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Flashcards in Digestive System Deck (145):
1

Functions of Digestive System

Take in Food
Breakdown food
absorb digested molecules
provide nutrients
Eliminate waste

2

Two Main Divisions/Groups

Digestive/Gastrointestinal Tract/ Alimentary Canal
Accessory Digestive Organs

3

Alimentary Canal

mouth
pharynx
esophagus
stomach
small intestine
large intestive
anus

4

Accessory Organs

teeth
tongue
salivary glands
liver
pancreas
gallbladder

5

Basic Tissue layers/tunics of GIT

Mucosa
Submucosa
Muscularis
Serosa

6

innermost tunic

mucosa

7

3 layers of mucosa

mucous epithelium
lamina propria
muscularis mucosa

8

thick layer of loose connective tissue;nerves, blood vessels

submucosa

9

contains nerve plexus and submucosa plexus = enteric plexus
control movement and secretion of the tract

Muscularis

10

outermost layer
composed of peritoneum, underlying connective tissue

serosa

11

a double sac serous membrane that covers the wall of the abdominal cavity and abdominal organs

peritoneum

12

covers the organ

visceral peritoneum

13

lines the wall of the abdominal cavity

parietal peritoneum

14

connective tissues that are held in place many organs of the abdominal cavity

nerve and blood vessels enter peritoneal cavity

mesenteries

15

Organs of Alimentary Canal

Mouth/ Oral cavity
Pharynx
Esophagus
Stomach
Small Intestines
Large Intestines

16

first part of digestive tract bounded by lips and cheeks

mouth

17

Associated structures of mouth

lips
cheeks
hard palate
soft palate
tongue
teeth

18

muscular structure that is covered by the skin at the outer surface

lips

19

muscles in lips

orbicularis oris

20

forms the lateral walls of the oral cavity

cheeks

21

muscles in cheeks

buccinators

22

the bony roof of mouth; palatine rugae

hard palate

23

forms the posterior roof of the mouth composed of skeletal and connective tissue

closes nasopharynx when swallowing

soft palate

24

large, muscular organ that occupies most of the oral cavity

most powerful organ

aids in articulation

tongue

25

teeth consists of

crown
neck
root

26

parts of teeth

enamel
dentin
pulp cavity
cementum

27

protects tooth from abrasion and acid

enamel

28

living, cellular, bonelike tissue that surrounds the pulp cavity

dentin

29

conains blood vessels, nerves and connective tissue

pulp cavity

30

helps anchor the tooth

cementum

31

each quadrant contains

1 central incisor
1 lateral incisor
1 canine
fist and second premolars
3 molars

32

function of incisors

cutting

33

function of canine

tearing

34

function of premolars

crushing

35

function of molars

grinding

36

20 teeth that make up the first dentition which are shed and replaced by the permanent teeth

deciduous teeth

37

32 teeth that develop as the second dentition, replacing the deciduous teeth

premanent teeth

38

located in the lateral posterior walls of the oral cavity

tonsils

39

produce saliva which is a mixture of serous and mucus fluids

dissolve food chemicals so that they can be tasted

contains lysozymes and antibodies (IgA)

salivary glands

40

3 pairs of salivary glands

parotid, submandibular, sublingual

41

inflammation of parotid glands

mumps or parotidis

42

inflammation of testes

orchitis

43

passageway for both air and food, only the oropharynx and laryngopharynx transmit food

pharynx

44

muscular tube lined with moist stratified squamous epithelium that extends from the pharynx to the stomach
lies anterior to the vertebrae and posterior to the trachea
transport food by peristalsis to the stomach

esophagus

45

regulate movement of food into and out of the esophagus

esophageal sphincter
upper and lower cardiac sphincters

46

enlarged segment of the digestive tract in the left superior part of the abdomen
primarily for storage and mixing chamber for digested food
a sac

stomach

47

Parts of stomach

Cardiac region
fundus
body
pyloric opening
pyloric region
pyloric sphincter
muscular layer
rugae

