Amphibians

Amphibians Have Adapted for Life on Land.

• Amphibians have large shoulders and hip bones to support their weight.
• Interlocking vertebrae also keep their backbones from sagging.
• The three-chambered heart is used for breathing out of water.

Amphibian Skin

• Amphibians have thin and wet skin with several glands.
• Several amphibians use their skin to breathe.
• There are two layers:
• Epidermis contains keratin 
• Dermis contains chromatophores and glands, some poisonous.

The Senses

• Tympanic membrane and stapes in the middle ears allow hearing out of water.
• Their eyes have cornea for primary light refraction.
• Amphibians can also detect chemicals through their skin.

Breathing on Land

• Amphibians have paired nostrils to take air in.
• Depending on species, they breathe through gills, skin, or buccal pumping.
• Buccal pumping uses lungs.

Circulatory Circuits

• There are two circulatory circuits in amphibians:
• Pulmonary circuit transports blood amid the heart and lungs, skin, or gills
• Systemic circuit transports blood to the body organs.

Excretion

• Mesonephric kidneys filter the blood.
• Nitrogenous waste is released as ammonia in aquatics.
• Nitrogenous waste is released as urea in land dwellers.
• Bladder stores waste until excreted.

Amphibian Habitats

• Amphibians live in semi-aquatic habitats such as streams, bogs and marshes.
• Their thin skin requires moisture so they don't dry out.
• They also require these water areas to produce their aquatic larvae.
• Some amphibians also use water for protection or to hide.

Digestion

• The mouth starts the digestion. This is where prey is caught.
• Food then travels through the pharynx where it then passes to the esophagus
• The esophagus connects the pharynx to the stomach where food is broken down
•  The small intestines takes nutrients and the large intestines takes water
• Pancreas secretes enzymes while the liver and gallbladder secrete bile.  

Amphibian Metamorphosis