Duncombe Ap2 Lecture- Digestion

Front 1

digestive system functions are:

Back 1

Ingestion-selective food intake
Digestion-breakdown to useable form
Absorption- uptake nutrients
Defecate- elimination of residue

Front 2

2 facets involved in digestion:

Back 2

mechanical- movement
chemical- chemical rxns

Front 3

what is needed for chemical digestion?

Back 3

enzymes- in salivary glands, stomach, pancreas, small intestines, and some food

Front 4

what is a hydrolysis reaction?

Back 4

uses water to break down polymers into monomers. all digestion (carbs, lipids, proteins, nucleic acids) consists of hydrolysis reactions

Front 5

what is the process when carbohydrates have a hydrolysis reaction?

Back 5

water donates a hydrogen atom to 1 monomer and a hydroxyl group to another breaking it down to glucose which is oxidized to make ATP

Front 6

brain uses glucose for?

Back 6

metabolism/energy

Front 7

monomers for lipids are:

Back 7

fatty acids and when combined with glycerol makes lipids

Front 8

monomers for proteins are:

Back 8

amino acids (there are 20 types)

Front 9

what makes up a nucleic acid?

Back 9

sugar, phosphate group, and nitrogenous base

Front 10

monomers for carbohydrates?

Back 10

monosaccharides and disaccharides (di= 2 mono)

Front 11

glucose + ____= monosaccharides

Back 11

+glucose= maltose
+fructose= sucrose
+galactose= lactose

Front 12

vitamins are:

Back 12

enzymes

Front 13

anything inside digestive GI tract is considered:

Back 13

external to the body

Front 14

GI tract is:

Back 14

tube from mouth to anus

Front 15

when is food considered inside the body from digestive tract?

Back 15

only when nutrients are absorbed by small intestine

Front 16

liver is a ____ organ

Back 16

vital

Front 17

accessory organs are teeth, tongue, liver, gallbladder, pancreas, salivary glands. what are they for?

Back 17

not considered organs of digestion tract but they assist in digestion

Front 18

what is the enteric nervous system?

Back 18

esophagus, stomach, & intestines have 2 nervous networks submucosal plexus and myenteric plexus

Front 19

the enteric nervous system has more neurons than?

Back 19

spinal cord

Front 20

submucosal plexus controls:

Back 20

gland secretion

Front 21

myenteric plexus controls:

Back 21

peristalsis (contractions)

Front 22

the motility & secretion of digestive tract are controlled by?

Back 22

neural, hormonal, & paracrine mechanisms

Front 23

in digestive tract the neural controls motility & secretion by means of?

Back 23

short myenteric reflexes (perstalsis & swallowing) & long vagovagal reflexes (autonomic parasympathetic fibers stimulate)

Front 24

in digestive tract hormones function to:

Back 24

(gastrin & secretin) secrete into blood & stimulate relatively distant targets

Front 25

in digestive tract paracrine secretions function to:

Back 25

diffuse through tissue fluid & stimulate nearby target cells. caused by chemical control (chemicals that cause stomach to bubble)

Front 26

what is the major connective tissue of the digestive tract?

Back 26

omentum

Front 27

how does lesser omentum attach?

Back 27

attaches stomach to liver

Front 28

how does greater omentum attach?

Back 28

covers small intestines like an apron.

Front 29

messentary of small intestine holds:

Back 29

many blood vessels and nerves that supply digestive tract

Front 30

what is messentary?

Back 30

connective tissue sheets that loosely hold stomach & intestines to protect from twisting/ tangling from changes in body position/ contractions

Front 31

what is mesocolon?

Back 31

mesentery that anchors colon to posterior body wall & it supports large intestine.

Front 32

beginning of digestion starts:

Back 32

in mouth with teeth

Front 33

what are dentitions?

Back 33

teeth

Front 34

what are deciduants?

Back 34

baby teeth (20 by 2 years)

Front 35

what are permanent teeth?

Back 35

adult (32 between age 6-25)

Front 36

what are occlusal surfaces?

Back 36

where teeth meet at closing of mouth

Front 37

what are cusps?

Back 37

humps, bumps, & lumps

Front 38

what are the purpose of incisors?

Back 38

chisel like cutting teeth used to bite off piece of food

Front 39

what are the purpose of canines?

