AP Chapter 41

1
AP Chapter 41

• Animal Nutrition
• Campbell 6e

2
Nutritional Requirements

• Animals have 3 main dietary needs
• Fuel (chemical energy)
• Raw materials for biosynthesis
• Essential nutrients

3
Homeostatic Mechanisms

• Animals must regulate their cellular fuel.
• The flow of food energy into and out of an animal
  can be viewed as an energy budget.
• ATP accounts for the largest fraction of the
  energy budget of most animals.

4

• ATP powers an animal at rest and during times of
  activity.
• ATP comes form the oxidation of organic fuel
  molecules- carbohydrates, lipids, and proteins.
• Carbohydrates are the preferred energy source
  although they only contain about half as much
  energy as lipids.
• The storage and use of glucose is regulated so
  the cellular fuel is used efficiently.

5
Glucose Regulation

• When more calories are taken in than needed,
  biosynthesis can occur.
• If too many more are taken in than can be stored
  in the liver as glycogen, then the excess is
  converted to fat for long term-storage.
• When fewer calories are taken in than needed, the
  body will draw on its fat reserves for fuel.

6
Caloric Imbalance

• If the energy budget is not in balance, then
  under or over nourishment can occur.
• If the body is undernourished, it will breakdown
  its own proteins for fuel and this will
  eventually result in death.
• Overnourishment can also contribute to health
  problems, namely obesity.

7
Obesity

• Leptin is a hormone produced in adipose (fat)
  tissue in mammals that regulates appetite and
  muscular activity. This regulates the body weight
  of an individual.
• Obesity can be beneficial in some organisms (ex.
  Petrels)

8
Essential Nutrients

• The diet must supply the fuel necessary to make
  ATP.
• Animal diets must also supply the raw materials
  needed for biosynthesis of proteins and other
  organic compounds in the body.
• There are essential nutrients that must be in the
  diet because the body cannot manufacture them.

9

• Some of these materials are needed by all
  animals, but others are specific for certain
  species (ex. Vitamin C).
• If the diet is lacking in any of the essential
  nutrients, then it is said to be malnourished.

10
Classes of Essential Nutrients

• There are 4 classes of essential nutrients
• Essential amino acids
• Essential fatty acids
• Vitamins
• Minerals

11
Essential Amino Acids

• Animals need 20 amino acids to synthesize
  proteins.
• Most animals can make about half of these amino
  acids provided their diet contains the raw
  materials.
• The others, the essential a.a.s (8) must be taken
  in through diet.
• Protein deficiency results if these are not
  consumed.

12

• Protein deficiency is the most common form of
  malnourishment in humans. Results in physical and
  mental retardation.
• Meat, eggs, and cheese are the best sources of
  these essential a.a.s.
• Proteins from animal products are complete
  (provide all essential a.a.s in the correct
  amounts).
• Most plant proteins are incomplete (deficient
  in one or more essential a.a.s).

13
Essential Fatty Acids

• Most fatty acids can be synthesized in the body.
• The essential ones (some unsat. fats) must be
  consumed.
• Linoleic acid is an essential one that must be
  consumed as it is needed for some of the
  phospholipids in cell membranes.
• Deficiencies of essential fatty acids are rare.

14
Vitamins

• Organic molecules
• Needed in small quantities
• There are 13 essential vitamins for humans
• Two kinds of vitamins
• Fat-soluble
• Water-soluble

15
Water-Soluble Vitamins

• B-complex and C
• Not stored in the body, must be replaced each
  day.
• The B-complex group is found in a variety of
  foods cereal grains, meat, poultry, eggs, fish,
  milk, legumes and fresh vegetables.
• Citrus fruits are good sources of vitamin C.

16

• Function as coenzymes in key metabolic processes.
• Needed for production of connective tissue.
• Excesses are eliminated in urine and mild
  overdoses pose few problems.

17
Fat-Soluble Vitamins

• (A, D, E and K). Unlike water-soluble vitamins
  that need regular replacement in the body,
  fat-soluble vitamins are stored in the liver and
  fatty tissues, and are eliminated much more
  slowly than water-soluble vitamins.
• Variety of functions
• Can overdose on these vitamins.

18
Vitamin A

• Vitamin A, also called retinol has these
  functions
• helps the eyes adjust to light changes,
• important role in bone growth, tooth development,
  reproduction, cell division and gene expression.
• Also, the skin, eyes and mucous membranes of the
  mouth, nose, throat and lungs depend on vitamin A
  to remain moist.

