Download Nutrition and Digestion PPT Notes

The Digestive Process
Supplying Energy for all Life
Processes
What is Digestion?
• Process by which large molecules are
broken down to provide energy and
raw materials for the organism
Energy
• Energy content in foods can be
measured by burning them. (Release
all of the energy at one time.)
• Unit of energy - Calorie
• Calorie - amount of energy to raise
one ml of water one degree Celsius.
• Calorie on packages - 1000 calories (1
kcal)
• Avg. Teenager -> 1800-2800 kcal/day
Nutrients
• Raw materials the body needs
• Water, Carbohydrates, Fats,
Proteins, Vitamins, and Minerals
Water
• Most important of
all nutrients
• Needed by every
cell, makes up the
bulk of blood,
lymph, and other
body fluids,
dissolves food,
cools the body
(sweat)
• Need about 4-8
cups a day
Carbohydrates
• Major Source of
Energy (used 1st)
• Simple Sugars
– Glucose, Sucrose,
Fructose
– Fruits, Honey,
Sugar Cane, Sugar
Beets
• Complex
– Starch / Cellulose
Fats
• Need a little fat in
diet
• Cell membranes and
hormones
• 60 grams (2
Tbs.)/day
• Avg. American
– 40% Calories come
from fat.
– High BP, heart
disease, obesity,
diabetes
Proteins
• Contain Amino
Acids
• Build new cells and
tissues
• 22 common Amino
Acids
– Body makes 14
– the rest (8) from
diet
Vitamins / Minerals
• Vitamins needed in important
chemical reactions
– making hormones, metabolism, etc.
• Minerals
– Calcium - bones
– Iron - hemoglobin
– Iodine - Thyroxin (growth)
Digestive Processes
• We will examine the Digestive
Processes of the following Organisms
–
–
–
–
–
Protozoa
Hydra
Earthworm
Grasshopper
Humans
Protozoa
• Single celled
organisms
• Live in water
(FW/SW)
• Obtain food via
DIFFUSION
• Some cases of
Active Transport
Hydra
• 2 cells thick
• stinging cells on
tentacles
• cousins of jellyfish
• One digestive
opening
– Mouth/Anus
Earthworm
• Multi-cells thick
• Specialized organs
to help break down
materials
• Mouth / Anus
– Sequential
Digestion
– Continuously remove
food and nutrients
Grasshopper
• Multi-celled
• Keeps many of the
advancements of
the Earthworm
• Sequential
Digestion
Humans
Mouth
• Starts digestion
• Teeth - cut, tear,
crush food
• Saliva - moistens
food to make
easier to chew
• Enzyme - Amylase
– breaks down sugars
• Enzyme - lysozyme
– breaks walls bacteria
Esophagus
• Food tube to the stomach
• pushes food to stomach by muscle
contractions
– food moves to stomach whether you are
sitting, lying down, upside down, or in
space
Stomach
• Stores food so
body can break it
down at a slower
pace
• Gastric Glands
– protect stomach
lining
– hydrochloric acid
– Pepsin (enzyme)
• breaks down
proteins
• needs acid
environment
Stomach
Small Intestine
• 23 feet long - small
diameter
• food / nutrients
are absorbed
• tiny projections
called villi
– increases surface
area of the
intestine to
maximize
absorption
Accessory Organs
• Pancreas
– enzymes to break down carbohydrates,
proteins, fats, and nucleic acids.
– secretes sodium bicarbonate (baking
soda) to neutralize stomach acids
• Liver
– secretes Bile - like a detergent
• dissolves/disperses fat droplets for
digestion
Large Intestine
• Primary Job Remove water from
food
• Undigested or
unabsorbed
material is released
out the anus.
Digestion Summary
• Protozoa - Diffusion (1 cell)
• Active Transport (bring
things in and make food
vacuoles)
• Hydra - Diffusion (mouth, primitive
gut)
• Planaria - Multi-celled
• Mouth/Anus, Intestine
Digestion Summary (cont.)
• Earthworm - multi-celled, non-flat
• mouth, crop, gizzard, intestine,
anus
• Grasshopper - multi-celled, non-flat
• mouth, crop, gizzard, intestine,
accesary organs (Malpigian
tubules), anus
Digestion Summary (cont.)
• Human
– mouth, esophagus, stomach,
accessory organs (liver, pancreas),
small intestine, large intestine, anus