NutritionHow the body converts food into nutrients and wasteExcretion/AP Biology – F Period – May 1, 2011Mary Boci, Stephanie Lai, Diana Nguyen

Nutrition Facts:• Animals fit into 3 dietary categories:Herbivores – consumes mainly autotrophsCarnivores – consumes mainly other animalsOmnivores – generally consumes both plants and animals

• Nutritional needs must provide:1) Fuel for all cellular work of the body2) Organic raw materials used in biosynthesis3) Essential nutrients

• Four main feeding mechanisms of animals1) Suspension feeders – sift small food particles from the water2) Substrate feeders – live on or in their food source, eating

their way through the food3) Fluid feeders – suck nutrient-rich fluid from a living host4) Bulk feeders – eat relatively large pieces of food

Images obtained from these websites: http://mycozynook.com/102RGCh20OH.htm andhttp://bioh.wikispaces.com/Digestion+and+Nutrition

Suspension feeder

Substrate Feeder Fluid Feeder

Bulk Feeder

Nutrition Facts cont..• Each animal requires a specific amount of calories

depending on weight, size, and species.– Undernourishment – diet deficient in calories– Overnourishment – diet with excess intake of calories

• Excess food is stored as fat• Often leads to obesity

• An animal’s diet must also supply essential nutrients– Malnourished – diet missing one or more essential

nutrients– Essential nutrients – organic materials in preassembled

form that the animal cannot make on its own• Essential Amino Acids

– Eight are essential in adult humans; nine for infants (histidine)

– Provides proteins– Some external sources are meat, eggs, cheese, and

certain animal products

Nutrition Facts cont.• Essential Fatty Acids

– Certain unsaturated fats– Makes phospholipids found in membranes

• Vitamins– Organic molecules required in small amounts compared

to essential amino acids and fatty acids– 13 identified vitamins– Fat-soluble – A,D, E, and K– Water-soluble – B and C

• Minerals– Inorganic nutrients, usually required in small amounts– Requirements vary with species– Ex. Humans need calcium (builds bones and used for

muscle and nerve function), phosphorus(used in ATP and nucleic acids), iron(found in blood), magnesium, iodine(make thyroid hormones), sodium, potassium, chlorine, etc.

Human Digestive System

The Digestive System is important in absorbing external nutrients into the body.

Digestion is the process of breaking down large molecules of food into smaller molecules that can be utilized by the body. The food is broken down by catalysts and digestive juices in the digestive tract and its organs.

The Digestive System helps the body maintain homeostasis:• The saliva in the mouth is slightly acidic so that food can be broken down more easily without damaging teeth and gums.• Digestive juices in the stomach, however, are extremely acidic to radically increase the rate of digestion and to protect the body from any harmful microbes.• The small intestine is very basic – in contrast to the stomach – so that digestive enzymes can properly function.• The large intestine contains many species of helpful bacteria that help with digestion

Human Digestive System

Food’s Journey Through the Body

Food travels from…

MOUTH ↓

PHARYNX↓

ESOPHAGUS↓

STOMACH↓

SMALLINTESTINE

↓LARGE

INTESTINE↓

RECTUM

Mouth (Oral Cavity)

• Process of Ingestion occurs– Teeth begin the physical breakdown of food

into smaller pieces making it easier to digest

• Food triggers salivary glands in oral cavity– Contains mucin which protects lining of

mouth from abrasion and lubricates food for easier swallowing

– Acts as a buffer to prevent tooth decay– Kills bacteria– Accessory gland of the digestive system

• Saliva contains the enzyme, salivary amylase– Begins chemical digestion of carbohydrates by

hydrolyzing starch and glycogen into smaller polysaccharides and maltose

• Tongue manipulates food into a ball called a bolus

• When swallowing tongue pushes bolus into the pharynx (back of mouth)

:

