Nbde Biochemistry/physiology Gi S

Front 1

Depressions in the epithelial lining of the stomach.

Back 1

Gastric Pits

Front 2

What is at the bottom of the gastric pits in the stomach?

Back 2

Gastric glands

Front 3

What cells produce the enzymes of gastric juice?

Back 3

Chief Cells

Front 4

What cells produce stomach acid?

Back 4

Parietal cells

Front 5

What is the pH of gastric secretion?

Back 5

1.0-3.5

Front 6

The mucous produced by mucus-secreting cells is very _____ and protects the stomach wall from being exposed to the highly _____ gastric secretions.

Back 6

Alkaline
Acidic

Front 7

What part of the stomach are parietal cells located?

Back 7

Body (fundus)

Front 8

What part of the stomach are the chief cells located?

Back 8

Body (fundus)

Front 9

What part of the stomach are the G cells located?

Back 9

Antrum

Front 10

What part of the stomach are the mucous cells located?

Back 10

Antrum

Front 11

What are the secretion products of parietal cells?

Back 11

HCL
Intrinsic factor (essential)

Front 12

What are the secretion products of chief cells?

Back 12

Pepsinogen (converted to pepsin at low pH)

Front 13

What are the secretion products of G cells?

Back 13

Gastrin

Front 14

What are the secretion products of Mucous cells?

Back 14

Mucus pepsinogen

Front 15

What is the stimulus for secretion for Parietal cells?

Back 15

Gastrin
Vagal Stimulation (ACh)
Histamine

Front 16

What is the stimulus for secretion for chief cells?

Back 16

Vagal Stimulation (ACh)

Front 17

What is the stimulus for secretion for G cells?

Back 17

Vagal stimulation (via GRP)
Protein

Front 18

What is the stimulus for secretion for Mucous cells?

Back 18

Vagal stimulation (ACh)

Front 19

Gastric inhibitory peptide slows/speeds up gastric emptying.

Back 19

Slows

Front 20

Activation of the sympathetic nervous system slows/speeds up gastric emptying.

Back 20

Slow

Front 21

Activation of the parasympathetic nervous system slows/speeds up gastric emptying.

Back 21

Speeds up

Front 22

Cholecystokinin slows/speeds up gastric emptying.

Back 22

Slow

Front 23

Secretin slows/speeds up gastric emptying.

Back 23

Slow

Front 24

Activation of the enteric nervous system slows/speeds up gastric emptying.

Back 24

Slow

Front 25

Ingestion of food and its presence in the stomach slows/speeds up gastric emptying.

Back 25

Speeds up

Front 26

What stimulates the release of hormones in the GI tract?

Back 26

Food entering duodenum esp. fats and acidic chyme

Front 27

What are the hormones that are stimulated which inhibit the pyloric pump?

Back 27

Cholecystokinin
Secretin
Gastric inhibitory peptide (GIP)

Front 28

What is stomach emptying enhanced by?

Back 28

Presence of food in the stomach and gastrin

Front 29

In what ways does the small intestine send inhibitory signals to the stomach to slow secretion and motility?

Back 29

Nervous and Endocrine

Front 30

Distension of the small intestine, as well as _____ and _____ irritation in the mucosa, is transduced into gastric inhibitory impulses which are known as what?

Back 30

Enterogastric reflex

chemical
osmotic

Front 31

What are the hormones that are released from the small intestine which contribute to suppression of gastric activity?

Back 31

Cholecystokinin
Secretin

Front 32

What are the two major types of contractions in the GI tract?

Back 32

Peristalsis
Mixing contractions

Front 33

Contractions that generate propulsive movements.

Back 33

Peristalsis

Front 34

Contractions which serve to spread out the foodstuffs and increase the surface area available for digestion and absorption.

Back 34

Mixing Contractions

Front 35

What are the three secretions from the enteric endocrine system that stimulate the pancreas?

Back 35

Cholecystokinin
Secretin
Gastrin

Front 36

What are the three secretions from the pancreas acinar cells?

Back 36

Amylase
Chymotrtpsin
Trypsin

Front 37

What is the single secretion from the pancreas duct cells?

Back 37

Bicarbonate ion

Front 38

What nerve innervates the pancreas and the stomach?

Back 38

Vagus nerve
requires low level stimulation

Front 39

What is the daily secretion of the pancreas?

Back 39

0.7-2.5

Front 40

What is the pH of pancreatic secretions?

Back 40

7.5-8.8

Front 41

What are the enzymes involved in protein breakdown that are secreted from the acinar cells of the pancreas?

Back 41

Trypsin
Chymotrypsin
Carboxypolypeptidase

Front 42

What is the enzyme involved in carbohydrate breakdown that is secreted from the acinar cells of the pancreas?

Back 42

Amylase

Front 43

What are the enzymes involved in fat breakdown that are secreted from acinar cells of the pancreas?

