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Concept 41.1: An animals diet must supply chemical energy, organic molecules, and essential nutrients An animals diet provides: 1.Chemical energy, which.

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Presentation on theme: "Concept 41.1: An animals diet must supply chemical energy, organic molecules, and essential nutrients An animals diet provides: 1.Chemical energy, which."— Presentation transcript:

1 Concept 41.1: An animals diet must supply chemical energy, organic molecules, and essential nutrients An animals diet provides: 1.Chemical energy, which is converted into ATP to power cellular processes 2.Organic building blocks, such as organic carbon and organic nitrogen, to synthesize a variety of organic molecules 3.Essential nutrients, which are required by cells and must be obtained from dietary sources © 2011 Pearson Education, Inc.

2 Essential Nutrients There are four classes of essential nutrients: 1.Essential amino acids 2.Essential fatty acids 3.Vitamins - organic 4.Minerals - inorganic © 2011 Pearson Education, Inc.

3 Animals require 20 amino acids and can synthesize about half from molecules in their diet The remaining amino acids, the essential amino acids, must be obtained from food in preassembled form © 2011 Pearson Education, Inc. What is the problem with a vegan diet?

4 Table 41.1

5 Table 41.2

6 Figure 41.3 Why is this fella licking the ground?

7 Review of Key points Essential amino acids are only those which the organism cannot self-produce Recall metabolism; why are vitamins needed in small capacity? They form coenzymes vital for catalysis If an animal is eating plenty of food but still appears malnourished, how could you tell which nutrient in its diet it is lacking? By adding individual nutrient supplements to its diet and observing which nutrient eliminates signs of malnutrition

8 41.2: The main stages of food processing are ingestion, digestion, absorption, and elimination Hannah Ragozzino Chapter 41: Nutrition

9 Ingestion o the act of eating Digestion o the process of breaking down molecules small enough for the body to absorb Mechanical digestion breaking up food into smaller pieces (chewing) Chemical digestion enzymatic hydrolysis splits bonds in molecules with addition of water Absorption o uptake of nutrients by body cells Elimination o passage of undigested material through the digestive system

10 http://hodnett-

11 Suspended (filter) Feeders Suspended feeders eat small organisms or food particles suspended in the water o Most aquatic animals ex./ clams and oysters 72157594514167479/ Baleen

12 Substrate Feeders Animals that live in or on their food source o Leaf miner caterpillar (moth larva),16,17/003.%20Lecture%2017%20B10 02.htm Caterpillar Feces

13 Fluid Feeders Suck nutrient rich fluid from a living host o Mosquitoes suck blood o Aphids tap phloem sap of plants ystem hid

14 Bulk Feeders Eat relatively large pieces of food o Most animals, includes humans winning-photographs-from-around-the-world.html m/2012/05/5-huge-eating- challenges-world/

15 Extracellular Digestion o Breakdown of food particles in compartments that are continuous within the outside of the animals body Digestive Compartments Intracellular Digestion o Food particles engulfed by endocytosis and digested within food vacuoles

16 Gastrovascular Cavity Many animals with simple body plans have digestive compartment with single opening o Functions in digestion and distribution of nutrients 41/deck/2482484

17 Alimentary Canals Most animals have a complete digestive cavity o Two openings- mouth and anus Organized into specialized compartments that carry out digestion and nutrient absorption stepwise

18 Concept 41.3: Organs specialized for sequential stages of food processing form the mammalian digestive system © 2011 Pearson Education, Inc.

19 mammalian digestive system- alimentary canal + accessory glands that secrete digestive juices through ducts Liver Salivary glands Gall- bladder Esophagus Pharynx Oral cavity Sphincter Mouth Stomach Esophagus Tongue Pancreas Small intestine Large intestine Rectum Anus Sphincter Stomach Duodenum of small intestine Pancreas Schematic diagram Anus Rectum Large intestine Small intestine Liver Salivary glands Gall- bladder Peristalsis-rhythmic contractions of muscles in the wall of the canal

20 Tongue Pharynx Glottis Larynx Bolus of food Epiglottis up Esophageal sphincter contracted Esophagus To lungsTo stomach Relaxed muscles Contracted muscles Sphincter relaxed Stomach Trachea Figure 41.10-3 The first stage of digestion is mechanical and takes place in the oral cavity Salivary glands-deliver saliva to lubricate food salivary amylase initiates breakdown of glucose polymers Saliva contains mucus, a viscous mixture of water, salts, cells, and glycoproteins

21 Digestion in the Stomach Stomach-stores food and secretes gastric juice, which converts a meal to acid chyme – Gastric juice has a low pH of about 2, which kills bacteria and denatures proteins Gastric juice is made up of hydrochloric acid (HCl) and pepsin Pepsin is a protease, or protein-digesting enzyme, that cleaves proteins into smaller peptides © 2011 Pearson Education, Inc.

