1. Digestion
• Groups of organs that work together to
digest food so that it can be used by the
body (nutrients)
• Food is digested as it passed through the
body: needs H2O, carbohydrates, fats,
proteins, vitamins, minerals
• Composed of the mouth, pharynx,
esophagus, stomach, small intestine,
large intestine, rectum, anus

2. • Substance are secreted by the liver,
gallbladder, pancreas and salivary glands
to help with digestion
• Two types of digestion:
– Mechanical – physical breaking and crushing
of food
– Chemical – large molecules are broken down
by enzymes (chemical scissors) into smaller
particles that the body can use for growth,
maintenance, and repair

3. • Major nutrients – protein, carbohydrates
and fats
• Steps in digestion
• (1) Digestion begins in the mouth where
teeth (enamel) used to break down and
grind food into small manageable pieces
• Teeth are composed of molars, premolars,
incisors and canines adults have 32 teeth

4. • Saliva – (amylase - enzyme) liquid
produced by the salivary glands in the
gums to begin breaking down complex
carbohydrates into simple sugars and
moisten food
• (2) pharynx – throat, food is pushed by the
tongue to the back of the mouth and
enters the pharynx which splits into 2
tubes

5. • (3)Esophagus – passageway to the
stomach
• Squeezes food along the tube with muscle
contractions called peristalsis forcing food
into the stomach
• (4) stomach – muscular baglike organ
connected to the end of the esophagus
• Continues physical digestion by churning
food with muscle contractions

6. • Continues chemical digestion by releasing
enzymes and acids (HCl)
• Resulting mixture is called chyme
• (5) small intestine – (three parts
duodenum, Jejunum, ileum) chyme is
released by pyloric valve into the small
intestine slowly allowing the small intestine
time to mix chyme with fluids from the liver
and pancreas

7. • Small intestine is approx. 2.5 cm in
diameter and about 6 m long (the length of
a car) and flattened out would be larger
than a tennis court
• Inside wall is covered with villi – fingerlike
projections covered with nutrient
absorbing cells that allows nutrients to be
diffused into the bloodstream by capillaries

8. • Pancreas is located between the stomach and
sm intestine that makes enzymes to help in food
digestion and produces an acid neutralizer
called bicarbonate
– Also part of the endocrine system that makes
hormones that regulate blood sugar (insulin)
• Liver – large as a football located on the right
side of abdomen, most massive internal organ

9. • Weighing up to 1.5 kg and has many jobs:
• Makes green liquid called bile which is
used to digest fat molecules
• Stores nutrients
• Breaks down toxic substances in the blood
• Makes cholesterol for cell membranes
– HDL – high density phospholipids (good)
– LDL – low density phospholipids (bad)

10. • Gallbladder – stores bile made by the liver
and is squeezed into the sm intestine to
break up large fat droplets, allowing for
easier digestion

11. • (6) large intestine – stores, compacts, and
expels material that are indigestible
• About 7.5 cm in diameter and about 1.5 m
long
• No nutrient absorption takes place in the
large intestine
• Water absorption takes place and creates
a solid mass called feces

12. • Fiber found in fruits, grains, and vegetables
called cellulose is not digestible by humans and
is used by the body to keep feces soft and
moving in the lg. intestine
• Lg intestine also secretes mucus to allow feces
to move smoothly
• Last part of the lg intestine is the rectum where
feces is stored before passing out of the body
through the anus

13. • Complete digestion from start (mouth) to
finish (anus) takes approx. 24 hrs.

14. Excretory
• Removes waste products from
blood/balances fluids
• Excretion – process of removing wastes
and excess products (fluids and some
solid matter; filtrates) from the body
• 3 systems remove waste
– Urinary, respiratory, integumentary
• Urinary sys. removes waste like CO2 and
ammonia from the body

15. • Blood moves through the kidney’s 350 X’s
per day
• Each kidney is composed of over 1 million
tiny filters called nephrons
• Each nephron is surrounded by capillaries
called the glomerulus encased in a hollow
cup-shaped structure called Bowman’s
capsule (permeable)

16. • Materials diffuse across: water, urea,
glucose, salts, amino acids and some
vitamins (filtrate)
• Plasma, cells, and platelets are to large to
pass and remain in blood.
• Removes toxic substances containing
nitrogen called urea, which forms as the
cells use protein for energy, maintains pH,
and blood volume by regulating water

18. • Ureter – passageway from kidney’s to the
bladder
• Urinary bladder – storage area for urine
• Urethra – tube where urine leaves the
body
• Urine – liquid waste (yellow) that remains
behind when nephrons remove water and
other substances and returns these to the
bloodstream

20. • Urination – process of expelling urine
• ADH – antidiuretic hormone produced
when your body lacks water
• Signals the kidney’s to take back water
from the nephrons and return the water
back to the bloodstream
• The process makes less urine but a higher
concentration of urine

21. • Diuretics – thirst is an indication the body
needs water
• Diuretics cause the kidneys to make more
urine decreasing the amount of water in
blood
• caffeine