Digestive System & Metabolism - Exam 3 Flashcards
1
Q
What are the main organs involved in digestion?
A
everything along the alimentary canal (gastrointestinal tract)
2
Q
What does the alimentary canal include?
A
mouth pharynx esophagus stomach small intestine large intestine rectum
3
Q
What is the alimentary canal made up of?
A
continuous muscular tube
4
Q
What are the accessory digestive organs?
A
teeth tongue gall bladder salivary glands liver pancreas
5
Q
What is the role of the lips in digestion?
A
mechanical
help break down food
6
Q
What is the role of the teeth in digestion?
A
mechanical
chew food into smaller particles
7
Q
What is the role of the tongue in digestion?
A
mechanical
kneads food into smoother, smaller particles
8
Q
What is the role of the hard and soft palate in digestion?
A
mechanical
hard palate is used to knead food against
soft palate relates to gag reflex
9
Q
What is the role of the epithelium and salivary glands in digestion?
A
chemical
both secrete saliva and enzymes that both lubricate and help break down food into easily digested and absorbed pieces
10
Q
How is saliva produced?
A
controlled by the senses
smell, sight etc
11
Q
What starts the process of digestion?
A
senses
12
Q
What is the composition of saliva?
A
- mainly water
- electrolytes
- digestive enzymes
- proteins (musin)
- protective substances
- metabolic wastes
13
Q
What is the average output of saliva?
A
1-1.5 L per day
14
Q
What is another word for swallowing?
A
deglutition
15
Q
What is the purpose of the gag reflex?
A
to keep food from going into the wrong places
16
Q
What are the main digestive enzymes that digest the macromolecules?
A
protease
lipase
amylase
nuclease
17
Q
What is extrinsic control?
A
outside wall of digestive tract
18
Q
Where does extrinsic control stimuli come from?
A
- info obtained by CNS
- emotion, special senses
19
Q
How could extrinsic control change saliva production and digestive activity?
A
- sights and smells can increase saliva production
- senses are what begin digestive activities
20
Q
What is intrinsic control?
A
in wall of digestive tract
21
Q
Intrinsic controls are detected by which receptors?
A
nerve plexuses
hormone-producing cells
22
Q
What controls digestive activity?
A
intrinsic and extrinsic controls
23
Q
What does an increase in sympathetic nervous system stimulation do to saliva production and digestive activity?
A
inhibits saliva production and digestive acitivities
24
Q
What is the difference between segmentation and peristalsis?
A
- segmentation is when nonadjacent alimentary canal organs contract and relax, breaking apart and moving food forwards and backwards
- peristalsis is when adjacent segments of alimentary canal contract and relax to propel food forward
25
What tissue drives segmentation and peristalsis
smooth muscle tissue
| muscular mucosa
26
What cells are responsible for the acidic environment of the stomach?
parietal cells
| chief cells
27
What do chief cells do?
release inactive pepsinogen
28
What do parietal cells do?
release HCl
29
Where are chief and parietal cells found?
gastric pits and glands of the stomach
30
What happens when pepsinogen mixes with HCl?
it is converted to active pepsin
31
What is pepsin?
a protease
32
How do bile and pancreatic juices influence the chemical environment of the duodenum?
bile, pancreatic juices and chyme are mixed together through duodenum's contractions to create a final spot for chemical break down to occur
33
How do bile and pancreatic juices influence digestion?
bile emulsifies fats into smaller globules to increase surface area
pancreatic juices break down every type of macro
34
What controls produce short and long reflexes?
intrinsic and extrinsic controls
35
What causes a short reflex?
chemoreceptors, osmoreceptors, or mechanoreceptors go straight to the intrinsic nerve plexus (gut brain) rather than passing through the CNS
36
What causes a long reflex?
External or internal stimuli passes through the CNS before being translated to the intrinsic nerve plexus
37
What increases waves of peristalsis?
gastrocolic reflex
38
What modifications are present in the digestive system that increase surface area?
villi in the small intestine dramatically increase surface area for absorption
39
What other part of digestion increases surface area?
bile emulsifying fats
| chewing of foods
40
What is the path of absorption of lipids?
