The Science of Nutrition: The GI tract Flashcards
1
Q
What is in the food we eat?
A
Macronutrients Micronutrients Phytonutrients, Myconutrients, Zoonutrients Water Other: Alchohol etc.
2
Q
Enteric nervous system
A
A branch of the autonomic nervous system that governs the gastrointestinal tract
3
Q
Gut microbiome
A
ecosystem of bacteria that live in the GI tract
4
Q
Functions of the digestive system
A
-processes nutrients
-provides a barrier to pathogens
-detoxifies harmful substances
-contains the enteric nervous system
-secretes and processes hormones
-regulates immune system
-It’s innervated by nerves also involved in social
engagement and emotion, giving us important signals
about the world and how we feel.
-home to our microbiome
5
Q
Where does digestion start?
A
The brain and is organized by the nervous system
6
Q
What role does the brain play in digestion?
A
When the brain receives hunger cues, it stimulates and directs our efforts to find food. The brain also tells the rest of the body to prepare for eating, by stimulating salivation and stomach acid production.
7
Q
Autonomic nervous system
A
A branch of the nervous system that regulates digestion and internal organs outside of our conscious control
8
Q
Sympathetic nervous system
A
A branch of the autonomic nervious system that controls the flight and fight response
9
Q
Parasympathetic nervous system
A
A branch of the autonomic nervous system taht controls the rest, digest and repair function
10
Q
What effect does the SNS have on digestion?
A
Tends to shut down digestion and appetite. Our mouth goes dry, we stop wanting food, our GI tract stops moving food through the system, and we may get butterflies in our stomach or experience nausea, vomiting, or diarrhea.
11
Q
What activates the SNS?
A
intense activity, stress or stimulation
12
Q
What effect does teh PNS have on digestion?
A
tends to regulated digestion and movement through the GI tract, so that things proceed steadily and calmy
13
Q
What activates the PNS?
A
Rest and relaxation
14
Q
What are the 3 levels of the “Eat slowly” exercise
A
Level one: Eat slowly and put your utensils down between bites
Level two: Eat slowly, without distractions (phone, tv etc)
Level three: Eat slowly, without distractions and with full presence and attention, noticing the taste, texture, and experience of each bite”
15
Q
What are the benefits of the “Eat slowly” exercise?
A
- helps clients recognize their physiological hunger and fullness cues
- eat less, but feel more satisfied, because it gives our GI tract time to send satiety signals to the brain.
- Experience their food more fully
- digest their food better
16
Q
What role does olfaction play in the digestive process?
A
Olfaction, especially retronasal olfaction is imortant for satiety. It tells our brains that we are getting enough nutrients and it increases our satisfaction with our food.
17
Q
Retronasal olfaction
A
Sensing odors from food that’s traveled through the backof our through and to our nasal passages as we chew and swallow
18
Q
Papillae
A
Tiny bumps on the tongue that increase the surface area and help move food around the mouth
19
Q
What does salivae consist out of?
A
95% water mucus enzymes (amylase, lipase) glycoproteins, antimicrobials
20
Q
How much saliva do we produce every day?
A
approx. 1.5 liters
21
Q
What is the role of saliva in the mouht?
A
To break down carbohydrates
To keep mucus membranes of the mouth healthy
To moisten the mouth and food
22
Q
Where in the mouth do we find the saliva glands?
A
sublingual -under the tongue
submandibular -along the bottom of the jaw
parotid - in our cheeks alon the baks of our jaws
23
Q
Which gene regulates amylase production
A
AMY1 gene
24
Q
What influences food preferences
A
genetics
Age and neurological development
health and reproduction
cultural background
25
How can we help clients explore their food preferences
red-yellow-green food chart
1. why does the client feel attached to certain foods?
2. what do those foods mean to them?
3. What are teh stories behind those foods?
26
Anorexia of aging
Older people wanting to eat less or becoming less interested in food.
27
What role does genetics play in food preferences?