Back 39

pointed teeth that act to puncture & shred

Front 40

what are the purpose of premolars & molars?

Back 40

broad for crushing & grinding

Front 41

what is periodontal ligament?

Back 41

modified periosteum that anchors to alveolus

Front 42

what are cementum and dentin are?

Back 42

living tissue of the tooth

Front 43

what is enamel?

Back 43

non cellular

Front 44

what is root canal?

Back 44

canal of nerves and blood vessels of tooth that leads into pulp cavity

Front 45

what is gingiva?

Back 45

gums

Front 46

what does apical mean?

Back 46

end of structure

Front 47

where does chemical digestion begin?

Back 47

salivary glands

Front 48

what are intrinsic glands?

Back 48

constant secretion (not through ducts)

Front 49

what are extrinsic glands?

Back 49

major salivary glands through ducts

Front 50

where are intrinsic glands found?

Back 50

under mucous membrane of mouth, lips, cheeks & tongue

Front 51

what are the 3 extrinsic salivary glands?

Back 51

parotid, submandibular & sublingual

Front 52

parotid glands secrete by?

Back 52

parotid ducts

Front 53

sublingual means?

Back 53

several ducts

Front 54

in salivary glands, what do mucous cells secrete?

Back 54

mucus

Front 55

in salivary glands, what do serous cells secrete?

Back 55

thin fluid rich in amylase

Front 56

what are acinus?

Back 56

fingerlike projections found in cubodial tissue of salivary glands & pancreas

Front 57

what is mixed acinus?

Back 57

mixed acinus has both mucous & serous cells

Front 58

what is function of goblet cells?

Back 58

to secrete mucus

Front 59

what 3 things are secreted from tissue in salivary glands?

Back 59

mucus, amylase & other enzymes

Front 60

the average stomach holds?

Back 60

1 liter

Front 61

the stomach has what 3 muscles?

Back 61

longitudinal, circular, & oblique

Front 62

where is the sphincter in stomach located?

Back 62

around pyloris

Front 63

what does orifice mean?

Back 63

opening

Front 64

in the stomach wall what is the tissue of the mucosa?

Back 64

simple columnar glandular epithelium

Front 65

in the mucosa of the stomach wall, what is the lamina propria filled with?

Back 65

tubular glands (gastric pits)

Front 66

in stomach, muscularis externa has 3?

Back 66

muscles: longitudinal, oblique & circular

Front 67

what are the 5 cell types of gastric glands?

Back 67

Mucous
Regenerative
Parietal
Chief
Enteroendocrine

Front 68

what do the parietal cells of gastric glands function to do?

Back 68

secrete HCI acid & intrinsic factor

Front 69

what is HCI?

Back 69

major gastric liquid

Front 70

What do chief cells function to do?

Back 70

secrete pepsinogen (for protein) & in infancy chymosin & lipase

Front 71

what is lipase?

Back 71

an enzyme that digests lipids

Front 72

what is rugae?

Back 72

layers of wrinkles on stomach when it is empty

Front 73

what is the function of the enteroendocrine cells?

Back 73

secrete hormones and paracrine messengers

Front 74

what do paracrine function to?

Back 74

maintain homeostasis- they diffuse through tissue fluid and stimulate nearby targets

Front 75

what is pepsin needed for?

Back 75

protein digestion

Front 76

the 3 gastric secretions are:

Back 76

h2o, HCI, & pepsin

Front 77

where is CAH found in?

Back 77

parietal cells

Front 78

how does parietal cell form HCI?

Back 78

H+K+ pump uses ATP to pump H out and K in out cell. Then there is a chloride shift in the blood. HCO3 is added to blood (causing PH to go up) and CL is taken out to join H forming HCI

Front 79

what is the function of HCI?

Back 79

acts of pepsinogen & breaks off part leaving pepsin that digest proteins & makes more proteins or autocatalizes

Front 80

in infants lipase and chymosin function to?

Back 80

curdle milk, digest fats and milk

Front 81

what is an ulcer?

Back 81

sore in the stomach commonly caused by stress

Front 82

parietal cells also secrete a glycoprotein called intrinsic factor which is for?

Back 82

essential for absorption of b12 in small intestine

Front 83

without b12?

