09.11 GI track

Question 1

Answer 1

3. Taste buds contained by circumvallate and fungiform papillae

Question 2

Answer 2

3. Taste buds contained by circumvallate and fungiform papillae

Question 3

Answer 3

1. Salivary glands (tuboalveolar glands)
   
   1. Sublingual gland and ducts under the tongue
   2. Submandibular gland and duct under the mandible
   3. Parotid gland and duct behind the tongue
   4. Buccal glands (groups of salivary glandular cells) also line the cheek

Question 4

Answer 4

i. Mixture of water, ions, mucus and enzymes.
ii. Keeps mouth moist, dissolves food so can be tasted, moistens food, starts enzymatic digestion, and buffers acid
iii. Antibacterial and antiviral

Question 5

Answer 5

1. Mucosa: epithelium, lamina propria, muscularis mucosea
2. submucosa
3. muscularis externa
4. serosa or adventitia

Question 6

Answer 6

ii. Gastroesophageal junction

“Cardiac junction” or “cardiac sphincter”

• Esophagus has stratified squamous epithelium.
• Stomach has simple columnar epithelium.

Question 7

Answer 7

iii. Muscle (muscularis externa) changes as it goes down
a. Upper 1/3 of esophagus: skeletal muscle (like pharynx)
b. Middle 1/3: mixture of skeletal and smooth muscle
c. Lower 1/3: smooth muscle ( as in stomach and intestines)
d. When empty, mucosa and submucosa lie in longitudinal folds

Question 8

Answer 8

sphincter between stomach and small intestine.

Actual, structural sphincter.

Question 9

Answer 9

gastric pits visible

Question 10

Answer 10

The fundus is marked by deep glands and shorter pits. The fundus tends to be thinner than other stomach areas and exhibits less secretion. Parietal cells have more granules

Question 11

Answer 11

: greater curvature and lesser curvature. Have much more mucus-secreting cells than others

Question 12

Answer 12

i. Antrum, canal and sphincter (structural sphincter that regulates onward flow of chyme into duodenum)

Question 13

Answer 13

1. Simple columnar epithelium: secrete bicarbonate-buffered mucus
2. Gastric pits opening into gastric glands
   i. Mucus neck cells
   * *ii. Parietal cells: secrete HCl and intrinsic factor for B12 absorption**
   a. Produce H+ from reactions of CO2 and H2O.
   b. HCO3- is sent to blood in exchange for Cl-
   iii. Chief cells: secrete pepsinogen (activated to pepsin with HCl) and is stimulated by gastrin ( a stomach hormone)

Question 14

Answer 14

iv. Enteroendocrine (G) cells produce hormones such as gastrin which are secreted into bloodstream
v. Enterochromaffin-like cells (ECL) produce histamine in response to gastrin and ACh.

Question 15

Answer 15

a. Brunner’s gland produce a very alkaline mucus to protect against acidity

Question 16

Answer 16

• Duodenum, jejunum, ileum.
• All have vili and microvili.
• Duodenum has Brunner’s gland
• Ileum has Peyer’s patches

Question 17

Answer 17

lymphoid aggregates with germinal center (lighter circle) in Ileum

Question 18

Answer 18

1. No villi: fewer nutrients absorbed
2. “columnar cells” = absorptive cells that take in water and electrolytes
3. A lot of goblet cells for mucus to lubricate stool
4. More lymphoid tissue: a lot of bacteria in stool

Question 19

Answer 19

• Compound acinar (sac-like) glands opening into large ducts (therefore exocrine)
  
  • Acinar cells make 22 kinds of enzymes: stored in zymogen granules
• Islets of Langerhans (AKA “islet cells”) secrete hormones
  
  • Insulin (from beta cells) lowers blood glucose
  • Glucagon (from alpha cells) raises blood glucose