Question

What are the 11 major organ systems and their main functions?

Answer 1

CIRCULATORY SYSTEM

This system is made up of the heart, blood, blood vessels, and lymphatics. It is the body’s delivery system, concerned with circulating blood to deliver oxygen and nutrients to every part of the body.

DIGESTIVE SYSTEM

The purpose of the digestive system is to turn the food you eat into something useful for the body. When you eat, your body uses this system to digest food so your cells can use it to make energy. The organs involved in this system include the mouth, stomach, and intestines.

ENDOCRINE SYSTEM

This system is made up of a collection of glands, including the pituitary and thyroid glands, as well as the ovaries and testes. It regulates, coordinates, and controls a number of body functions by secreting chemicals into the bloodstream. These secretions help control moods, growth and development, and metabolism.

INTEGUMENTARY SYSTEM

This system consists of the skin, hair, nails, and sweat glands. Its main function is to act as a barrier to protect the body from the outside world. It also functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature.

MUSCULAR SYSTEM

This system is made up of muscle tissue that helps move the body and move materials through the body. Quite simply, muscles move you. Muscles are bundles of cells and fibers that work in a simple way: they tighten up and relax.

NERVOUS SYSTEM

The nervous system is the control center of the human body. It is made up of the brain, spinal cord, and nerves. It receives and interprets stimuli and transmits impulses to organs. Your brain uses the information it receives to coordinate all of your actions and reactions.

REPRODUCTIVE SYSTEM

The human reproductive system ensures that humans are able to reproduce and survive as a species. It is made up of organs such as the uterus, penis, ovaries, and testes.

RESPIRATORY SYSTEM

The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. It consists of the nose, larynx, trachea, diaphragm, bronchi, and lungs.

SKELETAL SYSTEM

The skeletal system provides the shape and form for our bodies in addition to supporting and protecting our bodies, allowing bodily movement, producing blood cells, and storing minerals. This system consists of bones, cartilage, and joints.

URINARY SYSTEM

The purpose of the urinary system is to filter out excess fluid and other substances from your bloodstream. Some fluid gets reabsorbed by your body but most gets expelled as urine. The organs found in this system are the kidneys, ureters, urinary bladder, and urethra.

Answer 2

Organ Systems

Different organs can work together to perform a common function, like how the parts of your digestive system break down food. We refer to an integrated unit as an organ system. Groups of organ systems work together to make complete, functional organisms, like us! There are 11 major organ systems in the human body, which include the circulatory, respiratory, digestive, excretory, nervous and endocrine systems. The immune, integumentary, skeletal, muscle and reproductive systems are also part of the human body.

The Circulatory & Respiratory Systems

The circulatory system is responsible for transporting blood throughout the body. It consists of the heart and blood vessels known as veins, arteries and capillaries. Think of blood vessels as the highways of the body, bringing important cargo to and from the cells. In the circulatory system, blood is pumped from the heart to the lungs, so they'll get oxygen, and then pumped to the body's cells. Here is a diagram of the human circulatory system, including the heart and major arteries, which are in red, and veins, which are in blue.

The Human Circulatory System

In order for blood to provide oxygen to the body, the body must have a way of obtaining that oxygen. The respiratory system allows air to enter the lungs and for oxygen to diffuse into the blood en route to the body's tissues. The entrance to the respiratory system can be found in the nose and the mouth, where air enters the body and then travels through the larynx and pharynx in the throat to the trachea or windpipe. From the trachea, right and left branches, known as bronchi, carry oxygen to the alveoli, where oxygen moves into the blood, while carbon dioxide moves into the lungs to be exhaled.

The alveoli are the smallest parts of the respiratory system and deal specifically with exchange of gases, like traders at a market. For example, they receive goods, like oxygen and carbon dioxide, from other sources and then trade them in the lungs. In the following illustration, you'll find the major organs of the respiratory system, as well as an illustration of gas exchange in the alveoli on the left.

The Human Respiratory System

Digestive & Excretory Systems

The digestive system is responsible for bringing food into the body and breaking it down to useable components. As shown in the diagram below, it starts at the mouth, where we ingest our food and use our saliva, teeth and tongue to bite and mash it. The food then travels through the esophagus into the stomach, where strong acids break it down even further. During the last two stages of digestion, nutrients and water are absorbed through the small intestine and the large intestine, respectively. Any remaining waste products are stored in the rectum and eliminated through the anus.

The Human Digestive System

The urinary or excretory system is where liquid waste is eliminated as urine. The excretory system starts with the kidneys, important organs for cleaning the blood and balancing water in the body. In the excretory system, the liquid part of the blood, or plasma, enters through the kidneys, where important nutrients, like sugar and some salt, are reabsorbed into the body. Compounds we don't need, like urea or excess water, are sent to the bladder in the form of urine. Urine leaves the body through the urinary tract and exits the body at the urethra, as shown in the following illustration of the female urinary system.

The Female Excretory System

Nervous, Endocrine & Immune Systems

Without a master control system that tells our bodies what to do, none of the organ systems we've talked about so far would work. The organs in the human nervous system are made up of cells, called neurons, that use chemicals and electricity to send messages. This system has two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS), which you can see in the diagram below. The central nervous systemconsists of the brain and the spinal cord, which serve as the main control centers for the body and process all incoming and outgoing messages. The peripheral nervous system includes all the nerves in your body that bring messages to the central nervous system and from the CNS to the muscles.

The Human Nervous System

Whereas the nervous system mainly uses electrical signals to communicate between cells, the endocrine system relies upon chemicals, called hormones, to send long distance messages through the body. For example, instead of communicating directly by talking to your neighbor, you decide to send him or her a letter. The main organs found in the human endocrine system are located in the brain and include the hypothalamus, thalamus and pituitary gland. They talk to other endocrine organs, like the adrenal glands, testes and ovaries to assist with other organ systems. The following is an image of the different organs that make up the endocrine system and secrete hormones