Pharynx• The pharynx opens into two pipes:

trachea (windpipe) and esophagus– Trachea: air passageway for

breathing– When swallowing, top of trachea (larynx) moves up and as a result, is

blocked by a flap called the epiglottis

• When larynx is up and trachea is blocked, bolus is able to enter the

esophagus

:

Esophagus

• The esophagus is a tube that carries the bolus into the stomach

• Bolus is pushed down the esophagus by peristalsis, rhythmic waves of contraction by

smooth muscles in the wall of the canal•Sphincters, muscular layers modified into ring-like

waves, close the esophagus from the stomachImage obtained from: http://www.webmd.com/digestive-disorders/picture-of-the-esophagus

:

Image obtained from: http://refluxdefense.com/heartburn_GERD_articles/stomach-acid.html

• Closed off from esophagus by cardiac orfice• Stores food • Presence of food stimulates glands in gastric pits to produce

gastric acid– Contains pepsinogen and hydrochloric acid (pepsin)– Pepsinogen is secreted by chief cells gastric pits– HCl is secreted by parietal cells in gastric pits– Pepsinogen and HCl combine to form pepsin, an enzyme that

begins the hydrolysis of proteins by breaking peptide bonds between amino acids

– Gastric acid has a pH of 2 – Strong acid helps break food down into smaller, easier pieces to

digest, along with the churning of food by muscles of the stomach wall

– Also denatures protein giving it greater exposure to its peptide bonds

• Has a mucus covering protecting it from its acidic juice• Resulting is acid chyme• Opening of stomach to small intestine is the pyloric sphincter,

squirts acid chyme into small intestine one at a time

STOMACH

Small Intestine [cont’d]…• Has three segments: duodenum, jejunum, and ileum

– Duodenum( approx. 25cm): upper part of small intestine• Acid chyme is mixed up with digestive juices from pancreas (bicarbonate,

which acts as a buffer, and proteases, which become activated once in extracellular space), liver (produces bile, which contain bile salts which break down fats), gallbladder (where bile is stored), and gland cells of the intestinal wall itself.

• Other accessory glands of digestive system are the pancreas, gallbladder, and liver.

• Epithelial lining secretes several digestive enzymes.• Most digestion is completed here

– Jejunum and ileum is where absorption of nutrients occur.– Contains large circular folds in lining that bear fingerlike projections

called villi, which each contains microscopic appendages called microvilli. – This large surface area allows for greater absorption.– Inside villi are capillaries and a small vessel of the lymphatic system

called lacteal.

• Nutrients, such amino acids and sugars, are absorbed across epithelium into blood vessels which converge into the hepatic portal vein which leads to the liver before going to the heart which in turn leads to the rest of the body.

• Glycerol and fatty acids are absorbed by epithelial cells and recombined into fats within those cells. The fats are then mixed with cholesterol and coated with proteins, forming small globules called chylomicrons.

• These are transported out of the epithelial cells and into lacteals, then to the heart.

Image obtained from: http://csnanatomy.pbworks.com/w/page/7844331/Duodenum,-jejunum,-and-ileum-to-the-ileocecal-valve

Anatomy of the Small

Intestine

The Large Intestine (Colon) :• Connected to the small intestine in a T-shaped junction• Has a small pouch, called a cecum, on lower right abdomen– Attached to cecum is an appendix, a vestigial organ for

humans– Connects colon to small intestine; entrance of the

processed material• Main function is to absorb water• Processes undigested material

RectumStores waste material before eliminated

:

Image obtained from: http://www.colorado.edu/intphys/Class/IPHY3430-200/image/21-31.jpg

Examples of Feedback Mechanisms in the Digestive System• In digestion, there are both positive and negative

feedback loops. An example of a positive feedback loop would be peptides which release acid and pepsinogen, which then causes more peptides in the stomach to release more acid and pepsinogen and so on and so forth.

• An example of a negative feedback loop would be when the stomach’s low pH restricts G cells from secreting gastrin. This results in less acid secretion.

