The Human Body in Health and Disease Chapter One: Introduction to the Human Body. Chapter Outline: The ‘sciences’ of anatomy and Physiology; Levels of Organization of Body; Homeostasis; and Physical ‘examination’. Chapter Objectives: Define de terms; identify the major levels of organization in humans and others living organisms; explain the importance of Homeostasis; describe how positive and negative ‘feedback’ are involved in homeostatic regulation; use anatomical terms to describe body ‘regions’, ‘sections’, and relative positions; identify the major body cavities and their subdivisions; distinguish between visceral and parietal portions of serous membranes; and describe the four common techniques used in physical examination. The scientific study of living organisms, including humans, is called ‘Biology’. Human biology: `body structure`, or anatomy, and `body function`, or physiology. There are three general themes in `The Human Body` in health and disease. The first is that the human body function as an `integrated` and coordinated unit. `Coordination` exists at ALL levels, from single ‘Cells’, the smallest living units in the body, to `Organs` like the Brain, Heart, and Lungs. The components of body work ‘together’ to maintain a `stable` internal environment. Anatomy = Structure. Anatomy comes from Greek words that mean “to cut open”, is the study of the body’s internal and external structures and the physical relationships among body parts. Physiology = Function. Physiology is the study of the body function, examines the physical and chemical process that keep us alive and healthy. LEVELS OF ORGANIZATION IN THE BODY Understanding how functions of one level affect other levels ‘allow’ us to predict how the body will respond to external or internal changes. Interacting atoms form molecules that combine to form cells, such as heart muscle cells. Groups of cells combine to form tissues with specific functions, such as heart muscle. Two or more tissues combine to form an organ, such as the heart. The heart is one component of the cardiovascular system, which also includes the blood and blood vessels. All the organs systems combine to form an organism, a living human being. MOLECULES – CELLS – TISSUES – ORGANS – SYSTEM MOLECULES: Atoms are the smallest ‘stable’ unit they combine to form ‘molecules’. Some molecules have only two atoms, but others consist of many dozens of atoms that form complex shapes. Even at this simplest level, the specialized shape of a molecule often determines its function, this is the ‘molecular’ level of organization. Cells: cells are the smallest living units in the body. Each cell contains numerous ‘organelles’ ( which in turn are composed of many different molecules). “Heart muscle cells contain large numbers of special molecules that give these cells the ability to contract or shorten.” Tissues: a tissue is composed of a group of similar cells working together to perform a specific function. “The muscle cells of the heart make up one form of muscle tissue, whose function is to contract and thereby cause movement”. Although there are over 200 different cells types, there are only ‘four’ basic tissues types: Epithelial: tissue includes epithelia, which cover exposed body surfaces and line internal passageways and body cavities, and glands that produce secretions. “The surface of the skin is a familiar example of an Epithelium”. Connective: Fill internal spaces, provide structural support, a means for transport within the body (through blood movement), and energy storage. “Bone, fat deposits, and blood are examples of this varying tissue”. Muscle: has the ability to contract and produce movement. Nervous: conduct information (electrical signal) from one part to other part of body. Histos, tissue + Logos, study Histology = study of tissues (microscopic anatomy). Organs: An organ consists of several different tissue that work together to perform specific functions. Organ System: different organs working together. The heart, blood, and blood vessels form the cardiovascular system, and example of an organ system. Organism: all 11 (eleven) organ systems of the body work together to maintain the highest level of organization, that of the individual organism, in this case, a Human being. “Each level of structural organization is ‘totally’ dependent on the others”. For example, damage at the cellular, tissue, or organ level may affect an entire organ system. A molecular change in heart cells can cause abnormal contractions or even stop the heartbeat. Physical damage to the heart muscle tissue, as in a chest wound, can make heart ineffective – even when most of the heart muscle cells are structurally intact. Abnormal structure at organ level can make heart an ineffective pump even if the muscle cells and muscle tissue are perfect normal. FINALLY, SOMETHING THAT AFFECTS AN ORGAN SYSTEM WILL SOONER OR LATER AFFECT ALL ITS COMPONENTS. For example, the heart, cannot pump blood effectively if the organism has experienced massive blood loss. If the heart cannot pump and blood cannot flow, the tissue will begin to break down as cells suffocate or starve. These changes will not be restricted to the cardiovascular system, all cells, tissues, and organs in the body will be damaged. ORGAN SYSTEM LEVEL Integumentary – Skeletal – Muscular – Nervous – Endocrine – Cardiovascular – Lymphatic – Respiratory – Digestive – Urinary – Reproductive The third theme is that diseases fall into a relatively limited number of categories. For example, diseases resulting from infection may affect ‘any’ system. “One View, one Vision”… Events in ‘molecular’ or cellular levels.
Posted on: Sat, 17 Aug 2013 22:23:55 +0000
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