Chapter 20: Unifying Concepts of Animal Structure and Function
NEW AIM: How are animals organized?
Animal form and function (anatomy and physiology)
Anatomy
- Structure of the organism
Physiology
- Function of the organism
Structure determines Function
Chapter 20: Unifying Concepts of Animal Structure and Function
NEW AIM: How are animals organized?
Anatomy and Physiology
Exchange with the environment
Chapter 20: Unifying Concepts of Animal Structure and Function
NEW AIM: How are animals organized?
Anatomy and Physiology
Exchange with the environment
Chapter 20: Unifying Concepts of Animal Structure and Function
NEW AIM: How are animals organized?
Anatomy and Physiology
Fig. 20.1
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Anatomy and Physiology
Tissue
- cooperative unit of cells with
similar structure and function
Fig. 20.2
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Anatomy and Physiology
Tissue
There are only 4 major types in animals:
Fig. 20.2
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Anatomy and Physiology
Tissue
There are only 4 major types in animals:
1. Epithelial tissue
- Covers outside of body and lines
the organs and cavities within the
body like the GI tract, bladder,
lungs, etc…
Fig. 20.4
- Cells packed side by side and
typically function as barrier
against mechanical injury,
pathogens and other microbes,
fluid loss.
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Anatomy and Physiology
Tissue
There are only 4 major types in animals:
1. Epithelial tissue
Two criteria for identifying type of
epithelia:
1. Is it…
“Simple” = single layer of cells
or
“stratified” = many layer of cells
Fig. 20.4
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Anatomy and Physiology
Tissue
There are only 4 major types in animals:
1. Epithelial tissue
Two criteria for identifying type of
epithelia:
2. Is it (shape)…
“cuboidal” = cube-shaped
“columnar” = column shaped like
bricks
or
“squamous” = flat like floor tiles
Fig. 20.4
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Anatomy and Physiology
Tissue
There are only 4 major types in animals:
1. Epithelial tissue
Structure / Function
Fig. 20.4
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Tissue
There are only 4 major types in animals:
1. Epithelial tissue
- Covers outside of body and lines
the organs and cavities within the
body like the GI tract
Simple columnar
Simple cuboidal
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Tissue :
4 major types in animals
1. Epithelial tissue
2. Connective tissue
- Serves to bind and support other
tissue
Fig. 20.5
- Cells are sparse and scattered through an ECM like raisons in bread
- Cells produce ECM (raisons make the bread)
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Tissue :
4 major types in animals
1. Epithelial tissue
2. Connective tissue
- Cells are sparse and scattered through an ECM like raisons in bread
- Cells produce ECM (raisons make the bread)
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Tissue :
4 major types in animals
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
- Cable of contraction – usually
when stimulated by a nerve signal
Fig. 20.6
- made up of muscle fibers (cells)
- most abundant tissue type in animals
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Tissue :
4 major types in animals
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
Three types:
1. Skeletal
2. Smooth
3. Cardiac
skeletal
- made up of muscle fibers (cells)
- most abundant tissue type in animals
smooth
cardiac
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Tissue :
4 major types in animals
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Nervous tissue
- neuron = a single nerve cell (a single wire)
- forms a rapid communication system
- senses stimuli, processes and directs response
Fig. 20.7
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Several tissues are organized to form an organ:
Fig. 20.8
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Several tissues are organized to form an organ:
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
Organ systems cooperate to complete the body…
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
Function is to bring in chemicals (nutrients:
monomers, fatty acids, glycerol, cholesterol,
vitamins [used as coenzymes – organic
cofactors], minerals [ions to be used as
cofactors, neuron firing, etc…]) to your cells for
building (biosynthesis), storing, or burning to
generate ATP for building.
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
Serves for gas exchange. Bring in
molecular oxygen (O2) to your blood,
which will be used to perform cell
respiration by your cells. To get rid of
(excrete) CO2 and H2O waste coming from
cell respiration (CO2 released during
grooming and Krebs, H2O formed at the
end of the ETC from the reduction of O2).
