1. How the body converts food into nutrients and waste/
Nutrition
How the body converts food into nutrients and waste
Excretion
AP Biology – F Period – May 1, 2011
Mary Boci, Stephanie Lai, Diana Nguyen

2. Nutrition Facts: Animals fit into 3 dietary categories:
Herbivores – consumes mainly autotrophs
Carnivores – consumes mainly other animals
Omnivores – generally consumes both plants and animals
Nutritional needs must provide:
Fuel for all cellular work of the body
Organic raw materials used in biosynthesis
Essential nutrients
Four main feeding mechanisms of animals
Suspension feeders – sift small food particles from the water
Substrate feeders – live on or in their food source, eating their way through the food
Fluid feeders – suck nutrient-rich fluid from a living host
Bulk feeders – eat relatively large pieces of food

3. Fluid Feeder Suspension feeder Bulk Feeder Substrate Feeder
Images obtained from these websites: and

4. 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

5. Nutrition Facts cont. Essential Fatty Acids Vitamins Minerals
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.

6. Human Digestive System

7. 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

8. Food’s Journey Through the Body
Food travels from…
MOUTH ↓ PHARYNX ESOPHAGUS STOMACH SMALL INTESTINE LARGE RECTUM

9. : 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)

10. :
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

11. 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 stomach
Image obtained from:

12. STOMACH 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
Image obtained from:

13. Anatomy of the Small Intestine 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.
Anatomy of the
Small Intestine
Image obtained from:

14. The Large Intestine (Colon):
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 :
Rectum
Stores waste material before eliminated
Image obtained from:

15. 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.

16. Human Excretory System
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.

17. Four major organs of the Excretory System
Urinary System
(Kidneys, Urinary Bladder, Ureters, Urethra)
Skin
Lungs
Liver
Image obtained from:
Image obtained from:
Image obtained from:
Image obtained from:

18. :
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

19. Functions in the Excretory System by removing excess Carbon Dioxide in the blood:
Lungs

20. :
Liver
Converts Ammonia (formed in the body during breakdown of proteins) to Urea and Uric Acid
Images obtained from: (Right) (Left)

21. Urinary System 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.

22. Examples of Feedback Mechanisms in the Excretory System
Regulation of Kidney Function:
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
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))
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

23. Excretory System

24. Clues for Excretory System Crossword Puzzle
Across 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.
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Excretory System
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(Answers)

25. Excretory System

26. Name that Part! Word Bank: Adrenal Gland Aorta Bladder
_____________
Word Bank:
Adrenal Gland
Aorta
Bladder
Inferior Vena Cava
Kidney
Ureter
Urethra
__________
_________
______
______
_______
_____

27. Name that Part! [Answers]
Image obtained from:

28. NUTRITION WORD SEARCH Vocabulary Carnivores Essential Amino Acids
S T N E I R T U N L A I T N E S S E J V
Vocabulary
Carnivores
Essential Amino Acids
Essential Fatty Acids
Essential Nutrients
Herbivores
Malnourished
Minerals
Omnivores
Overnourishment
Undernourishment
Vitamins
Z D I Z S N I M A T I V Y R O X T V T M
B V U A T N E M H S I R U O N R E D N U
P H H X M A L N O U R I S H E D E Q V P
W T K M E S B O R Y W X X I N U X P N G
K J P H Q O M N I V O R E S U I Q L R A
T M X K T R R J B H Q U E U J U T I N W
C F O V E R N O U R I S H M E N T O G B
E S S E N T I A L A M I N O A C I D SL
V N I A U W B W M T O F Q H S H P F IS
O M G V N R V O O U H S E N M W M T Z F
W M P T B T R Q H Y M R V A W M H I O R
P J L L A V N L R I B N L L Y R C M L Z
R L Z C E F E Q V I F G L V T Q G P I H
D F D S P D X A V A X F R N A D Q U G C
D F D S P D X A V A X F R N A D Q U G C
Q X T Y Z H S O O Y Z B K Q Q B U G H S
M K Q K I F R V S L A R E N I M V H D C
F I H G I E W I S E R O V I N R A C X Q
R O O G S Y S T S A V P U U S M P A C L

29. Nutrition Quiz
1. Proteins are broken down to _____ after digestion, while fats are broken down to _____. A. glycerol only…fatty acids only B. fatty acids only…monosaccharides C. monosaccharides…glycerol only D. -amino acids…both glycerol and fatty acids E. both glycerol and fatty acids…amino acids 2. _____ is a kind of starch. A. disaccharide B. nucleotide C. -polysaccharide D. fatty acid E. monosaccharide 3. Your small intestine is able to absorb ____ without their being further digested. A. starches B.Fats C. proteins D. -fructoses E. nucleic acids 4. ____ is an enzyme that begins the starch breakdown. A. disaccharidases B. lipase C. -amylase D. nucleases
5. Starch can be broken down into the disaccharide known as _____.
A. lactose
B. glucose
C. sucrose
D. fructose
E. -maltose
6. The ____ is where protein digestion begins.
A. mouth
B. Esophagus
C. -stomach
D. small intestine
E. large intestine
7. Gastric juice is mostly made up of which of the following?
A. inactive pepsin
B. amylase
C. hydrochloric acid
D. -water
E. Bile
8. _____ is secreted by the _____, which emulsifies fats.
A. Lipase ... small intestine
B. Trypsin ... pancreas
C. Nucleases ... pancreas
D. Amylase ... salivary glands
E. -Bile ... liver

30. Nutrition Quiz [cont’d]…
9. Stomach acidity is caused by which of the following acids? A. -hydrochloric acid B. carbonic acid C. sulfuric acid D. acetic acid E. sodium hydroxide 10.Secretin stimulates the _____ to secrete _____. A. -pancreas ... bicarbonate B. pancreas ... pancreatic enzymes C. small intestine ... disaccharidases D. stomach ... bicarbonate E. liver ... liver enzymes 11. Since the stomach is so acidic, the hormone _____ is secreted by the small intestine. A.cholecystokinin, or CCK B. histones C. TSH D. -secretin E. 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 CCK B. Histones C. insulin D. secretin E. thyroxine
13. Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine.
A. -liver ... gall bladder
B. pancreas ... gall bladder
C. liver ... pancreas
D. gall bladder ... liver
E. esophagus ... stomach

31. Nutrition Quiz [Answers]D C E A

32. REFERENCE PAGE
KVHS Webmaster (2011). Digestion. Retrieved on April 29, 2011 from the website: The Structure and Function of the Digestive System Retrieved April 23, 2011, from The Cleveland Clinic Foundation from the website: Stomach Retrieved April 23, 2011, from The Gastroenterological Society of Australia from the Website: Campbell, N.A. & Reece, J.B. (2005) Biology (Seventh Edition) Chapter 41 (pp ) and Chapter 44 (pp ). San Francisco, CA: Pearson Education, Inc.

33. Source Page [additional websites]
Nutrition: Excretion: