The Digestive SystemThe Digestive System

Prepares food for use by all Prepares food for use by all body cells.body cells.

DigestionDigestionThe chemical breakdown of complex The chemical breakdown of complex biological molecules into their component biological molecules into their component parts.parts.– Lipids to fatty acids Lipids to fatty acids – Proteins to individual amino acidsProteins to individual amino acids– Carbohydrates into simple sugarsCarbohydrates into simple sugars

DigestionDigestionMechanicalMechanical

–Changes the physical form of food Changes the physical form of food via chewing, etc.via chewing, etc.

ChemicalChemical– Changes the chemical composition of food Changes the chemical composition of food

with the aid of digestive enzymes with the aid of digestive enzymes (special (special molecules that break large molecules down molecules that break large molecules down into very small molecules that can be into very small molecules that can be absorbed and used by cells).absorbed and used by cells).

Phases of DigestionPhases of Digestion

IngestionIngestion

MovementMovement

DigestionDigestion

AbsorptionAbsorption

Further digestionFurther digestion

The Digestive TractThe Digestive TractParts of the Digestive Parts of the Digestive TractTract

– MouthMouth

– PharynxPharynx

– EsophagusEsophagus

– Stomach Stomach

– Small IntestineSmall Intestine

– Large IntestineLarge Intestine

Accessory PartsAccessory PartsOrgans that are not in the digestive tract Organs that are not in the digestive tract but helps in the digestionbut helps in the digestion– TeethTeeth– Tongue Tongue – Salivary glandsSalivary glands– LiverLiver– Gall bladderGall bladder– PancreasPancreas

MouthMouthFunctions:Functions:

– Food enters in the mouth or oral Food enters in the mouth or oral cavitycavity

– TastingTasting

– Mechanical breakdown of foodMechanical breakdown of food

– Secretion of salivary glandsSecretion of salivary glands

MouthMouthStructures in the mouth that aids digestion:Structures in the mouth that aids digestion:

Teeth – cut, tear, crush and grind food.Teeth – cut, tear, crush and grind food. Salivary glands – produce and secrete Salivary glands – produce and secrete saliva into the oral cavity. saliva into the oral cavity.

– Parotid (beneath the cheeks)Parotid (beneath the cheeks)– Submaxillary (below the jaw bone)Submaxillary (below the jaw bone)– Sublingual (below the tongue)Sublingual (below the tongue)

– – saliva moistens saliva moistens the food and contains enzymes (the food and contains enzymes (ptyalinptyalin or or salivarysalivary amylaseamylase) that begins ) that begins digestion of starch into smaller digestion of starch into smaller polysaccharides (sugars).polysaccharides (sugars).

MouthMouth TongueTongue

– Mixes and rolls food into tiny Mixes and rolls food into tiny mashed up bitsmashed up bits ( (BolusBolus))

– Pushes the bolus toward the Pushes the bolus toward the pharynx and into the esophagus pharynx and into the esophagus when swallowing.when swallowing.

Anatomy of the Mouth and Anatomy of the Mouth and ThroatThroat

Mechanism of SwallowingMechanism of SwallowingSwallowing is a coordinated activity of the Swallowing is a coordinated activity of the tongue, soft palate, pharynx and esophagus.tongue, soft palate, pharynx and esophagus.

PhasesPhases

– Food is pushed into the Food is pushed into the pharynx pharynx by the by the tongue. (voluntary) tongue. (voluntary)

– Tongue blocks the mouthTongue blocks the mouth

– Soft palate closes off the noseSoft palate closes off the nose

– Larynx (Adam’s Apple) rises so the Larynx (Adam’s Apple) rises so the Epiglottis Epiglottis (a flap of tissue) can close the (a flap of tissue) can close the opening of the trachea.opening of the trachea.

EsophagusEsophagusA straight muscular tube that is about 10 inches A straight muscular tube that is about 10 inches long which connects the mouth with the stomachlong which connects the mouth with the stomach

Food takes about 4 to 8 seconds as it passes Food takes about 4 to 8 seconds as it passes through to the stomach.through to the stomach.

Its walls contain smooth muscles that contracts Its walls contain smooth muscles that contracts in wavy motion (in wavy motion (PeristalsisPeristalsis).).

