HUMAN HUMAN ANATOMY & ANATOMY & PHYSIOLOGYPHYSIOLOGY

Human Digestive Human Digestive SystemSystem

Animation: Organs of Digestion

Warm-Up - journalWarm-Up - journal

1)1) Write down in correct sequence all Write down in correct sequence all the organs (at least 5) through the organs (at least 5) through which their food passes as it travels which their food passes as it travels along the digestive tract. along the digestive tract.

2)2) Then try to list any glands or organs Then try to list any glands or organs that are found along the digestive that are found along the digestive tract, but through which food does tract, but through which food does not pass.not pass.

Following the Digestive Following the Digestive TrailTrail

MouthMouth

EsophagusEsophagus

StomachStomach

Small IntestineSmall Intestine

Large IntestineLarge Intestine

PancreasPancreasLiverLiver

Gall BladderGall Bladder

Accessory Organs

Accessory Organs

TongueTongueEpiglottisEpiglottis

Pharynx (throat)Pharynx (throat)Salivary glandsSalivary glands

The Need for DigestionThe Need for Digestion

Major FunctionsMajor Functions::1. Ingestion - taking in food1. Ingestion - taking in food

2. Digestion-ability to process 2. Digestion-ability to process food in the body into a form that food in the body into a form that can be absorbed and used or can be absorbed and used or excreted.excreted.

3. Absorption -pulling nutrients 3. Absorption -pulling nutrients out of the food, occurs in the out of the food, occurs in the small intestinesmall intestine

4. Egestion-removal of 4. Egestion-removal of undigested foodundigested food

Overview: Food processing Overview: Food processing occurs in four stagesoccurs in four stages

Figure 21.2

1 INGESTION 2 DIGESTION 3 ABSORPTION 4 ELIMINATION

Food

Mechanicalbreakdown

Piecesof food

Chemical breakdown(enzymatic hydrolysis)

Smallmolecules

Nutrientmoleculesenter bodycells Undigested

material

A. PurposeA. PurposeProvides energy to stay aliveProvides energy to stay alive

Process of breaking food particles down into Process of breaking food particles down into molecules small enough to be absorbed by cellsmolecules small enough to be absorbed by cells

To help build cells, tissues and organsTo help build cells, tissues and organs

ATP energy for synthesisATP energy for synthesis

O2

food

ATP

mitochondria

B. Why?B. Why?

1.1. MECHANICAL MECHANICAL Changes the physical form of food (physical

changes) – Mouth- teeth chew (masticate) & crush Mouth- teeth chew (masticate) & crush

foodfood– stomach muscles (rugae) grinds & churnsstomach muscles (rugae) grinds & churns

2. CHEMICAL2. CHEMICAL Changes the chemical composition of

food into a new substance with the aid of digestive enzymes ( chemical changes)..

C. Types of digestionC. Types of digestion

Review: Nutrition Review: Nutrition Food broken down to usable nutrients and absorbed into the Food broken down to usable nutrients and absorbed into the

bloodstream. bloodstream. – They are used by the body for metabolism, building and They are used by the body for metabolism, building and

repairrepair Nutrients include carbohydrates, proteins, lipids, vitamins, Nutrients include carbohydrates, proteins, lipids, vitamins,

minerals and water. minerals and water. Carbohydrates Carbohydrates

– Broken down into Broken down into monosaccharidesmonosaccharides – Body’s main source of energy. Body’s main source of energy.

ProteinsProteins– Broken down to Broken down to amino acids amino acids – Supply the raw materials for growth and repair. Supply the raw materials for growth and repair.

Lipids Lipids – Broken down to 3 Broken down to 3 fatty acids and glycerolfatty acids and glycerol– They are used to make steroid hormones, cell They are used to make steroid hormones, cell

membranesmembranes– Store energyStore energy

NutrientNutrient End product End product (building blocks)(building blocks)

TransportTransport

CarbohydratCarbohydratee

Simple sugarsSimple sugars

(glucose & (glucose & fructose)fructose)

Diffusion Diffusion (w/out energy (w/out energy & high to low)& high to low)

ProteinsProteins Amino AcidsAmino Acids DiffusionDiffusion

Lipids (Fats)Lipids (Fats) 3 Fatty Acids3 Fatty Acids

1 glycerol1 glycerolDiffusion &Diffusion &

Active Active transport (with transport (with energy, low to energy, low to high)high)

Artery

To the cellsIN: Nutrients & O2

OUT: CO2

Draw/label this

D. Gastro Intestinal TractD. Gastro Intestinal Tract How is the digestive system similar to How is the digestive system similar to

a vacuole in a one celled organism?a vacuole in a one celled organism?

