Exam 2 Flashcards
(159 cards)
1
Q
Digestive system
A
Series of organs coordinated to facilitate nutrient intake and uptake
2
Q
Mouth
A
Saliva
Moisten food
Mucus
Amylase
2
Q
Stomach
A
Acidic
Protease enzymes (pepsin)
Gastric lipase (FA)
Intrinsic factor (B12)
Contractions grind and mix food
2
Q
Gastric emptying
A
Regulated movement from stomach to SI
2
Q
Small intestine
A
Primary site of digestion and absorption
Bile acids
Muscles (longitudinal, circular)
Rich blood supply
Microvilli
2
Q
Liver
A
Produce bile acids (stored in the gallbladder)
Process nutrients
2
Q
Pancreas
A
Produce digestive enzymes and insulin
Release bicarb
3
Q
Swallowing
A
Reflex initiated by movement of food from mouth to pharynx
Reflex closes the epiglottis over the larynx
Want to prevent food from ending up in airways or nasal passages
4
Q
Upper esophageal sphincter
A
Closes off upper esophagus
5
Q
Lower esophageal sphincter
A
Closed distal end of the esophagus
Blocks reflux of the stomach contents back into the esophagus
6
Q
Chyme
A
Stomach digested food
7
Q
Gastroesophageal reflux disease
A
Lower esophageal sphincter is loose
Stomach contents reflux back up into esophagus (constant)
Acid content irritates lower esophagus
Can wear away the lining, detrimental
8
Q
Drugs for GRD
A
Antacid neutralizes the acid
Block acid secretion
Proton pump inhibitor
9
Q
Lumen
A
Inside of small intestine
Where the food/contents are
Collectively called the mucosa
10
Q
Villi
A
Small folds
Rich blood supply
Lined with a single layer of epithelial cells
Increase surface area
Increases interaction with food
11
Q
Crypt cells
A
Complex organization of cells as a result of the villi structure
Crypts of cells that do not project out into the lumen
Stem cells that replenish them are at the bottom of the crypt
Cells migrate from crypt up the lumen
12
Q
Enterocytes
A
Majority of cells
Digestion and absorption
13
Q
Goblet cells
A
Secrete mucin
14
Q
Enteroendocrine cells
A
Hormone selection
15
Q
Paneth Cells
A
Immune monitoring
16
Q
Large intestine
A
Receives food residue from small intestine
Large population of bacteria
Absorb water and minerals
Beginning to form fecal matter
17
Q
Regularity depends on
A
Microbiome
Food intake
Genetics
18
Q
Autonomic nervous system
A
Regulates function of visceral organs
Unconscious functions
19
Q
GI hormones
A
Small polypeptides
Released in response to meals
Travel to different regions of the digestive system to regulate GI function
20
What do hormones do
Regulation of GI motility
Epithelial cell growth
Regulated to maintain homeostasis
Secretion of various chemicals
21
Peristalsis
Sweeping motion
Propels food forward
Sequential contractions
Swallowing, stomach, small sections of small intestine
22
Segmentation
Circular muscle in small intestine
Closely spaced contractions in discrete areas of the intestine
Increase contact with mucosal surface
23
Mass movement
Large intestine
Contractions that occur over a large area of intestine
Move waste towards the rectum
24
Salivary glands
Release saliva in the mouth
Easies swallowing, breaks down some carbs
25
Gastric glands
Produce gastric juice in the stomach
Uncoil proteins, enzymes break down proteins, mucus protects stomach cells
26
Pancreas excretion
Produces pancreatic juice
Bicarb neutralizes acidic gastric juices
Enzyme break down carbs, fats, proteins
27
Liver's job
Produce bile for the gallbladder
28
Gallbladder
Release bile to the small intestine
Emulsify fat
29
Intestinal glands
Product intestinal juice
Enzymes break down protein, fat, lipids
Mucus protects intestinal wall
30
Carb digestion
Starts in the mouth
Salivary amylase
Break down alpha 1,4 bonds
31
Carb digestion SI
Uses amylase from the pancreas
Converts amylose and amylopectin to dextrins (broken down by brush border)
32
Brush border
