NUTRIENT ABSORPTION
How many different
systems do you see?
Digestive-Breaks
down and absorbs
nutrients
1.
2. Respiratoryabsorbs oxygen
3. Circulatory –
transports nutrients
C6H12O6 + 6O2
glucose + oxygen
6 CO2 + 6H2O + 36 ATP
carbon dioxide + water + energy
1. Where does the glucose come from?
Food
2. Where does the oxygen come from?
Breathing
3. What are the final products of cellular respiration?
CO2, H2O, ATP
4. In which organelle does this take place in our cells?
Mitochondria
Types of digestive
Filter feeder
systems:
Digestive cavity:
Digestive tract:
1 opening
2 openings
(Gastrovascular cavity)
Description of system
Aquatic animals that
Digestive chamber with
strain tiny floating
food entering and waste
organisms from water
exiting through one
2 openings: mouth,
anus.
opening.
Picture of system
Jellyfish, Sea Anemone,
Examples
Sponges
Snails, oysters, squid, octopus,
Corals, Portuguese Man-of- starfish, sand dollar, crayfish,
War, Planaria (flatworm)
spiders, crabs, butterflies,
humans
Function of The Digestive System

The function of the
digestive system is to help
convert foods into simpler
molecules that can be
absorbed and used by
the cells of the body;
eliminates waste.
The Digestive System (aka. Alimentary
Canal) Includes:
Mouth
2.
Pharynx
3.
Esophagus
4.
Stomach
5.
Small Intestine
6.
Large Intestine/Colon
7.
Rectum
8.
(Accessory organs:
salivary glands, liver,
gallbladder, pancreas)
1.
The Mouth

Teeth
Cutting, tearing, and crushing food into small fragments.
 Begins the process of mechanical digestion or physical
breakdown.


Saliva
Secreted by the salivary glands.
 Helps moisten the food and make it easier to chew.
 Contains amylase, a digestive enzyme that begins the
breakdown of carbohydrates.
 Begins the process of chemical digestion, where chemicals
breakdown the large pieces into smaller pieces.

The Esophagus




Bolus – Chewed clump of
food.
From the throat, the bolus
passes through the esophagus,
or food tube, into the stomach.
Food travels through the
esophagus to the stomach by
smooth muscle contractions
(wave-like) called peristalsis.
The epiglottis (small flap
covering the trachea)
separates the food from air
when swallowing
The Stomach


Food from the esophagus empties into
a large
muscular sac called the stomach.
The stomach continues the mechanical and chemical
digestion of food.
Mechanical: Stomach muscles contract to churn and mix
stomach fluids and food, gradually producing a mixture
known as chyme.
 Chemical:

1.
2.
3.
Gastric glands release mucous to protect the stomach wall
Gastric glands produce hydrochloric acid and pepsin, which
begins the complex process of protein digestion.
Amylase is denatured by the stomach acid so carbohydrate
breakdown does not occur in the stomach.
The Small Intestine

Most of the chemical
digestion and beginning
absorption of the food
you eat occurs in the small
intestines.
The Small Intestine

Divided into three parts:
1.
2.
3.
Duodenum
Jejunum
Ileum
Together average about
6 meters (19.7 ft) long.

Duodenum



The first of three parts of
the small intestine.
It is where almost all of the
digestive enzymes enter the
intestine.
The pancreas and the liver
release digestive enzymes
and fluids to help with
digestion in the small
intestine.
Absorption in the Small Intestine

By the time chyme enters the
jejenum and the ileum parts of
the small intestine, much of the
chemical digestion has been
completed.
 Chyme
is now a rich mixture of
medium and small nutrient
molecules.
Absorption in the Small Intestine

The small intestine is
specially adapted for
absorption of nutrients.
 The
folded surfaces of the
small intestine are covered
with fingerlike projections
called villi.
 Villi increases the surface
area for absorption of
nutrients
Absorption of Nutrients in the
Small Intestine


Nutrients are absorbed
through the wall of the
small intestine directly
into the capillaries (blood)
by the process of diffusion.
Diffusion – movement of
substances from an area
of high concentration to
an area of low
concentration
Absorption in the Small Intestine

By the time food is ready to leave the small
intestine, it is basically nutrient-free.
 The
complex organic molecules have been digested
and absorbed, leaving only water, cellulose, and other
undigestible substances behind.
The Large Intestine




When the chyme leaves the
small intestine, it enters the
large
intestine, or colon.
Primary Function: Remove water from the undigested
material that is left.
The concentrated waste material (feces) that remains
after the water has been removed passes through
the rectum and is eliminated from the body.
http://www.youtube.com/watch?v=Z7xKYNz9AS0
Click on picture
Accessory Structures of Digestion
1.
2.
3.
4.
Pancreas
Liver
Gallbladder
Salivary
Glands
Pancreas


Located just behind
the stomach.
Gland that serves three
important functions:
1.
2.
3.
Produces insulin that regulate blood sugar levels.
Produces enzymes that break down carbohydrates,
proteins, lipids, and nucleic acids.
Produces sodium bicarbonate, a base that neutralizes
stomach acid so that these enzymes can be effective.
Liver


Assisting the pancreas is the
liver, a large organ located just
above and to the right of the
stomach.
Produces bile; to help digest fats
 Bile
acts like a detergent, dissolving and dispersing the
droplets of fat found in fatty foods.
 Makes it possible for enzymes to reach the smaller fat
molecules and break them down.
 Bile is stored in a small, pouch-like organ called the
gallbladder.
Gallbladder



http://www.youtube.com/watch?v=iCyk-670bdw
(dr. oz)
A pouch like organ that stores the bile
The bile is brought to the small intestine by the bile
duct
20 million ppl get gallstones, small hard mineral
deposits due to excess cholesterol buildup
Salivary Glands

There are 3 salivary glands:
1.
2.
3.
Parotid gland – largest of the salivary glands that
secretes saliva to assist with chewing and
swallowing; located in the cheek area inferior to
the ear
Submandibular gland – secretes amylase to help
breakdown starches in the mouth; located below
and inferior to the parotid gland
Sublingual gland – secretes mucous that helps coat
the food being swallowed; located in front of the
submandibular gland on the floor of the mouth
Digestive System
Levels of Organization
Epithelial cells, Liver cell, stomach cell, pancreatic cell,
etc….
epithelium, villi, smooth muscle
Mouth, esophagus, stomach, small & large intestines,
etc…
digestive
A. SALIVARY GLANDS
B. MOUTH
C. ESOPHAGUS
D. STOMACH
F. LARGE
INTESTINE
H. ANUS
E. SMALL
INTESTINE
G. RECTUM
Digestive System Disorders

Peptic Ulcer
 Hole
in the stomach wall
 Most peptic ulcers are caused by bacteria and most
can be cured by antibiotics.

Diarrhea or Constipation
 If
not enough water is absorbed by the large intestine,
diarrhea occurs.
 If too much water is absorbed from the undigested
materials, constipation occurs.

http://www.youtube.com/watch?v=cdijh32NiLs
(constipation)