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
The heart pumps blood around your body in
hollow tubes made of cell called arteries, veins,
and capillaries (these would be the roadways of
your body). EVERY cell is at most three cell
lengths away from a capillary (from the blood
supply). The system delivers nutrients and oxygen
to all cells for building, burning or storing, and
takes away the waste products that cells excrete
like CO2 and urea (nitrogen waste from the
deamination of amino acids). CO2 will be
eliminated by the lungs (resp./excretory system)
and the urea will be eliminated by the kidneys
(excretory system). The blood also carries other
substance like white blood cells (WBC’s).
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
Cleans the blood of metabolic waste (waste from
chemical reactions) like H2O from cell respiration,
and urea from deamination. The kidney are “blood
filters”, removing urea, excess salt or excess water
and other undesirable chemicals from the blood.
Although not shown, the respiratory system has
excretory function in the elimination of CO2 since
it is a gas along with the skin, which will release
some urea, salt and water as sweat.
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
CELLS TALK…
Your cells must be able to talk to each other. For example, growth hormone coming from
the pituitary gland in the brain instructs cells to undergo mitosis (bypass the G1
checkpoint) or insulin from the pancreas instructing the liver to take up glucose from the
blood.
What you must realize, however, is that no one cell knows what all other cells are doing.
They are mechanical and respond to internal and external signals. It is analogous to our
society. There is no one person that knows what all people are doing. I communicate with
certain people and they communicate with others etc… and in the end all people are
connected/networked.
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
Your cells must be able to talk to each other. For
example, growth hormone coming from the pituitary
gland in the brain instructs cells to undergo mitosis
(bypass the G1 checkpoint) or insulin from the
pancreas instructing the liver to take up glucose from
the blood.
The endocrine system uses hormones (chemicals:
steroids, amino acids, polypeptides, proteins) put
into the blood by endocrine cells, which bind to and
signal others cells to perform certain functions. This
system is typically slow and long term – takes a
while for the hormones to circulate and they will stay
around a while…
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
The nervous system is also all about cellular
communication, but instead of using chemicals
released into the blood, it uses cells that act like
wires called neurons that transmit electrical
signals. These signals are extremely fast (up to
120 m/s) and are typically short lived. An
example would be moving your finger or any
other skeletal muscle. The electrical signal is
sent from your brain, down your spinal cord
and out to the muscle in your finger.
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
There are millions upon millions of bacteria,
fungi, parasitic worms, etc… that would love
nothing than to take your organic molecules
and make them lunch. Luckily you have an
immune and lymphatic system. These systems
work together to clear your body of foreign
substance. White blood cells are responsible
for the destruction of these substances. They,
like all blood cells, are born in the bone
marrow and serve to protect…
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
What is life without a reproductive
system? Nonexistent. This one if
fairly self-explanatory. It is also the
only system not required for the
organism itself to survive.
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
The muscular system is composed of all the
skeletal muscles of the body. The skeletal
muscles allow the body to move when
combined with signals from the nervous
system (and a lot of ATP of course)
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
The skeletal system serves to support the body
(without it you would be a blob on the floor),
protects vital organs like your lungs, brain, spinal
cord and heart, and contains marrow that produces
blood cells.
The integumentary system is composed of the skin,
hair and nails (feathers and scales), all of which are
mostly non-living. This system serves to
waterproof, cushion and protect the deeper tissues,
excrete wastes, regulate temperature, is the
attachment site for sensory receptors to detect pain,
sensation, pressure and temperature, and may
attract a mate. In humans the integumentary system
additionally provides vitamin D synthesis.
Integere means “to cover” (latin)
Fig. 20.9
Chapter 20: Unifying Concepts of Animal Structure and Function
AIM: How are animals organized?
Organs cooperate to build organ systems:
Organ systems cooperate to complete the body…
Fig. 20.9
Chapter 21: Nutrition and Digestion
NEW AIM: How do animals obtain nutrition?
Nutrition and The Digestive System
Chapter 21: Nutrition and Digestion
NEW AIM: How do animals obtain nutrition?
Four Types of ANIMAL ingestion:
1. Filter (suspension) feeder
3. Fluid Feeder
2. Substrate Feeder
4. Bulk Feeder
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
macromolecules too large to cross plasma membrane
REASONS:
animals need monomers to make their polymers
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
What will the nutrients be used for?
