NUTR 202 Digestion and Absorption

and Carbs

Mechanical digestion

chewing, grinding, mixing and peristalsis

Chemical Digestion

secretions and enzymes breakdown large component into smaller units for easy absorption

the noses role in eating

flavor perception is 80% smell- strong connection between brain digestive system and semell

Chemical and mechanical digestive process in the mouth and esophagus

mechanical- mixing chewing and swallowing

chemical- saliva for lubircation and salivary amylase for breaking down the carbs

Epiglottis

skin flap to prevent chocking it closes when we swollow

Esophagus

food moves through the esophagus as bolus- the wave like motion of peristalsis occurs

Sphincters

circular muscles that separate organs of the GI tract

one way doors

prevent food from coming back up

improper functioning- heartburn or Gerd

antacids apply a short term buffer

three main sphincters

lower esophageal sphincter

pyloric sphincter

Ileoecal valve

three kinds of Stomach muscle assist in what digestion

longitudinal, circular, diagonal

mechanical digestion

segmentation

circular muscle contractions that churn the chyme

peristalsis

rhythmic contractions of longitudinal muscles to push chyme forward

chemical digestion

entrance of food stimulates

hydrochloric acid

mucus

pepsinogen turns in to pepsin with HCL

and hormone gastrin

what are the three portions of the small intestine and which one does most of the digestion and absorption

Duodenum

Jejunum- most of digestion and absorption

Ileum

Nutrient absorption assisted by what structures in the small intestine (4 structures)

Villi- small projections in the small intestine that increase surface area

Microvilli- the little hairs that surround the villi

Goblet cells- secrete mucus

Crypts- the spaces between the villi

Mucus

protects the lining od the stomach from HCI

otherwise the HCI would degrade the stomach proteins

Hydrochloric Acid

denature proteins

liquifies food

activates pepsin

lingual lipase- help iron absorption

Intrinsic Factor

essential for B12 absorption at the end of the ileum

(other b vitamins are fat soluble)

without it pernicious anemia

Hormones (20)`

control the movement of the stomach and HCI secretion communicates with pancreas liver and gallbladder small intestine and the rest of the body

ensures right enzyme at the right time

pyloric sphincter

separates stomach from small intestine

3ml intervals of chyme allowed in small intestine at a time

salivary glands target organ secretion and action

Mouth

saliva

saliva makes swallowing easier, salivary enzymes breakdown carbohydrates

Gastric glands target organ secretion and action

stomach

gastric juice

fluid mixes with bolus HCL uncoil proteins enzymes breakdown protein mucus protects stomach cells

Pancreas target organ secretion and action

small intestine

pancreatic juice

alkaline bicarbonate neutralizes the gastric juices and pancreatic enzymes breakdown carb fat and protien

liver target organ secretion and action

gallbladder

bile

bile is stored until we need

Gallbladder target organ secretion and action

small intestine

bile

bile emulsifies fat so that the enzymes can have access to break it down

Intestinal glands target organ secretion and action

small intestine

intestinal juice

intestinal enzymes break down carbohydrates fat and protein fragments mucus protects the intestinal wall

Water vs Fat soluble nutrients

Water soluble- absorbed through the intestinal wall- capillaries- nutrients to liver

fat soluble- lacteals- lymph system

what does the Duodenum absorb

most minerals

Jejunum and upper ileum

carbs amino acids and water soluble vitamins

Terminal segment of ileum

lipids and fat soluble vitamins

Carbohydrate absorption

eat carb - salivary amylase

pancreatic amylase turns carb into either Maltase sucrase lactate -stomach

in stomach turns into glucose fructose and galactose- small intestine

glucose in blood- capillarys

liver

Fat absorption

fat droplet

bile emulsify fat

lipase breaks down further into monoglycerides

then back into triglycerides with protein coating around it.

