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Concept 41.1: An animal’s diet must supply chemical energy, organic molecules, and essential nutrients An animal’s diet provides: Chemical energy, which.

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

1 Concept 41.1: An animal’s diet must supply chemical energy, organic molecules, and essential nutrients An animal’s diet provides: Chemical energy, which is converted into ATP to power cellular processes Organic building blocks, such as organic carbon and organic nitrogen, to synthesize a variety of organic molecules 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:
Essential amino acids Essential fatty acids Vitamins - organic Minerals - inorganic © 2011 Pearson Education, Inc.

3 What is the problem with a vegan diet?
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.

4 Table 41.1 Table 41.1 Vitamin Requirements of Humans

5 Table 41.2 Table 4.2 Mineral Requirements of Humans

6 Why is this fella licking the ground?
Figure 41.3 Why is this fella licking the ground? Figure 41.3 Obtaining essential nutrients.

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

9 Ingestion Digestion Absorption Elimination the act of eating
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 uptake of nutrients by body cells Elimination passage of undigested material through the digestive system


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

12 Substrate Feeders Animals that live in or on their food source
Leaf miner caterpillar (moth larva) Caterpillar Feces

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

14 Bulk Feeders Eat relatively large pieces of food
Most animals, includes humans

15 Digestive Compartments
Extracellular Digestion Breakdown of food particles in compartments that are continuous within the outside of the animals body Intracellular Digestion 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 Functions in digestion and distribution of nutrients

17 Alimentary Canals Most animals have a complete digestive cavity
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 Peristalsis-rhythmic contractions of muscles in the wall of the canal
mammalian digestive system- alimentary canal + accessory glands that secrete digestive juices through ducts Tongue Oral cavity Salivary glands Mouth Pharynx Salivary glands Esophagus Esophagus Liver Gall- bladder Stomach Sphincter Small intestine Gall- bladder Liver Sphincter Pancreas Large intestine Pancreas Stomach Figure 41.9 The human digestive system. Small intestine Rectum Anus Large intestine Schematic diagram Duodenum of small intestine Rectum Anus Peristalsis-rhythmic contractions of muscles in the wall of the canal

20 Salivary glands-deliver saliva to lubricate food
Figure Bolus of food Tongue Epiglottis up Pharynx Glottis Esophageal sphincter contracted Larynx Trachea Esophagus Relaxed muscles To lungs To stomach Contracted muscles 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 Figure From mouth to stomach: the swallowing reflex and esophageal peristalsis. Sphincter relaxed Stomach

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

23 Most of absorption happens in the small intestine
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.

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 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 © 2011 Pearson Education, Inc.

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

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

27 Absorption in the Large Intestine
The colon’s primary purpose is to absorb water from chyme. Ascending portion of colon > 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 Small intestine Figure Junction of the small and large intestines. Cecum Appendix

28 Symbiotic bacteria and digestion
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 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 © 2011 Pearson Education, Inc.

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 Carnivore Omnivore 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 Small intestine Stomach Cecum Colon (large intestine)
Figure The alimentary canals of a carnivore (coyote) and herbivore (koala). Colon (large intestine) Carnivore 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 Rumen Reticulum Esophagus Intestine Abomasum Omasum 1 2 4 3
Figure Ruminant digestion. 4 Abomasum 3 Omasum

36 Rachel Sylvia Mr. Reis AP Biology 18 March 2013
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 Food – stomach wall stretch- triggers hormone release- circulates via bloodstream- gastric juice stimulation- digestion

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

39 Humans store energy first in the liver and muscle cells
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 Not enough adipose tissue Too much 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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