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
(EGESTION)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Let’s now look at organisms form simple to more complex and see
how they perform nutrition.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Single celled organisms:
A. Phagocytose and fuse
lysosomes with the resulting
food vacuole
1. Digestion occurs in individual cells.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Sponges
Phylum: Porifera
1. Digestion occurs in individual cells – can only eat detritus.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Hydra:
Fig. 21.3A
Phylum: Cnidaria
(Coelentrates)
2. Gastrovascular cavity – allows organism to eat larger pieces of food
- Digestion (gastro) and circulation (vascular) of nutrients to body; only one opening
- Cells lining GV cavity secrete hydrolytic enzyme onto the ingested food to chemically
break it down (food its trapped in the cavity and circulated by flagella) and then
phagocytose the remaining pieces to be further broken down by lysosomes.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Cnidarians
Cnidocytes (stinger cells)
Chironex fleckeri (“Box jellyfish”)
- cell after which the phylum is named
- found on surface of tentacles
- each cell contains a coiled thread with a capsule (nematocyst)
- when triggered, coil shoots out and wraps around/stings prey
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Platyhelminthes also uses a GV cavity
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
SYMMETRY
No symmetry
Central axis where several
cuts can be made through Only one plane can be cut
to divide the organism into
axis to make many equal
two equal halves.
pieces (like a pizza pie).
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Fig. 21.3B
3. Alimentary canal (AC)
- A tube beginning with the mouth and ending with the anus having
specializations along the way for ingestion, digestion, absorption and egestion.
- All the remaining phyla (nematode to chordata) use an AC
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Annelida
Fig. 21.3B
1. Substrate feeders taking in soil through the mouth
2. Soil enters pharynx (throat) and then passes down the esophagus to the crop.
3. The crop is an organ that moistens and stores food as the organism can eat
soil quicker than it can digest and absorb the organic material.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Annelida
Fig. 21.3B
4. The crop will slowly release food into the gizzard, which contains a bit of
sand and serves to grind the food (mechanical digestion) like we do in our
mouth to increase surface area for the upcoming chemical digestion.
5. The pulverized material then enters the intestines where enzymes will be secreted
into the canal to chemically breakdown the food (hydrolysis of polymers).
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Annelida
Fig. 21.3B
6. The intestines is also the site of absorption of monomers into the blood.
7. The undigested material is egested through the anus.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Arthropoda
1. Similar to Annelids
2. Bulk feeder, food ingested through mouth, passes down esophagus into a crop and
then into a gizzard.
3. The gizzard of insects can have hard teeth-like appendages for grinding the food.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Arthropoda
4. Food then enters the stomach where enzymes are secreted by cells onto the food
resulting in chemical digestion.
5. The stomach is ALSO the site of absorption
6. Gastric pouches are extensions of the stomach, increasing surface area to aid in
absorption of nutrients into the haemolymph (“blood of the open circ. system”).
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Arthropoda
7. The intestine is short and mainly used for water absorption.
8. Undigested food is eliminated through the anus.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Chordata
Crop full with food
1. Bulk feeder, food ingested via mouth (no teeth, save on weight) and passes
down esophagus into crop.
2. Food is then slowly released into the stomach where some chemical digestion of
proteins begin and a bit of mechanical digestion occurs.
3. Partially digested food then enters the gizzard to be mechanically digested.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Chordata
Crop full with food
4. Many birds will eat stones, which will get caught in the gizzard and aid in the
grinding of the food to increase the surface area.
5. Food will then be passed back to the stomach for more chemical digestion now
that there is more surface area and then back to the gizzard. The food will go back
and forth a number of times before moving into the small intestines.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
3. Alimentary canal (AC)
Phylum: Chordata
Crop full with food
6. In the small intestines, the majority of the chemical digestion occurs
followed by absorption of nutrients into the blood.
7. Food then enters the large intestines where water and electrolytes (ions like Na+,
K+, Cl-, Mg++, etc…) are absorbed.
