DLA 9+10: lecture 13+14

Question 1

alimentary canal and its associated glands come from?

Answer 1

endoderm of the primitive gut tube

Question 2

oral cavity and anal canal come from?

Answer 2

ectoderm

Question 3

general layers of the gastrointestinal tract

Answer 3

1. mucosa
2. submucosa
3. muscular layer
4. serosa / adventitia

Question 4

three layers of the mucosa

Answer 4

1. epithelium
2. lamina propria
3. muscular layer (usually two layers)

Question 5

submucosa features

Answer 5

DICT
blood vessels
glands
submucosal plexus

Question 6

submucosal plexus??

Answer 6

can be identified as clusters of neuronal bodies

cell bodies of postganglionic parasympathetic neurons
innervates muscular layer

Question 7

inner vs outer longitudinal muscles

Answer 7

Inner:
sphincters: constricts lumen

outer:
peristalsis

Question 8

myenteric plexus

Answer 8

part of the enteric nervous system

located between the circular and longitudinal muscles of the muscularis externa

postganglionic parasympathetic neurons

peristalsis

Question 9

filiform lingual papillae

Answer 9

small and conical

lined by highly keratinized stratified squamous

entire dorsal surface of tongue (tips face backwards)

mechanical function; no taste buds

Question 10

fungiform lingual papillae

Answer 10

mushroom shaped

lined by stratified squamous

mostly seen on tip of tongue

taste buds

Question 11

foliate lingual papillae

Answer 11

found on the lateral edges of the tongue; separated by deep clefts

taste buds

rudimentary in adults

Question 12

circumvallate lingual papillae

Answer 12

8 to 12 large and dome shaped structures found anterior to the sulcus terminalis

surrounded by ducts of serous von ebner’s glands

taste buds on lateral surface

Question 13

epithelium of the esophagus

Answer 13

stratified squamous

Question 14

Esophageal Glands Proper

Answer 14

found in the submucosa of the esophagus

produces lightly acidic mucus

Question 15

gastroesophageal junction epithelium

Answer 15

quick change from stratified squamous to simple columnar

no glands in submucosa

Question 16

Barrett’s esophagus and gastro-esophageal reflux disease

Answer 16

frequent cause of chest pain (burning chest pain)

due to weakened lower esophageal sphincter

metaplasia will occur: from strat. squamous to simple columnar

untreated can lead to cancer

Question 17

cardiac vs pyloric regions of the stomach epithelium

Answer 17

cardiac: short pits and short cardiac glands
tubular with few branching

pyloric: long pits and short pyloric glands
branched and coiled

Question 18

fundic gland secretions?

Answer 18

HCl by parietal cells (activation of pepsin)
glycoprotein by parietal cells (need for B12)

pepsin by chief cells (protein breakdown)

Question 19

how is fructose converted to the two intermediates needed for glycolysis?

Answer 19

fructose to frucose-1-phosphate by fructokinase

F-1-P to glyceraldehyde by aldolase B

or direct conversion

Question 20

benign fructosuria

Answer 20

liver fructokinase deficiency

fructose is not metabolized and is excreted in the urine

asymptomatic

detected by abnormal urinalysis report

Question 21

hereditary fructose intolerance

Answer 21

liver aldolase B deficiency

fructose-1-P accumulates

leads to ATP deficiency and inhibits gluconeogenesis and glycogenolysis

leads to hypoglycemia
drowsy and apathetic

Question 22

polyol pathway

Answer 22

glucose to sorbitol by aldose reductase

sorbitol to fructose by sorbitol dehydrogenase

Question 23

importance of polyol pathway

Answer 23

sorbitol is implicated in the pathogenesis of eye issues in those with DM

increase water content of the lens

Question 24

eye issues in galactosemia

Answer 24

elevated blood galactose which enter the lens of the eye

converted to galactitol by aldose reductase

increase water content in lens and thus cataract

Question 25

galactosemia signs

Answer 25

jaundice
hepatomegaly 
cataract formation 
developmental delay 
urine + for galactose

Question 26

classical galactosemia

Answer 26

GALT deficiency
autosomal recessive

galactose and galactose-1-P accumulate
2-3rd week of life
hypoglycemia (due to Pi trapping)

trigger after lactose or galactose consumption

Question 27

non-classical galactosemia

Answer 27

galactokinase deficiency

will have cataract formation
no galactose-1-P accumulation
less severe
urine + for galactose