Small Intestine Structure that extends from pyloric Sphincter to the beginnings of large intestine.
-
Upload
sandra-hampton -
Category
Documents
-
view
222 -
download
0
Transcript of Small Intestine Structure that extends from pyloric Sphincter to the beginnings of large intestine.
SMALL INTESTINE
Small Intestine
Structure that extends from pyloric Sphincter to the beginnings of large intestine
Other Functions
Receives secretions from liver and pancreas
Moves Chyme around for better absorption
Parts of Small Intestine
Consists of 3 portions:Duodenum, Jejunum, ileum
Duodenum
~ 25 cm long, first portion It neutralizes stomach acids and breaks
down carbohydrates and fats.
Jejunum
Main section, ~ 15 feet
Responsible for absorption of most nutrients, except water
Ileum
Last section, ~ 6 feet
Responsible for absorbing water and vitamins
Intestinal Villi
Found in small intestine Consists of a layer of simple columnar
epithelium Contains Lacteal, which is a core of
blood capillaries and nerve fibers that absorbs nutrients
Enzymes
Enzymes embedded in membrane of Villi, used to break down food molecules
Peptidas- splits proteins down to amino acids
Sucrase, maltase, lactace- splits double sugars (disaccharides) into simple sugars (monosacchardies)
Lipase- splits lipids into single carbs
Passive Transport
Absorption of certain nutrients into villi without energy. Slow process
Concentration is greater outside the villi
Active Transport
Much faster process, requires energy With help of carrier proteins called
ATPase, Amino acid, monosaccharides, and fatty acids get absorbed
Carbohydrates and Protein Absorption Soluble in
water Gets broken
down and absorbed directly into blood stream
Fat Absorption Insoluble in
water, cannot be absorbed directly
Carrier protein take them to Lacteal where it passes through lymphatic system
Nutritional Terms
MacronutrientsCarbohydrates, Lipids and ProteinsMany bonds, longer to break down, may
build up
Nutritional Terms
MicronutrientsVitamins, mineralsSmaller bonds, easier to absorb
Free Radicals
When body takes in oxygen to pair and break down food, 1% of cells will get damaged in the process, creating “Free Radicals”
Very unstable, will steal from other cells to replace molecules.
When stolen, Free Radicals change DNA of cells, creating room for disease
Smoking is a great source of Free Radicals, can lead to cancer
Antioxidants
Chemicals that block free radicals from damaging other cells
Donate extra electrons
Example: Vitamin E, Flavonoids(Nuts, seeds, fish oil, green tea