Phylum Chordata (reptilia, amphibia, mammalia) lab notes

PHYLUM CHORDATA
SUBPHYLUM VERTEBRATA


Class Amphibia
 Return to water (to lay eggs)
 Breathe through their skin (excel most CO2 via skin, intake O2 through their lungs)
 Must keep skin moist (highly vascular ie desiccate otherwise)

SKIN
 Mucous gland (lubrication and moisture)
 Poison glands (some toads will get you high from licking)

SKELETON
 Thicker vertebrae
 Urostyle (fusion of lumbar and sacral vertebrae – provides more stability and acts as a
shock absorber when jumping/landing)
 Ilium (hip bone on either side of the urostyle)
 Tibiofibular (fusion of tibia and fibula)
 Calcaneum (fibulare)
 Radioulna (fused radius and ulna)
 Humerus (thickened for muscle absorption)
 5 digits on hind legs, 4 digits on front legs
 Pedicellaria (“steak knife” teeth for grabbing and holding prey)

INTERNAL ANATOMY
 Stomach and duodenum (digestion)
 Colon (water and electrolyte reabsorption)
 Cystic duct (connects liver to gall bladder)
 Jejunoileum (absorption)
 Spleen (immune response and blood filtration)
 Ureter (connective duct from kidney to bladder)
 Lungs
 Kidney (filtration)
 Heart (in the centre of the lungs)

CIRCULATORY SYSTEM
 Two atria and one ventricle
1. Left atria receives oxygenated blood from the lungs and skin
2. Right atria receives deoxygenated blood from the body
3. Ventricle receives oxygen from both atria
4. Deoxygenated blood pumped from the ventricle through the pulmocutaneous
arteries to the lungs and skin, where they will pick up oxygen
5. Oxygenated blood is pumped from the ventricle through the aorta to the body
6. Conus arteriosus (acts as a pressure reservoir and receives blood from the
ventricle)
Class Reptilia
 Have scales that will shed occasionally