48

region of the stomach around the cardiac opening

cardiac region

49

most superior part of the stomach

fundus

50

largest part of the stomach

body

51

opening from the stomach to the small intestine

pyloric opening

52

region of the stomach near the pyloric opening

pyloric region

53

thick ring of smooth muscle that guards the pyloric opening

pyloric sphincter

54

composed of outer longitudinal layer, middle circular layer, inner oblique layer

muscular layer

55

submucosa and mucosa that are thrown into large folds when the stomach is empty and allows the stomach to stretch when the stomach is fille

rugae

56

the semi-fluid mixture formed by food that mixes with stomach secretions

chyme

57

regulation of stomach secretions: 3 phases

cephalic phase
gastric phase
intestinal phase

58

anticipatory and prepares stomach to receive food

sensations of taste, smell of food, stimulation of tactile receptors during chewing/swallowing, pleasant thoughts of food stimulate centers within medulla oblongata

cephalic phase

59

period of greatest gastric secretion
activated by the presence of food in stomach

gastric phase

60

inhibit gastric secretions
controlled by the entrance of acidic chyme into duodenum

intestinal phase

61

major site of digestion and absorption of food
final site of digestion
longest section of alimentary canal

small intestine

62

3 parts of small intestine

duodenum
jejunum
ileum

63

3 modifications that increase surface area (600 fold) of small intestine

circular folds
villi
microvilli

64

formed by mucosa and submucosa

circular folds

65

finger-like projections of the mucosa

villi

66

cytoplasmic extensions of the cells on the villi and contains blood capillary network and lymphatic capillary (lacteals)

microvilli

67

mucosa of liver is simple columnar epithelium with 4 major cell types

absorptive cells
goblet cells
granular cells (paneth's cells)
endocrine cells

68

within microvilli, produce digestive enzymes and absorb digested food

absorptive cells

69

produce a protective mucus

goblet cells

70

help protect the intestinal epithelium from bacteria

granular cells

71

produce regulatory hormones

endocrine cells

72

cluster of lymph nodules which help protect the intestinal tract from harmful microorganisms

payer's patches

73

junction between small intestine and large intestine

Ileocecal junction

74

secretions of small intestine

peptidases
disaccharidases
mucus
hormones

75

break peptide bonds in CHONS to form amino acid

peptidases

76

breaks down disaccharides into monosaccharides

disaccharidases

77

produced by duodenal glands and by goblet cells

mucus

78

stimulate liver and pancreatic secretions

hormones

79

parts of large intestine

cecum
colon
rectum
anal canal

80

proximal end of large intestine

cecum

81

where the small intestine and large intestine meet
sac that extends inferiorly about 6 cm past the ileocecal junction
located in the right lower quadrant newar the iliac fossa

Ileocecal junction

82

blind tube about 9 cm long that is attached to the cecum

appendix

83

about 1.5 - 1.8 meters long

colon

84

parts of colon

ascending colon
transverse colon
descending colon
sigmoid colon

85

extends superiorly from the cecum to the right colic flexure near the liver where it turns right

ascending colon

86

extends from the right colic flexure to the left colic flexure near the spleen where it turns inferiorly

transverse colon

87

extends from the left colic flexure to the pelvis where it becomes the sigmoid colon

descending colon

88

form an S-shaped tube that extends medially and then inferiorly into the pelvic cavity and ends at the rectum

sigmoid colon

89

straight, muscular tube that begins at the termination of the sigmoid colon and ends at the anal canal

rectum

90

begins at the inferior end of the rectum and ends at the anus
the last 2-3 cm of digestive tract

anal canal

91

anal canal contains

internal anal sphincter
external anal sphincter

92

made up of smooth muscle and found at the superior end of the canal

internal anal sphincter

93

made of skeletal muscle and found at the inferior end of the canal

external anal sphincter

94

introduction of fluid in anal canal and colon

enema

95

special lymphatic vessel where fats are absorbed

lacteals

96

milky fluid containing fat droplets

chyle

97

no IF is produced

pernicious anemia

98

IF + Vitamin B12=

RBC

99

Muscularis: inner - ________
outer- _______

circular
longitudinal

100

Functions of Large Intestine

converts chyme into feces by 3 processes:
1. absorption of water and salts
2. secretion of mucus
3. action of microorganisms

stores feces until defecation occurs

101

largest organ of the body
weighs 1.4 kg/ 3 lbs
largest organ according to serface area
doesn't have capillaries
receives oxygenated and deoxygenated blood
located at RUQ tucked against the inferior of the diaphragm
divided into 2 major lobes: R and L lobe

liver

102

2 smaller lobes seen from the inferior view

caudate and quadrate

103

Functions of liver

produce bile
storage of nutrients
conversion of nutrients
detoxification of harmful chemicals
synthesis of new molecules

