Human Body Systems
As we have previously learned, cells are organized into tissues. Groups of tissues work together to fill a specific body function as an organ. Organs that interact with each other for a larger purpose are known as organ systems or body systems. There are 11 body systems in humans that each fill a critical function.
Some body systems are responsible for support and movement such as the skeletal and muscular systems. Body systems such as the respiratory, circulatory, digestive, and excretory systems helps the body obtain nutrients and eliminate wastes from the body. The endocrine and nervous systems send messages to control the body and the integumentary and lymphatic systems protect the body. Finally, the reproductive system is responsible for reproduction (obviously). Not every organ belongs to only one organ system. Some organs fill multiple functions or act as intermediary organs where material is transferred from one organ to another. For example, bones provide structure to the body, but bone marrow (the spongy core of our bones) produces blood cells. The testes and ovaries are reproductive organs that produce gametes. However, testes and ovaries both also produce hormones as chemical messengers for the body making them endocrine organs as well. |
The body systems each fill a critical function towards the ability to maintain homeostasis. If the body is too hot or too cold, then the integumentary system responds by causing you to sweat to cool off or shiver to heat up. Other body systems have their own ways to respond to imbalances. When body systems are unable to correct these imbalances, diseases develop. For example, cigarette smokers will produce extra mucus to clean away tar and burned material from their airways, however if the body cannot produce enough then the respiratory tract will become damaged.
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Skeletal System
The skeletal system provides structure and support for the body, as well as protection for critical organs. The skeletal system is made up of bones, joints, ligaments, tendons, and cartilage. Bonus are large organs that have become hardened with calcium. Joints are the locations where bones meet. Ligaments are tough tissue that connects bones like tape. Tendons are like ligaments but attach bones to muscles instead. Finally cartilage is the tough tissue that fills the space between bone joints. In addition, certain parts of your body like your nose and ears are made of cartilage.
Tendons allow the muscular system to interact with the muscular system, allowing you to move. The inside of bones has a matrix of calcified tissue filled with soft spongy tissue called marrow. This marrow is responsible for producing both red and white blood cells. In doing so the skeletal system also interacts with the circulatory system. |
Muscular System
The muscular system is made up of all the muscles in your body. Muscles themselves are organs that connect to bones to move the body, organs to move material within the body, or to other muscles to compound their strength for enhanced power.
There are 3 types of muscle tissue:
Muscles function by squeezing each cell tighter, causing the tissue to bunch up and shorter, thus pulling on the connected point.
There are 3 types of muscle tissue:
- Skeletal Muscle - Layers of long muscle cells that attach to the skeleton.
- Cardiac Muscle - Similar to skeletal muscle, but found only in the heart.
- Smooth Muscle - Unlike skeletal and cardiac muscle, smooth muscle is arranged into tubes that squeeze to push food and waste through your digestive tract
Muscles function by squeezing each cell tighter, causing the tissue to bunch up and shorter, thus pulling on the connected point.
Circulatory System
The circulatory system is actually a term used to describe the combination of the cardiovascular system and the lymphatic system. The circulatory system is the network of tubes that transport blood and lymph throughout the body.
The cardiovascular system includes the heart, blood, and blood vessels. Blood is the liquid used by the body to transport oxygen, carbon dioxide, food, and waste. Blood travels through blood vessels and is pushed through them by the squeezing of the heart muscles (cardiac muscles). Blood picks up oxygen in the lungs, transports it throughout the body where is slowly trades the oxygen for carbon dioxide. The carbon dioxide is the filtered out when the blood returns to the lungs. In this purpose the circulatory system interacts with the respiratory system.
In addition, blood picks up nutrients from the small intestines and transports them throughout the body. As it flows throughout the body, the blood also picks up waste material which is then filtered out by the liver and kidneys and excreted as urine. By doing this the circulatory system interacts with the digestive and excretory systems.
The other, less well known half of the circulatory system is the lymphatic system. The lymphatic system produces and transports lymph. Lymph is the clear liquid that lubricates the inside of your body and transports specialized immune cells. Lymph and these specialized cells are produced in in hundreds of small organs spread throughout your body called lymph nodes. The lyph is then transported throughout the body by tubes called lymphatic vessels. Unlike the cardiovascular system, lymph is not pumped and simply moves throughout the body by diffusion.
The cardiovascular system includes the heart, blood, and blood vessels. Blood is the liquid used by the body to transport oxygen, carbon dioxide, food, and waste. Blood travels through blood vessels and is pushed through them by the squeezing of the heart muscles (cardiac muscles). Blood picks up oxygen in the lungs, transports it throughout the body where is slowly trades the oxygen for carbon dioxide. The carbon dioxide is the filtered out when the blood returns to the lungs. In this purpose the circulatory system interacts with the respiratory system.
In addition, blood picks up nutrients from the small intestines and transports them throughout the body. As it flows throughout the body, the blood also picks up waste material which is then filtered out by the liver and kidneys and excreted as urine. By doing this the circulatory system interacts with the digestive and excretory systems.
The other, less well known half of the circulatory system is the lymphatic system. The lymphatic system produces and transports lymph. Lymph is the clear liquid that lubricates the inside of your body and transports specialized immune cells. Lymph and these specialized cells are produced in in hundreds of small organs spread throughout your body called lymph nodes. The lyph is then transported throughout the body by tubes called lymphatic vessels. Unlike the cardiovascular system, lymph is not pumped and simply moves throughout the body by diffusion.