Pre 9/14/22 Flashcards
1
Q
oral cavity
A
mouth + pharynx + salivary glands
2
Q
functions of oral cavity
A
- gustatory
- mastication
- digestion swallowing
- speech
- respiration
3
Q
main enzyme in saliva
A
alpha-amylase (aka ptyalin)
lingual lipace
4
Q
alpha-amylase function
A
hydrolyzes internal (alpha 1-4) bonds within starch
5
Q
lingual lipase function
A
hydrolyzes dietary triglycerides in mouth and stomach
6
Q
salivary glands must keep good regulation of…
A
conc of water
7
Q
stimulation of salivary glands
A
- tactile stimuli
- taste
- other inputs: olfactory, visual, etc.
8
Q
mechanics of digestion first two steps
A
- mastication (chewing): releases nutrients and increases total surface area of foods
- swallowing
8
Q
swallowing is…
A
highly regulated
9
Q
stages of swallowing
A
- voluntary stage
- pharyngeal stage
- esophageal stage
10
Q
voluntary stage of swallowing
A
pressure of tongue squeezes and rolls bolus to pharynx
swallowing can’t be stopped
everything else is involuntary
11
Q
pharyngeal stage
A
initiate a series of automatic pharyngeal contractions
forces bolus into upper esophagus
12
Q
esophageal stage of swallowing
A
bring food rapidly from esophagus to stomach
primary and secondary peristalsis
13
Q
primary digestive system organs
A
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
14
Q
secondary organs in the digestive system
A
- salivary glands
- liver
- gallbladder
- pancreas
15
Q
what are the main functions of the oral cavity
A
eating, speaking, beginning digestion
16
Q
which phase/s of swallowing is/are voluntary
A
voluntary phase/preparatory/oral phase
phase 1
17
Q
which part of nervous system controls swallowing
A
CNS
18
Q
pancreas anatomy
A
- ductless endocrine cells that secrete hormones into the blood
- acinar exocrine cells
19
Q
acinar exocrine cells
A
produce digestive juice and enzymes
20
Q
pancreas 3 parts
A
- head
- body
- tail
21
Q
pancreatic exocrine cells secrete
A
pancreatic digestive enzymes
lots of bicarbonate released into pancreatic ducts
22
Q
pancreatic enzymes + bicarbonate flow
A
pancreatic duct –> common bile duct to release
23
Q
what triggers pancreatic enzymes
A
chyme in upper portion of small intestine
24
insulin is secreted by...
pancreas
directly into blood by Islets of Langerhaans
25
pancreatic juice contains
1. bicarbonate
2. electrolytes (sodium, potassium, chloride), calcium
3. pancreatic digestive enzymes
4. -zymogens: proteases
5. -other enzyme: amylase, lipace, RNase and DNase
26
exocrine cells produce and release
bicarbonate soln into ducts
27
during post prandial period,
pancreas responds to acid in small intestine
secretes bicarbonate to restore neutral pH
28
S cells
cells in proximal small intestine
release secretin in response to deacrease in pH
secretin causes release of bicarb
29
enterokinase
secreted from duodenal epihtelial cells
secretes zymogens
30
trypsin inhibitor
synthesized by pancreas
protexts pancreas by binding to trypsin if protease is accidentally activation within pancreas
31
largest internal organ
liver
right lobe and left lobe
32
liver lobes are made up of
lobules
made of hepatocytes
33
central veins
drain blood from liver and bring nutrients into circulation through hepatic veins, then inferior vena cava
34
blood passes through...
sinusoids: act as channels
sinusoids arise from branches of hepatic artery and portal vein
35
portal vein
brings blood from digestive tract to liver
36
bile canaliculi
transports bile to main bile duct in liver
37
Kupffer cells
macrophage like cells in liver
38
stellate cells
liver cells
store Vitamin A
39
liver functions
1. centralize and segregate absorbed nutrients for metabolism, storage, or transport
2. produce bile acids and salts
3. excretes metabolic waste
4. detoxification
40
bile
alkaline soln (pH 7.6-8.6) composed of:
1. bile acids and salts
2. cholesterole and phospholipids
3. bile pigments (bilirubin and biliverdin)
41
2 primary bile acids
1. chenodeoxycholic acid
2. cholic acid
made in hepatocytes from cholesterol
combine with sodium, potassium, calcium to form bile salts
conjugate with glycine or taurine
42
conjugation of bile acids with amino acids helps
ability to form micelles
43
bile acids function
biological detergent
emulsify and break down large fat globules into small fat droplets
increases surface area
44
what are the main anatomical/functional areas of pancreas?
45
what are the main components of pancreatic exocrine secretions?
46
what are the main components of pancreatic endocrine secretions?
47
what are the main enzymes secreted by pancreas?
Lipase, amylase, protease
48
what are the components (hormones, cells, and chemical compounds) and sequence of events in the mechanism for the regulation of pH in the duodenum?
49
What are the main cell types in the liver and what are their functions?
50
What components (nutrients, gases, excretion products, etc.) are mainly treansported by the hepatic artery, the portal vein, and central vein, respectively?
