digestive study guide Flashcards
(126 cards)
1
Q
organs of the alimentary canal
A
mouth, pharynx, esophagus, stomach, small intestine, large intestine
2
Q
accessory organs
A
teeth, tongue, salivary glands, liver, gall bladder, pancreas
3
Q
ingestion
A
the process of taking food into the body through the mouth
4
Q
propulsion
A
swallowing and peristalsis- the waves of contraction and relaxation in the walls of the organs
5
Q
mechanical digestion
A
chewing, mixing, and churning food with saliva and in the stomach
6
Q
chemical digestion
A
catabolic breakdown of food by hydrolases
7
Q
absorption
A
movement of nutrients from the GI to the blood or lymph
8
Q
defecation
A
elimination of ingestible solid wastes
9
Q
enteric nervous system
A
the in house nerve supply of the alimentary canal that is linked to the autonomic nervous system the neurons communicate with eachother to regulate the peristalsis and segmentation
10
Q
enteric nervous system cont. the parasympathetic nervous system activates
A
digestive activities and the sympathetic nervous system inhibits them
11
Q
splanchnic circulation
A
arteries that branch off the abdominal aorta, and the hepatic portal circulation that delivers nutrient rich venous blood to the liver
12
Q
the celiac trunk serves
A
spleen, stomach, liver
13
Q
the mesenteric arteries serves
A
small intestine and large intestine
14
Q
digestion
A
disassembly GI tract that allows nutrients to become more available to the body with each step
15
Q
digestion in the mouth
A
mechanical: chewing chemical: salivary amylase
16
Q
digestion in the esophagus
A
mechanical
17
Q
digestion in the stomach
A
chemical: HCl, pepsinogen, intrinsic factor, gastrin, CCK, somatostatin mechanical: smooth muscle for churning
18
Q
digestion in the SI
A
chemical: alkaline mucus, pancreatic amylase, maltase, sucrose, lactase, trypsin, chemotrypsin, carboxypeptidase mechanical: segmentation
19
Q
peritoneum
A
serous membrane of the abdominal cavity visceral: covers the external surface of most digestive organs parietal: lines the body wall mesentery: double layer of peritoneum that provides vascular and nerve supply to the viscera, holds digestive organs in place, and stores fat
20
Q
peritoneal cavity
A
lubricates digestive organs and allows them to slide across one another
21
Q
retroperitoneal organs
A
organs outside the peritoneum
22
Q
peritoneal organs
A
intraperitoneal organs surrounded in peritoneum
23
Q
bolus
A
food that has been chewed and moistened with saliva the product of the mouth from the esophagus to the stomach
24
Q
chyme
A
food that has been chemically and mechanically digested in the stomach to small intestine
25
peristalsis
waves of contraction and relaxation from the smooth muscle in the organ walls
26
how peristalsis works
1. circular muscles above the bolus contract constricting the wall of the esophagus and squeezing the bolus downwards 2. longitudinal muscles below the bolus contract to shorten the section of esophagus below the bolus and push walls outward
27
segmentation
rhythmic local contractions of the SI
28
layers in the walls of the digestive organs
mucosa submucosa muscularis externa serosa
29
mucosa
moist epithelial layer that lines the lumen of the alimentary canal functions in secretion of mucus, absorption of digestive end products and protection against effective diseases
30
epithelial lining of the mucosa
simple columnar epi and mucus secreting goblet cells protects digestive organs from digesting themselves and eases food along the tract has enzyme secreting cells and hormone secreting cells
31
lamina propria of the mucoa layer
loose areolar and reticular CT nourishes the epi and absorbs nutrients contains lymph nodes MALT that is important in defense against bacteria
32
muscularis mucosa of the mucosa layer
smooth muscle cells that produce local movements of mucosa
33
submucosa
dense CT containing elastic fibers, blood, lymphatic vessels, lymph nodes, and nerves enables the stomach to return to its normal shape after being stretched
34
muscularis externa
responsible for segmentation and peristalsis involuntary contractions forms sphincters that act as valves to control food passage from organ to organ