- fatty acids and monoglycerides enter intestines via diffusion
- fatty acids and monos are recombined to form tryglycerides and are mixed with other lipids and proteins to form chylomicrons
- chylomicrons enter the lacteals of the villi and are transported to the systemic circulation via lymph in thoracic duct
- short chain fatty acids are absorbed, move into capillary blood in villi by diffusion, and are transported to liver
41
Where are long-chain fatty acids transported to?
lymphatic system
42
Where are short and medium-chain fatty acids transported to?
cardiovascular system
| blood circulation
43
How do we get fat out of the small intestines?
lipoproteins (chylomicron, VLDL, LDL, HDL)
44
What do chylomicrons do and where do they end up?
transport lipids from intestines to lymph
| end in liver
45
Where does VLDL start, what does it do, and where does it end?
- liver after consuming saturated fats
- deposits fats around body
- circulation
46
Where does LDL start, what does it do, and where does it end?
- converted VLDL
- deliver cholesterol to tissues
- liver or arteries
47
Where does HDL start, what does it do, and where does it end up?
- liver after consuming unsaturated fats
- artery scrubber
- returns cholesterol to liver
48
What is found in the large intestine that helps aid in digestion and produces vitamins?
gut bacteria aids in digestion and produces vitamin K
49
In what portion of the GI tract does most absorption occur?
small intestines
50
How does the GI tract protect itself from its own digestion in the stomach and small intestines?
- bicarbonate ions neutralizes HCl in stomach
| - pepsin and pepsinogen protect from self-digestion in small intestine
51
How is ATP generated from glucose?
Glycolysis reaction breaks down 6C glucose to 2 molecules of 3C pyruvate. Pyruvate is then converted to acetyl-CoA in the transition reaction. Acetyl. CoA enters Krebs with oxaloacetate presence, producing coenzymes that carry electrons to the ETC to produce ATP.
52
How are fatty acids broken down?
lingual lipase chemically breaks down large fat molecules, and bile later breaks down to micelles which later become chylomicrons
53
Why do fats produce more ATP than any other macromolecule?
Fat contains long carbon chains, so they have a lot of carbon to be converted to acetyl-CoA. More acetyl CoA equals more ATP generation.
54
In what form are simple carbs stored in the liver and skeletal muscle?
glycogen
55
Connect Type I diabetes to ketoacidosis and ketone bodies in the blood
Type I diabetes is characterized by the body's inability to produce its own insulin. When insulin is not present to process glucose for energy use, the body starts to burn fat for energy, which produces ketone bodies. The buildup of ketone bodies in the blood turns blood more acidic, causing DKA.
56
Why are vegetarians advised to eat multiple types of vegetables to get the proper amount of protein in their diet?
Many vegetables are incomplete proteins, which means they lack 1 or more of the essential amino acids. Eating a wide range of vegetables in combination with each other will ensure that each vegetable acts as a complimentary protein, to ensure that you are receiving adequate amino acids
57
Can glucose be converted to and stored as fat?
yes
58
How is fat used in the body?
as phospholipids in cell membranes
as cushion and insulation
as a fuel source
sterols
59
Why are minerals important in the diet?
aid in metabolism
60
What is the muscular layer of the esophagus made up of?
smooth muscle
61
What is the enteric nerve plexus?
gut brain
62
What factors in the stomach create a barrier to protect against the harsh environment?
mucus (bicarbonate ions)
high turnover of cells
tight junctions
63
How much gastric juice is produced daily?
3 Liters
64
Control of gastric secretion occurs in how many phases?
3
65
What are the 3 phases of gastric secretion control?
- before (cephalic/reflex phase)
- during (gastric phase)
- after (intestinal phase)
66
How does the intestinal phase control gastric secretions?
contents are released into duodenum which stimulates reduction of gastric juice production
67
How are the rhythmic contractions of the stomach paced?
stimulus influences peristaltic waves because of the presence of autorhythmic cells
68
When does the stomach empty?
within 4 hours after a meal
69
The emptying of the stomach is largely dependent upon what?
ability to liquefy food and digestion in duodenum
70
What part of the duodenum secretes bicarbonate-rich mucus?
duodenal glands
71
What accessory organs also secrete into the duodenum?
gallbladder
| pancreas
72
What stimulates the duodenum?
stretch and change in chemical environment
73
What is the role of the gallbladder?
storage site
74
What produces bile?
gallbladder
75
What are the characteristics of bile?
