the parts formed by hindgut?

Answer 57

transverse and descending colon cloaca (rectum and anal canal)

Question 58

Endoderm gives rise to the...

Answer 58

epithelial lining of the digestive tract

Question 59

Splanchnic mesoderm form...

Answer 59

connective tissue and smooth muscle

Question 60

ectoderm forms the...

Answer 60

ephithelial lining of the proctodeum and stomodeum

Question 61

The foregut becomes flattened or compressed laterally and presents in sequence 5 bilateral outpocketings of its endoderm to form the ______ walled in by a series of visceral arches.

Answer 61

pharyngeal pouches

Question 62

A midline evagination of the floor of the pharynx gives rise to the ______.

Answer 62

laryngotracheal groove

Question 63

One of the malformations of the pharyngeal pouches where epithelial-lined brachial cavity that does not open unto the skin surface. (no  opening)

Answer 63

Brachial cyst

Question 64

One of the malformations of the pharyngeal pouches. An epithelial-lined brachial cavity that opens unto the skin surface or into the  pharyngeal pouch. (one opening).

Answer 64

Brachial sinus

Question 65

One of the malformations of the pharyngeal pouches. An epithelial-lined brachial cavity that opens to both the skin surface and the  pharyngeal pouch. (two openings).

Answer 65

Brachial fistula

Question 66

It is present in most domestic mammals. This develops from a tubular segment of foregut caudal to the esophagus. Growth is more rapid dorsally than it is ventrally;

Answer 66

Simple Stomach

Question 67

The tube becomes convex dorsally.

Answer 67

Greater curvature

Question 68

The simple stomach in young embryo is relatively _______.

Answer 68

straight

Question 69

Greater omentum becomes folded creating a blind cavity.

Answer 69

omental bursa

Question 70

It opens into the peritoneal cavity via an opening the gastroepiploic foramen.

Answer 70

Omental bursa

Question 71

What is the degree of the 2nd rotation around a dorsoventral axis, counter clockwise in direction and resulting in the caudal end of the stomach tube shifting to the right and cranially?

Answer 71

90°

Question 72

It consists of three compartments (rumen, reticulum, and omasum) and one glandular compartment (abomasum). Early development of this stomach is the same as the simple stomach.

Answer 72

Ruminant Stomach -

Question 73

What are the 3 compartments of the ruminant stomach?

Answer 73

Rumen Reticulum Omasum Omasum (glandular compartment)

Question 74

It develops as an expansion of the fundus.

Answer 74

rumen

Question 75

A caudoventral pocket of the developing rumen forms the _______.

Answer 75

reticulum

Question 76

It develops as a bulge (ventral sac) along the lesser curvature.

Answer 76

omasum

Question 77

The rest of the stomach becomes what?

Answer 77

abomasum

Question 78

What consists the intestinal tract?

Answer 78

small intestine: duodenum (divided into descending and  ascending regions) jejunum ileum large intestine: colon (divided into ascending, transverse, and descending regions) cecum (diverticulum at the beginning of the colon) rectum anal canal

Question 79

The small intestine is derived from the....

Answer 79

foregut and midgut

Question 80

After the loss of the yolk stalk, the intestinal loop rotates how many degrees?

Answer 80

rotates 360⁰ twice

Question 81

After the loss of the yolk stalk the intestinal loop rotates 360⁰ twice around the cranial mesenteric artery to form the __________.

Answer 81

root of the mesentery

Question 82

The cranial limb of the loop expands to form the coiled _______.

Answer 82

jejunum

Question 83

It becomes the ileum.

Answer 83

Caudal limb

Question 84

The large intestine is derived from...

Answer 84

Midgut and Hindgut

Question 85

Among the different parts of the colon, this colon shows the most extensive change.

Answer 85

ascending colon

Question 86

The ascending colon of these animals are short and straight and the entire colon is shaped like an inverted letter J.

Answer 86

Dog & cat

Question 87

It is the terminal part of the hindgut, a chamber that communicates with the digestive, urinary and genital systems.

Answer 87

Cloaca

Question 88

2 types of stomach

Answer 88

Simple stomach Ruminant stomach

Question 89

The caudal wall of the cloaca is formed by what membrane

Answer 89

cloacal membrane

Question 90

It is the depression of the surface ectoderm under the root of the tail and is the counterpart of stomodeum in the oral region.

Answer 90

proctodeum

Question 91

It is derived from the cloaca. It is formed when a mesenchyme partition (urorectal septum) divided the cloaca into dorsal and ventral chambers.

Answer 91

Rectum

Question 92

It is formed with the rectum; part of the anal canal is lined by a mucosal epithelium derived from endoderm.

Answer 92

Cranial part

Question 93

It is derived from the proctodaeum it is lined by stratified squamous epithelium.

Answer 93

Caudal part

Question 94

A depression where tissues surrounding the anal membrane grow caudally.

Answer 94

proctodeum

Question 95

In carnivores, lateral diventicula of proctodeum ectoderm becomes what?

Answer 95

anal sacs

Question 96

It develops as a diverticulum of the esophagus.

Answer 96

Crop

Question 97

What are the two compartment stomach?

Answer 97

Proventriculus Ventriculus or gizzard

Question 98

It is a muscular stomach with thick smooth muscles for grinding

Answer 98

Ventriculus or gizzard

Question 99

It opens externally by means of a vent.

Answer 99

Cloaca

Question 100

5 Malformation of the digestive system

Answer 100

Meckel’s diverticulum Atresia of the jejunum, ileum, colon, rectum Atresia ani or imperforate anus Urorectal Fistula Urorectal Fistula

Question 101

It is an appendix-like remnant of the yolk stalk that persist, may cause inflammation and rupture resulting in colic with peritonitis.

Answer 101

Meckel’s diverticulum

Question 102

It is a lack of epethilial canalization and gut wall   development. Results in feed impaction and death if surgical intervention cannot be madde. Some evidence suggests that one cause is manual manipulation of fetal membranes rectally in pregnancy diagnosis. 

Answer 102

Atresia of the jejunum, ileum, colon, rectum

Question 103

It is a failure of anal membrane to break and remain patent . Caused by lack of involution of the cloacal membrane and leads to fetal feed impaction. Where anal musculature is developed, surgical removal of the cloacal membrane offers temporary if not permanent relief.

Answer 103

Atresia ani or imperforate anus

Question 104

It is an abnormal developed of urorectal folds that allows communication between the rectum and urogenital sinus. 

Answer 104

Urorectal Fistula

Question 105

It is a muscular defect in the umbilical that allows abdominal organs to protrude through the umbilical underneath the skin. Maybe inherited. 

Answer 105

Umbilical hernia