Chapter 46

Chapter 46 - BiologyNotes CHAPTER46...

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Biology Notes 12/03/2009 14:57:00 CHAPTER 46     Processing Food and Nutrition     Ingestion, Digestion, Absorption, and Elimination  Nutrition The process of taking in and using food o Carnivorous snake strangles its prey; then it dislocates and expands its  jaw to eat the larger body Food Processing     o Feeding Selection, acquisition, and ingestion of food o Digestion  Breaking down food mechanically, chemically by enzymatic  hydrolysis o Absorption Nutrients pass from lining of digestive tract into blood for  transport to body cells o Egestion (Elimination) Undigested, unabsorbed food discharged  Nutritional Adaptation     o Herbivores: Feed directly on producers (autotrophs); eat large quantities to  get nutrients; eliminate majority undigested e.g. cows, horses,  termites Ruminants (Cow) have four chambers to stomach- first two  have symbiotic bacteria to digest cellulose- undigested material  regurgitated back into mouth; saliva added and chewed again  o Carnivores:
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Eat herbivores, predators- have mechanisms for feeding  (tentacles, claws, teeth…etc) o Omnivores: Consume both plants and animals; sometimes in soil, water,  adaptations help identify food- suspension feeders such as  whales, mollusks, echinoderms o Specialized mechanisms such as sucking, piercing, long tongues etc… Gastrovascular Cavities (Fig 46-2 a and b)     o A. Hydra-  Food digested in gastrovascular cavity; one opening serves as  both mouth and anus Cells lining digestive cavity secrete proteolytic enzymes  (digestion in food vacuoles; nutrients diffuse into other cells) o B. Flatworm- Digestion begins prior to ingestion- extends pharynx through  mouth, secretes digestive enzymes on to prey; continued  digestion in gastrovascular cavity in food vacuoles o For both- Body contractions promote Egestion of undigested food  particles through the mouth Complex Invertebrates and Vertebrates     o Digestive tract is complete tube Opening at each end (mouth and anus) o Food passes through tube Digestion takes place o Parts of digestive tract are specialized To perform specific functions  Complete Digestive Tract (Fig 46-3)     o Earthworm with complete digestive tract from mouth to anus food  digested in various regions; moved propulsively via peristalsis. Moved  down as more food ingested and processed. 
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Trace the Pathway of the Human Digestive System Sequence     o Mouth- pharynx (throat)- esophagus- stomach- small intestine- large  intestine- anus o Liver, pancreas, salivary glands are accessory glands that secrete  digestive juices into the digestive tract
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This note was uploaded on 10/08/2010 for the course BIO 380 taught by Professor Martin during the Spring '10 term at Rutgers.

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Chapter 46 - BiologyNotes CHAPTER46...

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