It determines the amount and type of food taste receptors in the mouth. Some people have more fat taste receptors and so food with fat might taste too rich for them, other people might be "super" tasters making even ordinary food taste bitter.
28
What could gum disease be an indication of
untreated diabetes
inflamatory disorders, such as Inflamatory bowerl disease
Colon cancer
Potential heart disease
29
What can cause bad breath
gum disease
cavities
diabetes
Gerd or acid reflux
30
Why may older people struggle to chew
missalignment of TMJ
| dental work
31
What could teeth erosion be an indication of
Bulimia
32
What happens when we swallow?
The epiglottis involuntarily closes to stop food from entering our trachea. The uvula also closes off the nasopharynx, preventing food from entering the nose.
33
What is the esophagus?
muscular tube, lined with a mucous memebrane, that transports food and water from the mouth to the stomach.
34
peristalsis
A seiries of wavelike muscular contractions that moves a substance through a tube.
35
What is the role of the LES(lower esophageal sphincter)?
regulates food entering the stomach from esophagus.
prevents food stomach acid and food from splashing upwards into the esophagus.
36
TMJ
temporomandibular joint. The joint that connects the jaw to the skull.
37
Bulimia
A type of disordered eating characterized by chronic self-inflicted purging
38
Bolus
The small rounded mass of chewed food before swallowing
39
Pharynx
The cone-shaped passageway connecting the oral and nasal cavities to esophagus and larynx
40
Epiglottis
The cartilage flap in the throat that keeps food from entering the trachea and the lungs
41
ubula
little danlgy bit that hangs from the uper palated down the back of the throught
42
nasopharynx
The upper part of the pharynx, connecting with the nasal cavity above the soft palate
43
Lower esohageal sphincter
Aka the cardiac sphincter, a ring like muscle at the end of teh esophagus which regulates food's passage into the stomach.
44
Gastroesophageal reflux disease (GERD)
A digestive malfunction of food and acidic stomach juices splashing back upwards into the esophagus. Caused by the sphincter opening more often that it should, or opening at the wrong times. Diet can make it worse.
45
Short chain fatty acids
Fatty acids with less than 6 carbon atoms.
46
What are the symptoms of GERD
```
burning in the back of the throat
heart burn (especially after eating)
persistant cough, hoarseness
pressure and pain in the chest
bloating and burping
tooth erosion
```
47
What is the stomach's capacity?
0.25 to 1.7 liters
48
which nutrients can be absorbed by the stomach lining and enter general circulation
```
certain drugs
water,
some vitamins,
alcohol,
some short chain fattyacids(acetate, butyrate and propionate)
```
49
Chyme
the acidic fluid of gastric juices and partly digested food that passes from the stomach to the samll intestine
50
Pyloric sphincter
The ring like muscle that lies at the end ot the stomach and controls the passage of chyme into the small intestine
51
Gastric mucosa
The mucous membrane layer of the stomach that secretes gastric juices and mucus.
52
What are proton pump inhibitors and what are they commonly used for?
PPI's are a class of drugs used to reduce stomach acid production and is commonly prescribed for GERD
53
What are the causes of GERD
- Gravity: eating while lying down
- Stress: Activates SNS which slows the movement of
food through GI tract
- Processed foods, especially fatty acids: Fat Slows
gastric emptying, and triggers the relaxation of LES
when entering the small entestine.
- excess body fat: visceral fat compresses organs
- bacterial overgrowth: H.polori may be involved
- age: muscles, like sphincters, become weaker.
-smoking: Worsens GERD and Causes esophageal
cancer
-Genes: Might have a genetic component
-pregnancy: progesterone levels increase, causing the
les to relax. There is also physical pressure
on the stomach
-particular foods: Alchohol, peppermint, tomatoes, spicy
foods, scholate, coffee, carbonated
drinks, and citrus
54
What can you do as a Nutrition Coach to help alleviate GERD?
```
Help clients:
-eat slowly
-eat minduflly and in a relaxed setting
-eat smaller meals
-sit upright for one to two hourse after eating.