22 Gastric gland Gastric pits on interior surface of stomach Sphincter Small intestine Epithelium Mucous cell Chief cell Parietal cell Chief cell Pepsinogen Parietal cell Pepsin Folds of epithelial tissue Sphincter Esophagus Stomach 3 2 1 10 m HCl H Cl Figure 41.11 Mucus protects the stomach lining from gastric juice

23 15 – 32 feet in humans Duodenum- first portion of the small intestine – chyme from the stomach mixes with digestive juices from the pancreas, liver, gallbladder, and the small intestine itself – Most of nutrient digestion here Most nutrients pumped against gradient © 2011 Pearson Education, Inc. Most of absorption happens in the small intestine

24 Pancreatic Secretions The pancreas produces proteases trypsin and chymotrypsin that are activated in the lumen of the duodenum Its solution is alkaline to act as a buffer © 2011 Pearson Education, Inc. Bile Production by the Liver In the small intestine, bile aids in digestion and absorption of fats Bile is made in the liver and stored in the gallbladder Bile also destroys nonfunctional red blood cells

25 Vein carrying blood to liver Muscle layers Blood capillaries Villi Intestinal wall Epithelial cells Large circular folds Key Nutrient absorption Villi Microvilli (brush border) at apical (lumenal) surface Epithelial cells Lumen Basal surface Lacteal Lymph vessel Hepatic portal vein-carries nutrient-rich blood from the capillaries of the villi to the liver, then to the heart The liver regulates nutrient distribution, interconverts many organic molecules, and detoxifies many organic molecules

26 Fat digestionNucleic acid digestion Protein digestion Fat (triglycerides) DNA, RNA Nucleotides Pancreatic nucleases Pancreatic lipase Glycerol, fatty acids, monoglycerides Nucleotidases Nucleosides Nucleosidases and phosphatases Nitrogenous bases, sugars, phosphates Amino acids Dipeptidases, carboxy- peptidase, and aminopeptidase Small peptides Pancreatic carboxypeptidase Smaller polypeptides Pancreatic trypsin and chymotrypsin Small polypeptides Proteins Pepsin Carbohydrate digestion PolysaccharidesDisaccharides Salivary amylase Smaller polysaccharides Maltose Pancreatic amylases Disaccharides Disaccharidases Monosaccharides Small intestine (enzymes from epithelium) Small intestine (enzymes from pancreas) Stomach Oral cavity, pharynx, esophagus Figure 41.12-4

27 Ascending portion of colon Small intestine Appendix Cecum The colons primary purpose is to absorb water from chyme. Absorption in the Large Intestine > 90% of water reabsorbed –not enough water absorbed back to body »diarrhea –too much water absorbed back to body »constipation Cecum-aids in the fermentation of plant material and connects where the small and large intestines meet The human cecum has an extension called the appendix, which plays a very minor role in immunity

28 There are approximately 500 species of bacteria comprising the gut flora (part of the human microbiome) that aid in digestion – 100 trillion cells compared to 10 trillion actual body cells Feces, including undigested material and bacteria (30% of dry weight), become more solid as they move through the colon © 2011 Pearson Education, Inc. Symbiotic bacteria and digestion Feces are stored in the rectum until they can be eliminated through the anus Two sphincters between the rectum and anus control bowel movements, the top being involuntary, the bottom (anus) being voluntary

29 Concept 41.4 Evolutionary adaptations of vertebrate digestive systems correlate with diet

30 Dental Adaptations The evolutionary adaptation of teeth for processing different kinds of food is one of the reasons why mammals are so successful

31 Omnivore Carnivore Herbivore

32 Stomach and Intestinal Adaptations Many carnivores have large, expandable stomachs Herbivores and omnivores generally have longer alimentary canals than carnivores, reflecting the longer time needed to digest vegetation

33 Small intestine Stomach Cecum Carnivore Colon (large intestine) Small intestine Herbivore

34 Mutualistic Adaptations Many herbivores have fermentation chambers, where mutualistic microorganisms digest cellulose The most elaborate adaptations for an herbivorous diet have evolved in the animals called ruminants

35 Reticulum Esophagus OmasumAbomasum Intestine Rumen 1 2 34

36 Concept 41.5 : Feedback circuits regulate digestion, energy storage, and appetite Rachel Sylvia Mr. Reis AP Biology 18 March 2013

37 Regulation of Digestion: Arrival of food triggers secretion of substances which promote next stage of chemical digestion &muscle contractions which move food along canal

38 Hormones: - make sure digestive secretions are only around when they need to be - transported through bloodstream Chyme= partially digested food

39 When an animal takes in more energy- rich molecules than it needs- it stores them Humans store energy first in the liver and muscle cells Stored in glycogen = polymer made of glucose units Excess energy is stored as fat in adipose cells Adipose tissue provides the most space efficient way for the body to store large amounts of energy Too much adipose tissue Not enough adipose tissue

40 Synthesis and breakdown of glycogen is central to - energy storage -maintaining metabolic balance Tissues in the body rely on ATP generation by oxidation of glucose in order to fuel cellular processes

41 Overnourishment = consumption of more calories than needed Causes obesity => health problems (colon & breast cancer, diabeetus, and cardiovascular disease)

42 Hormones can contribute to appetite Ghrelin- triggers feelings or hunger as mealtime approaches Insulin- secreted after eating- blood sugar level rises Leptin- suppresses appetite/ produced by adipose *body fat decreases = leptin level decrease = appetite increase PYY- appetite suppressant which counters ghrelin and is secreted by the small intestine after a meal

43 So basically…..


45 Healthy weight is hard to maintain possibly because of evolution In the past fat hoarding was important to some for survival Ex. Baby petrels need protein/lipid rich foods in order to survive Babies are obese

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