Download Digestive Systems

Daily Food
for Thought
• List the Basic
Trace of Food
through the
Digestive
System
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1
Basic Organization
 Mouth
 Esophagus
 Stomach
 Small intestine
 Large intestine
 Anus
Learning Target:
I can list the parts of the monogastric
digestive system and describe the functions
of each.
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3
Digestion is the process by which large, complex
nutrient molecules are broken down into simpler
molecules capable of being used by the organism
for food.
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4
Different Digestive
Systems
 The three different types of digestive systems
are:
 Monogastric
 Pseudo-Ruminant or Modified Monogastric
 Ruminant
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5
Humans, swine, and dogs all have a simple
stomach, which is also known as a monogastric
digestive system.
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Monogastric
 Carnivores and omnivores
have monogastric digestive
systems.
 Monogastric systems have a
simple stomach structure
and only one compartment.
 Some animals with
monogastric digestive
systems are pigs and dogs.
Humans also have
monogastric digestive
systems.
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Structures in Mouth
 Lips
 Teeth
 Tongue
 Salivary glands
Monogastric Teeth
 Function:
 Mechanically reduce particle
size
 Increase surface area
Four types:
 Incisors are used for cutting


Canine (fangs, eye teeth, tusks)
are tearing teeth
Premolars and molars (cheek
teeth) grind the food
Monogastric Tongue
Function:
 Comprised of three muscles
 Maneuvers food in the mouth

Moves feed to teeth for grinding and to the back of the mouth
for swallowing
 Can distinguish between feed and toxins by papillae or
taste buds
Monogastric Salivary Glands
Types of Glands:
Zygomatic
Parotid
Sublingual
Mandibular
Functions of Saliva
 Moisten feed (salt and water)
 Lubrication (aids swallowing)
 Starch and(or) lipid digestion (amylase and(or) lipase)
 Volume of saliva
 1 - 1.5 L/d man and pig
 7 - 10 L/d horse
Deglutition (Swallowing)
 Reflex initiated by presence of food in pharnyx
 Propulsion of food to stomach by esophageal
peristalsis
Digestive System
 Mouth: “Prehension” tool (grasps food)
 Salivary glands secrete juices containing enzymes
(digest food)
 Chewing food breaks down
 Esophagus: muscular tube that connects mouth to
stomach
 Peristaltic Movement: sequential contraction of
ringlike muscles
 Reverse Peristalsis = vomiting
Gastric Digestion
• Functions
– Reservoir for controlled release of digesta to small
intestine
– Mixing food
– Mechanical breakdown of feed
– Hydrolytic digestion by acid and enzymes
•
Mainly protein
– Kill bacteria
Parts and functions of the monogastric
mammal digestive system continued…
•Small Intestine
-enzymatic digestion and absorption
-Functions of the small intestine: digestion of
proteins, carbohydrates, and fats; absorption of
the end products of digestion
1. duodenum - most digestion occurs here
2. jejunum - some digestion and some
absorption occur
3. ileum - mostly absorption
-Bile - made in liver, stored in gall bladder, active in
the small intestine, emulsifies fat to aid in
digestion
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Enhanced Surface Area for
Increased Nutrient Absorption
Intestinal villi
Digestive System
 Accessory organs:
 Pancreas secretes enzymes to break down fat
 Liver (largest internal organ) and gall bladder which
secretes bile, which digests fats
 also stores iron
Large Intestine
• Composed of three segments
– Cecum
– Colon
– Rectum
• Function
– Fermentative digestion
• No enzyme secretion
• Relies on microbes or secretions washed out of the SI
– Absorption of remaining water, volatile fatty acids (VFAs)
from microbial fermentation and minerals
– Digesta storage
Degree of development is species dependent
Monogastric Large Intestine
 Function:
 Absorption of liquid
 Mass movements move fecal matter to anus
 Usually only a few times a day

Associated with defecation
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Different Digestive
Systems
 The three different types of digestive systems
are:



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Digestion is the process by which large,
________________ molecules are broken down
into simpler molecules capable of being used by
the organism for food.
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Humans,________, rabbits, _________and
horses all have a simple stomach, which is also
known as a _______________digestive system.
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Monogastric
 _________and omnivores
have monogastric
digestive systems.
 Monogastric systems
have a simple stomach
structure and only
______ compartment.
 Some animals with
monogastric digestive
systems are pigs and
dogs. _______ also have
monogastric digestive
systems.
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Parts and functions of the monogastric
mammal digestive system continued…
•Small Intestine
-enzymatic digestion and absorption
-Functions of the small intestine: digestion of
____________, carbohydrates, and_______;
absorption of the end products of digestion
1. duodenum -______________________
2. ________- some digestion and some
absorption occur
3. ileum -_________________________
-Bile - made in liver, stored in gall bladder, active in
the small intestine, ___________________to
aid in digestion.
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Large Intestine
• Composed of three segments
– ______________
– ______________
– ______________
• Function
– ________________ digestion
• No enzyme secretion
• Relies on microbes or secretions washed out of the SI
– ______________ of remaining water, volatile fatty acids
(VFAs) from microbial fermentation and minerals
– Digesta storage