-keep a food journal to see if there is a link between
what they eat and their GERD symptoms,
- choose less processed, whole foods.
-reduce bodyfat
```
55
gastric mucosal secretions
chief cells secrete pepsin and gastric lipase to begin protein and fat breakdown, respectively.
parietal cells secrete hydrochloric acid, along with intrinsic factor, a glycoprotein that we need to absorb vitamin b12
histamine, which isn involved in the immune response and increases gastric acid production
ghrelin, a hormone that stimulates appetite
serotonin, a mulfiunctional bioamine
56
Does drinking water with food dilute stomach acid?
Not really. You would have to drink 50.5 liters of water in order to increase stomach acid ph to 3.5, which is the point where enzymes such as pepsinogen don't work as well.
if a clients digestion is impaired by drinking less than a liter of water during meals, they need ot be refered to a gastroenterologist.
57
How long does it take for the stomach to empty
between 1 - 4 hours
58
What factors influences gastric emptying times?
Carbohydrates empty first, then proteins, then fat and fiber
liquids empty before solids
small particles empty more quickly than large particles.
Other factors include: Stress, medication, hormones etc.
59
Taking into consideration gastric emptyinig time, what would you recomend for someone who needs a quick energy boost that won't wight htem down such as an athlete with several training session a day?
Liquid meals that are lower in fat and higher in carbohydrates, with quick digesting proteins, such as whey or rice protein powder.
60
considering gastric emptying times, what would you recomend for someone who is trying to lose weight and who doesn't like feeling hungry?
meals that are higher in slow digesting proteins and fiver to slow down gastric emptying and help them feel more satisfied for longer
61
Gastric juice
A mix of acids secreted by the stomach to promote digestion
62
Pepsin
An enzyme that breaks down protein in to smaller peptides
63
Intrinsic factor
A glycoprotein secreted by the stomach that enables absorption of vitamin B12
64
H. pylori
Helicobacter pylori.
A bacterial species that makes up part of our microbiome. Lives mainly in the mucosa of the stomach.
H.pylori protects us from the overgrowth of other harmful bacteria.
Overgrowth of certain strains of H.pylori, can cause inflamation and ulcers or even cancer.
65
Considering gastric emptying times, what recomendations would you give to someone who is under constant stress?
Eat smaller meals, and take an extra 5 - 10 minutes at each meal to eat a litle more slowly
66
Ghrelin
A hormone that stimulates appetite
67
Celiac disease
An immune reaction to eating gluten, a protein found in wheat, barley and rye
68
Brush border
The distinctive cellular shape and lining that create a large surface area of the small intestine.
69
villous atrophy
A flattened brush border of the small intestine, commonly a sign of intestinal disease.
70
How long does it take for food to get through the small intestine?
4 to 8 hours
71
What are the 3 parts of the small intestine?
duodenum: 45cm
jejunum: 2 - 3 meters
ileum: 3 - 4 meters (absorbs b12, bile salts and products not absorbed by jejunum)
72
anatomy of vilus
Each vilus is coverd with thousands of individual enterocytes. Each entrocyte has hundreds of cytplasmic extensions called microvilli, which protrude out into the lumen of the intestine where the food is.
73
Deuodenum
First section of small intestine. About 45cm long. Receives chyme from stomach. Secretes juices made by pancreas, containing bicarbonate, lipase, amylase and proteolytic ensymes, whos job it is to neutralize the acid in the chyme (bicarbonate) and to break down the foodstuff (enzymes). During this time the gallbladder relseases bile (made form bile salts and cholesterol)to emulsify fat. (The emulsification makes the fat more soluble which in turn makes it easier to absorb)
74
Bicarbonate
A type of salt that acts as a buffer against acid
75
Proteolytic enzymes
Enzymes that breaks down proteins
76
Gallbladder
A small pouch under the liver where gall is stored
77
Bile
A fluid that aids digestion through emulsification
78
Emulsification
When two otherwise unblendable substance such as oil and water are mixed
79
Enterohepatic circulation
The process of moving substances from the samll intestine to the liver through the portal vien, a key part of digestion and detoxifying potentially harmful chemical
80
Portal vein
a sturdy network of vessels that shuttles material from the intestines to the liver
81
How are bile salts recycled?
via the enterophepatic circulation
82
Nutrient absorbtion in small intestine
Nutrients are mainly absorbed in the small intestine across the cell membrane of the intestinal cells, into the blood stream, where it makes it's way to the liver via the portal vein.
