GI System

Question 1

What is the difference between serosa and adventitia?

Answer 1

Serosa-mesothelium, associated with movement

Adventitia-relatively rigid and fixed

Question 2

What are the three layers of mucosa in the digestive tract?

Answer 2

1-epithelium
2-lamina propria
3-muscularis mucosa (smooth muscle layer under lamina propria

Question 3

What 3 things distinguish the submucosa?

Answer 3

1-dense irregular ct
2-large blood vessels
3-meissner sub mucosal enteric nerve plexus

Question 4

What 3 things distinguish the muscular layer?

Answer 4

1-inner circular smooth muscle layer
2-outer longitudinal smooth muscle
3-auerbachs enteric plexus between the muscle layers

Question 5

What are the three regions of the pharynx?

Answer 5

1-nasopharynx
2-oropharynx
3-laryngopharynx

Question 6

What three layers make up the pharynx?

Answer 6

1-Mucosa
2-Muscularis externa (skeletal longitudinal and circular)
3-Adventitia

Question 7

What is characteristic of the mucosa in the pharynx?

Answer 7

• SSQE
• lamina propria contains elastic fibers
• lack both muscularis mucosa and submucosa

Question 8

What is the ratio of voluntary vs involuntary muscle in the esophagus?

Answer 8

Upper 1/3 voluntary

Lower 2/3 involuntary (middle third is somewhat mixed though)

Question 9

What is the movement caused my alternating contraction called?

Answer 9

Peristalsis

Question 10

How can you tell if a tissue is esophagus and not vagina?

Answer 10

Glands are found in the submucosa

Question 11

The stratified squamous non keratinized epithelium of the esophagus transitions to what kind of epithelium in the stomach?

Answer 11

Simple columnar

Question 12

What happens if the esophageal sphincter doesn’t close properly?

Answer 12

Heartburn. Repeated occurrence leads to esophagitis

Question 13

Chronic esophagitis is called?

Answer 13

Gastro esophageal reflux disease (GERD) (10% of GERD results in Barrett esophagus)

Question 14

What happens in Barrett esophagus?

Answer 14

Epithelium transitions to intestinal epithelium which is more unstable but more resistant to acid

Question 15

What two main enzymes are secreted in the stomach?

Answer 15

Lipase

Pepsin

Question 16

What three major mechanisms regulate digestive activities?

Answer 16

• Local factors
• Neural control mechanisms
• Hormonal control mechanisms

Question 17

What 2 landmarks are found in the stomach mucosa?

Answer 17

Gastric pits

Gastric glands

Question 18

What is characteristic of Cardia mucosal region?

Answer 18

• Pits are shorter than glands

- Glands are almost all mucous

Question 19

What is characteristic of body and Fundus mucosal region?

Answer 19

Long glands with parietal and chief cells

Question 20

What is characteristic of Pylorus mucosa

Region?

Answer 20

• mostly mucous glands

- pits are relatively longer

Question 21

What are the 5 important cells of stomach epithelium?

Answer 21

1-surface mucous cell
2-mucous neck cell
3-parietal cell
4-chief cell
5-g cell (enteroendocrine)

Question 22

What do enteroendocrine (DNES) cells secrete? 6 things

Answer 22

Gastrin
Glucagon
Gherlin
Histamine
Somatostatin
Serotonin

Question 23

What do parietal cells do?

Answer 23

Secrete 0.1 N HCl

Secrete gastric intrinsic factor

Question 24

How does parietal cell acid secretion work?

Answer 24

HCO3 is transported out of cell in blood.

H+ and Cl- pumped out apically. These combine in lumen

Question 25

What are the three phases of gastric secretory control?

Answer 25

Cephalic Gastric Intestinal

Question 26

What do chief cells secrete?

Answer 26

Pepsinogen Gastric lipase They are found at the bottom of glands

Question 27

How can you tell between parietal and chief cells?

Answer 27

Parietal are eosinophilic and fried eggish

Question 28

What can form when the gastric mucosa | Is attacked and eroded?

Answer 28

Ulceration

Question 29

What are the four general layers of the gut?

