11 Secrets Inside The Human Body

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Updated on: Educator Review By: Michelle Connolly

Our body holds many secrets. The human body has cells, tissues, organs, and systems all working together. There are 206 bones that make up the human body called “The skeleton”.

Our bodies contain eleven major organ systems. The eleven major organ systems are the reproductive system, the nervous system, the integumentary system, the musculoskeletal system, the circulatory system, the excretory system, the Immune system, the urinary system, and the endocrine system, the digestive system, and the respiratory system.

1-The Reproductive System

The reproductive system is important for species to continue in humans, plants, and animals. There are many organs and tissues that are involved in producing offspring “children”.

In” humans”: The reproductive system in males includes the prostate, testes, and penis.

In females, it includes the fallopian tubes, the uterus, the cervix, the ovaries, and the vagina. The process of pregnancy in a female’s uterus takes about nine months.

2-The Respiratory System

A respiratory system is a group of organs and tissues. It is responsible for inhaling and exhaling “breathing’’ and delivers oxygen to the cells in your body. 

The respiratory system includes airways, lungs and blood vessels. It has many different parts that work together to help you breathe such as the lungs, mouth, sinuses, throat, and windpipes. 

Our Lungs

The most important part of our respiratory system. The lungs are two organs that absorb oxygen from the air and pass it into our blood and release carbon dioxide.

Our lungs consist of two parts: the left lung and the right lung. Our left lung is about 10 per cent smaller than our right one. We breathe oxygen and other gases, each organ in our body needs oxygen to live.

3-The Nervous System

Each part of the nervous system plays a vital role in the body. Our nervous system is your body’s command centre. The nervous system controls other body systems, such as digestion, breathing and production. The nerves connect the spinal cord to skin, joints, muscles etc.

The nervous system is made up of two parts: The central nervous system and the peripheral nervous system. The brain and the spinal cord are the central nervous system. Our brain controls movements and thoughts. The peripheral system allows the brain and spinal cord to receive and send information to other areas of the body, which allows us to react to stimuli in our environment.

4-The Integumentary System

The integumentary system is the set of organs that is around you. If you look in the mirror you will see it. This system tells you whether the person is young or old. The integumentary system acts as a physical barrier between the external environment and the internal environment. The integumentary system consists of the skin, hair, nails, glands, and nerves. The integumentary system protects our inside elements from any harm. 

The skin is one of the largest organs of the body. Skin covers the human body from its head to toes. Skin is a vital organ because it protects our outside and inside organs. The skin of each human body is different from another. Some have white skin and some have dark.

5-The Musculoskeletal System

The musculoskeletal system is an organ system that helps humans to move using their muscular and skeletal systems. It is made up of the bones of the skeleton, muscles, and other connective tissue. Bones are important for our stability. Bones without muscles can’t keep in their place and give it the ability to move. 

Our body consists of 206 bones. The musculoskeletal system gives us the shape of the body. It’s considered a framework for many organs like the skull protects the brain and the rib cage protects the lungs.

6-The Circulatory System

The circulatory system carries oxygen, and nutrients to cells, and removes waste products. The circulatory system is made up of blood vessels. Blood vessels have types including veins, arteries, and capillaries. Blood vessels carry blood away from and towards the heart. The heart is a vital organ in our body. The heart is inside our chest and it pumps blood around the body. Arteries carry blood away from the heart and veins carry blood back to the heart.

What Are the Parts of the Circulatory System?

Two pathways come from the heart:

The pulmonary circulation is a short loop that moves the blood between the heart and the lungs.

The systemic circulation carries blood from the heart to all of the body.

7-The Excretory System

The Excretory System is responsible for the elimination of wastes and unnecessary materials from the body fluids of an organism. Different parts of the body are involved in this process, such as sweat glands, the liver, the lungs and the kidney system. 


Kidneys are one of the main organs of the excretory system. There are two kidneys located on each side of the backbone. Kidneys are bean-shaped. Nephrons are the functional units of the kidney. Nephrons’ function is to filter the blood.

The liver:

The liver is one of the organs of the excretory system, it sits on the right side of the stomach. The liver’s responsible for filtering the blood that comes from the digestive tract before passing it to the whole body. The liver also makes proteins that are for blood clotting.

8-The Urinary System

The urinary system is also known as the renal system. The urinary system is responsible for creating urine and filtering the blood. It works with the lungs, skin and other organs to preserve the balance of chemicals and water in the body. The urinary system includes the kidneys, urethra, ureters, bladder and renal pelvis.

The urine is made by the kidneys, it filters the wastes and water from the blood. Urine moves from the kidneys through two thin tubes called ureters and fills the bladder. When it is full, we urinate through the urethra to evict the waste.

9-The Endocrine System

The endocrine system works with the nervous system to organize the activity of the body’s cells. The endocrine system is made up of glands that make the hormones “body’s chemical messengers”.

Glands release hormones into the bloodstream. Hormones travel to cells in other parts of the body. Hormones have many functions like helping in controlling mood, growth development, and reproduction.

The parts of the endocrine system are the hypothalamus, pituitary, thyroid, parathyroid, adrenals, pineal body, ovaries, and testes.

10-The Immune System:

Our immune system is important for our survival. The immune system is considered a barrier to any attack from bacteria, viruses, and parasites.

The main parts of the Immune System are:

white blood cells, antibodies, complement system, lymphatic system, spleen, bone, marrow, and thymus.

Some infections, like the flu and the common cold, have to be fought many times because so many different viruses or strains of the same type of virus can cause these illnesses. Catching a cold or flu from one virus does not give you immunity against the others. So we should strengthen our immunity by eating healthy food and doing some exercise.

11-The Digestive System

Your digestive system breaks up the food we eat into small parts. Our body absorbs and moves nutrients like fats, vitamins, carbohydrates, proteins, and minerals to where they are needed. The digestive system includes the mouth, throat, oesophagus, stomach, small intestine, large intestine, rectum, and anus.

Your large intestine absorbs water, and the waste products of digestion create stool. The small intestine’s job is to absorb most of the nutrients from what we eat and drink. 

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