Endocrine System

-Mollusk- One of the few phylum that have a system instead of a few organs that regulate the endocrine system. Octopus- the optic gland in the octopus is one of the most established gland in the organism. The optic gland controls bodily growth. Common snail- the common snail is a hermaphrodite (both an egg and a sperm) The cerebral ganglion secretes a neurohormone the controls growth of both parts.

-Amphibians- most amphibians only have 1 thyroid gland. This gland controls growth, metabolic rate, and development throughout the organism. The size of the gland can vary, and is dependent on season and metabolic state.

-Annelids- the hormones regulate reproduction and regeneration. The neurosecretory cells are found in the ganglia. In Earthworms, hormones are secreted to regulate secondary sex characteristics. The ganglia is found in the brain.

Humans- The endocrine glands are controlled directly by the nervous system, as well as chemical receptors in blood. By regulating the glands, the body maintains homeostasis. Arthropods- hormones carry fluids that carry messages to synthesis sites. Hormones are produced by glands, neuro glands, and neuro centers. Arthropods have many organs that produce hormones for reproduction, metamorphosis, and moulting.

Echinoderms- Echinoderms don't possess a well developed glandular system, but they do have mediated reactions between cells.

Reptiles- compared to mammal, their thyroids and parathyroids have a different morphology. The ardenals are paired and located in the mesorehuim or the mesovarium and must be avoided during neutering.

Arthropods- Hormones carry fluids (haemotymph) that carry messages to synthesis sites. Hormones are produced by glandular, neuroglandular and neural centres. they have several organs that produce hormones controlling reproductin, metamorphisis, and moulting.