Hepatic artery: oxygenated blood
Portal vein: nutrients toxins from digestion
Central vein:
51
what are the main biochemical components of bile?
52
what are the main biochemical modifications of bile salts? what is the functional purpose?
53
what are the main functions of bile?
54
esophagus
connects pharynx to stomach
lined by mucosa (a type of epithelial tissue)
55
how does food enter the esophagus
bolus is sent from pharynx to esophagus
upper esophageal sphincter (UES) relaxes AND larynx pushes upwards to open UES and allow entry
56
is upper esophageal sphincter under voluntary or involuntary control?
voluntary
allows for breathing, eating, swallowing
57
closed lower esophageal sphincter
prevents stomach acid and contents from traveling backwards
58
closed lower esophageal sphincter
prevents stomach acid and contents from traveling backwards
59
is upper esophageal sphincter under voluntary or involuntary control?
involuntary
60
stomach histology: muscularis
has oblique layer
allows mechanical digestion by churning
61
stomach epithelial lining is made of
ONLY surface mucous cells
secrete protective coat of alkaline mucous
62
cardiac glands
found in a narrow rim at the juncture of the espohagus and the stomach
63
oxyntic glands
aka gastric glands
found in the body and fundus of the stomach
64
pyloric glands
located primarily in the pyloric antrum
secrete mucous and gastrin
65
stomach glands are made up of
parietal cells
cief cells
enteroendocrine cells
66
somatostatin
main regulator of gastric motility and acid secretion
67
what is the main type of digestion in the stomach?
mechanical!
68
stomach: digestion role
1. initiates protein hydrolysis/degradation by releasing pesinogen
2. limited continuation of starch hydrolysis
3. limited lipolysis
4. absorption of water, alcohol, and a few drugs and mineralas
5. intrinsic factor release
69
why is starch hydrolysis limited in stomach?
acid induced inactivation of saliary amylases limits starch digestion in the stomach
70
gastric lipase in stomach digestion
limited lipolysis of short- and medium chain triglycerides (EX: ones in milk)
71
only organ that releases intrinsic factor (IF)
stomach
72
small intestine 3 regions
duodenum, ileum, jejunum
73
small intestine: ileocecal sphincter
last segment of small intestine
74
cecum
first segment of large intestine
75
duodenum
receives secretions from gallbladder via common bile duct
76
where do pancreatic secretions go in the small intestine?
pancreatic duct which drains to common bile duct
77
Sphincter of Oddi
regulates flow of secretions into duodenum
78
small intestine surface area
very large!
79
small intestine mucosa and submucosa are arranged in circular folds called
folds of Kerckring
prutrude into lumen of small intestine
80
villi
each villus is made of enterocytes (absorptive cells)
81
folds of Kerckring are covered by
finger-like projections called villi
each villi has a capillary network and lymphatic vessel
82
enterocytes
absorptive cells
covered with microvilli
83
brush border is made up of
microvilli
impact nutrient absorption
84
how does chyme move through the small intestine? (type1)
mixing movements: pushed back and forth within adjacent segments of intestine
circular muscles alternate contracting and relaxing
85
chyme flow
bidirectional bc of segmentation contractions
86
how does chyme move through the small intestine? (type 2)
propulsive movements: peristaltic waves
takes 3-5 hours for chyme to go from duodenum to ileocecal valve
87
pathway of movement after entering large intestine
1. cecum
2. ascending colon
3. transverse colon
4. descending colon
5. sigmoid colon
6. anal canal
88
functions of colon:
1. absorption of water and exchange of electrolytes (proximal half)
2. storage of fecal amtter (distal half)
3. habitat of gut microbiome
89
movements of large intestine
slower, but similar to small intestine (mixing movememnts and propulsive movements)
takes 12-20 hours
90
poor motility in colon leads to...
excessive absorption of water
hard feces, constipation
91
excess motility in colon leads to...
less absorption of water and diarrhea
92
mechanism of defacation
constriction of internal and external anal sphincter
93
anal sphincters are made of
striated voluntary muscle
94
external anal sphincter is control by which nervous system
nerve fibers from somatic nervous system
voluntary conscious/subconscious control
95
intrinsic reflex of defecation
1. feces enters rectum
2. distention of rectal wall initiates peristaltic waves in descending colon (forces feces towards anus)
2. internal anal sphincter releaxation
3. if external anal sphincter is also voluntarily relaxed at the same time, defecation occurs
96
parasympathetic defecation reflex
signals from sacral cord intensify the peristaltic waves and relax the internal anal sphincter
97
what are the main anaotmical features of the esophagus?
98
what are the main regions of the stomach?
99
what are the main glands of the stomach?
100
which are the main cells in the oxyntic gland and what coumpound/s they secrete?
101
what are the main parts of the small intestine?
102
what are the folded structures of the small intestine (i.e. villi) and what are the main functions?
103
what are the main movements of the small intestine?
104
what are the main parts of the large intestine?
105
what are the main functions of the large intestine?
106
which are the phases of the mechanism of defecation and how is it controlled??
