Nutrition

� the activities by which organisms obtain and process material needed for

energy, growth, repair, and to maintain

homeostasis� humans are ____________ — they have � humans are ____________ — they have

to get their food from somewhere, they

cannot make it on their own.� humans need food; which can be described as either _____________ or

_____________

Why do humans need food?

� Animals make energyavailable using:

� food (glucose)

� oxygen

� Animals build bodies

food

� Animals build bodiesusing:

� food for raw materials� amino acids, sugars, fats, nucleotides

�ATP energy for synthesis

O2

ATP

mitochondria

How do some animals get their food?

filter feeding living in your food

fluid feeding bulk feeding

NUTRIENTS ROUGHAGE

� ____________*

� ____________*

� ____________*

� ____________¤

� ____________¤

� ____________¤

complex carbos that

cannot be broken down but

is necessary for the

digestive system to work;

found in _______________

_______________________� ____________¤ _______________________

*carbos, lipids, and proteins MUST be _______

first; vitamins minerals and water can be

absorbed without digestion

¤ vitamins, minerals, and water are not used for

energy or building structures, but are needed!

Different diets; different lives� All animals eat other organisms

�Herbivores

� eat mainly plants

� gorillas, cows,

rabbits, snails

�Carnivores

� eat other animals

� sharks, hawks, spiders, snakes

�Omnivores

� eat animals & plants

� cockroaches, bears, raccoons, humans

� humans evolved as hunters, scavengers & gatherers

1. Ingestion: ____________________________2. Digestion: ____________________________ mechanically (physically) and chemically (enzymatic hydrolysis)

3. Absorption: __________________________ _____________________________________

The human digestive system is responsible for:

_____________________________________

4. Elimination: __________________________ _____________________________________

the human digestive system (also called

alimentary canal) is a one-way

gastrointestinal tract with two openings

Other gastrointestinal tracts…

Everybody’s got one!

Human digestive

system

food is moved in the correct direction by slow

muscle contractions called _______________

Ingestion

1) oral cavity (mouth)� __________ of food

occurs here� contains teeth, tongue and openings

of the salivary glands

A.A. teeth� used to break down food physically

( ) to increase surface area for digestive enzymes ( )

IngestionB. tongue

� moves food around mouth so that the teeth work more effectively

� helps mix food with saliva, and moves food to the back of the mouth for

C. salivary glands� secretes ______ into digestive system

which contains the hydrolytic enzyme _________ which digests starch

food to the back of the mouth for swallowing

� ________________________________ ___________________________________

Swallowing (& not choking)

2) esophagus� when you swallow, food goes into this

tube then to the stomach

� mucus is secreted here to lubricate

the food to ‘slide down’ easier

� __________________________

__________________________

Swallowing (& not choking)

A. epiglottis� when you swallow, this ___________

________________________________

(trachea) so that food will not go into

the lungs

� this momentarily stops

breathing!

3) stomach� a thick-walled,

muscular sac

(organ) whose main

job is to liquify the

food ingested

� the lining of the

stomach contains stomach contains

gastric glands

which secrete

gastric juices which

contain:a) gastric proteaseb) hydrochloric acidc) mucusd) water

3) stomach� gastric protease—an enzyme which begins

the digestion of ______________

� the hydrochloric acid (HCl) lowers the pH of the stomach… not to break down food, but to provide the ____________________ ____________________________________!

stomach

pepsin (protease)

pH

reaction

rate

7

3) stomach� the _________

protects the stomach walls from being eaten away away

� the water is used for chemical digestion ( __________ )

4) small intestine� partially digested food

then enters the small intestine

� is a long tube (over 20 feet!) where ______

____________________________________

Digestion/Absorption

____________________________________

� intestinal glands line the intestinal walls

and secrete lipase, maltase, and intestinal

protease to __________________________

� food is digested along with the help of

accessory organs

Accessory Digestive Organs A. liver

� produces ______

� ___________________; however it does

break down fats—big globs to little

‘globblets’—called ____________________

bile contains

colors from old red

blood cells

collected in liver =

iron in RBC rusts &

makes feces brown

Accessory Digestive Organs B. gall bladder

� ____________________________________C. pancreas

� secretes enzymes into the small intestine

such as intestinal amylase, intestinal

protease, and lipase

the pancreas

also produces

insulin and

glucagon to

regulate blood

sugar levels

protease, and lipase

5) large intestine� takes the undigested food

and ___________________

______________________

� solidifies the liquid wastes

into solid feces (includes

Absorption/Egestion

into solid feces (includes

undigested and

indigestible material—

roughage, bacteria, bile,

mucus, worn out cells)

� ______________________

______________________

You’ve got company!