Answer 29

1-mucosa 2-submucosa 3-muscularis externa 4-serosa/adventitia

Question 30

What does gastric intrinsic factor (GIF) help absorb?

Answer 30

B12

Question 31

Loss of parietal cells leads to what?

Answer 31

Pernicious anemia (because of lack of B12)

Question 32

What are he three gastric movements?

Answer 32

Propulsion Grinding Retropulsion

Question 33

What are the two main functions of small | Intestine?

Answer 33

- complete the digestion process | - adsorption (90% of nutrients)

Question 34

What are he three structural modifications of intestinal tissue that increase adsorptive area?

Answer 34

- plica circularis (3-fold) - villi (10-fold) - microvilli (20-fold)

Question 35

What are plica circulares?

Answer 35

Permanent circular or semilunar folds of mucosa and submucosa

Question 36

What are villi?

Answer 36

Dense covering of fingerlike projections

Question 37

What do villi contain internally?

Answer 37

Lamina propria with microvasculature and lymphatics

Question 38

What do villi contain externally?

Answer 38

Simple columnar epithelium with microvilli at the apical ends

Question 39

What happens to villi in a person with celiac disease when they have gluten proteins present?

Answer 39

-they shrink or disappear resulting in malabsorption

Question 40

What are enterocytes?

Answer 40

Absorptive columnar cells (microvilli at apical end)

Question 41

What are the four important cells in the intestinal epithelium?

Answer 41

- enterocytes - goblet cells - paneth cells - enteroendocrine cells

Question 42

How are lipids absorbed into the blood from the digestive system through enterocytes?

Answer 42

- bile emulsifies into micelles - gastric lipase breaks into glycerol,FA, monoglyceride - diffuses across membrane - resynthesize triglyceride in SER - Golgi packs chylomicrons that end up in the lymphatic capillaries

Question 43

How are disaccharides and dipeptides absorbed into the blood from the digestive system through enterocytes?

Answer 43

- disaccharidases and amino peptidases secreted by enterocytes break things down - absorbed through active transport - released to capillaries

Question 44

What do goblet cells do?

Answer 44

Produce mucins to form mucous which protect and lubricate lining

Question 45

What do paneth cells do?

Answer 45

- first line of defense | - release lysozyme, phospholipase A, defensins

Question 46

What are intestinal crypts?

Answer 46

Paneth cell containing, short tubular glands with stem cells at the base

Question 47

What four endocrine hormones do enteroendocrine cells secrete?

Answer 47

1-secretin (stimulates bicarbonate and water secretion in pancreas and bile duct) 2-CCK (signals satiety to brain) 3-GIP (stimulates insulin) 4-peptide YY (long term satiety)

Question 48

What penetrates the core of each villus?

Answer 48

Loose CT

Question 49

What are the three components of the lamina propria in a villus?

Answer 49

- arteries/veins - lymphatic capillary - smooth muscle

Question 50

In the duodenum, what role do brunners glands play?

Answer 50

They are large bundles of mucous secreting glands

Question 51

Where are plica circulares (valve of kerkring) best identified?

Answer 51

Jejunum

Question 52

Where are peyers patches (lymphatic patches) found?

Answer 52

Ileum (increasing as you approach the rectum)

Question 53

What do M cells do?

Answer 53

Endocytose antigens and present them to lymphocytes and dendritic cells to activate immune response

Question 54

What controls the muscularis externa?

Answer 54

Myenteric plexus (auerbachs)

Question 55

What controls the muscularis mucosa and DNES cells?

Answer 55

Submucosal plexus (meissners)

Question 56

What are the three functions of the large intestine?

Answer 56

- absorb water and electrolytes - storage of feces - secrete bicarbonate and mucous

Question 57

Characteristics of colon mucosa?

Answer 57

- lack villi - penetrated by tubular intestinal glands - goblet and absorptive cells (colonocytes)

Question 58

How can you distinguish the anal canal junction in a slide?

Answer 58

Epithelium transitions from glands to SSQE non keratinized. Also the location of some anal cancers

Question 59

What three disease arise from defects in intestinal tissue components?

Answer 59

- inflammatory bowel disease - chrohns diseas - ulcerative colitis