Back 83

hemoglobin could not be synthesized & anemia develops

Front 84

what is the only indispensable function of the stomach?

Back 84

the secretion of intrinsic factor

Front 85

Gastric activity is divided into 3 stages based on whether the stomach is being controlled by the brain, by itself, or small intestine:

Back 85

cephalic, gastric, & intestinal

Front 86

cephalic phase?

Back 86

before eating- responds to sight, smell, taste, or thought of food from hypothalamus to medulla to vagus nerve & stimulates enteric nervous system of stomach & stimulates gastric activity.

Front 87

gastric phase?

Back 87

when ingested food stimulates gastric secretion by stretching stomach & raising PH of its contents

Front 88

stretching the stomach activates what reflexes with ACH?

Back 88

myenteric and vagovagal

Front 89

what chemicals stimulate the gastric phase?

Back 89

ACH, histamine, & gastrin

Front 90

where does histamine come from?

Back 90

histamine is a paracrine secretion from enteroendocrine cells in gastric glands

Front 91

what is gastrin?

Back 91

a hormone produced by enteroendocrine G cells in pyloric glands

Front 92

what stimulates parietal cells to secrete HCI and intrinsic factor?

Back 92

ACH, gastrin, & histamine

Front 93

what stimulates chief cells to secrete pepsinogen?

Back 93

gastrin & ACH (ACH stimulates mucus secretion)

Front 94

what is the positive feedback loop in gastric phase?

Back 94

when protein digests it breaks down into smaller peptides & amino acids which directly stimulates G cells to secrete more gastrin. this accelerates protein digestion

Front 95

what is the negative feedback loop of the gastric phase?

Back 95

small peptides buffer stomach acid so PH is not too low. as digestion occurs peptides leave stomach causing PH to cont' to drop. loop then inhibits parietal & G cells winding down gastric phase

Front 96

high PH in stomach stimulates release of gastrin as positive feedback which:

Back 96

stimulate chief and parietal cell to get digestion occurring

Front 97

what are buffers in stomach for?

Back 97

to regulate acidity and maintain homeostasis

Front 98

what are the buffers in stomach?

Back 98

oligopeptides & amino acids

Front 99

what is negative feedback?

Back 99

fixes something that is wrong. BP, PH, blood sugar, homeostasis

Front 100

what is positive feedback?

Back 100

keeping action flowing in direction to complete something. giving birth, digestion

Front 101

What is the intestinal phase?

Back 101

duodenum responds to arriving chyme & moderates gastric activity with hormones & nervous reflexes. sympathetic nerve fibers suppress gastric activity while GIP & CCK cause juices to slow

Front 102

what is chyme?

Back 102

churned up food in stomach

Front 103

what is bolus?

Back 103

churned up food in mouth

Front 104

what does hepa refer to?

Back 104

liver

Front 105

where is the liver located?

Back 105

inferior to the diaphragm in the abdominal cavity

Front 106

what ligament separates the liver into right and left?

Back 106

the falciform ligament

Front 107

what is the round ligament?

Back 107

remnant of umbilical vein. carried blood from umbilical cord to liver of a fetus

Front 108

in the liver what is the relay vessel system that function together and link to other accessory organs?

Back 108

porta hepatis

Front 109

what are hepatocytes?

Back 109

liver cells (cubodial)

Front 110

what are lobules?

Back 110

sections of liver (microscopic) with central vein in middle of it. liver lobe made of thousands of lobules

Front 111

is pancreas an accessory organ?

Back 111

yes

Front 112

what tissue and cells are found in pancreas?

Back 112

cubodial tissue, acinar cells

Front 113

what are Zymogens?

Back 113

enzymes found in pancreatic acinar cells that digest proteins

Front 114

what are 3 types of Zymogens?

Back 114

Trypsinogen
Chymotrypsinogen
Procarboxypeptidase

Front 115

What enzymes digest carbs in the pancreatic acinar cells?

Back 115

Amylase

Front 116

Nearly all chemical digestion & nutrient absorption occurs in the?

Back 116

small intestine

Front 117

Where does the ileum lead to?

Back 117

from small intestine to large intestine/colon

Front 118

the small intestine has circular folds (plicae circularis) that involve only (2):

Back 118

mucosa and submucosa

Front 119

What are villi?

