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Chapter 40Amphibians
Section 2
Characteristics of Amphibians
Skin• Respiration & protection
• Moist and permeable to gas and water
• Mucous glands- supply lubricant that keeps the skin moist
• Skin also provides a foul-tasting secretion which protect frogs
Skin• Live in moist areas to avoid drying out• If in desert, they burrow to survive
drying out• Affected by pollution- chemicals in
water can affect amphibians• Can serve as indicators of the health
in an ecosystem
Skeleton• Strong internal skeleton
(vertebrate, legs)
• Pectoral and pelvic girdles transfer body’s weight to the limbs
• In frogs, they have strong bones for jumping and landing
Circulatory System• Heart is separated into two loops
• Pulmonary circulation- carries deoxygenated blood from the heart to the lungs and back to the heart
• Systemic circulation- carries oxygenated blood from the heart to the body and back to the heart
Circulatory System• Three chambered heart
• All other terrestrial vertebrates also have a “double loop” circulatory pattern
• Allows for faster blood flow
Respiration• Larval amphibians respire
(exchange carbon dioxide and oxygen) through their gills and skin
• Pulmonary respiration- respiration through the lungs
• Cutaneous respiration- respiration through the skin
Digestive System• Adults- carnivorous- eat insects,
mice, snake, birds, other amphibians, etc
• Larva- herbivores- eat plants
• Pharynx esophagus stomach liver gallbladder small intestine large intestine cloaca
Accessory Glands• Liver produces bile- stored in the
gallbladder
• Bile helps break down fat
• Pancreas secretes enzymes that help break down food
Nervous System• Olfactory lobes- sense of smell• Cerebrum- behavior and learning• Optic lobes- process information from
the eyes• Cerebellum- muscular coordination• Medulla Oblongata- organ functions
(heart & respiration rate)
Sense Organs• Sight, smell, hearing
• Nictitating membrane- eyes covered by a transparent, movable membrane
• Tympanic membrane- eardrum
• Columella- small bone that extends between the tympanic membrane and inner ear
REVIEW!!!• Identify an advantage and a
disadvantage to the permeability of amphibian skin?
• Explain how a frog uses positive pressure to move air into and out of its lungs.