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.