6.1 A The Digestive System · 2018. 7. 6. · U4: Villi increase the surface area of the epithelium...

6.1 – A – The Digestive System

Skills

S1: Production of an annotated diagram of the digestive system.

IB BIO – 6.1

Key Terms

Digestive System

Alimentary canal

The Digestive System

Breaks down food into small

particles, which can be

absorbed by the body.

Structures form a ‘tube’ called

the alimentary canal.

2

https://www.britannica.com/science/alimentary-canal

Skills


IB BIO – 6.1

Key Terms

Digestive System

Alimentary canal

The Digestive System

Major structures include:

• Mouth

• Esophagus

• Stomach

• Small Intestine

• Gall Bladder

• Pancreas

• Liver

• Large Intestine

3


Skills


IB BIO – 6.1

Key Terms

Mouth

Esophagus

Stomach

Structures of the Digestive System

• Mouth - chewing mechanical

digests food, which increases

surface area

• Esophagus – transports food

to stomach via peristalsis

• Stomach – churns food and

has acidic environment that

kills pathogens and activates

enzymes.

4

http://www.roshdypharmacies.com/images/healthcare/

Skills


IB BIO – 6.1

Key Terms

Small Intestine

Large Intestine

Liver

Gall Bladder

Pancreas

Large Intestine

• Small Intestine – has

enzymes that chemically

digest biomolecules. Wall

absorbs small molecules.

• Liver – secretes bile

• Gall Bladder – stores and

regulates bile

• Pancreas – secretes lipase,

amylase and protease

• Large Intestine - absorbs

water and compacts waste to

form feces

5

http://blogs.egusd.net/eettalfonso/files/2014/04/

Structures of the Digestive System

REVIE

WIB BIO – 6.1 6

https://i.ytimg.com/vi/48XO9iyZevs/maxresdefault.jpg

Identify and

state the

function

6.1 – B – Small Intestine & Enzymes

Understandings

U1: The contraction of circular and longitudinal muscle of the small intestine mixes the food with enzymes and moves it along the gut.

IB BIO – 6.1

Key Terms

Peristalsis

Peristalsis

Peristalsis is a wave of muscle

contractions that pushes food

through the gut and mixes it with

enzymes.

8

http://www.bodecology.com/images/Body411/small-intestine.jpg

http://gireviewers.com/wp-content/uploads/2013/08/

Circular muscles contract to prevent food from moving backwards.

Longitudinal muscles contract to push food forward down the small

intestine tract

Understandings


IB BIO – 6.1

Key Terms

Peristalsis

9

http://pathwayofasandwich.weebly.com/uploads/1/5/0/6/15062092/6093572_orig.jpg

Understandings


IB BIO – 6.1

Key Terms

Digestive System

Alimentary canal

10

https://www.youtube.com/watch?v=Ujr0UAbyPS4

In the digestive system, accessory organs are those that are not

part of the alimentary canal, but that aid in digestion. They

include:

• Liver

• Gall Bladder

• Pancreas

In this section,

we will be focusing

on the role

that the pancreas

plays.

Understandings

U2: The pancreas secretes enzyme into the lumen of the small intestine.

Guidance

G1: Student should know that amylase, lipase and an endopeptidase are secreted by the pancreas.

IB BIO – 6.1 11

https://upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Diagram_showing_the_position_of_the_pancreas_CRUK_356.svg/

Understandings

U2: The pancreas secretes enzyme into the lumen of the small intestine.

Guidance

G1: Student should know that amylase, lipase and an endopeptidase are secreted by the pancreas.

IB BIO – 6.1 The pancreas is an accessory organ that secretes enzyme ‘juice’

into the small intestine. These digestive enzymes include:

- amylase

- lipase

- endopeptidase

These enzymes

are released into

a small section of

the intestine called

the duodenum.

12

www.londonbridgehospital.com/userfiles/pancreas-text.jpg

Understandings

U3: Enzymes digest most macromolecules in food into monomers in the small intestine.

Key Terms

Hydrolysis

IB BIO – 6.1 Recall that, enzymes break

macromolecules into

monomers that can be

absorbed by the intestinal

wall. This is done via

hydrolysis.

The left shows how

sucrase breaks sucros

down into its subunits.

13

http://sciencelearn.org.nz/var/sciencelearn/storage/images/contexts/digestion-chemistry/

Understandings


Key Terms

Hydrolysis

IB BIO – 6.1 14

https://classconnection.s3.amazonaws.com/902/flashcards/2815902/

Monomers resulting from enzyme digestion are used to synthesize

molecules throughout our body. Some example are shown below.

Enzymes used in

digestion include:

• Protease/peptidase

• Amylase

• Nuclease

• Lipase

Understandings


Guidance

G2: Students should know that starch, glycogen and nucleic acids are digested into monomers and that cellulose remains undigested.