The process of absorption is facilitated throu four major processes, namely:
- simple diffusion
- passive transport through a channel
- passive transport using a carrier protein
- active transport using a carrier protein
There are hundreds of enzymes and carrier proteins present in the small intestine, each desing to help absorb particular nutrients.
This system enables the body to absob many things in a crolled way. The most critical nutrients are easily taken in, unwanted substances are kept out.
83
How does fiber help lower cholesterol levels?
Fiber binds with bile salts which are then excreted instead of recycled. In order the produce more bile salts the body uses cholesterol, which lowers the overall cholesterol in the body?
84
What is the relationship between fiber and reproductive hormones and menstrual cycles?
Fiber binds to sex hormones in the digestive tract, which is then excreted, lowering the overall levels of these hormones in the body. An excess of fiber can lead to low levels of these hormones and disrupted menstrual cycles.
85
simple diffusion
When compounds move accross a membrane from a high concentration to and area of lower concentration, without the assistance of carrier proteins, energy or channels.
86
Channel transport
Nutrients move through a pore rather than through the membrane itself. channel transport doesn't require energy and moves along a concentration gradient.
87
carrier protein
proteins that ficilitate transport accross membranes and throughout the body. Speed of transport or absorption is dependend the amount and type of proteins available for transport.
88
Electrolytes
disolved mineral ions with an electrical charge
89
Concentration gradient
A difference in the chemical concentration between two regions. Neccesary for diffusion
90
How much does the liver weigh?
about 1.4 - 1.8 kg
91
Location of the liver?
The upper right portion of the abdomen, just under the diaphragm and next to the stomach.
92
First pass metabolism
Initial screening of nutrients and other substances via the liver
93
Lipoprotein
A type of protein that binds to fats to make them water soluble for circulation in the bloodstream
94
How are fat absorbed by the small intestine?
Enteroycytes absorb small particals of fatthen convert the fat particles within their endoplasmic reticulum repackaging them as lipoproteins called chylomicrons. Chylomicrons are absorbed by the intestinal lyumphatic vessels, called lacteals. The chylomicrons within the lymphatic fluid eventually rejoins systemic circulation at the heart and is eventually picked up by the liver where they are either covnerted to triglycerides or released in circulaiton as other types of lipoproteins.
95
What is hepatic steatosis?
Non Alchoholic Fatty Liver Disease NAFLD. It is caused by carrying high amounts of body fat. Excess fat can also build up in the heart, kidneys and muscle tissues.
Fatty liver disease is a hallmark of metabolic syndrome.
96
What compounds are formed by the liver from fat when carbohydrate intake is very low?
Ketones
97
chylomicron
A type of lipoprotein that carries fats from the intestines to other parts of the body
98
Triglyceride
A molecule built of three fatty acids attached to a glycerol. The primary storage form of fat in the body
99
Sterols
a large family of waxy lipids that are found in plants, animals, fungi and some bacteria. Sterols are an essential molecule in the body
100
very low density lipoprotein (VLDL)
A large lipprotein made in the liver that carries triglycerides to our cells.
101
Low density lipoprotiens (LDL)
A type of lipprotein that carries triglycerides to our cells, can cause plague leading to heart disease and is often called "bad cholesterol"
102
Why does the body need cholesterol?
To make cell membranes and hormones
103
Where does the majority of the cholesterol in circulation in the body come from?
Produced by the liver and not from the food we eat. A lot of the cholesterol in food, such as eggs, are not well absorbed by the gut.
