Classification Symmetry
Body Direction
Classification of Humans
• Kingdom Animalia• Phylum Chordata• Class Mammalia• Order Primates• Family Hominidae• Genus Homo• Species sapiens
Classification of Dogs
• Kingdom Animalia• Phylum Chordata• Class Mammalia• Order Carnivora• Family Canidae• Genus Canis• Species familiaris
Animal Symmetry
• Asymmetry—no central axis or point • Example: sponge
Animal Symmetry
• Bilateral symmetry—animal has identical right and left images
• Example: crayfish
Animal Symmetry
• Radial symmetry—any plane passing through the center of animal produces identical mirror images
• Example: sea star
Terms of Direction in the Body
• Aboral—end opposite the mouth• Oral—end containing the mouth
Body Direction
• Anterior—head end• Posterior—tail end
Body Direction
• Caudal—toward the tail• Cephalic—toward the head
Body Direction
• Distal—away from the point of attachment of a structure on the body (toes are distal to the knee)
Body Direction
• Proximal—toward the point of attachment of a structure on the body (hip is proximal to the knee)
Body Direction
• Dorsal—back of an animal
Body Direction
• Ventral—belly of an animal
Body Direction
• Inferior—below a point of reference (mouth is inferior to the nose)
Body Direction
• Superior—above a point of reference (the neck is superior to the chest)
Body Direction
• Lateral—away from the plane that divides a bilateral animal into mirror images
Body Direction
• Medial (median)—on or near the plane that divides a bilateral animal into mirror images