� Living in the large intestine is a community of helpful bacteria

� Escherichia coli (E. coli)

� produce vitamins

� vitamin K; B vitamins� vitamin K; B vitamins

� generate gases

� by-product of bacterial metabolism

�methane, hydrogen sulfide

A. appendix� has no known function in modern humans,

however, if inflammed, can be life

threatening!

Vestigial organ B. rectum� where solid wastes are temporarily stored

C. anus� opening in the alimentary canal where

feces are removed (egested)

Different diets; different bodies

� Adaptations of herbivore vs. carnivore

� teeth

� length of digestive system

Teeth

� Carnivore

� sharp ripping teeth

� “canines”

� Herbivore

wide grinding �wide grinding teeth

�molars

� Omnivore

� both kinds of teeth

Length of digestive system

� Carnivores

� short digestive

systems

� protein easier to

digest than cellulose

� Herbivores & omnivores� Herbivores & omnivores

� long digestive

systems

� harder to digest

cellulose (cell walls)

� bacteria in intestines

help

REVIEW OF CHEMICAL DIGESTION

_________

+

H2O

� ____________________________________________________________________

REVIEW OF CHEMICAL DIGESTION� in organisms, this process is regulated by hydrolytic enzymes

a protease

� remember, the first part of the enzyme’s name tells you what the enzyme works

on ( _____________ )!

a protease

Digesting important polymers

glucose – glucose – glucose – glucose – glucose

Carbohydrates = digested to ______________

Proteins = digested to _______________Proteins = digested to _______________

Lipids = digested to _____________________

aminoacid

aminoacid–

aminoacid–

aminoacid–

aminoacid–

aminoacid–

ABSORPTION OF DIGESTED MATERIALS� ____________________________________________________________________________

� the intestinal wall is lined with millions of ______ which ___________________________

ABSORPTION OF DIGESTED MATERIALS� in each individual villi (shown below with their microvilli) there are capillaries (small blood vessels) and other small ducts (pipes) of the lymphatic system called lacteals

ABSORPTION OF DIGESTED MATERIALSI. CARBOHYDRATES:

� glucose (a _______________ ) is absorbed into the bloodstream by the capillaries

� it there can be sent to the liver to be stored temporarily as _________________ ____________________________________

when the body needs energy (more � when the body needs energy (more glucose) the glycogen can be broken back down and released into the bloodstream

ABSORPTION OF DIGESTED MATERIALS

II. PROTEINS:

� ____________________________________

____________________________________

� amino acids can be stored in the liver until

they are needed

� there are 20 different � there are 20 different

amino acids that

humans need to

make up proteins

� __________________

__________________

__________________

__________________

� Need to make sure you get enough protein

� 20 amino acids to make protein

� 12 amino acids humans can produce

� 8 we have to eat = “essential amino acids”

� Grains (like corn) have 6 (missing 2)

� Beans (like soybean & red beans)

Vegetarian Diets!

� Beans (like soybean & red beans)

have 6 (missing different 2)

� mix beans & grainsfor complete group of

amino acids

� rice & beans

� taco/tortilla & beans

� tofu & rice

� peanut butter & bread

ABSORPTION OF DIGESTED MATERIALS

III. LIPIDS:� the building blocks of lipids fatty acids

and glycerol are absorbed into the ______

and are passed along to the lymph (other

transport fluid—besides the blood)

� they _________________________ through � they _________________________ through

this other set of pipes

Saturated fats

� ________________________________(

butter, grease)

� lots of hydrogen atomsatoms

� too much in the diet can be linked

to ______________

________________

Unsaturated fats

� ____________________________

(oils)

� less hydrogen atoms than atoms than

saturated fats

� does not appear to be linked to

cardiovascular

disease

Saturated vs. unsaturatedsaturated unsaturated

1) Ulcers:� ____________________________________

� used to think ulcers were caused by stress

� now know ulcers caused by bacterial

infection of stomach

MALFUNCTIONS OF THE HUMAN

DIGESTIVE SYSTEM

infection of stomach� H. pylori

� now cure with antibiotics

2) Appendicitis: ( ___ = inflammation)� ____________________________________

� can be life threatening if it ruptures

3) Gallstones:� ________________________________________

________________________________________

� affects secretion of bile into small intestine

4) Constipation: � a condition in which the large intestine is

emptied with great difficulty due to:

5) Diarrhea: � a gastrointestinal disturbance which results

in:

� ____________________________________________

� ____________________________________________

� can result in severe dehydration!

� ____________________________________________

� ____________________________________________