Organization of microvilli on enterocytes
Microvilli membrane is studded w/ glycosidases
Food pushes against the border during contractions
33
Carb absorption
Only absorb monosaccharides
34
GLUT2
Basal transporter
Moves monosaccharides out of the enterocyte and into the blood
Facilitated transport
35
SGLT1
Transport glucose and galactose
Active transport
Need NRG
36
GLUT5
Transport fructose
Faciliated transport
37
Protein digestion
Starts in the stomach
HCL uncoils
Pepsin breaks into pieces
38
Protein digestion SI
The pancreas secretes digestive enzymes and bicarb
Hydrolyze peptide bonds → oligopeptides
39
Protein absorption
Brush border peptidases hydrolyze oligopeptides (AA, mon/di/tri peptide)
Transported across the intestinal cell membrane
Active and facilitated transport
Transporters move the AA and small peptides out of the basal region + into the blood
40
Lipid digestion
Starts in the stomach
Gastric lipase (TG --> FFA + monoglycerides)
41
Lipids SI
Bile acids and lecithin from gallbladder
Pancreatic lipases work with protein co-lipase to hydrolyze TG
Emulsification of fat droplets gives lipases access
42
Micelles
Form from monoglycerides and FFA surrounded by bile acids
Give lipids access to epithelial cells
Vitamin absorption
43
Anabolic reactions
Make glycogen, triglycerides, protein
Require NRG
44
Catabolic reactions
Breakdown glycogen, triglycerides, protein
Releases NRG
45
Glucose used for
Metabolism
Stored as glycogen
Convert to fat for storage
Distribute to the rest of the body
46
Glycolysis
1 glucose → 2 pyruvate
Cell uses 2 ATP to go through glycolysis
Gains 4 ATP (2 Net) per glucose
47
Fats (cell level)
TG broken down and absorbed as FA
Packaged as lipoproteins
Processed through the liver
Beta oxidation
48
Proteins (cellular)
Broken down and absorbed as single AA
Processed through the liver
Don’t generally use for NRG
49
Citric acid cycle
All NRG yielding nutrients can be broken down to acetyl CoA
Acetyl CoA can enter CAC or be used to make fat
Electrons are carried to electron transport chain
50
Feasting
Person eats excess of NRG needs
Body stores glycogen and fat
51
Fasting
Nutrients from a meal are no longer able to provide NRG
2-3 hours after a meal
Body draws on glycogen and fat stores
52
Fasting beyond glycogen depletion
Glycogen stores dwindle
24 hours of starvation
Break down protein sources to synthesize glucose
Liver convert fats to ketone bodies
53
Caloric restriction
Decrease in food intake from what an organism would eat on its own
Increase lifespan
Model of delayed aging
54
Neutral balance
Energy in = energy out
Maintain weight
Consumed = burned
55
Positive balance
Energy in > energy out
Gain weight
Primarily stored as fat
56
Negative balance
Energy in < energy out
Lose weight
57
NRG stores
Gain weight: stored as fat b/c it is essentially endless storage
Adipose tissue TG = greatest tissue depot of NRG
58
Gross NRG
From bomb calorimeter
59
Digestible NRG
Gross NRG - fecal NRG loss
60
Metabolizable NRG
Diegstable NRG - urinary and gaseous NRG loss
61
Caloric content of macronutrients
Protein/carb = 4 kcal/g
Fat = 9 kcal/g
62
Non biological factors (NRG in)
Accessibility
Geographical
Socioeconomic, income
Culture
Family
Climate
Time
Etc
63
Biological factors (NRG in)
Hunger
Satiation
Appetite
Satiety
64
Hunger
Physiological response (to nerve signals and hormones) after a lack of sufficient food
65
Satiation
Sensation that prompts the cessation of eating during a meal
Feel full while you are eating, acute
66
Appetite
Desire to eat
67
Satiety
Feeling of fullness and satisfaction that persists after a meal
Feeling between meals, occurs over time
68
CCK
Protein hormone
Station response
Stimulate gallbladder to contract → bile acids
69
GLP1
Released from SI
Satiation signal
Release insulin independent of blood glucose levels