19
Vitamin D

• Vitamin D functions
• plays a critical role in the bodys use of
  calcium and phosphorous. It increases the amount
  of calcium absorbed from the small intestine and
  helps form and maintain bones.
• Children especially need adequate amounts of
  vitamin D to develop strong bones and healthy
  teeth.

20
Vitamin E

• Vitamin E acts as an antioxidant, protecting
  vitamins A and C, red blood cells and essential
  fatty acids from destruction.

21
Vitamin K

• Naturally produced by the bacteria in the
  intestines, vitamin K plays an essential role in
  normal blood clotting and helps promote bone
  health.

22
Minerals

• Minerals are elements that originate in the Earth
  and cannot be made by living systems.
• Plants obtain minerals from the soil, and most of
  the minerals in our diets come from directly from
  plants or indirectly from animal sources.

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Minerals Continued

• Minerals are trace elements required for normal
  metabolism, as components of cells and tissues,
  and for nerve conduction and muscle contraction.
• They can only be obtained from the diet.
• Iron for hemoglobin
• calcium (for bones)
• sodium nerve message transmission

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Food Types and Feeding Mechanisms
25
Feeding Styles

• All animals eat other organisms --- dead or
  alive, whole or by the piece.
• Animals fit into 1 of 3 dietary categories.
• Herbivores
• Carnivores
• Omnivores

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Herbivores

• A herbivore is an animal that gets its energy
  from eating plants, and only plants.
• Many herbivores have special digestive systems
  that let them digest all kinds of plants,
  including grasses.
• Herbivores need a lot of energy to stay alive.
  Many of them, like cows and sheep, eat all day
  long.

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Carnivores

• A carnivore is an animal that gets food from
  killing and eating other animals.
• Carnivores generally eat herbivores, but can eat
  omnivores, and occasionally other carnivores.
• Since carnivores have to hunt down and kill other
  animals they require a large amount of calories.
• This means that they have to eat many other
  animals over the course of the year. The bigger
  the carnivore, the more it has to eat.

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Omnivores

• An omnivore is a kind of animal that eats either
  other animals or plants.
• Some omnivores will hunt and eat their food,
  eating herbivores and other omnivores.
• Some others are scavengers and will eat dead
  matter.
• Omnivores eat plants, but not all kinds of
  plants. Unlike herbivores, omnivores can't digest
  some of the substances in grains.

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Feeding Adaptations

• There are 5 main ways animals ingest food.
• Suspension-feeders
• Substrate-feeders
• Fluid-feeders
• Bulk-feeders
• Absorptive

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Suspension Feeders

• Organisms such as sponges that feed by removing
  food from water that filters through their body.

31
Substrate Feeders

• Such as earthworms and termites, eat the material
  (dirt or wood) they burrow through

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Fluid-Feeders

• such as aphids, pierce the body of a plant or
  animal and withdraw fluids.

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Bulk Feeders

• Eat large pieces of food.

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Absorptive Feeders

• Absorptive feeders, such as tapeworms, live in a
  digestive system of another animal and absorb
  nutrients from that animal directly through their
  body wall

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Digestion
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Digestion

• There are 4 main stages of food processing.
• Ingestion
• Digestion
• Absorption
• Elimination

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Ingestion

• Ingestion is the act of eating.
• Nearly all animals must do some sort of
  processing to food that is in bulk form

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Digestion

• The second stage of food processing.
• Breaking down of food into small molecules that
  the body can absorb.
• These small molecules can then be used as raw
  materials for biosynthesis.
• Uses enzymatic hydrolysis (with H2O) to break
  monomers into useable molecules.

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Absorption

• The cells of the digestive tract absorb the small
  molecules that result from the digestive process.
• Small molecules include glucose and other simple
  sugars, amino acids.

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Elimination

• The undigested materials must pass out of the
  digestive compartment.

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Types of Digestion

• Digestion occurs in specialized compartments.
• Two types of digestion
• Intracellular
• Extracellular

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Intracellular Digestion

• Some organisms use food vacuoles- small
  organelles in the cell that contain digestive
  enzymes.
• This compartmentalizes the digestive process so
  the organism does not digest its own tissues.

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Extracellular Digestion

• Digestion occurs outside of cells.
• Occurs within specialized compartments- a
  digestive cavity.
• Gastrovascular cavities are pouches that have one
  opening- found in simple organisms like
  Cniderians.

The mouth is the anus, too
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Digestive Tracts

• In higher organisms, such as mollusks,
  arthropods, and echinoderms, the digestive tract
  has 2 openings.
• The digestive cavity is termed a digestive tract
  or alimentary canal.
• Food only moves in 1 direction.