• Excretion is the process of removal of metabolic waste from your body. Carbon dioxide, uric acid, water, salt and urea are all wastes removed by excretion. The primary organs of excretion are the kidneys, lungs, and skin. Although excretory systems are diverse, they all produce urine in a process that involves several steps. • First, body fluid is collected. The collection usually involves filtration through

permeable membranes that are made up of a single layer of transport epithelium. These permeable membranes help to retain cells and proteins in the bodily fluid.• Blood pressure then forces water and other small solutes into the excretory

system, and that fluid is known as filtrate. • The fluid collection is nonselective, and so it’s very important that the essential

small molecules are recovered from the filtrate and brought back to the body fluids.

• The second step of the process is known as selective re-absorption. The excretory system uses active transport to reabsorb come important solutes like glucose, amino acids, and certain salts while the nonessential solutes are left in the filtrate or added to the filtrate by selective secretion.

• Excretion helps the body in maintaining homeostasis because it removed metabolic waste from the body. If metabolic waste, like urine, remained in the body, there would a build-up of water concentration in the body; pH would change as well, and this would arouse problems in the structure of proteins, irritating the body’s internal environment.

Human Excretory System

Four major organs of the Excretory System

Skin

Image obtained from: http://healthguide.howstuffworks.com/skin-layers-picture-a.htm

Lungs

Image obtained from: http://www.allergydot.com/2009/05/04/how-do-our-lungs-work/

Liver

Image obtained from: http://www.epidemic.org/theFacts/essentials/yourLiver/

Urinary System (Kidneys, Urinary Bladder, Ureters, Urethra)

Image obtained from: http://www.worsleyschool.net/science/files/urinary/system.html

Skin:• Has two layers

– Outer layer: epidermis

– Inner layer: contains sensory nerve endings, tiny blood vessels, sweat and oil glands, hair follicles, and fat cells.

• Functions in the Excretory System by removing excess water, salt, urea, and uric acid through sweat from sweat glands

Lungs:

• Functions in the Excretory System by removing excess Carbon Dioxide in the blood

Liver:• Converts Ammonia (formed in the body during breakdown of proteins) to Urea and Uric Acid

Images obtained from: (Right) http://www.edoctoronline.com/medical-atlas.asp?c=4&id=20712&m=3&p=517&cid=1064&s= (Left) http://www.healthcentral.com/allergy/h/is-urea-breath-test-safe.html

• Includes Kidneys, Ureter, Urinary Bladder, and Urethra• This systems releases the body’s toxins through urine – a waste made from the body

that contains urea and uric acid.• Kidneys are relatively small, bean-shaped organs located just below the rib cage by

the spinal cord. There are two kidneys – one on each side of the spine.• They filter the body’s blood (about 200 quarts daily) and sift out waste and

excess water. • Kidneys contain about a million nephrons – a small capillary, called a

glomerulus, intertwined with a urine-collecting tubule.• Each nephron receives blood containing wastes. The glomerulus filters the

necessary material from the unnecessary. • Unwanted water and waste will travel on to the ureters, and the filtered

blood containing all its necessary elements returns to the blood stream.• The extra water and waste then becomes urine

• The urine travels from the kidney, through the ureters and into the urinary bladder where it is stored until it is released from the body by exiting through the urethra.