Peristalsis propels food and liquid slowly Peristalsis propels food and liquid slowly down the esophagus into the stomach.down the esophagus into the stomach.

Cardiac Sphincter (ring-like valve) relaxes to Cardiac Sphincter (ring-like valve) relaxes to allow food into the stomach.allow food into the stomach.

PeristalsisPeristalsis

StomachStomach

Churns and grinds together the bolus into Churns and grinds together the bolus into smaller pieces.smaller pieces.

Food is mixed with gastric juices Food is mixed with gastric juices (hydrochloric acid and enzymes) secreted (hydrochloric acid and enzymes) secreted by the stomach walls.by the stomach walls.

HCL helps break down food and kills HCL helps break down food and kills bacteria that came along with the food.bacteria that came along with the food.

StomachStomach

StomachStomachPepsinPepsin – major enzyme; converts – major enzyme; converts proteins into peptides in the presence of proteins into peptides in the presence of HCL.HCL.MucusMucus – lubricates food and protects the – lubricates food and protects the gastric lining from strong digestive juices.gastric lining from strong digestive juices.Converts the bolus into a liquid Converts the bolus into a liquid ((chymechyme)) after 4 hrs of mechanical and after 4 hrs of mechanical and chemical digestionchemical digestionChyme passes through the Chyme passes through the pyloric pyloric sphinctersphincter into the small intestine. into the small intestine.

Movements in StomachMovements in Stomach

Small IntestineSmall IntestineLong (20 ft), coiled tube beneath the Long (20 ft), coiled tube beneath the stomach.stomach.

Has three parts:Has three parts:Duodenum – upper part; about 10 in; connected to Duodenum – upper part; about 10 in; connected to the stomach.the stomach.

– – where the digestive juices where the digestive juices from the pancreas and the liver combine with from the pancreas and the liver combine with chyme making it thin and watery. chyme making it thin and watery.

Jejunum – about 8 ftJejunum – about 8 ft

Ileum – about 12 ftIleum – about 12 ft

Small IntestineSmall IntestineSite of greatest amount of digestion and absorptionSite of greatest amount of digestion and absorption

Small IntestineSmall IntestineTakes about 4 – 8 hrs to complete its journey.Takes about 4 – 8 hrs to complete its journey.

Mucosa (inner wall) – secretes several enzymes Mucosa (inner wall) – secretes several enzymes that acts on the food.that acts on the food.

Where the pancreatic enzymes are emptied into.Where the pancreatic enzymes are emptied into.

Digested nutrients are absorbed through Digested nutrients are absorbed through intestinal walls.intestinal walls.

Absorbed materials cross the mucosa into the Absorbed materials cross the mucosa into the blood then other parts of the body for storage or blood then other parts of the body for storage or further chemical change.further chemical change.

Movement in small intestine:Movement in small intestine:

Peristalsis moves the undigested food to the Peristalsis moves the undigested food to the large intestine. It also spreads out the chyme large intestine. It also spreads out the chyme and mixes it to ease absorption of nutrients.and mixes it to ease absorption of nutrients.

Large IntestineLarge Intestinea.k.a. Colona.k.a. Colon

larger diameter, but shorter (5 ft)larger diameter, but shorter (5 ft)

Water is absorbed from the Water is absorbed from the undigested food making the waste undigested food making the waste harder until it becomes solid.harder until it becomes solid.

Waste stays for an average of 10 – Waste stays for an average of 10 – 12 hours.12 hours.

Large IntestineLarge Intestine

Large IntestineLarge IntestineWaste is pushed into the expanded Waste is pushed into the expanded portion (rectum) of the large intestine.portion (rectum) of the large intestine.

Solid waste stays in the rectum until it Solid waste stays in the rectum until it is excreted through the anus as is excreted through the anus as feces.feces.

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Accessory OrgansAccessory OrgansProduce or store enzymes that helps in Produce or store enzymes that helps in digestion. digestion.