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Earthworm Digestion

• Earthworms have a pharynx to suck food into the
  mouth.
• Food passes through the esophagus, is stored and
  moistened in the crop and sand and gravel in the
  gizzard grinds the food.
• The intestine digests and absorbs the nutrients.

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Grasshopper Digestion

• A grasshopper has several digestive chambers
  grouped into a foregut (with an esophagus and
  crop), a midgut and a hindgut.
• Food is moistened and stored in the crop, but
  most digestion occurs in the hindgut.
• The gastric ceca, pouches extending from the
  midgut, absorb the nutrients.

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Avian Digestion

• Many birds have 3 chambers, the crop, stomach,
  stomach and gizzard.
• Chemical digestion and absorption of nutrients
  occur in the intestine.

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Mammalian Digestion

• The mammalian digestive system consists of the
  alimentary canal and accessory glands.
• Peristalsis is the rhythmic waves of contraction
  by smooth muscles in the walls of the canal. It
  pushes food along the tract.
• The system also has valves called sphincters.

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Digestive System Anatomy

• Digestive tract (mouth to anus)
• Alimentary tract or canal
• GI tract (stomach and intestines)
• Accessory organs
• Primarily glands
• Regions
• Mouth or oral cavity
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large intestine
• Anus

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Oral Cavity

• Mouth or oral cavity
• Tongue Involved in speech, taste, mastication,
  swallowing.
• Salivary glands
• Parotid
• Sublingual
• Submandibular

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Teeth

• Two sets
• Primary, deciduous, milk Childhood
• Permanent or secondary Adult (32)
• Types
• Incisors, canine, premolar and molars

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Teeth
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Salivary Glands

• Produce saliva
• Prevents bacterial infection
• Lubrication
• Contains salivary amylase
• Breaks down starch
• Mucous
• Secreted by the submandibular and sublingual
  glands
• lubricate
• Three pairs
• Parotid
• Submandibular
• Sublingual.

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Deglutition (Swallowing)

• Three phases
• Voluntary
• Bolus of food moved by tongue from oral cavity to
  pharynx
• Pharyngeal
• Reflex Upper esophageal sphincter relaxes,
  elevated soft palate, which closes nasopharynx
  and oropharynx. Pharynx elevates and opens the
  esophagus, food pushed into esophagus
• Esophageal
• Reflex Epiglottis is tipped posteriorly, larynx
  elevated to prevent food from passing into larynx

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Pharynx

• Pharynx
• Nasopharynx
• Oropharynx Transmits food
• Laryngopharynx Transmits food
• Extends from oropharynx to esophagus and post. to
  the larynx.

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Animations

• http//greenfield.fortunecity.com/rattler/46/upali
  4.htm
• http//hopkins-gi.org/multimedia/database/intro_25
  0_Swallow.swf

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Esophagus

• Esophagus
• Transports food from pharynx to stomach
• Passes through esophageal hiatus (opening) of
  diaphragm and ends at stomach
• Sphincters
• Upper
• Lower
• Regulate movement of material into and out of the
  esophagus

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Peristalsis

• http//www.lionden.com/peristalsis.htm

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Stomach
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Stomach Anatomy

• Openings
• Gastroesophageal or cardiac to fundus
• Pyloric to duodenum
• Regions
• Cardiac
• Fundus
• Body
• Pyloric

3
4
1
2
8
7
6
5
9
10
Located in the left superior abdomen
61
Stomach Histology

• Rugae Folds in stomach when empty
• Gastric pits Openings for gastric glands
• Mucosa cells
• Endocrine regulatory hormones
• Chief - pepsinogen
• Parietal - hydrochloric acid
• Mucous neck - mucus

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Movements in Stomach
Ingested food and stomach secretion mixed together
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Small Intestine

• Site of greatest amount of digestion and
  absorption
• Divisions
• Duodenum
• Jejunum
• Ileum Peyers patches or lymph nodules in mucosa
  and submucosa where some absorption of nutrients
  take place
• Illeocecal sphincter junction between the ileum
  and the large intestine

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Duodenum Anatomy and Histology
3
2
1

• Modifications
• The mucosa and submucosa form a series of folds
  (Circular folds or plicae)
• At the top of each fold are located villi which
  are covered in microvilli
• Lacteal capillary network

