Summary:
- Vertebrates are a subphylum of the phylum Chordata.
- The vertebrate endoskeleton includes a vertebral column, cranium, limbs, and limb girdles.
- Vertebrates have a closed circulatory system with a heart.
- The immune system is the organ system that defends the body from pathogens and other causes of disease.
- The nervous system consists of a brain in the head region and a long spinal cord that runs from the brain to the tail end of the backbone.
- The heart is divided into chambers that work together to pump blood.