104

a thick, viscid, bitter-tasting fluid secreted by the liver
about 700 ml secreted by liver per day
plays a very important role in diluting and neutralizing stomach acid
emulsifies fats, breaking fat globules into smaller droplets
90% of bile salts are reabsorbed in the ileum and carried by blood to the liver

bile

105

pH of bile

7.6 - 8.6 (basic)

106

the gate through which blood vessels, ducts and nerves enter and exit the liver

porta

107

divisions of the liver containing portal triads at its corner

lobules

108

portal triads

hepatic artery
hepatic portal vein
hepatic duct

109

macrophages of the liver
aka stellate reticuloendothelial cells
breakdown of RBC

Kupffer cells

110

formed by platelike groups of cell called hepatocytes

hepatic cords

111

blood channels which separates hepatic cords from one another

consist of phagocytic cells that help remove foreign particles from the blood

hepatic sinusoids

112

brings oxygenated blood to liver

hepatic artery

113

carries oxygen-poor blood but rich in absorbed nutrients and other substances from the digestive tract to the liver

hepatic portal vein

114

where blood exits from the liver and empties into the IVC

hepatic vein

115

small sac on the inferior surface of the liver that stores and concentrates bile

gall bladder

116

organ composed of both endocrine and exocrine tissues

located retoperitoneal and posterior to the stomach in the inferior part of the LUQ
has a head located near the midline of the body and tail that extends to the left and touches the spleen

pancreas

117

endocrine part of pancreas

Islet of Langerhans (1%) that produces insulin and glucagon

118

exocrine part of pancreas

acini (99%) that produces digestive enzymes

119

join the common bile duct and empty into duodenum

pancreatic duct or duct of Wirsung

120

function of pancreas (exocrine)

Bicarbonate - neutralizes acidic chyme that enter the duodenum from the stomach

pancreatic enzyme - important for digestion of the major classes of food

121

continue protein digestion started in the stomach

proteolytic enzyme (protein-digesting enzyme)

122

continues polysaccharide digestion that began in oral cavity

pancreatic amylase

123

continue lipid digestion

pancreatic lipase

124

reduce DNA and RNA to their component nucleotides

nucleases

125

Hormones secreted by duodenum that control pancreatic secretion

secretin
cholecystokinin

126

initiates release of HCO3

secretin

127

stimulates pancreas to release an enzyme-rich solution

cholecystokinin

128

chewing of food by teeth

mastication

129

swallowing of food

deglutition

130

2 Types of movements in the stomach

mixing waves
peristaltic waves

131

weak contractions of the stomach
mix ingested food with stomach secretions to form chyme

mixing waves

132

stronger contractions
forced chyme toward and through the pyloric sphincter

peristaltic waves

133

movement of food in small intestines

peristaltic contraction
segmental contraction

134

cause chyme to move along the small intestine

peristaltic contraction

135

function to mix intestinal contents

segmental contraction

136

movement in large intestines

mass movement

137

large part of the colon undergo several strong contractions every 8-12 hours to propel colon contents a considerable distance toward the anus

mass movement

138

accessory duct

duct of santorini

139

neutralizes acidic chyme in duodenum

NaHCO3 ( pH 7.1 - 8.2)

140

breakdown of food to molecules that are small enough to be absorbed in the circulation

digestion

141

Types of Digestion

Mechanical
chemical

142

breaks large food particles to smaller ones

mechanical digestion

143

breaking of covalent chemical bonds in organic molecules by digestive enzymes

chemical digestion

144

examples of chemical digestion

CHO - monosaccharides
CHON - amino acids
Fats - fatty acid and glycerol

145

initiated by the distention of the rectal wall

defecation reflex