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Overview of Anatomy and Physiology
Defining Anatomy and Physiology
Anatomy refers to the study of the structure and shape of the body and other body parts, along with their relationship to each other. The word Anatomy is derived from the Greek words ‘tomy’ meaning to cut and ‘ana’ meaning apart.
Physiology refers to the study of how the body and body parts function or work. It is also derived from the Greek; ‘physio’ meaning nature, ‘ology’ meaning the study of.
Anatomy and physiology have an intrinsic relationship to each other and often the two divisions are studied as one whole unit, in much the same way as the body forms a whole unit while physiology gives purpose to it.
Structural Levels of Organisation
There are several different levels of structural organisation within the body. The simplest level of organisation is the Chemical Level. At this level of organisation atoms combine to form molecules which are the basis for the next level of structural organisation; the Cellular Level. At the Cellular Level molecules band together to form cells. These cells vary in their size and shape and have specific purposes within the body. The next level of organisation is the Tissue Level. Tissue is formed when cells which are similar in shape and size come together and form groups to perform a common function. Next there is the Organ Level of structural organisation. Organs are structures containing two or more tissue types which perform a specific function in the human body. The fifth level of structural organisation is the Organ System Level. This consists of different organs which work closely together to perform specific functions. An example of this would be the cardiovascular system, where the heart, veins, arteries and blood work together within the body. Finally, there is the Organismal Level of structural organisation, which refers to the whole organism – in this instance, the example is a human being made up of many different organ systems which function to allow the human to survive.
There are several different organ systems of the human body. The integumentary system is the skin, or external covering of the body. This system provides a waterproof barrier and protection for underlying tissue and organs and also regulates processes such as body temperature. Pain, pressure and temperature receptors in the skin can assist the rest of the body to know what is happening at skin surface level.
The skeletal system is the framework for the human body. It supports the body, protects organs, and when muscle is attached it allows for movement. The skeletal system consists of the bones, cartilages, ligaments and joints within the body. Bones also store minerals and the formation of blood cells (hematopoiesis) occurs within the bone structures as well. The muscular system is comprised of muscles which allow the body to move through their contracting movement. The nervous system is effectively the control system of the human body and consists of the brain, spinal cord, nerves and sensory receptors.
Next there is the endocrine system which consists of a number of glands that produce hormones and control a large number of the activities of the body.
The cardiovascular system consists of the heart and blood vessels. Using blood as a transport medium, the cardiovascular system is responsible for carrying oxygen, nutrients, and hormones around the body.
The lymphatic system consists of the lymphatic vessels, lymph nodes and lymphoid organs such as the tonsils and spleen. It’s commonly referred to as the immune system, as the cells involved in immunity are found in this system.
The respiratory system supplies the body with oxygen and removes carbon dioxide. The nasal passages, pharynx, larynx, trachea, bronchi and lungs are all parts of the respiratory system.
The digestive system runs from the mouth to the anus and is responsible for breaking down food and delivering the nutrients from it to other areas of the body. The digestive system is made up of the mouth, esophagus, stomach, small intestine, large intestine and rectum.
The urinary system removes waste products from the blood and flushes them out of the body. The system is comprised of the kdneys, ureters, bladder and urethra. One major function of this system is that it maintains the balance of water and salt throughout the body.
The reproductive system’s only purpose is to produce offspring. The male and female reproductive systems differ greatly and are made of different organs, accessory glands and duct systems. In the male system sperm is produced by the testes, in the female system the ova (or eggs) are produced by the ovaries.
Ultimately, the goal of all these systems in the human body is to maintain life. For this to occur there are a number of different factors which need to exist, these factors are referred to as survival needs. These include oxygen, water, nutrients, and appropriate temperature and atmospheric pressure.
Oxygen and water are essential for survival. Our bodies are comprised of between 60 to 80 percent water and it provides the base for body excretions and secretions.
Nutrients are necessary to the human body as they provide energy and the chemicals needed to build or repair cells. They are also required for chemical reactions and oxygen transportation to occur around the body.
Unless the body maintains a temperature of around 37 degrees Celsius, it cannot survive. If body temperature drops too low metabolic reactions slow and eventually cease, if the body temperature is too high chemical reactions happen too rapidly and proteins begin to break down. The result of these temperature extremes is death.
Atmospheric pressure refers to the force which is exerted on the surface of the body by the weight of the air surrounding it. If atmospheric pressure is too low then the body’s gas exchange may not be able to support cellular metabolism. An example of this would be at high altitudes where the air is thinner and the pressure is lower.
Learn more about anatomy and physiology
Homeostasis is a term which describes the body’s ability to maintain a mostly stable internal environment even when faced with external changes. Examples of processes which maintain homeostasis include the regulation of body temperature, such as the act of perspiration when the weather is hot in an effort to cool the body, regulation of heart rate, blood pressure and respiration rate, and the blood levels of oxygen, carbon dioxide, glucose and other minerals.