Overarching Function

The endocrine system is composed of glands and functions as a communication system in order to elicit a response from the body and regulate and maintain homeostasis. Endocrine glands produce hormones, which are released into the bloodstream and distributed to body cells. Hormones can then act as chemical messengers to target specific cells to produce a response. Hormones can further be classified as steroid hormones and amino acid hormones, as described below.

Basic structures and functions

Macroscopic structures

  1. Brain

    The brain has a pituitary gland that secretes hormones. These hormones help regulate many body functions and other endocrine glands, such as the thyroid gland, adrenal glands, and sex organs. A pituitary hormone, human growth hormone (hGH), stimulates cell division in tissues in order to regulate the body’s growth and development.

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  1. Pancreas

    The pancreas serves an important role in producing enzymes that digest carbohydrates, proteins, and fats. For example, the pancreas secretes the hormones insulin and glucagon, which helps to regulate blood glucose levels.

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Microscopic structures

  1. Steroids hormones

    Steroid hormones can go directly inside the cell. Once inside, it binds to a receptor and activates a specific strand of DNA in the nucleus.

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  2. Amino acid hormones

    Amino acid hormones do not go directly inside the cell. Instead, it must bind to receptors found on the plasma membrane of a target cell. Once the hormone binds to the receptor, it activates an enzyme inside the membrane and instantiates a chain of events, causing the cell to respond. This type of hormone is usually short-lived compared to steroid hormones.

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Connection to other systems

The nervous system interacts with the endocrine system to regulate and control the hormones produced. The hypothalamus in the brain acts as a communicator between the endocrine system and nervous system. It controls the release of hormones from the pituitary gland, which affects the hormones stimulated in other glands.

Differences between a frog and human

Because the endocrine system is mostly microscopic, it will be quite hard to observe it. In Dr. Buchholz’s research, “Frogs and humans have identical hormones that peak at birth and metamorphosis, have conserved hormone receptors and mechanisms of gene regulation, and have comparable roles for hormones in many target organs.” This shows that the endocrine systems between frogs and humans are similar.