35
serosa
protective visceral peritoneum replaced by fibrous adventitia in the esophagus retroperitoneal organs have both adventitia and serosa
36
mouth
opens via the oral orifice anteriorly and is bound by lips cheeks palate and tongue. opens posteriorly to the oropharynx
37
features of the mouth
stratified squamous epithelium that can be slightly keratinized only structure where food is ingested digestion of carbs starts here
38
lips
fleshy folds around the opening of the mouth covered by skin on the outside and mucous membrane on the inside
39
cheeks
keeps food between the teeth and assist in speech
40
hard palate
underlain by palatine bones and palatine process of the maxillae to assist the tongue in chewing
41
soft palate
mobile fold formed mostly of skeletal muscle that closes off the nasopharynx during swallowing
42
uvula
projects downward from its free edge and prevents entry of food into the nasal cavity
43
tongue
skeletal muscle covered with mucous membrane that occupies the floor of the mouth and fills the oral cavity when the mouth is closed functions in gripping and repositioning and mixing of food, and initiation of swallowing and speech secured by the lingual frenulum
44
filiform papillae
give tongue its roughness and provide friction
45
fungiform papillae
scattered widely over the tongue and give it a reddish hue
46
curcumvallate papillae
v shaped row at the back of the tongue
47
sulcus teminalis of the tongue
groove that separates the tongue into two areas the anterior 2/3 in the oral cavity and the posterior third in the oropharynx
48
functions of the salivary glands
-cleanse the mouth, moisten and dissolve food chemicals, aid in bolus formation, and contain enzymes to break down starch
49
features of the salivary glands
extrinsic glands- (parotid, submandibular, and sublingual) larger glands that secrete saliva when you eat, drink, or think about it intrinsic glands (buccal glands) scattered throughout the oral mucosa to keep the mouth moist
50
secretion of salivary glands
saliva from serous and mucous cells 97-99.5% water, electrolytes, proteins (mucin, lysozyme, defensins, IgA), metabolic wastes (urea, uric acid) and enzymes ph 6.75-7
51
enzyme of the salivary gland
salivary amylase breaks down starch to maltose
52
hormones secreted by salivary gland
N/A
53
features of the pharynx
nasopharynx: pseudostratified ciliated columnar epithelium oro/laryngopharynx: stratified squamous epithelium that takes food and fluid to the esophagus and air to the trachea
54
secretion of the pharynx
mucus
55
pharynx enzymes
N/A
56
hormones of the pharynx
N/A
57
features of the esophagus
no serosa but fibrous CT and stratified squamous epithelium muscularis externa made up of skeletal and smooth muscle takes bolus to the stomach by going through the mediastinum and diaphragm
58
esophagus secretions
mucus
59
esophagus enzymes
N/A
60
esophagus hormones
N/A
61
features of the stomach muscularis externa
3 layer outer: longitudinal middle: circular inner: oblique
62
features of the stomach mucosa
simple columnar and goblet cells gastric glands
63
features of the stomach submucosa
areolar CT
64
features of the stomach cells of the epithelial lining
1. mucous neck cells-fundus produce acid mucus 2. parietal cells- secrete HCl and intrinsic factor 3. chief cells- produce pepsinogen an inactive enzyme 4. enteroendocrine cells-secrete gastrin, histamine, endorphins, serotonin, CCK, and somatostain in the lamina propria proteins make an alkaline pH and increase the amount of gastric juices
65
stomach secretion
goblet cells- alkaline mucus gastric gland- HCl, gastric juice, mucus, pepsinogen, and gastrin intrinsic factor- to absorb b12 need to allow the complete maturation of erythrocytes
66
stomach enzymes
pepsinogen activated by HCL and turned into pepsin able to turn large proteins into small chains of amino acids
67
stomach hormones
gastrin- increases gastric juices, mobility, and relaxes pyloric sphinter CCK- slows down stomach when fats are present secretin- released by SI to decrease the amt of gastric juices
68
features of the SI