1. One celled organism (ameoba, parameciu, euglena)- it is intracellular (vacuoles release digestive enzymes)

2. Humans- it is Extracellular (outside the cells then absorbed into the bloodstream)

Reference: RB: pg 13 table 1-1

Review: Which type of digestion (mechanical or chemical)?

1) Chewing a saltine?2) Saliva breaking the saltine down

into molecules of glucose?3) Your tongue breaking pieces of a

hamburger apart?4) Pepsin (an enzyme) in your stomach

breaking the hamburger into amino acids?

Digestion System video clip –click on imageDigestion biology Animation

Your Turn…learn the functions of the Your Turn…learn the functions of the organsorgans

Group Activity - match function card with Group Activity - match function card with the organs in your activity packetthe organs in your activity packet

As a Pair - Go to: My computer As a Pair - Go to: My computer Assignments (drive R:) KE Connelly Assignments (drive R:) KE Connelly Living Environment Digestion ppt Living Environment Digestion ppt

Return to seats and check your cards – Return to seats and check your cards – rearrange if necessary to make it correctrearrange if necessary to make it correct

Write the functions in your chartWrite the functions in your chart

Following the Digestive Trail – a one way tubeFollowing the Digestive Trail – a one way tube

MouthMouth

EsophagusEsophagus

StomachStomach

Small IntestineSmall Intestine

Large IntestineLarge Intestine

PancreasPancreasLiverLiver

Gall BladderGall Bladder

Accessory Organs

Accessory Organs

TongueTongueEpiglottisEpiglottis

Pharynx (throat)Pharynx (throat)Salivary glandsSalivary glands

MouthMouth Mechanical digestion begins Mechanical digestion begins

here - chere - chewing/crushing hewing/crushing foodfood

Salivary glands secrete Salivary glands secrete salivasaliva, which , which moistens moistens and lubricates food and lubricates food for for swallowing. swallowing.

Saliva contains amylases Saliva contains amylases (enzymes), which start (enzymes), which start the the chemical breakdown chemical breakdown of of carbohydrates carbohydrates (starch)(starch)..

All thatin spit!

Following the Trail 1Following the Trail 1

EsophagusEsophagus Muscular tube (aka: food tube) As we swallow, we push food

along the tube until the food reaches our stomach. This process of pushing down the food uses muscular wave-like contractions is called peristalsis– Peristaltic contractions

transport food to the stomach and allow a person to swallow even if he/she are upside down.

– Peristalsis biology Animation Click Here for animationClick Here for animation

Following the Trail 2Following the Trail 2

StomachStomachFood (bolus) mixes with acidic

gastric juices (HCl) and an enzyme called pepsin to form chyme.

The chemical digestion of proteins begins in the stomach. Mechanical digestion continues-stomach

grinds & churns the bolus https://www.youtube.com/watch?

v=hBaE22s64IUBut the stomach is made out of protein!What stops the stomach from digesting itself?

mucus secreted by stomach cells protects stomach lining

Following the Trail 3Following the Trail 3

Small Small intestineintestine• Secretes digestive enzymes to begin breaking down fats

• Continues and completes ALL chemical digestion of carbs, proteins and fats

• Absorbs nutrients into the blood stream• S.I. lined with fingerlike

projections, called villi, which, in turn, are covered by microvilli which increase surface area

• The villi contain capillaries and lymphatic vessels for the absorption of nutrients

• Nutrients move into blood stream by what process (Think H to L!)? DIFFUSION!!!!!!!!!