8. Undigested material is egested via anus.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
The Human Digestive
System
Spincters
- Rings of muscle that close off tubes
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Uvula
1. The Mouth
a. Digestion Begins
Fig. 21.5
i. Salivary Glands and saliva
- 98% water
- Slippery glycoprotein
- Buffers
- Antibacterial compounds (antibodies - IgA)
Chemical digestion - Salivary amylase
ii. Chewing
Mechanical
Digestion
- easier to swallow
- increase surface area
- Types of teeth
iii. Tongue
- bolus
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Salivary amylase is an enzyme that
catalyzes the hydrolysis of starch
and glycogen in the mouth.
Main products are small polysaccharides and
disaccharides
Calcium cofactor
Salivary amylase
Prefix (Amyl-) - Starch
Suffix (-ase) - Enzyme
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.6
2. The Pharynx
a. the swallowing reflex
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.6
2. The Pharynx
a. the swallowing reflex
- larynx moves up and epiglottis (elastic cartilage) swings down to cover trachea
- esophageal sphincter loosens up
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.6
2. The Pharynx
a. the swallowing reflex
- larynx moves up and epiglottis swings down to cover trachea
- esophageal sphincter loosens up
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.7
3. The Esophagus
a. peristalsis
- circular muscle layer - contracts to push food down
- longitudinal muscle layer - contracts to shorten esophagus
- 5 to 6 seconds to get to stomach
**Entire digestive tract (alimentary canal, Gastrointestinal tract, GI tract) is wrapped in smooth muscle for peristalsis
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.8
4. The Stomach
a. Holds 2 liters of food/drink (storage)
b. Pinched off by sphincters on either end – cardiac orifice (lower esophageal
sphincter – not a true sphincter, not shown) and pyloric sphincter
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.8
4. The Stomach
c. Surface highly folded
-Allows for expansion
-Gastric Distension
-(distention – an enlargement or ballooning effect) Rugae (rugal folds)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.8
4. The Stomach
c. Surface highly folded
i. tubular gastric glands (pits) line rugal folds
- 3 cell types in pits
1. Parietal cells - Secrete HCl (hydrochloric acid) – pH of stomach is ~2 to 3,
which will denature proteins and expose their peptide bonds to
proteolytic (protein digesting) enzymes.
2. Chief cells - Secretes the proenzyme (an inactive enzyme – aka zymogen)
called pepsinogen
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.8
4. The Stomach
c. Surface highly folded
i. tubular gastric glands
- 3 cell types
3. Mucous cells - secrete mucus (slippery glycoproteins and other substances) to
protect the stomach epithelial lining from the gastric juices.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.8
4. The Stomach
c. Surface highly folded
i. tubular gastric glands
- 3 cell types
1. Mucous cells
2. Parietal cells
3. Chief cells
Secretions = gastric juice
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
HCl
or
pepsin
Fig. 21.8
pepsinogen
pepsin
4. The Stomach
d. Pepsinogen activation
1. Activated first by low pH – low pH causes conformational change in pepsinogen resulting in
autocatalysis (it cuts itself removing green polypeptide – see above) to become pepsin
2. Pepsin
i protease (performs proteolysis – the hydrolysis of protein)
- enzyme that hydrolyzes proteins
ii. Begins protein digestion in stomach
(positive feedback)
iii. Pepsin cleaves/activates other pepsinogens
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Fig. 21.8
Gastrin – Small peptide
4. The Stomach
e. Gastric glands OFF by default
1,2) See, smell, taste food sends nerve signal to initially activate glands
3,4) Food in stomach activates cells to secrete hormone gastrin into blood
- gastrin binds to gland cells and keeps them active (increase HCl output)
- low pH inhibits gastrin release (negative feedback)
5) Food is gone, glands are off
***All hormones are either steroids or amino acid based (modified amino acids, polypeptides, proteins)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
4. The Stomach
f. Mechanical digestion
i. smooth muscle contracts to churn
ii acid chyme
- churned food + gastric juices
- squirted into duodenum of small intestines
- 2-6 hours to empty stomach
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
i. Liver
i. Produces bile
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
Glycocholic acid
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
i. Liver
i. Produces bile
-contains bile salts (amphiphilic)
- (steroid acids)
Taurocholic acid
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
i. Liver
i. Produces bile
- contains bile salts
- emulsifies fat
- Increases surface area Glycocholic acid
for chemical digestion
Taurocholic acid
emulsification is NOT chemical digestion. It is mechanical. These acids break apart large collections of fat
molecules into small, soluble collections of fat molecules. NO covalent bonds have been broken here!!!
