Transcript the digestive system

/
Nutrition
How the body converts food into nutrients and waste
Excretion
A P
B i o l o g y
M a r y
B o c i ,
–
F
P e r i o d
–
S t e p h a n i e
L a i ,
M a y
1 ,
2 0 1 1
D i a n a
N g u y e n
Nutrition Facts:
• Animals fit into 3 dietary categories:
Herbivores – consumes mainly autotrophs
Carnivores – consumes mainly other animals
Omnivores – generally consumes both plants and animals
•
1)
2)
3)
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
1) Suspension feeders – sift small food particles from the water
2) Substrate feeders – live on or in their food source, eating their
way through the food
3) Fluid feeders – suck nutrient-rich fluid from a living host
4) Bulk feeders – eat relatively large pieces of food
Suspension feeder
Substrate Feeder
Bulk Feeder
Fluid Feeder
Images obtained from these websites: http://mycozynook.com/102RGCh20OH.htm and
http://bioh.wikispaces.com/Digestion+and+Nutrition
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
↓
SMALL
INTESTINE
↓
LARGE
INTESTINE
↓
RECTUM
Mouth (Oral Cavity):
•
Process of Ingestion occurs
–
•
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
–
•
Teeth begin the physical breakdown of food
into smaller pieces making it easier to digest
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 ringlike waves, close the esophagus from the stomach
Image obtained from: http://www.webmd.com/digestive-disorders/picture-of-the-esophagus
S
T
O
M
A
C
H
•
•
•
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: http://refluxdefense.com/heartburn_GERD_articles/stomach-acid.html
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. into blood
• Nutrients,
such
amino
acids
and sugars,
are absorbed
across epithelium
vessels
which converge
into the
hepatic
portalthat
veinbear
whichfingerlike
leads to the
liver before going
– Contains
large circular
folds
in lining
projections
to the
heartvilli,
which
in turn
leads
to the rest
of the body.appendages called microvilli.
called
which
each
contains
microscopic
• Glycerol and fatty acids are absorbed by epithelial cells and recombined into fats within
– This large surface area allows for greater absorption.
those cells. The fats are then mixed with cholesterol and coated with proteins, forming
– Inside
villicalled
are capillaries
and a small vessel of the lymphatic system
small
globules
chylomicrons.
called
lacteal. out of the epithelial cells and into lacteals, then to the heart.
•These
are transported
Anatomy of the
Small Intestine
Image obtained from: http://csnanatomy.pbworks.com/w/page/7844331/Duodenum,-jejunum,-and-ileum-to-the-ileocecal-valve
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: 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.
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.
Four major organs
of the Excretory System
Urinary
Lungs
Liver
Skin
System
(Kidneys, Urinary Bladder, Ureters, Urethra)
Image
Image
Image
obtained
obtained
obtained
from:
from:
from:
http://www.allergydot.com/2009/05/04/how-do-our-lungs-work/
http://www.worsleyschool.net/science/files/urinary/system.html
http://healthguide.howstuffworks.com/skin-layers-picture-a.htm
http://www.epidemic.org/theFacts/essentials/yourLiver/
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
• Functions in the Excretory System by removing excess Carbon Dioxide in
the blood
Lungs:
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
U
• Includes Kidneys, Ureter, Urinary Bladder, and Urethra
S
• This systems releases the body’s toxins through urine – a waste made from the body
rthat contains urea and uric acid.
• Kidneysyare relatively small, bean-shaped organs located just below the rib cage by
cord. There are two kidneys – one on each side of the spine.
ithe• spinal
They
filter the body’s blood (about 200 quarts daily) and sift out waste and
s
water.
n• excess
Kidneys contain about a million nephrons – a small capillary, called a
t intertwined with a urine-collecting tubule.
glomerulus,
nephron receives blood containing wastes. The glomerulus filters the
a • Each
necessary material from the unnecessary.
e
water and waste will travel on to the ureters, and the filtered
r • Unwanted
blood containing all its necessary elements returns to the blood stream.
m
• The extra water and waste then becomes urine
• y
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.