Liver Liver

– Stores sugar and glycogenStores sugar and glycogen

– Produces Produces bilebile (watery, greenish (watery, greenish substance) substance)

– Secretes bile to the gall bladderSecretes bile to the gall bladder

Accessory OrgansAccessory OrgansGall bladder Gall bladder

– Stores bile in between mealsStores bile in between meals

– Secretes bile to the duodenum through Secretes bile to the duodenum through the bile duct during mealtime. the bile duct during mealtime.

dissolves fat into usable smaller partsdissolves fat into usable smaller parts

Accessory OrgansAccessory OrgansPancreasPancreas– Produces a juice that contains Produces a juice that contains

enzymes (enzymes (amylase and insulinamylase and insulin) to ) to break down carbohydrates, fats break down carbohydrates, fats and protein.and protein.

– Secretes the juice into the Secretes the juice into the duodenum through the pancreatic duodenum through the pancreatic duct.duct.

Path of DigestionPath of Digestion

MouthMouth

PharynxPharynx

EsophagusEsophagus

StomachStomach

Small IntestineSmall Intestine

Large IntestineLarge Intestine

AnusAnus

The Excretory SystemThe Excretory System

Gets rid of wastes and other Gets rid of wastes and other substances that the body doesn’t substances that the body doesn’t

need.need.

Two Types of WastesTwo Types of Wastes

Solid Waste – from the Digestive System Solid Waste – from the Digestive System in the form of feces.in the form of feces.Metabolic Wastes – produced by chemical Metabolic Wastes – produced by chemical reactions like respiration, hydrolysis, reactions like respiration, hydrolysis, synthesis and neutralization.synthesis and neutralization.– WaterWater– Carbon DioxideCarbon Dioxide– Salts Salts – UreaUrea

Removal of WastesRemoval of Wastes

Egestion Egestion – removal of digestive waste.removal of digestive waste.

Excretion Excretion – removal of metabolic waste.removal of metabolic waste.

Organs of ExcretionOrgans of Excretion

Skin Skin

–Allows water, salt and urea to Allows water, salt and urea to diffuse from the blood (capillaries) diffuse from the blood (capillaries) into the sweat glands. into the sweat glands.

–Releases sweat from the sweat Releases sweat from the sweat glands through the sweat ducts out glands through the sweat ducts out to the skin pores.to the skin pores.

Organs of ExcretionOrgans of Excretion

Lungs Lungs

– Excretes the waste product of Excretes the waste product of respiration during exhalation.respiration during exhalation.

– Carbon Dioxide and Water Carbon Dioxide and Water Vapor.Vapor.

Organs of ExcretionOrgans of ExcretionLiver Liver

–Part of the digestive, circulatory and Part of the digestive, circulatory and excretory systems.excretory systems.

–Removes excess amino acids from Removes excess amino acids from the body.the body.

–Breaks down the amino acids Breaks down the amino acids through through deaminationdeamination to form the to form the urea which is excreted in the urine.urea which is excreted in the urine.

Organs of ExcretionOrgans of Excretion

KidneysKidneys

– Major excretory organs of the body Major excretory organs of the body which removes most of the body which removes most of the body wastes.wastes.

– Purify blood by filtering out water, salts, Purify blood by filtering out water, salts, digested food particles and urea in the digested food particles and urea in the form of urine.form of urine.

– Urine passes out through the urinary Urine passes out through the urinary tract.tract.

Urinary SystemUrinary System

Excretion of UrineExcretion of Urine

KidneyKidney

Ureter – a tube that transports urine to the Ureter – a tube that transports urine to the urinary bladder.urinary bladder.

Urinary Bladder – a sac of tissue that has Urinary Bladder – a sac of tissue that has the ability to expand as it fills with urine.the ability to expand as it fills with urine.

Urethra – a tube at the bottom of the Urethra – a tube at the bottom of the bladder where urine passes out of the bladder where urine passes out of the body.body.

AssignmentAssignment

Research and make a table about the different Research and make a table about the different Digestive Enzymes.Digestive Enzymes.

Follow the following format:Follow the following format:

Digestive Digestive GlandGland EnzymesEnzymes SubstratesSubstrates ProductsProducts

Salivary GlandsSalivary Glands

Gastric GlandsGastric Glands

PancreasPancreas

Intestinal Intestinal GlandsGlands