Following the Trail 4Following the Trail 4 FYI- the small intestine has 3

parts:

Absorption through Absorption through increases surface area increases surface area for absorptionfor absorption

SMALL INTESTINES6 meters long,but can stretch

to cover a tennis court

A Closer look at the A Closer look at the villi & microvilli villi & microvilli of the small instestineof the small instestine

Cross-Section of small intestine Villi Microvilli

Food Food DOES NOTDOES NOT pass through these pass through these organsorgans

These organs These organs secretesecrete substances to aid in substances to aid in digestiondigestion

Following the Trail 4 cont….the accessory Following the Trail 4 cont….the accessory (helper) organs(helper) organs

PancreasPancreas Found under the Found under the

stomachstomach

Secretes enzymes (lipase, Secretes enzymes (lipase, amylase, protease) into amylase, protease) into the small intestine the small intestine

Secretes a base into S.I. Secretes a base into S.I. to neutralize stomach to neutralize stomach acidacid WHY??WHY??– So digestive enzymes So digestive enzymes

aren’t denatured and aren’t denatured and can work!can work!

Makes hormones insulin & Makes hormones insulin & glucagon to balance blood glucagon to balance blood sugar levels to maintain sugar levels to maintain homeostasishomeostasis

smallintestine

pancreas

Following the Trail 4 cont….Following the Trail 4 cont….

liver

pancreas

liver

Balancing Blood Sugar Balancing Blood Sugar levelslevels

blood sugar level

insulin

body cells takeup sugar

from blood

liver storessugar

reducesappetite

glucagon

pancreas

liver releases

sugartriggershunger

high

low

Feedback

Homeostasis

LiverLiver Produces & secretes Produces & secretes

bile to emulsify bile to emulsify ((breaks up) fatsbreaks up) fats

stores bile & releases to the small intestine

FYI - bile contains colors from old red blood cells collected in liver =iron in RBC rusts & makes feces brown

FYI - bile contains colors from old red blood cells collected in liver =iron in RBC rusts & makes feces brown

Following the Trail 4 cont….Following the Trail 4 cont….

Gall Gall Bladder Bladder

• NO digestion occurs hereNO digestion occurs here• WATER and vitamin K gets reabsorbedWATER and vitamin K gets reabsorbed from from

undigested chymeundigested chyme• Lined with bacteria (Lined with bacteria (E. coli) E. coli)

• Holds undigested or unabsorbed food Holds undigested or unabsorbed food wastes (feces)wastes (feces)

• mainly cellulose from plants called roughage mainly cellulose from plants called roughage or fiber- keeps everything moving & cleans or fiber- keeps everything moving & cleans out intestinesout intestines

• Masses of bacteriaMasses of bacteria

• Final stop for undigested material…Final stop for undigested material…eliminate eliminate fecesfeces

Large intestines Large intestines (colon)(colon)

Following the Trail 5Following the Trail 5

RectumRectum

AnusAnus

So don’t forget to wash

your hands!

E. Digestive Homeostasis Disorders

1. Stomach 1) Mucus that prevents stomach from digesting itselfa) Peptic ulcer occurs when layer of mucus fails (open sores)open sores)b) Gastric juices reach wall of stomach and begin to break down (painful)Ulcers biology Animation

2) TreatmentBefore: Antacid would reduce amount of acid in stomach but would returnRecently: Ulcer is an infection by acid resistant bacteria Helicobacter pyloriTreatment – antibiotics

Body Invaders: Digestive Problems : Video : Discovery Health

2. Appendix No function – may have once been used to digest plants (vestigal organ)Appendicitis – inflammation of the appendix – caused by E. Coli bacteria

3. Large Intestine Constipation- too much too much waterwater

reabsorbed from the feces reabsorbed from the feces Diarrhea-too little water reabsorbed too little water reabsorbed

from the of feces; prolonged diarrhea from the of feces; prolonged diarrhea can cause can cause dehydrationdehydration of body of body tissues.tissues.

4. Colon Cancer One of the most common

types of cancers in North America

Colon – section before the rectum on lg. Intestine

Cause:– Diet low in fiber causes

feces to move too slow through colon

– Hereditary predisposition– https://www.youtube.com/watch?v=hRC37QTiZg8

– https://www.youtube.com/watch?v=QokyQOftWGQ

5. Gallstones5. Gallstones small hard stones made small hard stones made

of of cholesterolcholesterol that that collect in the collect in the gallbladder.gallbladder.

Due to a high saturated Due to a high saturated fat dietfat diet

hereditaryhereditary

Heart Burn Heartburn Heart Burn Heartburn biology Animationbiology Animation

Digestive System Fill-InDigestive System Fill-In

Digestive System Fill-In Digestive System Fill-In AnswersAnswers