Back 119

fingerlike projections in small intestine

Front 120

What 2 kinds of epithelial cells are villi covered with?

Back 120

enterocytes (columnar absorptive cells) and goblet cells for mucus secreting joined by tight junctions preventing enzymes from seeping through

Front 121

What do blood vessels in villi function to do?

Back 121

absorb nutrients

Front 122

what do lymphatics or lacteal in villi function to do?

Back 122

absorbs fat

Front 123

what are microvilli?

Back 123

brush border on villi of small intestine contains enzymes for final stages of digestion

Front 124

what are intestinal crypts?

Back 124

pore openings between villi consists of absorptive, goblet, & dividing stem cells that migrate to tip, get sloughed off, & digested

Front 125

What are paneth cells?

Back 125

found in small intestine- antibacterial secretions

Front 126

what are brunners glands?

Back 126

found in submucosa of small intestine that secrete bicarbonate (baking soda) which neutralizes acids

Front 127

what are peyers patches?

Back 127

populations of lymphocytes to fight pathogens (bacteria) for immunity

Front 128

the intestinal crypts secrete 1-2 L of intestinal juice per day. what is in this juice and what is PH?

Back 128

water and mucus PH 7.4-7.8

Front 129

define segmentation in small intestine?

Back 129

to mix and churn

Front 130

what is peristalsis of small intestine?

Back 130

after absorption migrating motor complex controls waves of contraction to move food along (positive feedback)

Front 131

where are carbs and proteins the body needs carried to after digestion?

Back 131

the blood stream

Front 132

nutrients are absorbed in small intestine and remainder goes where?

Back 132

large intestine. fluids are removed from small & large intestine during this process

Front 133

where does carbohydrate digestion begin?

Back 133

in mouth chemical digestion with salivary amylase (PH 4.5 and up)

Front 134

pancreatic amylase converts oligosaccharides to _____ within 10 minutes

Back 134

maltose (disaccharide)

Front 135

what 3 brush border enzymes digest maltose & oligosaccharides to glucose?

Back 135

Maltase
Dextrinase
Glucoamylase

Front 136

What happens to glucose after brush border enzymes digest starch to glucose?

Back 136

epithelial cells absorb them, they then go to the blood

Front 137

when the small intestine undergoes peristalsis, what does this tissue change to?

Back 137

smooth muscle

Front 138

what is facilitated diffusion?

Back 138

when a protein carries a substance across a membrane

Front 139

define symport?

Back 139

when 2 substances move across a membrane at the same time (symbiotic relationship)

Front 140

define antiport?

Back 140

opposite of symport. 1 substance goes out of cell & 1 substance goes in cell. 1 cant go without the other.

Front 141

define solvent drag?

Back 141

H2O moving by passive diffusion

Front 142

where does protein digestion begin?

Back 142

in stomach

Front 143

what is peptin's function in stomach?

Back 143

to hydrolyze peptide bonds (protein) & breaks it down to smaller polypeptides

Front 144

after breaking down proteins, brush border enzymes in small intestine use ____ to move into epithelial cells

Back 144

cotransporters

Front 145

after amino acid cotransporters move into epithelial cells, they are then transported via ____ to _____.

Back 145

facilitated diffusion to blood stream

Front 146

infants absorb proteins by pinocytosis which allows IGA to?

Back 146

pass into blood stream (anitbodies)

Front 147

what is an anitbody?

Back 147

a protein that reacts with an antigen which triggers an immune response

Front 148

what converts lipids to emulsification droplets?

Back 148

lecithin & bile acid

Front 149

during fat hydrolysis, emulsification droplets are acted upon by ____ to digest to fatty acid

Back 149

pancreatic lipase

Front 150

_____ in the bile acid pass to small intestine & pick up several types of semidigested lipids

Back 150

micelles

Front 151

what are monoglycerides?

Back 151

fatty acids & glycerol

Front 152

some fatty acids & monoglycerides need to be packaged into _______ to transfer where they are needed.

Back 152

Chylomicron

Front 153

the nerves in the myenteric plexus is parasympathetic perstalsis for defecation. is this voluntary?

Back 153

no involuntary

Front 154

is the external anal sphincter voluntary?

Back 154

yes

Front 155

what connects small intestine to large?

Back 155

ileocecal valve