- yellow-green, alkaline solution
- contains bile salts, pigments, cholesterol, triglycerides, phospholipids, and electrolytes
- main pigment is bilirubin
76
What is the backbone of bile salts?
cholesterol
77
What are gallstones?
crystals formed from an imbalanced chemistry, which are then surrounded by cholesterol
78
What is the result of gallstones?
trapping of material which could result in Jaundice and impairment of digestion of fats
79
What is the role of the pancreas?
secretes pancreatic juice
80
What is found in pancreatic juice?
bicarbonate ions
| digestive enzymes
81
What are released in an inactive form and become active in the duodenum?
proteases
82
The release of bile is stimulated by what?
bile salts
| Cholecystokinin (CCK)
83
CCK is released by what cells in response to what?
released by intestinal cells in response to high fat content of chyme
84
CCK also stimulates the release of what type of juice?
pancreatic juice
85
Pancreatic juices are released from what type of cells?
enteroendocrine
86
How does sympathetic stimulation alter digestive activity?
inhibits digestive activities
87
How does parasympathetic stimulation alter digestive activities?
enhances secretion and motility
88
What makes up the abdominal (peritoneal) cavity?
- serous membrane
- peritoneal cavity (parietal and visceral)
- mesentery
89
What is peritonitis and what is it caused by?
inflammation of peritoneum
| bacterial or fungal infection
90
What are the modifications of the small intestine that increases absorption?
- muscular layers force chyme to spiral through lumen, slowing its movement and increasing absorption
- villi increase surface area
91
Compare and contrast water-soluble and fat soluble vitamins
water-soluble are soluble in water and are excreted in excess
fat-soluble are soluble in fats and are stored
92
Where are electrolytes absorbed?
- most absorbed throughout small intestine
| - iron and calcium absorbed in duodenum
93
Where is most of the water absorbed?
small intestine, 95%
94
Why can water move freely back and forth across the intestinal mucosa by osmosis?
moving solutes across makes water follow
95
What are common disorders of the digestive system?
constipation/diarrhea
| appendicitis
96
What is Celiac's disease?
an autoimmune disorder that destroys villi, making digestion and absorption difficult
97
What happens due to Celiac disease?
surface area decreases
| nutrient deficiencies
98
What is Crohn's disease?
inflammatory condition
| immune system treats foods/bacteria/other beneficial substances as foreign
99
What causes Crohns?
cause not well-understood, but is due to abnormal reaction of immune system
100
What happens because of Crohns?
build up of white blood cells, inflammation, and ulcerations
101
How is Crohns treated?
removal of infected parts, which decreases surface area and decreases digestion and absorption
102
What is metabolism?
sum of all reactions taking place
103
What is anabolic?
growth
| like steroids
104
What is catabolic?
breakdown
| like fasting
105
What does your heart prefer?
fatty acids
106
Which type of lipoproteins matter more when considering heart disease, heart attack etc.?
LDL
107
What can the heart take up and lose for energy?
lactate
108
What is a simple carbohydrate?
glucose
109
What is a complex carbohydrate?
glycogen
110
What are carbohydrates used for?
energy
111
Carbohydrates are stored as what?
glycogen or fat
112
What is glycogenesis?
formation of glycogen
113
What is glycogenolysis?
liver
| glycogen breakdown
114
What hormones are involved in metabolism?
insulin
| glucagon
115
What does insulin do?
stimulates uptake (removal from blood) and use of glucose inside the cell
116
What does glucagon do?
breakdown into glucose to enter circulation
117
Where does each phase of metabolism take place?
Glycolysis - cytosol
Transition Reaction - between cytosol and mitochondria
Krebs - mitochondria
ETC - mitochondria
118
What are the major forms of lipids?
triglycerides
| cholesterol
119
What are the characteristics of saturated fat?
saturated by hydrogen
| linear carbon chain makes it solid at room temperature
120
What are the characteristics of unsaturated fat?
not saturated by hydrogen
| makes kink in chain that allows it to be liquid at room temperature
121
What is cholesterol used for?
sex hormones
| membranes
122
Lipogenesis vs. Lipolysis
formation vs. breakdown
123
What are proteins composed of?
amino acids
124
The metabolism of proteins makes what?
ammonia
ammonia is toxic
urea
125
Vitamins act as what in metabolism?
coenzymes
126
K and B vitamins are produced by what?
bacteria
127
What are the water-soluble vitamins?
B and C
128
What are the fat-soluble vitamins?
A, D, E, & K
129
Minerals act as what in metabolism?
cofactors
