Do you know there are messages sent within your body?

In this second part of “What are you made of?”, we are going to look at another 6 organ systems.

You will discover that many of these systems make use of hormones and cells to send and receive messages to instruct specific organs what to do and when to do them.

12 Major Systems

Our body has 78 organs and 12 major systems:

1.Digestive System

2.Excretion/ Urinary System

3.Circulatory System

4.Respiratory System

5.Skeletal System

6.Muscular System

7.Endocrine System

8.Immune/ Lymphatic System

9.Reproductive System

10.Integumentary System

11.Nervous System

12.Endocannabinoid System

In part 1 we have covered the first 6 systems.  In this deck, we will learn the remaining 6 systems. You will discover that cells and hormones are very much involved in these systems, enabling the systems to receive messages on what to do and when to do them. There are many processes that take place to protect us from the external environments and from harmful bacteria and viruses.

1. The Endocrine System

Image by Open Stax & Tomáš Kebert &, CC BY-SA 4.0 via Wikimedia Commons

Our endocrine system is composed of several organs all over our body. These organs, called glands make and release hormones. Hormones are chemical messengers that travel in your bloodstream to tissues, muscles, internal organs and skin. They send messages to tell each part of our body what to do and when to do it.

Hormones affect nearly every process in our body, including:

  • Metabolism (the way our body break down food and get energy from nutrients).
  • Growth and development.
  • Sleep, emotions and mood.
  • Fertility and sexual function.

Many things can affect how our body makes and releases hormones. Illness, stress, depressing situations, aging and certain medications can cause our glands to produce too much or too little of a hormone. This imbalance can cause health problems, such as weight gain, high blood pressure, changes in sleep, mood and behavior.

The Endocrine system works hand in hand with the nervous system for internalized communication and regulation of bodily functions. It utilizes your brain, thymus, pancreas, and more to transfer signals throughout the body.

2. The Nervous System

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Note the difference : the nervous system uses electrical impulses to send messages through neurons while endocrine glands use hormones to send messages to the target cells through the bloodstream

The nervous system comprises of our brain, nerves, ganglia, and spinal cord. The system uses 2 basic types of cells:

1.Neurons (nerve cells that send and receive signals)

2.Glia (any of the cells that hold nerve cells in place and help them work the way they should.)


Neurons are nerve cells that use electrical and chemical signals to send messages all over your body to allow us to do everything from breathing to talking, eating, walking, and even the blinking of our eyes. It helps all the parts of the body to communicate with each other. It also reacts to changes both outside and inside the body.

Our nervous system controls both our conscious and unconscious bodily processes.

LadyofHats, Public domain, via Wikimedia Commons

3. The Immune System

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The Immune system is also called the Lymphatic system. Its key function is to protect our body from external viruses and bacteria infection. It also helps in wound healing. When bacteria enter the bloodstream, white blood cells jump into action, attacking this foreign substance, absorbing it into the cell, and then destroying the pathogen inside. The white blood cells may then flush it from the system. This is the inflammation process by which the body’s white blood cells and substances they produce protect us from infection with foreign organisms, such as bacteria and viruses.

4. The Reproduction System

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In the human reproduction process, two kinds of cells are involved. A sperm cell produced by the male reproductive system has to fertilize an egg in the female reproductive system to form an embryo that will develop into a fetus.

Male Reproductive System

When a guy reached puberty, the two oval-shaped testicles make and store millions of tiny sperm cells. The testicles are also part of the endocrine system because they make hormones, including testosterone. Testosterone is the hormone that causes boys to develop deeper voices and stimulates the production of sperm.

Female Reproduction System

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When a baby girl is born, her ovaries contain millions of eggs. At puberty, the pituitary gland (in the central part of her brain) starts making hormones that stimulate the ovaries to make female sex hormones.

The female reproduction system go through the following phases:

  • The Follicular phase – Oestrogen hormones are released and that the lining of the female uterus to thicken. Meanwhile the Follicle stimulating hormone(FSH), cause an egg in the ovary to mature.
  • The Ovulation -Luteinising hormone (LH) stimulates the release of the egg.
  • The Luteal phase – The egg leaves the female ovary and begins to travel through the fallopian tubes to the uterus. The level of the hormone progesterone rises to help prepare the uterine lining for pregnancy.

If the egg becomes fertilized by a sperm and attaches itself to the uterine wall (implantation), the woman become pregnant. More progesterone hormones will be made by the gland called the corpus luteum to thicken the uterine lining and creating a good environment for a fertilized egg to implant. Corpus luteum is a temporary gland that develops after a woman ovulate. Once the placenta is formed, it will take over the progesterone production.

If the egg is not fertilized, estrogen and progesterone hormone levels will drop and the thick lining of the uterus start to shed. The Menses phase will begin where the woman will bleed for a period between 3 to 7 days.

5. The Intergumentary System

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The integumentary system is made up of our skin, nails, hair, the glands and nerves on our skin.  It protects our body from the external environment. This system has many functions and plays a vital role in helping other systems maintain their functions.

Functions of the Intergumentary  System

1.Sends white blood cells to injuries to begin the healing process.

2.Helps us absorb vitamin D, which acts as a hormone and is crucial to our bone health because it affects calcium absorption.

3.The tiny hairs in our nose help our respiratory system because they filter out dust and other particles before we inhale them into our lungs.

4.It is our body’s coat of armor and the first line of defense against viruses, bacteria and other microbes.

5.Stores fat, water, glucose and vitamin D, and helps support our immune system to protect us from diseases.

6.Regulates our body temperature, allow us to stay cool and helps us feel the sensation of hot and cold temperatures.

7.Protects us from the sun’s ultraviolet (UV) rays and sunburn.

8.Excretes sebum, sweat and other waste from our body.

6. The Endocannabinoid System


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The Endocannabinoid System (ECS) is the unifying system that ensures balance in all other functions of the body. It is the background code running in our human-computer that allows the software of the other systems to be useful.   The ECS is a complex cell-signaling system that was identified in 1988 by researchers Allyn Howlett and William Devane at Saint Louis University School of Medicine in a government-controlled study.

The ECS regulates and controls many of our most critical bodily functions.  It is crucial for your body to achieve “balance”. For example, when the weather is hot, your ECS will cause your body to sweat so that your body will cool down. If you are hungry, it is because your ECS is reminding you that your body is in need of energy.

The ECS uses cannabinoid receptors found in select tissues to help regulate important functions such as:

  • Appetite
  • Digestion
  • Immune function
  • Inflammatory cascade, including neuroinflammation
  • Mood
  • Sleep
  • Reproduction/fertility
  • Motor control
  • Temperature regulation
  • Memory
  • Discomfort
  • Pleasure/reward


Give it a thought

There are many processes taking place within our body that we do not even understand. The hormones, chemicals and even electrical signals produced and transmitted all around our bodies are somewhat beyond our knowing and understanding. Yet, all the processes are there to keep us protected, comfortable and healthy. It appears as if there is a Mastermind, a main Programmer who wrote the codes in such a way that every algorithm is for our good. It tells us one thing – this Master Programmer loves us deeply.