E x a m p l e s o f F e e d b a ck M e ch a n i s m s
in the Excretory System
Regulation of Kidney Function:
1)3)When
When blood
osmolarity
is high
(above
300increases
mosm/L)
blood
volume
and
blood
•
•
Osmoreceptor cells in hypothalamus of brain produces antidiuretic hormone (ADH),
A peptide
called
atrial
which
is stored and
released
from natriuretic
pituitary gland. factor (ANF) opposes
ADH increases permeability of distal tubes and collecting ducts which, in turn, increases
RAAS
reabsorption of water and osmolarity of urine by decreasing its volume
– ANF
released
by the
walls
of (by
theincreased
atria ofsalt
the
heart
When
bloodispressure
or blood
volume
is low
intake
or loss
of –
blood)
Inhibits release of renin from the JGA
Juxtaglomerular apparatus (JGA) releases the enzyme renin which initiates a
– Inhibits
NaCl
by the collecting
ducts
chemical
reaction
to a reabsorption
peptide called angiotensin
II
– – Reduces
Raises blood aldosterone
pressure by constricting
arterioles
decreasing
blood flow to
release
fromandadrenal
glands
kidneys
lowering
blood aldosterone
pressurebyand
volume
– – Thereby,
Stimulates release
of the hormone
the adrenal
glands; causes
–
2)
•
nephrons’ distal tubes to absorb more sodium and water and increasing blood
volume and pressure.
(altogether is called renin-angiotensin-aldosterone system (RAAS))
Excretory System
Clues for Excretory System Crossword Puzzle
Across
3. Outer region of a mammalian kidney.
7 The capillaries that serve the loop of Henle.
dioxide.
2 Urine exits the kidney through this duct.
12 Regulation of solute concentrations.
4 Hormone produced by hypothalamus to lower blood
osmolarity.
13 Small, toxic molecule produced by nitrogen fixation
and is a metabolic waste product of protein and nucleic
acid metabolism.
5 A region of a nephron with a descending and ascending
limb.
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
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 Answers
(Answers)
Excretory 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 SEARCH
S T N E
Z D I
I
R T U N L A
I
T N E S S E
J V
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
K
J
P H Q O M N I
I N U X P N G
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
C F O V E R N O U R
E S S E N T
V N I
I
I
I N W
S H M E N T O G B
A L A M I N O A C
I D S L
A U W B W M T O F Q H S H P F I S
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
F
I
I H G I
F R V S L A R E N I M V H D C
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
Vocabulary
Carnivores
Essential Amino Acids
Essential Fatty Acids
Essential Nutrients
Herbivores
Malnourished
Minerals
Omnivores
Overnourishment
Undernourishment
Vitamins
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
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
Nutrition Quiz [Answers]
1.
2.
3.
4.
5.
6.
7.
8.
9.
D
C
D
C
E
C
D
E
A
10. A
11. D
12. A
13. A
REFERENCE PAGE
KVHS 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/healthinfo/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/digestivesystem/stomach.cfm
Campbell, N.A. & Reece, J.B. (2005) Biology (Seventh Edition) Chapter 41 (pp. 844862) 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.html
http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/
http://www.vivo.colostate.edu/hbooks/pathphys/digestion/
http://hes.ucfsd.org/gclaypo/digestive_system.html
http://www.colorado.edu/intphys/Class/IPHY3430-200/020digestion.htm
Excretion:
http://www2.estrellamountain.edu/faculty/farabee/biobk/biobookexcret.ht
ml
http://biology.clc.uc.edu/courses/bio105/kidney.htm
http://www.ashlandschools.org/morgan_cottle/body/excretory.htm
http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bi
o%20102%20lectures/excretory%20system/excretor.htm
http://qldscienceteachers.tripod.com/junior/biology/excretory.html