IB BIO – 6.1 Enzymes

• Protease/peptidase digest

proteins into amino acids

• Amylase digests starches

& glycogens into simple

sugars

• Nuclease digests nucleic

acids into nucleotides

• Lipase digests lipids into

fatty acids

15

https://classconnection.s3.amazonaws.com/902/flashcards/2815902/

Understandings


Guidance

G2: Students should know that starch, glycogen and nucleic acids are digested into monomers and that cellulose remains undigested.

IB BIO – 6.1 However, cellulose polymers remain undigested and are passed

through the digestive tract. This has the result of pushing

substances through the intestine and so is a primary component of

dietary fiber supplments.

16

http://alevelnotes.com/content_images/i18_image001.gif

REVIE

WIB BIO – 6.1

http://watcut.uwaterloo.ca/webnotes/Metabolism/graphics/digestive-system-5f781.png

Small Intestine & Enzymes

REVIE

WIB BIO – 6.1

1. State the function of the small intestine.

2. Outline the role of peristalsis in digestion.

3. Outline the role of enzymes in digestion.

4. List the types of enzymes produced by the

pancreas.

5. Identify the molecule not absorbed by the

epithelium cells.

18

6.1 – C – Villi & Absorption

Understandings

U4: Villi increase the surface area of the epithelium over which absorption is carried out.

IB BIO – 6.1

Key Terms

Absorption

Absorption is the process of

taking substances into cells

and mainly occurrs in the

small intestine. The rate of

absorption depends on the

surface area available.

20

http://www.bbc.co.uk/bitesize/ks3/science/organisms_behaviour_health/diet_drugs/revision/6/

Understandings


IB BIO – 6.1

Key Terms

Villi

Villi are finger-like projections of the mucosa that the inner

intestine wall. They increase the surface area by a factor of 10.

21

http://www.thepatientceliac.com/wp-content/uploads/2013/08/villi.jpg

Understandings


IB BIO – 6.1

Key Terms

Villi

Epithelium

22

https://image.winudf.com/68/56e215ffa302e2/screen-3.jpg

Villi are well-adapated to facilitate absorption as a result of of

their thin epithelium and network of capillaries.

Understandings


IB BIO – 6.1

Key Terms

Villi

Epithelium

23

http://biology-

igcse.weebly.com/uploads/1/5/0/7/15070316/7856072_orig.p

ng

Villi are well-adapated to facilitate absorption as a result of of

their thin epithelium and network of capillaries.

Understandings

U5: Villi absorb monomers formed by digestion as well as mineral ions and vitamins.

IB BIO – 6.1 As digestion takes place, villi

absorb the monomers that result

as well as mineral ions and

vitamins. These include:

• Monosaccharides (glucose,

fructose, etc.)

• Amino Acids

• Fatty Acids

• Nitrogenous bases

• Calcium, Potassium, Sodium

• Vitamins like ascorbic acid

24


Understandings


IB BIO – 6.1 25

http://www.slideshare.net/roszelan/bio-f4-absorption

Villi Absorption

Understandings


U6: Different methods of membrane transport are required to absorb different nutrients.

IB BIO – 6.1 26

http://biology-igcse.weebly.com/uploads/1/5/0/7/15070316/3669884_orig.png

Since villi are responsible for absorbing a variety of nutrients, a variety of transport methods are needed, including both active and passive:

• Simple diffusion

• Facilitated diffusion

• Exocytosis

• Protein pumps

• Co-transportation

Understandings



IB BIO – 6.1

http://bio100.class.uic.edu/lectures/glucose-transport01.jpg

27Molecules

pass through:

• Lumen

• Epithelium

• Cell interior

• Interstitial

space

• Capillary

wall

Understandings



IB BIO – 6.1 28

http://www.austincc.edu/apreview/NursingPics/Carbsmallintesttine.jpg

Glucose Transport

Glucose is transported from the lumen to the capillaries through a

combination of Na+/K+ pumps (active) and Na+/glucose co-

transporter proteins (passive).