duodenum, jejunum, ileum receives chime plicae circularis, villi, microvilli enteroendocrine cells MALT interspersed T cells to release cytokines when antigens are encountered
69
secretion in SI
alkaline mucus with water and no enzymes secreted by brunners glands in the duodenum pH 7.4-7.8
70
enzymes of SI
pancreatic amylase maltase sucrose lactase trypsin, chemotrypsin, carboxypeptidase pancreatic juice and bile salts
71
Paracrine of SI
VIP NOT A HORMONE dilutes interstitial capillaries stimulates a buffer (bicarbonate) secretion to increase alkalinity
72
liver features
largest gland in the body hexagonal liver lobules-right, left, caudate, and quadrate sinusoids-kupffer cells
73
function of hepatocytes
production of bile carb metabolism lipid metabolism protein metabolism detox vit/min storage vitD
74
liver secretion
bile- cholesterol, fatty acids, phospholipids, electrolytes, bilirubin (break down of heme) and bile salts
75
enzymes of the liver
N/A
76
liver hormones
CCK- contracts the gall bladder to release bile and relax hepatopancreatic sphinter (ampulla) Secretin- increases bicarbonate production
77
features of the pancreas
endocrine function: insulin and glucagon exocrine function: acinar cells to make pancreatic juice stimulation by vagus nerve head encircles the duodenum, tail abuts the spleen
78
pancreas secretion
pancreatic juice- produced by acinar cells and can be released by vagal stimulation contains zymogen granules and enzymes, bicarbonate, water, electrolytes neutralizes acid chime bile goes to duodenum
79
pancreatic enzymes require bile for optimal activity
pancreatic amylase lipase nucleases trypsin, carboxypeptidase, chemotrypsin
80
pancreatic hormones
CCK- released when fatty acids are present to release pancreatic juice secretin- protects duodenum from acid bc of bicarbonate insulin and glucagon secreted by islets of langerhans
81
features of the large intestine
simple columnar and goblet cells cecum, colon, rectum, anal canal, and appendix haustrum anal canal is stratified squamous and a lot of mucus digestion of enteric bacteria bacteria flora reclaiming vit, water, and electrolytes propulsion of fecal matter to anus
82
secretions of the large intestine
mucus
83
large intestine enzymes
N/A
84
hormones
N/A
85
bile
yellow green alkaline solution that contains bile salts bile pigments cholesterol neural fats, phospholipids and electrolytes
86
digestive function of bile salts
emulsify fats facilitate fat and cholesterol absorption help solubilize cholesterol
87
bile is stored and concentrated in
the gall bladder
88
why is it necessary to have the stomach be acidic
to carry out chemical digestion
89
how does the stomach protect itself from digestion
a thick coat of bicarbonate rich mucus on the wall epithelial cells are joined by tight junctions and gastric gland cells are impermeable to HCl damaged epi are quickly replaced pepsinogen not active till HCl is present
90
two regions in the digestive tract where mech food breakdown processes are very important
mouth, stomach/esophagus
91
organs that are primarily food conduits
mouth and esophagus
92
swallowing is
a coordinated activity of the tongue, soft palate, pharynx, esophagus, and 22 separate muscle groups
93
3 stages of swallowing
buccal phase- bolus forced into oropharynx pharyngeal phase- all routes except those leading to the digestive tract are sealed off esophageal phase- peristalsis moves through the pharnx to the esophagus
94
what is stimulated in the stomach when food is going to enter it
Celiac phase
Refelexes stimulate parasympathetic of the ANS and enteric neurons
Stimulation of gastric glands to make gastric juices-pepsinogen, HCl, mucus, and gastrin
Gastrin stimuluates secretion of large amounts of gastric juices, increases stomach mobility, relaxes pyloric sphincter
95
what molecules or chemicals are digested and absorbed in the stomach
-proteins via pepsin -vitamin b12 via intrinsic factor -lipids via gastric lipase -a little bit of water, ions, short chain fatty acids aspirin and alcohol
96
what triggers gastric emptying
distention of the stomach gastrin partially digested proteins vagus nerve each mixing wave forces only a small amt of chime thru the pyloric sphinter into the duodenum after some contents are emptied this is slowed down