then to the lymphatic system

Protein Absorption

Protein- pepsin - pancreatic enzymes- amino acids- blood-liver

Chylomicron

fat packages

not always dietary fat can be vitamins

fat soluble vitamin absorption facilitated by dietary fat

Alcohol

some absorption in stomach

most in small intestine

travels to liver for detoxification

Mineral absorption

absorbed in the douduem

sodium is best absorbed with glucose and amino acid

Some nutrients are absorbed based on bodies need (iron calcium)

water

most absorbed in small intestine

small amount in large intestine

water follow salt

Ileocecal Valve

separates the ileum of the small intestine from the cecum of the large

sphincter prevents reflux of waste into small intestine

large intestine takes care of things that were not absorbed (ready to poop out) (insoluble fiber)

If sphincter fails-infection

Microbiota

responsible for the production of vitamin k and B vitamins

break down plant fibers

metabolize any remaining nutrients

prebiotic

food for bacteria

Probiotic

adds good bacteria

Peptic Ulcer Disease

Caused by H pylori most commonly

makes legions in the lining of the stomach or the duodenum of small intestine

simple carbohydrates

less than 10 monosaccharides

ex of monos- fructose, glucose, galactose

ex of disaccharide- sucrose, maltose, lactose

complex carbohydrates

more than 10 monosaccharides

polysaccharides- thousands of glucose molecules

starch- carbohydrates in plants straight or branched

example- potatoes

Glycogen

storage form of carbohydrate found in liver and muscle

body uses this when we don’t eat enough carbs but it doesn’t prefer to do this

whole grains

all components of the grain are present

Endersperm, Bran, Germ

Refined Grains

lose fiber

b vitamins

fats

vitamins can be added back in but the fiber can not

only the endosperm is present in the product

Non- Nutritive

do not provide calories

overuse of these can cause diarrhea or GI discomfort

we don’t really consume a lot of these because they are so strong

example- aspartame and sucralose

Nutritive

provides calories

example- sucrose, fructose, honey

Carbohydrate Absorption

small about is absorbed in the mouth- salivary amylase

most of the absorption is in the small intestine (enzymes)

fructose and galactose circulates in the blood for cell energy then put in liver for later use (glycogen)

Dietary Fiber

made of repeating units of glucose and can’t be digested by human enzymes

Soluble Fiber

can be dissolved in water

aids in weight management and CV health

lovers cholesterol

binds to bile in the small intestine

ex potatos and oats

Insoluble Fiber

can not be dissolved water

softens stool and accelerates passage

ex whole grains legumes

Glucose Homeostasis

normal glucose levels are 70-99

insulin moves glucose from the blood into cells

Glucagon moves glycogen from the liver when we need to convert it into glucose

Glycemic index

measures how fast blood glucose raises after ingestion of a food

Glycemic Load

equation to adjust the glycemic index based on the serving size of a food (watermelon)

Recommended Sugar intake

1 tsp sugar = 4g of carbs =20 kcals

limit added sugars to less that 10% of daily kcal

when do we dip into protein for energy

when we eat under 130g of carbs in a day

ketones

we use fat for energy when we don’t eat carbs (ketogenesis)

Ketone bodies

they form when we don’t eat enough carbs and are the alternative form of fuel

Ketosis

when an excess of kettle bodies accumulate ketosis occurs

-acid base imbalance

-dehydration

-dizziness

-fainting

A1C test

2-3 month average of the glycated hemoglobin in RBC

diabetes 6.5% and up

pre-diabetes 5.7-6.4

normal under 5.7%

Fasting Blood Glucose

Normal under 99, pre 100-125 diabetes 126

Glucose Tolerance Test

Diabetes 200mg/dL pre 140-199mg/dL normal 140mg/dL

Type one diabetes is

an autoimmune disease

typ 2 Diabetes

is largely influenced by lifestyle and is developed more later in life most commonly

insulin resistance

Gestational diabetes

7% of pregnancys

high birth weitght

diabetes later in life

low blood glucose post delivery

Fiber ranges

25 grams/day women

38 grams/day men

overconsumption of fiber can lead to decreased levels of calcium copper zinc iron

wheat allergy

triggers an auto immune response

mild symptoms- anaphylaxis

treatment avoid all foods with wheat

Gluten intolerance

mild GI distress

treatment- avoid some if not all foods with gluten

Celiac disease

intolerance to gluten that triggers and autoimmune response

-flattens the intestinal wall

the villi get flatten