70
Leptin
Protein hormone released from adipose
Interact w/ receptor in hypothalamus
Satiety signal
Concentration related to concentration of adipose
71
Ob/ob mice
Mutation in gene that encodes leptin
Don’t produce leptin
Have a receptor and can respond
72
Db/db mice
Mutation in gene responsible for coding leptin receptor
Produce leptin
Can’t respond
73
Gas exchange
Most accurate and most complicated
Measure O2 consumed and CO2 expelled to digest macronutrients
Works b/c different macronutrients require different amounts of CO2 and O2
74
Gas exchange comparisons
Fat = most O2, CO2
Carbs = equal CO2 and O2
Protein = 2nd most O2, least CO2
75
EER
Only works for people ≥ 19 years old
Different inputs for men and women
Derived from population data, uses averages
76
EER factors
Age (NRG expenditure decreases)
Physical activity (NRG expenditure increases)
Weight (NRG expenditure increases)
Height (NRG expenditure increases)
77
Fitness wearables
Uses velocity and heart rate measurements
20-90% margin of error
Cool to look at
78
Physical activities
Everything above basal metabolism
Chewing gum to all out competitive sports
79
Basal metabolism
NRG required to exist, keep the lights on
Breathing, heart rate
80
Homeostatic regulation of core body temp
Core needs to resist temp changes
Heat and cold
81
Cold but not freezing
NST
Adaptive thermogenesis players
Metabolic rate increases, don’t depend on shivering
Mediated by adipocytes
82
ST
Metabolic rate increases
Use shivering (muscle contraction) to generate heat
83
White adipocytes
NRG storage depot
Not cool
84
Brown adipocytes
Start out as a different cell → brown adipocytes
Very special, very cool
85
Brite or beige adipocytes
Come from white adipocytes
Gain extra functions
Used to not be cool → become cool
86
Brown and beige adipocytes
Have increased mitochondrial density
Uncouple the electron transport chain
87
BMI equation
weight (kg) / height^2 (m^2)
88
Underweight
BMI < 18.5
89
Normal
18.5 - 24.9
90
Overweight
25-29.9
91
Obese
30-34.9
92
Extremely obese
BMI > 35
93
Obesity has been continuously increasing in the US
Obesity is a driver of every chronic disease
Public health systems will be more burdened
94
Hydro densitometry
Weight of person in water compared to on land
Difference provides a measure of the body volume
Not as accurate as other methods
95
Air displacement plethysmography
Measure air displaced by a person’s body
Can tell body fat
96
Bioelectric impedance
Measures body fat using electric current
Leaner the person = less resistance
Look at conduction of tissues
97
Dual X-ray absorptiometry
Uses X-rays to differentiate lean body mass from fat and bone tissue
Precise measurement of total fat and distribution
Gold standard
98
Skinfold
Estimate body fat
Gauge thickness of a fold of skin
Compare with standards
External only
99
Fed state
Insulin > glucagon
Favor NRG storage
Blood glucose is elevated
Glycogen storage increases
100
Postabsorptive state
Insulin decreases
Glucagon increases
Blood glucose decreases
Liver glycogen breakdown
Increase use of FA for NRG
101
Fasting state
Glucagon > insulin
Liver glycogen = depleted
Gluconeogenesis
TG broken down, use FA for NRG
Ketone formation, ketogenesis
102
Type 1 diabetes
Decreased insulin production
Increased glucose due to low insulin
Muscle unable to use glucose
Behaves as if there is low glucose
103
Type 2 diabetes
Failure to respond to insulin
Sufficient insulin secreted
Muscle unable to use glucose due to insulin resistance
104
Insulin
Secreted from the pancreas (beta cells)
Response to elevated blood glucose levels
105
Glucagon
Secreted from alpha cells
Response to low blood glucose
106
Glycogenolysis
Glycogen breakdown; glucose production
107
Glycolysis
Glucose breakdown; forming two molecules of pyruvates
