Mouth, Esophagus, Digestive Tract

Question 1

structure of the oral cavity

Answer 1

stratified squamous epithelium, lamina propria, salivary glands serous and mucous, skeletal muscle in deep layers, and filiform papillae on top layer of tongue

Question 2

structure of taste buds

Answer 2

occur only on the sides of fungiform papillae scattered on the surface of the tongue, and rarely on the circumvallate papillae at the back of the tongue
egg shaped and consist of elongated sensory cells which extend from the lamina propria to the surface taste pore
also contains support cells and stem cells at the base

Question 3

structure and function of the esophagus

Answer 3

hollow tube 25cm long, moves partially digested food from the pharynx to the stomach

Question 4

four layers of the esophagus

Answer 4

mucosa (non keratinized stratified squamous epithelium)
submucosa (blood vessels, glands, and connective tissue)
muscularis externa (upper third is skeletal, lower third is smooth, middle is a mix)
adventitia (connective tissue that merges with connective tissue of surrounding structures)

Question 5

characteristics of Barrett Esophagus

Answer 5

heartburn and chest pain

simple columnar epithelium replaces the stratified squamous epithelium to withstand stress

Question 6

histologic changes at the Z-line of the gastroesophageal junction

Answer 6

abrupt transition from nonkeratinized stratified squamous to simple columnar epithelium

Question 7

three nerve components of the ENS (enteric nervous system)

Answer 7

nerve fibers, ganglion cells, and glial cells

Question 8

origin of the ENS

Answer 8

neural crest

Question 9

two parts of the ENS

Answer 9

Auerbach plexus: larger myenteric plexus
lies between the inner and outer layers of smooth muscle in the muscularis externae
regulates contraction, peristalsis, and gastrointestinal mobility

Meissner plexus: regulates glandular secretion and local blood flow, innervates cells in the epithelium and smooth muscle of the muscularis mucosae

Question 10

characteristics of hirschprung disease

Answer 10

absence of ganglion cells in the ENS, only nerves can be seen, not the normally present pink ganglia

uncoordinated peristalsis, constipation, and possible obstruction

Question 11

four regions of the stomach

Answer 11

cardia (cardiac region near GE juntion), fundus (uppermost portion), body (majority), and pylorus (end near pyloric sphincter)

Question 12

cells of the stomach

Answer 12

parietal cells, chief cells, enteroendocrine cells

Question 13

three segments of the small intestine

Answer 13

duodenum: short, leaf shaped villi, enterocytes, and goblet cells
jejunum: tall, slender, finger-shaped villi
ileum: paneth cells are most numerous here, they regulate flora and produce lysozyme

Question 14

segments of the large intestine

Answer 14

ileocecal junction, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anus

Question 15

function and location of goblet cells, paneth cells, and enterocytes

Answer 15

goblet cells increase towards colon, paneth cells dense in ileum, enterocytes line the lumen of small and large intestine

Question 16

histological features of the appendix

Answer 16

worm shaped tube

large number of lymph nodules in mucosa and submucosa, part of GALT

Question 17

histological features of the anorectal junction

Answer 17

pectinate line divides simple columnar epithelium from nonkeratinized stratified squamous epithelium

Question 18

3 regions of the gastric gland

Answer 18

apical isthmus, neck, and body