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
i. Liver
i. Produces bile
- contains bile salts
- emulsifies fat
emulsification is NOT chemical digestion. It is
mechanical. These acids break apart large
collections of fat molecules into small, soluble
collections of fat molecules. NO covalent bonds
have been broken here!!!
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
i. Liver
i. Produces bile
- contains bile salts
- emulsifies fat
ii. Gallbladder
- stores and concentrates
bile (up to 60 ml) made
by liver
Fig. 41.19
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Gallstones - 80% are
cholesterol stones (green
in color)
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
i. Liver
i. Produces bile
- contains bile salts
- emulsifies fat
ii. Gallbladder
- stores and concentrates
bile (up to 60 ml)
Caused by too much
cholesterol and not
enough bile salts in gall
bladder
Fig. 21.10A
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iii. Why is fecal material brown?
-The brown color comes a combination
of bile and a compound called bilirubin,
-What is bilirubin?
-The liver breaks down excess heme
(hemoglobin cofactor) and bilirubin is a
yellow breakdown product of heme –
brown in high concentration.
- bilirubin is also in urine giving it its
yellow color
bilirubin
Fig. 21.10A
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
bilirubin
iii. Why is fecal material brown?
- Bilirubin is also the cause of yellowing
around bruises and the yellowing in
jaundice indicating potential liver disease
(hepatitis – viral), liver cancer,
obstruction of biliary tract by gallstones,
poor kidney function, etc...
Jaundice - Look at the yellowing of the
eyes…caused by too much bilirubin in
the blood.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
chymotrypsin
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iii. Pancreas (its exocrine function)
i. Produces digestive enzymes
-Trypsin
endopeptidases
- Chymotrypsin
Exocrine gland
Gland (cells) that secrete their products into a duct
(tube) that leads outside the body
Fig. 21.10A
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
chymotrypsin
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iii. Pancreas
i. Produces digestive enzymes
-Trypsin
- Chymotrypsin
Trypsin and chymotrypsin, like most digestive
enzymes, are made as proenzymes (zymogens) and
are activated after secretion. The proenzymes are
called chymotrypsinogen and trypsinogen 
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iii. Pancreas
i. Produces digestive enzymes
-Trypsin
- Chymotrypsin
- Carboxypeptidase
Carboxypeptidase
- This enzyme is an exopeptidase meaning it hydrolyzes polypeptides from the ends. In this
case the C-terminal end…hence its name.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iii. Pancreas
i. Produces digestive enzymes
-Trypsin
- Chymotrypsin
- Carboxypeptidase
- Pancreatic Lipase
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iii. Pancreas
i. Produces digestive enzymes
-Trypsin
- Chymotrypsin
- Carboxypeptidase
- Pancreatic Lipase
- Pancreatic Amylase
- Ribonuclease
- DeoxyRibonuclease
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. Duodenum
- first 25 cm of small intestines
- acid chyme meets bile, pancreatic enzymes, enzymes from intestine wall
(maltase, aminopeptidase (exopeptidase), dipeptidase, sucrase, lactase)
- all macromolecules digested
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. Duodenum
Carbohydrates
- pancreatic amylase
- maltase, sucrase, lactase
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. Duodenum
Proteins (proteases)
- trypsin, chymotrypsin
- aminopeptidase, carboxypeptidase
- dipeptidase
(work together as a team)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. Duodenum
Nucleic acids (nucleases)
- ribonuclease
- deoxyribonuclease
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
Mechanical digestion
iv. Duodenum
Fats
- lipase with the help of bile salts
Chemical digestion (hydrolysis)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Hormonal Control of Digestion
- Hormones are chemicals secreted into BLOOD that circulate and bind receptors on target organs
1. Gastrin
- Secreted by stomach when food present. Circulates in
blood and binds receptors on stomach cells stimulating
production of gastric juice.
