DigestionFood: The easiest thing you will pass in school

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Table 41.2

Table 41.1

Figure 41.5

Mechanicaldigestion Chemical

digestion(enzymatichydrolysis)

Nutrient moleculesenter body cells

Undigestedmaterial

EliminationAbsorptionDigestionIngestion1 2 3 4

Liver

Salivaryglands

Gall-bladder

Esophagus

Pharynx

Oral cavity

Sphincter

Tongue

Pancreas

SmallintestineLargeintestine

RectumAnus

SphincterStomach

Duodenum ofsmall intestine

Figure 41.9a

Figure 41.9b

Mouth

Stomach

Esophagus

Pancreas

Schematic diagramAnusRectum

Largeintestine

SmallintestineLiver

Salivaryglands

Gall-bladder

Tongue

Pharynx

Glottis

Larynx

Bolus offood

Epiglottisup

EsophagealsphinctercontractedEsophagus

To lungs To stomach

Trachea

Figure 41.10-1

Tongue

Pharynx

Glottis

Larynx

Bolus offood

Epiglottisup

EsophagealsphinctercontractedEsophagus

To lungs To stomach

Trachea

Figure 41.10-2

Tongue

Pharynx

Glottis

Larynx

Bolus offood

Epiglottisup

EsophagealsphinctercontractedEsophagus

To lungs To stomach Relaxedmuscles

Contractedmuscles

Sphincterrelaxed

Stomach

Trachea

Figure 41.10-3

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

3

2

1

10

m

HCl

H

Cl

Figure 41.11

Figure 41.19a

Liver

Gallbladder

Food

Stomach

Duodenumof small intestine

Gastricjuices

Pancreas

1

Gastrin

Key

StimulationInhibition

Figure 41.19b

Bile

Chyme

CCK

HCO3, enzymes

Secretin

Key

StimulationInhibition

2

CCK

Figure 41.19c

Secretinand CCK

Gastricjuices

3

Key

StimulationInhibition

Figure 41.20

Transport ofglucose intobody cellsand storageof glucoseas glycogen

Breakdownof glycogenand releaseof glucoseinto blood

Homeostasis:70–110 mg glucose/100 mL blood

Stimulus:Blood glucose

level dropsbelow set point.

Pancreassecretesglucagon.

Stimulus:Blood glucose

level risesafter eating.

Pancreassecretesinsulin.

Figure 41.13a

Vein carryingblood to liver

Muscle layers

Villi

Intestinal wall

Largecircularfolds

Key

Nutrientabsorption

Key

Nutrientabsorption

Bloodcapillaries

Epithelialcells

VilliMicrovilli (brushborder) at apical(lumenal) surface

Epithelialcells

Lumen

Basalsurface

Lacteal

Lymphvessel

Figure 41.13b

Figure 41.14LUMENOF SMALLINTESTINE

Triglycerides

Epithelialcell Fatty acids

Mono-glycerides

Triglycerides

Chylomicron

Phospho-lipids,

cholesterol,and proteins

Lacteal

Figure 41.21

Satiety center

Ghrelin

Insulin

Leptin

PYY

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