Digestive and Excretory
Systems
Finz 2014
Function: To physically and chemically ingest,
digest, and absorb food and nutrients. The
path of food...
1) Mouth ingests and digests using teeth, tongue
(physical) and saliva (chemical).
2) Esophagus transports food to stomach through
peristalsis muscle contractions.
3) Stomach stores and digests food by contracting
(physical) and with acid (chemical)
4) Small intestine digests (chemical) and absorbs
food.
5) Large intestine absorbs water and vitamins and
minerals. (chemical)
6) Anus eliminates unused wastes.
Other organs of the digestive
system
• Food does NOT pass through these:
• Liver: produces bile for breaking down
fats.
• Gall bladder: stores the bile.
• Pancreas: produces enzymes for
breaking down starches.
Nutrition
• proteins:
– growth and repair, breaks down into amino acids,
examples are meats, nuts and fish.
• carbohydrates:
– main source of quick energy, breaks down into sugars,
examples are starchy foods like breads, pastas,
grains.
• fats:
– stored energy, breaks down into fatty acids and
glycerol, saturated (butter) and unsaturated (oils)
types.
Nutrition
• water:
– needed for chemical reactions to take place in the
cells.
• vitamins:
– organic molecules to regulate processes.
• minerals:
– inorganic molecules to regulate processes.
Food guide pyramid
Quiz
1.
What is the “food tube?”
Esophagus
2.
What substance breaks down fats?
Bile
3.
Name 1 part of the Digestive System that does
“Physical” digestion.
Mouth or stomach contractions
4.
Name 1 part of the Digestive System that does
“Chemical” digestion.
Saliva or stomach acid or small intestines
Excretory System
Functions of the Excretory System
• Every cell produces metabolic
wastes.
• The process by which these wastes
are eliminated is called excretion.
Organs that can excrete
• The skin excretes excess water and
salts in the form of sweat.
• The lungs excrete carbon dioxide.
• The kidneys also play a major role in
excretion.
The Kidney:
• remove waste products – mostly
urea- from the blood.
• maintain blood pH.
• regulate the water content of the
blood and, therefore, blood volume.
The Kidney:
• Blood enters the kidney through the
renal artery.
• The kidney removes urea, excess water,
and other waste products and passes
them to the ureter to the urinary
bladder.
• The clean, filtered blood leaves the
kidney through the renal vein and
returns to circulation.
The Kidney
The Kidney
• The mechanism of blood purification
involves two distinct processes:
filtration and reabsorption.
– Filter out wastes
– Reabsorb water