Understandings



IB BIO – 6.1 29

https://opentextbc.ca/anatomyandphysiology/wp-content/uploads/sites/142/2016/03/2431_Lipid_Absorption.jpg

Fatty Acid Transport

• Triglycerides are broken

down into fatty acids, which

diffuse into cells

• Inside, they combine with

cholesterol and proteins to

form lipoproteins

• The lipoproteins are

excreted via exocytosis

• They then enter the lacteal

and are carried away from

the intestines

Skills

S2: Identify tissue layers in transverse sections of the small intestine viewed with a microscope or in a micrograph

Guidance

G3: Tissue layers should include longitudinal and circular mucosa and epithelium

IB BIO – 6.1 Intestine Micrograph

When observing intestine tissue through a micrograph, four distinct

layers are visible:

• Mucosa

• Sub-mucosa

• Muscle Layers

- longtiudinal

- circular

• Serosa

30

http://anatomy.kmu.edu.tw/BlockHis/Block10-1/block10-1_23.jpg

REVIE

WIB BIO – 6.1

http://sciencelearn.org.nz/var/sciencelearn/storage/images/contexts/digestion-chemistry/sci-media/images/

Villi & Absorption

REVIE

WIB BIO – 6.1

1. Describe the structure of villi and how it

relates to their function.

2. Identify the types of molecules absorbed by

villi.

3. Outline different methods of transport used

to absorb nutrients.

4. Outline the four primary tissue layers that

can be seen in a longitudinal intestine

micrograph.

32

6.1 – D – Starch Digestion

Applications

A1: Processes occurring in the small intestine that result in the digestion of starch and transport of products of digestion to the liver

IB BIO – 6.1 Starch Digestion

Starch is a macromolecule that is made in plants by joining α-

glucose molecules. Because it is large, it must be digested by

enzymes in the intestine in order to be absorbed.

34

http://www.nutrientsreview.com/wp-content/uploads/2014/09/Starch.jpg

Applications


IB BIO – 6.1

A series of enzymes

break down starch into

glucose monomers,

which can be absorbed

be epithelium cells.

These enzymes

include:

• Amylase

• Maltase

• Dextrinase

• Glucosidase

35

http://csidcares.org/assets/D.O.S.png

Starch Digestion

Applications


IB BIO – 6.1 Glucose Transport 36

http://www.austincc.edu/apreview/NursingPics/Carbsmallintesttine.jpg

1. Na+/K+ pumps decrease internal concentration of Na+

2. Na/glucose co-transporters

transport glucose into the

cells along with Na+

3. Channel proteins allow

glucose to diffuse out

of the other side

of the cell

4. Glucose then

diffuses into

capillaries

through small

pores

Applications


IB BIO – 6.1 Storage in Liver

Glucose absorbed in the capillaries travels to the liver through the

hepatic vein. In the liver, cells convert extra glucose into glycogen

37

http://humanphysiology2011.wikispaces.com/file/view/liver.jpg/222203358/403x357/liver.jpg

which can be stored for later

use.

REVIE

WIB BIO – 6.1 Outline the digestion of starch molecules and the

transport of products to the liver.

http://archive.cnx.org/resources/9596c1774a9b3f3dc39a42f30079e8223d370244/2427_Carbon_Digestion1.jpg

38

6.1 – E – Dialysis Tubing Experiments

Applications

A2: Use of dialysis tubing to model absorption of digested food in the intestine

IB BIO – 6.1

Key Terms

Dialysis Tubing

Semi-permeable

Dialysis Tubing

Semi-permeable membrane

that can be used to model the

absorption of molecules in the

intestine.

The membrane contains small

pores that starch molecules are

able to pass through.

By filling the tubing with a

solution, indicators can show

whether molecules are able to

be absorbed.

40

http://www.carolina.com/images/product/large/684202.jpg

http://mequi.weebly.com/uploads/5/3/8/0/5380621/dialysis_tubing_experiment.pdf

Applications


IB BIO – 6.1

Key Terms

Dialysis Tubing

Iodine Indicator

When iodine is the in the

presence of starch, it turns a

dark blue/purple. When it is in

the presence of glucose, no

change is seen.

Iodine is able to pass through

the dialysis tubing and so is

able to react (or not react) with

the contents.

41

http://3.bp.blogspot.com/-3aSkuTf9aoM/UF2_hNOHuvI/AAAAAAAADbA/XE3Kzb1udFc/s1600/

Applications


IB BIO – 6.1

Key Terms

Dialysis Tubing Experimental Setup

The setup in the diagram shown below can be used to determine the

effects of an enzyme on a substrate. If iodine was added to both

beakers, what would you expect to see?

42

http://bio662.dyndns.info/s3b/b3n/b3n01FoodNutrition/images/EffectOfSalivaOnStarch_e.png

Applications


IB BIO – 6.1

Key Terms

Explanation of results 43


starch starch

Starch alone

Applications


IB BIO – 6.1

Key Terms

Explanation of results 44


starch+

saliva

starch +

saliva

Starch + Saliva (contains amylase)

REVIE

WIB BIO – 6.1

Design an experiment that would determine

the effect of amylase concentration on the rate

of diffusion in dialysis tubing filled with a starch

solution.

45

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6.1 A The Digestive System · 2018. 7. 6. · U4: Villi increase the surface area of the epithelium...

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