Urinary

System

3)When blood volume and blood increases• A peptide called atrial natriuretic factor (ANF) opposes

RAAS– ANF is released by the walls of the atria of the heart– Inhibits release of renin from the JGA– Inhibits NaCl reabsorption by the collecting ducts– Reduces aldosterone release from adrenal glands– Thereby, lowering blood pressure and volume

Regulation of Kidney Function:1) When blood osmolarity is high (above 300 mosm/L)• Osmoreceptor cells in hypothalamus of brain produces antidiuretic hormone (ADH),

which is stored and released from pituitary gland. – ADH increases permeability of distal tubes and collecting ducts which, in turn, increases

reabsorption of water and osmolarity of urine by decreasing its volume

2) When blood pressure or blood volume is low (by increased salt intake or loss of blood)

• Juxtaglomerular apparatus (JGA) releases the enzyme renin which initiates a chemical reaction to a peptide called angiotensin II– Raises blood pressure by constricting arterioles and decreasing blood flow to

kidneys– Stimulates release of the hormone aldosterone by the adrenal glands; causes

nephrons’ distal tubes to absorb more sodium and water and increasing blood volume and pressure.

(altogether is called renin-angiotensin-aldosterone system (RAAS))

Examples of Feedback Mechanisms in the Excretory System

Excretory System

(Answers)

Clues for Excretory System Crossword PuzzleAcross

3. Outer region of a mammalian kidney.

7 The capillaries that serve the loop of Henle.

12 Regulation of solute concentrations.

13 Small, toxic molecule produced by nitrogen fixation and is a metabolic waste product of protein and nucleic acid metabolism.

14 animals that cannot tolerate substantial changes in external osmolarity.

15 Fluid of water, salts, sugars, amino acids, and nitrogenous wastes of the excretory system.

16 Hormone released by adrenal glands that causes nephrons' distal tubules to absorb more sodium.

17 Nitrogenous waste that is insoluble in water.

Down

1. Substance produced in the vertebrate liver by a metabolic cycle that combines ammonia with carbon dioxide.

2 Urine exits the kidney through this duct.

4 Hormone produced by hypothalamus to lower blood osmolarity.

5 A region of a nephron with a descending and ascending limb.

6 Layer or layers of specialized epithelial cells that regulate solute movements.

8 Tube where urine is expelled from the urinary bladder.

9 Receives processed filtrate from many nephrons.

10 An animal that must control its internal osmolarity because its body fluids are not isoosmotic with the outside environment.

11 Blood vessel that supples blood to the kidney.

Click here to return to Puzzle

Click here to move on to AnswersExcretory

System

Excretory System

Name that Part!_____________

__________

_________

______

______

_______

_____

Word Bank:- Adrenal Gland

- Aorta- Bladder

- Inferior Vena Cava- Kidney- Ureter- Urethra

Name that Part! [Answers]

Image obtained from: www.comprehensive-kidney-facts.com

NUTRITION WORD SEARCHS T N E I R T U N L A I T N E S S E J VZ D I Z S N I M A T I V Y R O X T V T MB V U A T N E M H S I R U O N R E D N UP H H X M A L N O U R I S H E D E Q V PW T K M E S B O R Y W X X I N U X P N GK J P H Q O M N I V O R E S U I Q L R AT M X K T R R J B H Q U E U J U T I N WC F O V E R N O U R I S H M E N T O G BE S S E N T I A L A M I N O A C I D SLV N I A U W B W M T O F Q H S H P F ISO M G V N R V O O U H S E N M W M T Z FW M P T B T R Q H Y M R V A W M H I O RP J L L A V N L R I B N L L Y R C M L ZR L Z C E F E Q V I F G L V T Q G P I HD F D S P D X A V A X F R N A D Q U G CD F D S P D X A V A X F R N A D Q U G CQ X T Y Z H S O O Y Z B K Q Q B U G H SM K Q K I F R V S L A R E N I M V H D CF I H G I E W I S E R O V I N R A C X QR O O G S Y S T S A V P U U S M P A C L

VocabularyCarnivores

Essential Amino AcidsEssential Fatty AcidsEssential Nutrients

HerbivoresMalnourished

MineralsOmnivores

OvernourishmentUndernourishment

Vitamins

Nutrition Quiz1. Proteins are broken down to _____ after digestion, while fats are

broken down to _____. A. glycerol only…fatty acids onlyB. fatty acids only…monosaccharidesC. monosaccharides…glycerol onlyD. -amino acids…both glycerol and fatty acidsE. both glycerol and fatty acids…amino acids