104
What are the 4 main lipoproteins used to transport fat in our blood? From Largest to smallest
Chylomicrons: transports fat from small intestine to the liver. Contains more triglycerides than cholesterol
Very Low density lipoproteins: Packaged in the liver to be sent elsewhere in the body.
Low density lipoproteins: Carry waht people often call "bad" cholesterol, because they travel in teh bloodstream, carry fat to our cells and can oxidize in blood vessels, forming plaques that can lead to heart disease.
High density lipoproteins: carries more cholesterol relative to triglycerdies. They are like the cholesterol cleanup crew that picks up cholesterol and shuttles it back to the liver.
105
How does diet affect our lipid profile?
omega 3 lowers LDL and increases HDL
Saturated fat tends to increase LDL and triglycerides
Processed foods tends to worsen lipid profiles
Whole foods tend to improve lipid profiles
106
How does the liver maintain carbohydrate balance or homeostasis?
If blood glucose is high, the liver stores it as glycogen in it's own cells or later use.
If blood glucose is low, the liver proveds glucose to the blood form prevously stocked up liver glycogen stores.
The liver can convert non carbohydrates, such as amino acids and glycerol backbone of triglycerides, into glucose
The liver also converst other sugars, such as fructose and galactose into glucose.
107
Through which duct is pancreatic juice released into the duodenum?
The common bile duct
108
What enzymes are found in pancreatic juices?
trypsin and chymotrypsin: digests protein
amylase: digests carbs
lipase: digests fats
109
What are the 4 main glucoregulatory hormones produced by the pancreas?
insulin
glucagon
amylin
somatostatin
110
High density lipoprotein?
A type of lipoprotein that shuttles cholesterol back to the liver fo rrecycling. Acts as the cholesterol cleanup crew, and is often called good cholesterol
111
Galactose
A type of simple sugar molecule (monosacheride)
112
Deaminate
To remove an amine group (composed of nitrogen and hydrogen) form an amino acid molecule
113
Glucoregulatory hormones
hormones that help regulate glucose
114
Glucagon
A hormone that helps release stored glucose
115
Amylin
A hormone released with insulin that inhibits glucagon secretion, slows gastric emptying and increases satiety
116
somatostatin
A hormone that inhibits gastric secretion
117
Ileocecal valve
A sphincter-like structure separating the small intestine from the large intestine
118
Rectum
The final section of the large intestine, ending with the anus
119
Anus
The opening at the end of the rectum where solid waste leaves the body
120
Why are pancreatic enzymes released in a bicarbonate based fluid?
To help neutralize the acid in the chyme
121
Where is the ileocecal valve located?
Between the large intestine and the small intestine
122
How long does food stay in the large intestine?
12 - 25 hours
123
What is absorbed by the larged intestine?
```
Water
salts (sodium, potasium)
vitamin K
short chain fatty acids (acetate,butyrate, porpionate)
gases(hydrogen, carbon dioxide)
```
124
Length of the large intestine?
1.5 - 2 meters
125
What is the difference in colon and small intestine size between plant eaters and meat eaters in the animal kingdom, and what does this mean for humans?
Meat eaters: longer small intestine and shorter large intestine
Plant eaters: shorter small intestine and longer large intestine
Human's intestines are somewhere between that of meat eaters and of plant eaters, which means that we can consume a wide veriety of food.
126
What does feces consist out of ?
one third is dead bacteria
one third is inorganic material such as calcium phosphate and iron phosphate, and fats/cholesterol
The rest is made up out of protein, dead cells, fiber(cellulose), digestive juices and bile pigments (which gives feces it's color)
127
Gut associated lymphoid tissues (GALT)
Tissues in the gut that store, release and regulate immune cells and cell signals
128
Prostaglandins
A group of fat based molecules with hormone like effects?
129
What is the function of the appendix?
Contains GALT (gut associated lymphoid tissue) which store, release adn regulate immune cells and cell signals.
Acts a s a reserve tank for friendly gut bacteria.
People who have had their appendix removed are much more likely to suffer from inflammatory conditions and gut infections such as Clostridium difficile.