ATP production without oxygen (anaerobic energy metabolism)
107
Lipolysis
Breakdown of triacylglycerol (triglyceride) to fatty acids and
glycerol
107
Beta-oxidation
Breakdown of fatty acids to acetyl-CoA
107
Proteolysis
Breakdown of protein to amino acids
108
Transamination/Deamination
Transfer/ removal of amino group from the amino acids
108
Citric Acid cycle
A central metabolic pathway, oxidizing acetyl-CoA to CO2 and
generating reducing equivalents (NADH + H, FADH2), and GTP
(ATP)
108
Oxidative phosphorylation
A series of coupled processes in which reducing equivalents are
oxidized, and the resulting proton gradient enables ATP
production
108
Gluconeogensis
Glucose synthesis from noncarbohydrate sources
108
Ketogenesis
Formation of ketones from acetyl-CoA
109
Glycogenesis
Formation of glycogen
109
Lipogenesis
Synthesis of fatty acids and formation of triacylglycerol
109
Protein breakdown products
AA --> pyruvate, acetyl CoA, CAC
109
TG breakdown
Glycerol --> pyruvate
FA --> acetyl CoA
Alcohol --> acetyl CoA
110
Dietary Factors modulating glycemic responses
Quality
Quantity
Glycemic index/load
Type and amount of carvs
Fiber
Fat, protein
Timing
111
Host Factors modulating glycemic responses
Digestion and absorption
Insulin sensitivity
Insulin secretion
Physical activity
Lean body mass
Previous meal
Microbiome
112
Enzymes
Catalysts of metabolic reactions
Substrate binds to active site → complex → transformation → release
113
Cofactors and coenzymes
Derived from vitamins and minerals
Combines with the enzyme to form an active enzyme
114
Epiglottis
Blocks the larynx
Protects airways during swallowing
115
functions of muscles in the digestive system
Segmentation
Peristalsis
Sphincter contractions
116
Water soluble nutrients
Absorbed across enterocytes
Released into the blood
Deliverd to the liver
via the portal vein
117
Secretion and motility coordinated by
Hormonal system
Nervous system
118
Starch enzyme
Pancreatic amylase
119
Dextrins enzyme
Isomaltase
120
TG enzyme
Lipase
121
Protein enzyme
Pepsin
122
Nutrient with largest diff btwn gross and metabolizable NRG
Vitamins
123
Orlistat
Decreases digestible NRG
of foods with fat
124
Insulin decreases blood glucose by
Increase uptake in adipose
Increase uptake in muscle
Increase lipogenesis
Increase glycogenesis
125
FA can be made from
AA
Glucose
Acetyl CoA
Ethanol
126
Overexpression of UCP1
Increase NRG expenditure
127
Catabolic reactions to generate ATP
In all cells
Break down macronutrients
Consume O2
Release ATP, CO2, H2O
128
Anabolic reactions to store NRG
Glycogenesis
Lipogenesis
129
Anabolic during catabolic states
Gluconeogenesis
Ketogenesis
Long term fasting
130
Glycolysis
Split glucose into 2 x pyruvate
Generate ATP and NADH
131
Cori cycle
Liver produces pyruvate via glycolysis
Convert pyruvate to lactate to regenerate coenzyme
Lactate in muscle → liver → convert to glucose → return to muscle
132
Lipolysis
Glycerol can be used to make pyruvate
FA can be turned into Acetyl CoA
133
Beta oxidation
Need carnitine and CoA
Cleave FA into 2 carbon units
Each cleavage = 1 NADH + 1 FADH2
134
Glucogenic AA
Used to synthesize glucose
Or can enter the citric acid cycle directly
135
Ketogenic AA
Converted directly to acetyl CoA
136
Transamination
Keto acid + AA → keto acid + AA
137
Deamination
Make ammonia + keto acid
138
Alcohol digestion
Absorb as early as stomach
Liver catabolizes
Alcohol → acetyl CoA
139
CAC
Acetyl CoA = input
Oxaloacetate = needed to bring Acetyl CoA in
140
ETC
Passing e- releases NRG to pump H+
H+ gradient powers ATP synthase
Water formed
141
Glycogenesis
Liver and muscle
142
Lipogenesis
Liver and adipose
Take any substrate
Can be made from proteins, carb, fat
143
Gluconeogenesis substrate
Lactate
Glycerol
AA
Need oxaloacetate
144
Ketogenesis
Start with acetyl CoA
Builds up due to gluconeogenesis