2. Secretin
- Secreted into blood by duodenum when acid chyme
present. Target organ is pancreas. Stims pancrease to
secrete sodium bicarbonate (a base – baking soda –
Na+HCO3-) to neutralize acid chyme.
3. CCK (cholecystokinin)
- Secreted into blood by duodenum when acid chyme
present. Target organs are gall bladder and pancreas
stimulating release of bile and dig. Enzymes, respectively.
4. Enterogastrone
- Secreted into blood by duodenum when acid chyme
present. Inhibits gastric secretion and peristalsis in stomach
to slow down digestion when chyme rich in fats enters
duodenum (takes longer to break down fat so you need to
slow down the stomach)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
Jejunum
- Middle section of small intestines (2.5m long)
- Absorption of almost all nutrients (monomer, vitamins, minerals)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
Jejunum
- Huge surface area 300m2 (tennis court) due to:
- Large folds and projections that contain villi
Fig. 21.10B
- Villi are individual folds produced by many cells each containing microvilli.
- Microvilli – folds of membranes of individual cells
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
Jejunum
Where are all these nutrients going?
Fig. 21.10B
- blood vessels and lymph vessels (lacteals) penetrate villi
- Nutrients diffuse (facilitated if hydrophilic, simple if hydrophobic and
small) or are actively transported into blood.
- Lipids will enter the lacteals, other nutrients enter blood
- Nutrients go first to liver, then heart and rest of body
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
Jejunum
Where are all these nutrients going?
- Micelles of fatty acids, monoglycerides
and bile salts diffuse through epithelial
lining into lacteals – lymph system –
which will eventually drain into blood
near heart.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
Fig. 21.10B
Jejunum
Where are all these nutrients going?
- Nutrients go first to liver (the gatekeeper), then heart and rest of body
- Liver removes many of the absorbed nutrients
A. Glucose and other monnosaccharides are removed and converted to glycogen
B. Excess amino acids are removed and deaminated
- Amino group converted to urea (urea will be excreted in urine) and the rest
can be burned or used for biosynthesis
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
Jejunum
Where are all these nutrients going?
- Nutrients go first to liver, then heart and rest of body
- Liver removes many of the absorbed nutrients
Fig. 21.10B
C. Many toxins like ethanol are removed and converted to a non-toxic form
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
Hepatic Portal System
You can see the veins
wrapping stomach, small
intestines and large intestines
– all blood goes to liver via
hepatic portal vein.
Fig. 21.10B
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
ileum
- Final section of small intestines
Fig. 21.10B
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
5. The Small Intestines
a. 6 meters long, 2.5 cm diameter
b. Major site of chemical digestion
c. Aided by Liver/Gall Bladder and Pancreas
iv. The remainder of small intestines
ileum
- Final section of small intestines
A. Absorb Vitamin B12 (cobalamin)
B. Absorb bile salts
Vitamin B12
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
6. The Large Intestines (cecum, colon and rectum)
a. 1.5 meters long, 5 cm diameter
b. Sphincter controls entrance (ileocecal valve)
c. Cecum/Appendix
d. Function
- absorb water, salts and some vitamins
- 7 liters enter alimentary canal/day
- 90% absorbed by Small intestines
- rest absorbed by large intestines
e. peristalsis
f. Too little water absorbed = diarrhea
g. Too much water absorbed (peristalsis too slow) = constipation
h. Recum (store feces) / anus – double sphincter
Fig. 21.11
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
6. The Large Intestines (cecum, colon and rectum)
i. Bacteria in the colon (gut flora)
- 99% are anaerobes
- Make up 60% of the dry mass of feces
- ~500 different species including E. coli.
- One of the causes of flatulance
- Break down some of the fiber (cellulose)
and release waste products that your cells
can use…
- Produce vitamins like biotin (used by the “grooming”
enzymes), folic acid, several B vitamins and vitamin K
(needed for blood clotting).
- Mutualism
Fig. 21.11
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Digestion must be contained in specialized compartments:
6. The Large Intestines (cecum, colon and rectum)
j. cecum
- The cecum of herbivores tends to be
much larger than that of carnivores
- Filled with bacteria to break down plant
material.
