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Daily Foodfor Thought
•List the BasicTrace of Foodthrough theDigestiveSystem
Basic Organization
Mouth
Esophagus
Stomach
Small intestine
Large intestine
Anus
Learning Target:
I can list the parts of the monogastricdigestive system and describe the functionsof each.
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Digestion is the process by which large, complexnutrient molecules are broken down into simplermolecules capable of being used by the organismfor food.
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Different DigestiveSystems
The
three
different
types
of
digestive
systems
are:
Monogastric
Pseudo-Ruminant
or
Modified
Monogastric
Ruminant
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Humans, swine, and dogs all have a simplestomach, which is also known as a monogastricdigestive system.
Monogastric
Carnivores and omnivoreshave monogastric digestivesystems.
Monogastric systems have asimple stomach structureand only one compartment.
Some animals withmonogastric digestivesystems are pigs and dogs.Humans also havemonogastric digestivesystems.
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Structures in Mouth
Lips
Teeth
Tongue
Salivary glands
Monogastric Teeth
Function:
Mechanically reduce particlesize
Increase surface area
Four types:
Incisors are used for cutting
Canine (fangs, eye teeth, tusks)are tearing teeth
Premolars and molars (cheekteeth) 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 mouthfor swallowing
Can distinguish between feed and toxins by papillae ortaste buds
Monogastric Salivary Glands
Types of Glands:
Parotid
Sublingual
Mandibular
Zygomatic
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 esophagealperistalsis
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 tostomach
Peristaltic Movement: sequential contraction ofringlike muscles
Reverse Peristalsis = vomiting
Gastric Digestion
•Functions
–Reservoir for controlled release of digesta to smallintestine
–Mixing food
–Mechanical breakdown of feed
–Hydrolytic digestion by acid and enzymes
•Mainly protein
–Kill bacteria
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Parts and functions of the monogastricmammal 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 someabsorption occur
3. ileum - mostly absorption
-Bile - made in liver, stored in gall bladder, active in the small intestine, emulsifies fat to aid in digestion
Enhanced Surface Area forIncreased Nutrient Absorption
Intestinal villi
Digestive System
Accessory organs:
Pancreas secretes enzymes to break down fat
Liver (largest internal organ) and gall bladder whichsecretes 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 DigestiveSystems
The
three
different
types
of
digestive
systems
are:
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Digestion is the process by which large,________________ molecules are broken downinto simpler molecules capable of being used bythe organism for food.
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Humans,________, rabbits, _________andhorses all have a simple stomach, which is alsoknown as a _______________digestive system.
Monogastric
_________and omnivoreshave monogastricdigestive systems.
Monogastric systemshave a simple stomachstructure and only______ compartment.
Some animals withmonogastric digestivesystems are pigs anddogs. _______ also havemonogastric digestivesystems.
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Parts and functions of the monogastricmammal 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 someabsorption occur
3. ileum -_________________________
-Bile - made in liver, stored in gall bladder, active in the small intestine, ___________________toaid in digestion.
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