Concept 41.1: An animals diet must supply chemical energy, organic molecules, and essential...

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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:1. Chemical energy, which is converted into ATP to

power cellular processes2. 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

Essential Nutrients

• There are four classes of essential nutrients:1. Essential amino acids2. Essential fatty acids3. Vitamins - organic4. Minerals - inorganic

• 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

What is the problem with a vegan diet?

Table 41.1

Table 41.2

Figure 41.3

Why is this fella licking the ground?

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

41.2: The main stages of food processing are ingestion, digestion, absorption, and elimination

Hannah Ragozzino

Chapter 41: Nutrition

• 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

http://hodnett-ap.wikispaces.com/Chapter+41+Animal+Nutrition

Suspended (filter) Feeders• Suspended feeders

eat small organisms or food particles suspended in the watero Most aquatic

animals ex./ clams and oysters

http://www.flickr.com/groups/megaptera/discuss/72157594514167479/

Baleen

Substrate Feeders

• Animals that live in or on their food sourceo Leaf miner caterpillar (moth larva)

http://www.mun.ca/biology/mcolbo/Lectures%2015,16,17/003.%20Lecture%2017%20B1002.htm

Caterpillar

Fluid Feeders• Suck nutrient rich fluid from a living host

o Mosquitoes suck blood o Aphids tap phloem sap of plants

https://kleczekbiology.wikispaces.com/Digestive+Systemhttp://en.wikipedia.org/wiki/

Bulk Feeders• Eat relatively large pieces of food

o Most animals, includes humans

http://dpshots.com/photo-inspiration/35-award-winning-photographs-from-around-the-world.html

http://aspiringbackpacker.com/2012/05/5-huge-eating-challenges-world/

• Extracellular Digestiono Breakdown of food

particles in compartments that are continuous within the outside of the animals body

Digestive Compartments

• Intracellular Digestiono Food particles engulfed by

endocytosis and digested within food vacuoles

Gastrovascular Cavity

• Many animals with simple body plans have digestive compartment with single openingo Functions in digestion and

distribution of nutrients

http://www.studyblue.com/notes/note/n/chapter-41/deck/2482484

Alimentary Canals• Most animals have a

complete digestive cavityo Two openings- mouth and anus

• Organized into specialized compartments that carry out digestion and nutrient absorption stepwise

Concept 41.3: Organs specialized for sequential stages of food processing

mammalian digestive system- alimentary canal + accessory glands that secrete digestive juices through ducts

Salivaryglands

Gall-bladder

Esophagus

Pharynx

Oral cavity

Sphincter

Stomach

Esophagus

Tongue

Pancreas

SmallintestineLargeintestine

RectumAnus

SphincterStomach

Duodenum ofsmall intestine

Pancreas

Schematic diagramAnusRectum

Largeintestine

SmallintestineLiver

Salivaryglands

Gall-bladder

Peristalsis-rhythmic contractions of muscles in the wall of the canal

Tongue

Pharynx

Glottis

Larynx

Bolus offood

Epiglottisup

EsophagealsphinctercontractedEsophagus

To lungs To stomach Relaxedmuscles

Contractedmuscles

Sphincterrelaxed

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

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

Gastric gland

Gastric pits oninterior surface

of stomach

Sphincter

Smallintestine

Epithelium

Mucous cell

Chief cell

Parietal cell

Chiefcell

Pepsinogen

Parietalcell

Pepsin

Folds ofepithelialtissue

Sphincter

Esophagus

Stomach

Figure 41.11

• Mucus protects the stomach lining from gastric juice

• 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

Most of absorption happens in the small intestine

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

Vein carryingblood to liver

Muscle layers

Bloodcapillaries

Intestinal wall

Epithelialcells

Largecircularfolds

Nutrientabsorption

Villi Microvilli (brushborder) at apical(lumenal) surface

Epithelialcells

Basalsurface

Lacteal

Lymphvessel

• 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

Fat digestionNucleic acid digestion

Protein digestion

Fat (triglycerides)DNA, RNA

Nucleotides

Pancreaticnucleases

Pancreatic lipase

Glycerol, fatty acids,monoglycerides

Nucleotidases

Nucleosides

Nucleosidasesandphosphatases

Nitrogenous bases,sugars, phosphatesAmino acids

Dipeptidases, carboxy-peptidase, andaminopeptidase

Small peptides

Pancreatic carboxypeptidase

Smallerpolypeptides

Pancreatic trypsin andchymotrypsin

Small polypeptides

Proteins

Pepsin

Carbohydrate digestion

Polysaccharides Disaccharides

Salivary amylase

Smallerpolysaccharides

Maltose

Pancreatic amylases

Disaccharides

Disaccharidases

Monosaccharides

Smallintestine(enzymesfromepithelium)

Smallintestine(enzymesfrompancreas)

Stomach

Oral cavity,pharynx,esophagus

Figure 41.12-4

Ascendingportionof colon

Smallintestine

AppendixCecum

The colon’s 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

http://www.youtube.com/watch?v=f2vCHNHkHG8

• 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

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

Concept 41.4

Evolutionary adaptations of vertebrate digestive systems correlate with diet

Dental Adaptations

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

Omnivore

Carnivore

Herbivore

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

Smallintestine Stomach

Carnivore

Colon(largeintestine)

Small intestine

Herbivore

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

Reticulum

Esophagus

OmasumAbomasum

Intestine

Rumen1 2

Concept 41.5 : Feedback circuits regulate digestion,

energy storage, and appetite

Rachel Sylvia Mr. Reis

AP Biology 18 March 2013

Regulation of Digestion: • Arrival of food triggers

secretion of substances which promote next stage of chemical digestion &muscle contractions which move food along canal

• Hormones:• - make sure digestive

secretions are only around when they need to be

• - transported through bloodstream Chyme=

partially

digested

• 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

• 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

• Overnourishment = consumption of more calories than needed

• Causes obesity => health problems (colon & breast cancer, diabeetus, and cardiovascular disease)

• 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

So basically…..

• 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

Concept 41.1: An animals diet must supply chemical energy, organic molecules, and essential...

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