Nutrition. Autotrophs. plants, some protists & bacteria producers

Transcription

1 Nutrition Autotrophs plants, some protists & bacteria producers

2 Nutrition Heterotrophs animals, fungi, some protists & bacteria consumers

3 Animal Nutrition Most obtain food by ingestion take in their food whole or piece by piece

4 Animal Nutrition Classify based on what they eat: Herbivores (primary consumers) eat autotrophs Carnivores (secondary or higher consumers) eat heterotrophs Omnivores eat both

5 Stages of Food Processing Ingestion eating Digestion breaking down food into small molecules mechanical and chemical (enzymatic hydrolysis) Absorption body takes in small molecules Elimination undigested material exits the body

6 Digestion Must take place in specialized compartments to avoid damage to body cells

7 Food vacuoles food enters by endocytosis & then vacuole merges with lysosome Some protists Sponges only animal with only intracellular digestion

8 Figure Intracellular digestion in Paramecium

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10 Gastrovascular Cavities single opening serve to both digest & transport nutrients extracellular digestion, then intracellular Platyhelminthes (planaria) & Cnidarians (hydra)

11 What is the advantage of extracellular digestion? Eat larger food

12 Extracellular digestion in a gastrovascular cavity

13 Alimentary canals or Complete Digestive Tracts two openings: mouth & anus food passes in one direction Found in all other animals

14 What is the advantage of oneway movement of food? Allows for specialization of different regions of the digestive tract

15 Figure Alimentary canals

16 Types of Digestive Systems Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nematode Earthworm Salamander Pharynx Mouth Intestine Anus Pharynx Mouth Crop Gizzard Anus Intestine Stomach Intestine Cloaca Mouth Liver Anus Esophagus Pancreas

17 Mammalian Digestive System Four-layered wall surrounds the lumen Mucosa (epithelial tissue) Submuscosa (connective tissue) Muscularis (muscle) Serosa (connective tissue)

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19 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Oral cavity Salivary glands Salivary gland Pharynx Esophagus Liver Gallbladder Stomach Pancreas Small intestine Cecum Appendix Colon Rectum Anus

20 Human Digestive System Mouth teeth mechanically break down food Similar in function to the gizzard of birds and worms saliva is secreted from salivary glands mucous protects mouth antibacterial agents buffer to neutralize acidity salivary amylase hydrolyzes glucose polymers

21 Human Digestive System Pharynx (throat) swallowing Esophagus peristalsis

22 Swallowing Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pharynx Air Larynx Trachea Esophagus Hard palate Tongue Soft palate Epiglottis 1. As food moves to the back of the mouth, the soft palate seals off the nasal cavity. 2. During swallowing, the larynx rises and is sealed off by the epiglottis. This forces the bolus into the esophagus and prevents entry into the trachea. As the bolus moves into the esophagus the larynx relaxes.

23 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Peristalic movement Esophagus Relaxation Contraction Food Bolus Relaxation

24 Human Digestive System Stomach stores food (as does the crop in other organisms) lining secretes gastric juice Pepsinogen (inactive) becomes pepsin (active) in low ph smooth muscles churn the food Acid chyme

25 The Stomach Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Esophagus Stomach Gastric pit Gastric pit Serosa Duodenum Pyloric sphincter Mucosa Muscularis Longitudinal Circular Mucosa Oblique Mucous cell Chief cell Muscularis Submucosa Oblique Circular Longitudinal Serosa Gastric glands Parietal cell

26 Human Digestive System Small Intestine Longest part of the canal (6 m in humans) Duodenum (first 25 cm) most digestion takes place Jejunum and ileum mainly absorption Very large surface area (300 m 2 ) folds, villi & microvilli Similar to mycelium in fungi & roots in plants

27 The Small Intestine Small intestine Villus Mucosa Submucosa Muscularis Serosa Villi Epithelial cell Capillary Lacteal Lymphatic duct Vein Artery

28 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pancreatic islet (of Langerhans) From liver cell cell Common bile duct Pancreas Gallbladder Pancreatic duct Duodenum

29 Human Digestive System Accessory Glands: Pancreas digestive enzymes Lipase-lipids; pancreatic amylase-starch; trypsin - proteins Bicarbonate- buffer

30 Human Digestive System Accessory Glands: Liver produces bile salts which are stored in the gallbladder until needed aid in the digestion of fats by emulsification Gallbladder

31 Human Digestive System Large Intestine or Colon main function is concentration & storage of wastes absorption of water, sodium, vitamin K Feces are moved along by peristalsis and exit the body through the anus

32 Hormonal Control of Digestion Gastrin released by the stomach feeds back to cause the secretion of gastric juices Low ph inhibits its production negative feedback

33 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stomach Liver ph Proteins Gastrin GIP ( ) ( + ) ( + ) Chief cells Parietal cells Pepsin HCl ( + ) Bile Pancreas Enzymes Bicarbonate Acinar cells Gallbladder ( + ) ( + ) CCK Secretin Duodenum

34 Hormonal Control of Digestion Enterogastrones Released by duodenum of small intestine inhibit peristalsis & secretions in the stomach Secretin Stimulated by low ph causes pancreas to release bicarbonate CCK (cholecystokinin) Stimulated by high fat content Stimulates gall bladder to release bile GIP (gastric inhibitory peptide) Inhibits emptying of the stomach

35 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stomach Liver ph Proteins Gastrin GIP ( ) ( + ) ( + ) Chief cells Parietal cells Pepsin HCl ( + ) Bile Pancreas Enzymes Bicarbonate Acinar cells Gallbladder ( + ) ( + ) CCK Secretin Duodenum

36 Evolutionary Adaptations to Diet Teeth pointed in carnivores, flat in herbivores

37 Mouth and Teeth Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Herbivore Carnivore Omnivore Horse Lion Human Incisors Canines Premolars Molars

38 Evolutionary Adaptations to Diet Length of gut longer in herbivores than carnivores Cecum houses bacteria that aid in digestion

39 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nonruminant Herbivore Simple stomach, large cecum Ruminant Herbivore Four-chambered stomach with large rumen; long small and large intestine Esophagus Stomach Small intestine Esophagus Reticulum Omasum Rumen Abomasum Anus Cecum Large intestine Spiral loop Small intestine Cecum Large intestine Anus Insectivore Short intestine, no cecum Carnivore Short intestine and colon, small cecum Esophagus Stomach Small intestine Esophagus Stomach Small intestine Anus Large intestine Anus Cecum Large intestine

40 Evolutionary Adaptations to Diet Ruminant Stomach- cows, deer

41 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Small intestine Rumen Esophagus Reticulum Abomasum Omasum

42 Evolutionary Adaptations to Diet Coprophagy rodents, rabbits