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Small Intestine Secretions

• Mucus
• Protects against digestive enzymes and stomach
  acids
• Digestive enzymes
• Disaccharidases Break down disaccharides to
  monosaccharides
• Peptidases Hydrolyze peptide bonds
• Nucleases Break down nucleic acids
• Duodenal glands (Brunner's glands)
• Stimulated by vagus nerve, secretin, chemical or
  tactile irritation of duodenal mucosa

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Duodenum and Pancreas
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Pancreas

• Anatomy
• Endocrine
• Pancreatic islets produce insulin and glucagon
• Control blood levels of nutrients such as
  glucose, amino acids
• Exocrine
• Acini produce digestive enzymes
• Regions Head, body, tail

• Secretions
• Pancreatic juice (exocrine) produced in the
  pancreas and delivered through the pancreatic
  duct to the small intestine.
• Trypsin
• Chymotrypsin
• Carboxypeptidase
• Pancreatic amylase
• Pancreatic lipases
• Enzymes that reduce DNA and ribonucleic acid

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Liver

• Lobes
• Major Left and right
• Minor Caudate and quadrate
• Ducts
• Common hepatic
• Transport bile out of the liver
• Cystic
• From gallbladder, joins CH duct to form common
  bile duct
• Common bile
• Joins pancreatic duct at hepatopancreatic ampulla

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• Hepatic cords
• Contain hepatocytes, the functional cell of the
  liver
• Bile production
• Storage
• Interconversion of nutrients
• Detoxification
• Phagocytosis
• Synthesis of blood
• Spaces btw the cords are sinusoids.
• Bile canaliculus lies btw the cells within each
  cord

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Functions of the Liver

• Bile production
• Salts emulsify fats, contain pigments as
  bilirubin (results from break down of hemoglobin)
• No digestive enzymes but plays an important role
  in digestion by neutralizing stomach acid making
  it suitable for pancreatic enzymes
• Storage
• Glycogen, fat, vitamins (A, B12, D, E, 7 K),
  copper and iron
• Nutrient interconversion

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• Detoxification
• Hepatocytes remove ammonia and convert to urea
• Phagocytosis
• Kupffer cells phagocytize worn-out and dying red
  and white blood cells, some bacteria
• Synthesis
• Albumins, fibrinogen, globulins, heparin,
  clotting factors

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Duct System
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Gallbladder

• Cystic duct connects gallbladder to common bile
  duct
• Bile is stored and concentrated
• Dumps large amounts of concentrated bile into
  small intestine
• Production of gallstones possible
• Drastic dieting with rapid weight loss

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Large Intestine
4
5
3
1
6
2

• Extends from ileocecal junction to anus
• Consists of cecum, colon, rectum, anal canal
• Movements sluggish (18-24 hours)

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Large Intestine

• Cecum
• Blind sac, vermiform appendix attached (lymphatic
  nodes)
• Colon
• Ascending, transverse, descending, sigmoid
• Rectum
• Straight muscular tube
• Anal canal
• Internal anal sphincter (smooth muscle)
• External anal sphincter (skeletal muscle)
• Hemorrhoids Vein enlargement or inflammation

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Secretions of Large Intestine

• Mucus provides protection
• Parasympathetic stimulation increases rate of
  goblet cell secretion
• Pumps
• Exchange of bicarbonate ions for chloride ions
• Exchange of sodium ions for hydrogen ions
• Bacterial actions produce gases called flatus

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Digestion Animations

• http//www.constipationadvice.co.uk/understanding-
  constipation/normal-digestive-system.html
• http//health.howstuffworks.com/adam-200088.htm

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Digestion, Absorption, Transport

• Digestion
• Breakdown of food molecules for absorption into
  circulation
• Mechanical Breaks large food particles to small
• Chemical Breaking of covalent bonds by digestive
  enzymes
• Absorption and transport
• Molecules are moved out of digestive tract and
  into circulation for distribution throughout body

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Functions

• Ingestion Introduction of food into stomach
• Mastication Chewing
• Propulsion
• Deglutition Swallowing
• Peristalsis Moves material through digestive
  tract

1. Wave of circular smooth muscle relaxation
moves ahead of the bolus allowing the digestive
tract to expand 2. A wave of contraction of the
circular smooth muscle behind the bolus propels
it through the tract
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Reflexes in Colon and Rectum
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Digestive System Regulation

• Nervous regulation
• Involves enteric nervous system
• Types of neurons sensory, motor, interneurons
• Coordinates peristalsis and regulates local
  reflexes

• Chemical regulation
• Production of hormones
• Gastrin, secretin
• Production of paracrine chemicals
• Histamine
• Help local reflexes in ENS control digestive
  environments as pH levels