2. _____ is a kind of starch.A. disaccharideB. nucleotideC. -polysaccharideD. fatty acidE. monosaccharide

3. Your small intestine is able to absorb ____ without their being further digested.

A. starchesB.FatsC. proteinsD. -fructosesE. nucleic acids

4. ____ is an enzyme that begins the starch breakdown.A. disaccharidasesB. lipaseC. -amylaseD. nucleases

5. Starch can be broken down into the disaccharide known as _____. A. lactoseB. glucoseC. sucroseD. fructoseE. -maltose

6. The ____ is where protein digestion begins.A. mouthB. EsophagusC. -stomachD. small intestineE. large intestine

7. Gastric juice is mostly made up of which of the following?A. inactive pepsinB. amylaseC. hydrochloric acidD. -waterE. Bile

8. _____ is secreted by the _____, which emulsifies fats.A. Lipase ... small intestineB. Trypsin ... pancreas C. Nucleases ... pancreasD. Amylase ... salivary glandsE. -Bile ... liver

Nutrition Quiz [cont’d]…9. Stomach acidity is caused by which of the following acids?A. -hydrochloric acidB. carbonic acidC. sulfuric acidD. acetic acidE. sodium hydroxide

10.Secretin stimulates the _____ to secrete _____.A. -pancreas ... bicarbonateB. pancreas ... pancreatic enzymesC. small intestine ... disaccharidasesD. stomach ... bicarbonateE. liver ... liver enzymes

11. Since the stomach is so acidic, the hormone _____ is secreted by the small intestine.

A.cholecystokinin, or CCKB. histonesC. TSHD. -secretinE. pepsin

12. The presence of fatty acids and amino acids in the stomach contents triggers the small intestine to secrete a hormone known as _____.

A. -cholecystokinin, or CCKB. HistonesC. insulinD. secretinE. thyroxine

13. Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine. A. -liver ... gall bladderB. pancreas ... gall bladderC. liver ... pancreasD. gall bladder ... liverE. esophagus ... stomach

Nutrition Quiz [Answers]1. D2. C3. D4. C5. E6. C7. D8. E9. A

10. A11. D12. A13. A

REFERENCE PAGEKVHS Webmaster (2011). Digestion. Retrieved on April 29, 2011 from the

website: http://mcb.berkeley.edu/courses/mcb32/Miller%20notes-%20digestive%20system%20

The Structure and Function of the Digestive System Retrieved April 23, 2011, from The Cleveland Clinic Foundation from the website: http://www.clevelandclinic.org/health/health-info/docs/1600/1699.asp?index=7041

Stomach Retrieved April 23, 2011, from The Gastroenterological Society of Australia from the Website: http://www.gesa.org.au/digestive-system/stomach.cfm

Campbell, N.A. & Reece, J.B. (2005) Biology (Seventh Edition) Chapter 41 (pp. 844-862) and Chapter 44 (pp. 928-937). San Francisco, CA: Pearson Education, Inc.

Source Page [additional websites]

Nutrition:http://kvhs.nbed.nb.ca/gallant/biology/Nutrition_Notes.htmlhttp://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/http://www.vivo.colostate.edu/hbooks/pathphys/digestion/http://hes.ucfsd.org/gclaypo/digestive_system.htmlhttp://www.colorado.edu/intphys/Class/IPHY3430-200/020digestion.htm

Excretion:http://www2.estrellamountain.edu/faculty/farabee/biobk/biobookexcret.htmlhttp://biology.clc.uc.edu/courses/bio105/kidney.htmhttp://www.ashlandschools.org/morgan_cottle/body/excretory.htmhttp://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bio%20102%20lectures/excretory%20system/excretor.htmhttp://qldscienceteachers.tripod.com/junior/biology/excretory.html