LEVELS OF ORGANIZATION OF HUMAN BODY

Transcription

1 LEVELS OF ORGANIZATION OF HUMAN BODY OBJECTIVES At the end of lecture student should be able to: Describe the levels of structural organization that make up the human body List the 11(eleven) systems of the human body, representative organs present in each, and their general functions. Define the terms like atoms, molecules, cell, tissue, organs, system, and organism. STRUCTURAL ORGANIZATION OF HUMAN BODY Anatomy is the study of the structure of the body and arrangement of body parts. Anatomy is the study of the structure or form of human body parts and how the body parts are arranged in relation with each other. There are many disciplines within anatomy. GROSS ANATOMY is the study of what can be seen with the naked eye.it is the study of large structures such as organs,bones muscles etc & Involves the technique of DISSECTION. Dissection means to section or to cut. STRUCTURAL ORGANIZATION OF HUMAN BODY The human body consists of many levels of structural complexity. The structural levels go from the most simple to most complex.each level builds upon the previous one, so that all of the levels are interrelated. The simplest level is the CHEMICAL LEVEL. The most basic chemicals are ELEMENTS which consists of ATOMS. eg carbon, hydrogen, oxygen, nitrogen. phosphorus and sulfur.

2 Atoms combine to form MOLECULES. eg Water(H 2 O),Oxygen(O 2 ),and carbon dioxide (CO 2 ). BIOMOLECULES which are molecules found in living tissue. The biomolicules are CARBOHYDRATES(Sugar and starch), LIPIDS(fats), and NUCLEIC AIDS (DNA & RNA). Organic molecules aggregate to form cellular ORGANELLES responsible for specific cell function such as cell membranes, that regulate the movement of chemical substances into and out of the cell, mitochondria, that convert energy of organic nutrients into ATP, and ribosomes, that are involved in the production of protein molecules.. Molecules combine in specific ways to from microscopic cells. Therefore, the next level of structural organization in the body is the CELLULAR LEVEL. The cell is the basic living structural and functional unit of the organisms (plants and animals), cells are the living building blocks of the organism. Examples of cell in animals: blood cells, nerve cells, muscle cells, skin cells, cells that fight disease, etc. Cells are structural and functional units of life. Each organism begins life as a single cell formed when a sperm injects the male genetic material(paternal chromosomes) into the ovum, forming a zygote, or fertilized ovum. Growth and development of a zygote through the stages of embryo, fetus, new born,

3 Child and adult requires two fundamental processes: mitosis and cellular differentiation. MITOSIS is a cell replication process- a type of cell xeroxing that results in an increase in the number of somatic cells in an organism. During mitosis, all the chromosomes and other cellular components in the present cell are replicated so that each daughter cell receives a full set of 46 chromosomes and all essential cell components. Each somatic cell is formed from an existing cell by the process of MITOSIS. The process of CELLURLAR DIFFERENTIATION allows cells, by SELECTIVE EXPRESSION OF GENES,to become anatomically distinct and functionally specialized. Although all cells contain 46 choromosomes and hence the complete human genome, cells generally only express about 15% of the genes they contain. Together, cells form tissue. The next higher level of organization is the TISSUSE LEVEL. TISSUE are made up of groups of cells that together perform a specific function or functions. Smooth muscle tissue is made up of smooth muscle cells and it is one of many tissues found in the wall of the stomach. When the smooth muscle tissue in the stomach wall contracts, it churns the food inside the stomach, which helps with the breakdown(digestion) of food.

4 The 4 basic tissue types in the human body are epithelial tissue, muscle tissue, connective tissue and nervous tissue. EPITHELIAL TISSUE(EPITHELIUM) Covers the body surface and lines the inside walls of organs. MUSCLE TISSUE Creates movement. CONNECTIVE TISSUE supports the body and protects organs. NERVOUS TISSUE provides a rapid internal communication system by transmitting electrical impulses. Different tissues join together to make up the next level of organization, the ORGAN LEVEL An ORGAN is a discrete structure that performs specific functions and is composed of at least 2 tissue types. The heart, Liver, Stomach, intestines, lungs, pancreas and brain are examples of organs. It consists o at least three different tissue types, all of which contributes to the stomach s functions of digestion. The epithelial tissue lines the stomach and aids in digestion by producing digestive juices that help to chemically break down food. The stomah also contain smooth muscle tissue that contracts.

5 These contractions churn the food and mix the food with the digestive juices. The serosa is the outer covering of the stomach and it is made of connective tissue and epithelial tissue. Te serosa protects the stomach from the friction that results from the stomach churning and rubbing against other organs. The next level is the ORGAN SYSTEM LEVEL. This is an association of organs that accomplish a common function. The digestive system consists of the mouth, throat, esophagus, stomach, small and large intestines, liver and gall bladder, pancreas and other associated structures. These organs work together to break down food so that the nutrients can be absorbed into the blood. INTEGUMENTARY, SKELETAL, MUSCULAR, CARDIOVASCULAR, LYMPHATIC,NERVOUS, ENDOCRINE, RESPIRATORY, DIGESTIVE,URINARY and REPRODUCTIVE SYSTEMS. The highest level of organization is the ORGANISMAL LEVEL. All organ systems work together to keep the ORGANISM alive. The organismal level represents the sum total of all levels (chemical, cell,tissue, organs, organs systems) working in unison to allow the organism to live. All organ systems interact and are interdependent. For Example, the respiratory system needs the cardiovascular system to carry oxygen from the lungs to the body,s cells. A dysfunction in one system can cause the other systems to malfunction as well. For example, diabetes is a malfunction of the endocrine system. Diabetes causes abnormal increases in blood sugar levels, which can result in blindness, kidney shutdown and circulation problems. This is all due to side efects brought on by the abnormal increase in blood sugar levels. THANK YOU