Back 43

Lipase
Cholesterol Esterase
Phospholipase

Front 44

What is the inactive form of the secreted pancreatic enzymes?
Where is it activated?

Back 44

Zymogen
Small intestine

Front 45

What is composed of mucous, parietal, and chief cells and makes up the gastric juice?

Back 45

Exocrine gastric glands

Front 46

What is the daily secretion of gastric juice?
What is the pH?

Back 46

2-3 liters
1.0-3.0

Front 47

What is the pH of intestinal secretions?
What are they mainly?
What are they secreted by?

Back 47

6.5-7.8
Mucus
Goblet cells / Enterocytes

Front 48

What is the pH of Bile?

Back 48

7.8

Front 49

What does bile aid in?

Back 49

Emulsification, digestion, and absorption of fats

Front 50

What is the hormone that is produced by the wall of the upper part of the intestine?

Back 50

Cholecystokinin

Front 51

What does cholecystokinin stimulate?

Back 51

Contraction of gall bladder, releasing bile

Front 52

What are the three regions in the stomach which delineate the different secretory glands?

Back 52

Cardiac
Gastric
Pyloric

Front 53

Mucus secreting glands found primarily in the proximal stomach

Back 53

Cardiac glands

Front 54

Glands which release gastrin, pepsinogen, and mucous.

Back 54

Gastric/oxyntic glands

Front 55

Glands where mucous secretion into the stomach and gastrin into the blood occurs. Found in the Antrum.

Back 55

Pyloric glands

Front 56

Produces an acid environment that helps to kill bacteria and to activate pepsin. Solubilizes connective tissue.

Back 56

HCL

Front 57

What increases the secretion of HCL?

Back 57

Acetylcholine
Gastrin
Histamine

Front 58

The proteolytic enzyme secreted in an inactive form _____ and converted by stomach acidity or by autocatalysis to pepsin. Active at pH _____.

Back 58

Pepsin
Pepsinogen
<5

Front 59

Viscous and alkaline, produces a barrier along the walls of the stomach to protect the stomach from acid and abrasion.

Back 59

Mucous

Front 60

A glycoprotein that is essential for normal absorption of vitamin B12 in the intestine. Without it _____ _____ develops.

Back 60

Intrinsic Factor
Pernicious Anemia

Front 61

What are the coordinated contractions of smooth muscle which facilitate digestion and absorption by chopping, mixing and rolling food?

Back 61

Segmentation contractions

Front 62

What is the semifluid contents of the stomach consisting of partially digested food and gastric secretions?

Back 62

Chyme

Front 63

What constitutes the bulk of dietary fat which is composed of a glycerol backbone with each carbon linked to a fatty acid?

Back 63

Neutral fat or triglyceride

Front 64

What two processes have to occur in order for triglycerides to be absorbed?

Back 64

Emulsification
Enzymatic breakdown into monoglycerides and free fatty acids

Front 65

Large aggregates of dietary triglyceride, which are virtually insoluble in an aqueous environment, must be broken down physically and held in suspension by what process?

Back 65

Emulsification

Front 66

How does a monoglyceride or free fatty acid enter an enterocyte?

Back 66

Simple Diffusion

Front 67

What are the key components to the breakdown of triglycerides?
Where does this take place?

Back 67

Bile Salts
Pancreatic Lipase
W/ chyme in the small intestine

Front 68

What are the end products of protein digestion?

Back 68

Dipeptides
Amino Acids

Front 69

What facilitates the final stage of digestion?
How is absorption across the brush boarder of the lumen done?

Back 69

Peptidases
Secondary active transport

Front 70

What kind of secondary transporters are used in the absorption of dipeptides and amino acids?

Back 70

Sodium or Hydrogen Co-transporters

Front 71

What are used to hydrolyze disaccharides and small glucose molecules at the brush boarder during absorption?

Back 71

Lactase
Sucrase
Maltase
Alpha-dextrinase

Front 72

How are glucose and galactose absorbed into the lumen?

Back 72

Sodium secondary active transporters

Front 73

How is Fructose absorbed into the lumen?

Back 73

Facilitated Diffusion

Front 74

What are the three phases of gastric secretion?

Back 74

Cephalic Phase
Gastric Phase
Intestinal Phase

Front 75

In this phase sensations of thoughts about food are relayed to the brainstem, where parasympathetic signals to the gastric mucosa are initiated. This directly stimulates gastric juice secretion and stimulates the release of gastrin, which prolongs and enhances the effect.

Back 75

Cephalic Phase

Front 76

The presence of food, especially the distension food causes, triggers local parasympathetic nervous reflexes that increase the secretion of gastric juice and gastrin. Products of protein digestion can also trigger the gastrin mechanism.

Back 76

Gastric Phase

Front 77

As food moves into the duodenum, the presence of fats, carbohydrates, and acid stimulates hormonal and nervous reflexes that inhibit stomach activity.

Back 77

Intestinal Phase