Organizations of the Human Body PDF

ORGANIZATI ONS OF THE HUMAN BODY HUMAN ORGANISM Humans – are organisms and have many characteristics in common with other organisms. Life – is the most common important feature of all organisms. Essential characteristics of life : 1.Organization 4. Growth...

ORGANIZATI ONS OF THE HUMAN BODY HUMAN ORGANISM Humans – are organisms and have many characteristics in common with other organisms. Life – is the most common important feature of all organisms. Essential characteristics of life : 1.Organization 4. Growth & Development 2. Metabolism 5. Reproduction 3. Responsiveness 6. Homeostasis CHARACTERISTICS OF LIFE 1. Organization- living things are highly organized, and basically composed of cells. These cells are composed of highly organized organelles, which depend on the precise organization of large molecules. Disruption of this organized state can result in loss of functions and death. 2. Metabolism – the ability to use energy to perform vital functions, such as growth, movement, and reproduction. Plants can capture energy from sunlight, and humans obtain energy from food. 3. Responsiveness – being responsive means that an organism can sense changes in the environment and make adjustments that help maintain one’s life. Ex: movement towards food or water, away from danger or poor environmental conditions 4. Growth and Development – the ability of the cells to increase in size or number, producing an overall enlargement of all or part of the organism, leading towards the changes an organism undergoes through time. It begins with fertilization and ends with death. The generalized cells specialize to become specific cell types, such as skin, bone, muscle or nerve cells. As the cells specialize, tissues and organs take shape. 5. Reproduction – is the formation of new cells, leading to the transformation of new organisms. Without reproduction of cells, growth and development will not be possible. 6. Homeostasis – is the existence and maintenance of a relatively constant environment within the body. Each cell of the body is surrounded by a small amount of fluid, and the normal functions of each cell depend on the maintenance of its fluid environment within a narrow range of conditions, which include volume, temperature, and chemical content. These conditions are known as variables. Ex: body temperature is a variable that can increase in a hot environment, or decrease in a cold environment TERMINOLOGY AND THE BODY PLAN Etymology – this refers to derivations of new terms, that are commonly used in the study of anatomy and physiology. Most of the terms are derived from Latin or Greek and are descriptive in the original languages. Ex: foramen – is a latin word for hole, while magnum means large. The foramen magnum is therefore a large hole in the skull through which the spinal cord attaches to the brain. Words are often modified by adding a prefix or suffix. Example of which is the suffix “itis” which means an inflammation, so appendicitis is an inflammation of the appendix. DIRECTIONAL TERMS When describing parts of the body, it is often important to refer to their relative positions , and these directional terms have been developed to facilitate such references. It will always refer to the body in the anatomic position. Superior – upper parts of the body Inferior – lower parts of the body Anterior – front part of the body Posterior- back part of the body Cephalic – toward the head Caudal – toward the tail Ventral – the word anterior means that which goes before, and ventral means belly. The anterior surface of the human body is therefore the ventral surface, or belly, because the belly “goes first” when we are walking. Posterior – means that which follows, and dorsal means back. The posterior surface of the body is the dorsal surface, or back, which follows as we are walking. Proximal – means nearest Distal – means distant These terms are used to refer to linear structures, such as the limbs, in which one end is near some other structure, and the other end is farther away. Medial – means toward the midline Lateral – away from the midline Ex: the nose is located in a medial position in the face, and the eyes are lateral to the nose Superficial – refers to a structure close to the surface of a body Deep – towards the interior of the body Ex: the skin is superficial to the muscle and bone Prone – means to lie or be placed with the anterior surface down Supine – to lie or be placed with the anterior surface facing up