Hormones vs. Neurotransmitters

Main Difference

The main difference between hormones and neurotransmitter is that hormones belong to the endocrine system whereas neurotransmitters belong to the nervous system.

Difference Between Hormones and Neurotransmitters

Comparison Chart

Hormones vs. Neurotransmitters

Hormones are regulatory chemical substances which are produced in an organism and transported in tissue fluids like sap or blood and stimulate specific cells or tissues. Neurotransmitters are endogenous chemical substances which are released at the end point of a nerve cell by the arrival of nerve impulse, transmitting the impulse into another muscle, neuron or some other structure. Hormones are synthesized in both plants and animals whereas neurotransmitters are synthesized only in animals. Hormones are polypeptides, terpenoids, amines, steroids or phenolic compounds whereas neurotransmitters are amino acids, proteins or gases.

Hormones are secreted by specific glands and released into the bloodstream, but they show their action at a distant place, at target cells. Melatonin and cortisol are produced by the brain and released into the blood and affect other parts of the body. Contrary to the glands, neurotransmitters are released from the presynaptic nerve terminal in the brain. They travel across the synaptic cleft, a small space between two adjacent neurons and move to the next neurons, postsynaptic neurons. There they bind to specific receptors, causing changes in the electrical properties of target cells, which can cause various postsynaptic effects. Hormones act for longer periods of times and always work involuntarily whereas neurotransmitters actions are short-lived and can affect both voluntary activities (eating, walking, bathing, etc) and involuntary actions (breathing, blinking, etc)

What is Hormones?

Hormones are specific chemical messengers in the body that are synthesized in the endocrine glands. These messengers control body functions from simple basic needs like hunger to complex systems like reproduction even the mood and emotions. There are almost 20 endocrine glands which produce numerous hormones. Hypothalamus is responsible for controlling body temperature, moods, hunger, and synthesis of hormones for other glands and also controls sleep, thirst and sex drive. Parathyroid gland produces Triiodothyronine and thyroxine which controls the metabolism of the body. The pancreas releases insulin which helps to control blood sugar level. The thyroid releases hormones associated with heart rate and calorie burning. The pineal gland also known as thalamus produces serotonin derivatives which affect sleep pattern. The adrenal gland produces adrenaline which controls sex desire and cortisol which is the stress hormone. The pituitary is the major glands also known as the master gland. It produces hormones (somatotropin) which play a role in growth and development. It also produces prolactin in a woman at the time of childbirth for lactation. Prolactin also plays a role in fertility by influencing FSH and GnRH. Ovaries produce estrogen, progesterone, and testosterone, all are sex hormones, in the female body whereas tests produce male sex hormones (testosterone). Estrogen causes puberty and prepares the uterus for the pregnancy. All these hormones and glands work together to manage and control the activities of the whole body.

What is Neurotransmitters?

Neurotransmitters are endogenous substances which send signals across a chemical synapse from one nerve cell to the other target cell, muscle cell or gland cell and primarily present in the nervous system. Neurotransmitters affect transmembrane ion flow and either increase or decrease the chance that the cell will produce an action potential. These are classified based on the facilitation of ion flow and structure. On the basis of facilitation of ion flow, these are of two types, excitatory neurotransmitter, an inhibitory neurotransmitter. Excitatory neurotransmitters excite the brain and are somewhat overactive. They allow the postsynaptic neuron to produce action potential which enhances the transmembrane ion flow. Examples of such neurotransmitters are dopamine, epinephrine, and norepinephrine.

The second type is inhibitory neurotransmitters which help to create balance by calming the brain. They slow the transmembrane ion flow and inhibit the postsynaptic neuron from producing an action potential. Examples are GABA, serotonin, and dopamine. Neurotransmitters can also be classified based on molecular or chemical structure; small molecule neurotransmitters and neuropeptide neurotransmitters. Small molecule neurotransmitters are synthesized locally within the axon terminal and are smaller than neuropeptides. Examples are amino acid neurotransmitter (GABA, glycine, glutamate), biogenic amines (dopamine, norepinephrine, epinephrine, histamine, and serotonin), purinergic neurotransmitters (ATP adenosine triphosphate, adenosine) and acetylcholine. The second class is neuropeptide which is larger as their structures are made up of three or more amino acids (3 to 36 amino acids). Endorphins Enkephalins, oxytocin, vasopressin, insulin and glucagon are examples of neuropeptides.

Conclusion

It has concluded that hormones and neurotransmitters are two types of chemical messengers and differ from each other based on the production system, type of action and functions.