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
ULCERS
How is the wall of the stomach protected from gastric juice?
Gastric (stomach) Ulcers - occur when the mucous protection fails
Symptoms
- pain in upper abdomen several hours after eating
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
ULCERS
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
ULCERS
How is the wall of the stomach protected from gastric juice?
Gastric Ulcers - occur when the mucous protection fails
Symptoms
- pain in upper abdomen several hours after eating
What would you hypothesize is the reason people get gastric ulcers?
Helicobacter pylori
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
ULCERS
How is the wall of the stomach protected from gastric juice?
Gastric Ulcers - occur when the mucous protection fails
Symptoms
- pain in upper abdomen several hours after eating
What would you hypothesize is the reason people get gastric ulcers?
Helicobacter pylori
- spiral bacterium
- can survive low pH of stomach
- attaches to lining and secretes neutralizing chemicals
- mucous lining breaks down in region of infection
- gastric juice now kills stomach cells quicker than mitosis can replace them
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
VEGETARIANS
Can people get all the nutrients they need without eating animal products?
Essential amino acids - humans CAN’T make 8 of the 20 amino acids
Simplest way to get all the nutrients?
Eat meat and animal by-products - eggs, cheese and milk
- Complete proteins (have all amino acids)
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
VEGETARIANS
Can people get all the nutrients they need without eat animal products?
Essential amino acids - humans CAN’T make 8 of the 20 amino acids
Simplest way to get all the nutrients?
Eat meat and animal by-products - eggs, cheese and milk
- Complete proteins (have all amino acids)
Most plant proteins are deficient in one
or more amino acids
- Incomplete proteins
Fig. 21.16
Vegetarians MUST eat a variety of plant foods that collectively
supply the essential amino acids
Ex. Beans + corn
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
VITAMINS
- most are coenzymes
NAD+
MenB
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
ESSENTIAL VITAMINS
- most are coenzymes
- 13 vitamins are essential
Table - Page 445
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
NON-ESSENTIAL VITAMINS
Nearly all vitamins are considered essential.
Vitamin D, which is important for calcium absorption and the
maintenance of bone tissue, is synthesized by skin cells
following exposure to ultraviolet B radiation from sunlight.
Vitamin K and Biotin are synthesized by the gastrointestinal
bacteria that constitute your gut flora.
Table - Page 445
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
MINERALS (ALL ESSENTIAL)
- chemical elements other than C,H,O,N
- must be obtained in our diets
Table - Page 446
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
ESSENTIAL FATTY ACIDS (ALA [ω-3] and LA [ω-6])
These polyunsaturated fatty acids (ALA and
LA) are necessary to synthesize other fatty
acids used to build phospholipids for cell
membranes of your cells…
Food with high levels of these - fish and
shellfish, flaxseed (linseed), hemp oil, soya
oil, canola (rapeseed) oil, chia seeds,
pumpkin seeds, sunflower seeds, leafy
vegetables, and walnuts.
Both polyunsaturated fats
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
REVIEW
I. Nutrition
- ingestion, digestion, absorption, egestion (elimination)
- individual cells (porifera)
- Gastrovascular cavity (Cnidarians)
- Alimentary Canal (Arthropods, Annelids, Chordates)
Mouth -> pharynx -> esophagus -> crop, gizzard, stomach > intestines -> anus
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
REVIEW
II. Humans
Mouth
- Mechanical and chemical digestion (saliva/chewing)
Swallowing reflex
Esophagus (peristalsis)
Stomach
- Mechanical and chemical digestion
Small intestines
- Duodenum
- Major site of chemical digestion with help from liver and
pancreas
Large intestines
- Water absorption
- Rectum and anus
III. Humans Nutrition
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Milestone Questions
1. In the weightless environment of space, how does food swallowed by an
astronaut reach the stomach?
2. Describe the digestion of a protein – what happens and where.
3. Where are carbohydrates digested in the body?
4. What is the function of the hepatic portal system?
5. Describe emulsification. Is the chemical, mechanical or both in terms of
digestion?
Chapter 21: Nutrition and Digestion
AIM: How do animals obtain nutrition?
Appetite Regulating Hormones