suspension feeders -sift small food particles through water clams oysters baleen whales
TRANSCRIPT
Suspension feeders-sift small food particles through water
Clams oystersbaleen whales
Substrate-feeders-live in or on their food
Caterpillars, worms
Fluid-feedersmay be parasites that live on the fluid of other organisms
-aphids (on phloem sap of plants)-mosquitoes (on blood of mammals)
May not be parasites-hummingbirds and insects on nectar
Bulk-feeders-eat large quantity of food-most animals
Digestion occurs in specialized compartments
The simplest is the gastrovascular cavity
No anusWastes leave via the mouth
Crop -moisten & store
Gizzard-grind
Intestine/ceca-absorb
Oral cavity
Bulk-feeders-eat large quantity of food-most animals
Human Digestive System
• True digestive structures vs. accessory structures
• Mechanical digestion vs. chemical digestion
Digestion begins in the oral cavity:chewing (mechanical digestion) and addition of saliva to food to form a bolus
Salivary amylase digests starch and glycogen (chemical digestion)Antibacterial agents
pharynx
Involuntary contractions of smooth muscle surrounding the digestive tract propels food
Occurs in esophagus and the intestines
Stomach structuresecrete pepsinogen.
secrete HCl
HCl converts pepsinogen into pepsinAn adaptation which prevents stomach from digesting itself
Mucus cells secrete mucus-lubricates and protects stomach
Helicobacter pylori
Bile emulsifies fat Physically breaks up fat globules
Made in Liver Stored in gall bladder
Including bicarbonate
Pancreatic enzymes(released into the duodenum via
a duct)
• Trypsin (protein digestion)
• Pancreatic amylase (glycogen/starch)
• Lipase (fats)
• Nucleases (nucleic acids)
Intestinal enzymes(from wall of small intestine)
• Disaccharidases (maltase, sucrase, lactase)
• Dipeptidases
Anatomy of the small intestine
LACTEAL-part of lymphatic system
-contains fluid called lymph-collects components of fat digestion-will eventually empty into blood vessels
Blood vessels-absorbs amino acids-absorbs monosaccharides-takes nutrient rich blood to liver
Villi
Hepatic Portal system
Largeintestine(colon)
Endof smallintestine
AppendixCecum
Unabsorbedfood material
Anus
Rectum
Smallintestine
Cecum is blind pouch at the intersection of the small and large intestinesIn humans it is a vestigial organ called the ????
Fig. 21-13a
Small intestine
Cecum
Stomach
Colon(large intestine)
Carnivore Herbivore