Root Words
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

Lipids

Molecule used for stored energy and creates
structure for cell membranes.
Lipids
Molecule used for stored energy and creates
structure for cell membranes. Lots of C-H bonds;
may have some C=C bonds
 Saturated Fat: Contains no double bond in
Carbon-Hydrogen Bond. Solid at room
temperature (Bacon, grease)

Lipids
Molecule used for stored energy and creates
structure for cell membranes.
 Saturated Fat: Contains no double bond in
Carbon-Hydrogen Bond. Solid at room
temperature (Bacon, grease)
 Unsaturated Fat: Contains double bond. Liquid at
room temperature (Olive Oil)

Lipids
Fat Absorption
Insoluble in
water, cannot
be absorbed
directly
 Carrier protein
take them to
Lacteal where
it passes
through
lymphatic
system

Nutritional Terms

Macronutrients
 Carbohydrates, Lipids and Proteins
 Many bonds, longer to break down, may
build up
Nutritional Terms

Micronutrients
 Vitamins, minerals
 Smaller 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