97
salivary amylase
breaks starch into maltose
98
pepsinogen (stomach)
activated by HCl to form pepsin which digests large proteins into small chains
99
maltase (SI)
breaks maltose into glucose and glucose
100
sucrose (SI)
breaks sucrose into glucose and fructose
101
lactase SI
breaks lactose into glucose and galactose
102
enteropeptidase SI
activates trypsin, chemotrypsin, carboxypeptidase to break down large proteins into smaller ones
103
trypsin, chemotrypsin, carboxypeptidase (pancreas)
activated in duodenum by enteropeptidase
104
pancreatic amylase (pancreas)
breaks starch into maltose requires ions or bile
105
pancreatic lipase and bile salts (pancreas)
breaks fats/triglycerides into fatty acids and monoglycerides requires ions or bile
106
nucleases (pancreas)
ribo/deoxy break down nucleotides
107
major hormones acting on the stomach
Gastrin- secreted by enteroendocrine cells of stomach and increase the amount of gastric juices, mobility, and relaxes pyloric sphincter CCK- slows down the stomach and is released by gall bladder when fats are present Secretin- secreted by endothelial cells of stomach, decreases gastric juices when acid chyme
108
major hormones acting on pancreas
CCK- when fatty acids or acidic chime enters the duodenum; induces secretion of enzyme rich pancreatic juice Secretin- protects duodenum from acid chime Insulin glucagon
109
gall bladder hormones
CCK- causes contraction of gall bladder and release of bile
110
hormones of liver
CCK- contracts gall bladder to release bile and relax hepatopancreatic sphincter
111
hormone of the SI
VIP is a PARACRINE not a hormone dilates intestinal capillaries and stimulates the alkaline bicarbonate buffer system
112
chemical digestion of carbs begins in the
mouth
113
chemical digestion of fats begins in the
stomach
114
chemical digestion of proteins begins in the
stomach
115
chemical digestion of nucleic acids begins in the
duodenum
116
proteins are digested by
pancreatic juice enzymes trypsin, chymotrypsin, elastase, carboxypeptidase digestion is completed by peptidases on epithelial cells---final product is tripeptides, dipeptides, and amino acids
117
carbs are digested by
starches and dextrins are not reduced to maltose by the time chime leaves the stomach so they need the help of pancreatic amylase 3 enzymes in the intestinal juice for digestion of disaccharides to monosacc on surface of epi cells (lactase, maltase, sucrose)
118
fats are digested by
pancreatic lipase and bile salts
119
nucleotides are digested by
ribonucleases and deoxyribonucleases
120
absorption of monosaccarides
glucose and galactose are moved into the blood through active transport fructose is moved into the blood capillaries through facilitated diffusion
121
absorption of aminos
in duodenum and jejunum half come from dead cells and digestive juices other half comes from foods move into epi cells by active transport peptides inside of the cell are digested into aminos moves to capillaries by diffusion and then to general cirulation
122
absorption of lipids
moved by simple diffusion and 95% in SI reach the epi cells of villi by micelles inside epi lipase breaks down monoglycerides to fatty acids and glycerol which are recombined to form triglycerides triglycerides combine w cholesterol and proteins to form chylomicrons to be released by exocytosis and moved to lacteals
123
absorption of vitamins
fat soluble vit ADEK included with lipids in micelles and are absorbed by simple diffusion and end in lacteal water soluble vit C and B absorbed by simple diffusion and end in blood
124
importance of bacterial flora
colonizes colon so others cant ferments indigestible carbs breaks down proteins and aminos decomposes bilirubin into stercobilin to make feces brown releases irritating acids and gases produces some complex B vitamins and most of vit K
125
the colon is not the same as the large intestine because
it is only part of the large intestine
126
process of defecation
distention of rectal walls by feces stimulates contraction of rectum and relaxes the internal anal sphincter voluntary signals stimulate the relaxation of external anal sphinter
