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
• LEVELS OF STRUCTURAL ORGANIZATION
– 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.
LEVELS OF STRUCTURAL ORGANIZATION
• Atoms combine to form MOLECULES. eg Water(H2O),Oxygen(O2),and
carbon dioxide (CO2).
• 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..
ATOMS AND MOLECULES
LEVELS OF STRUCTURAL ORGANIZATION
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,
•
LEVELS OF STRUCTURAL ORGANIZATION
• 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.
LEVELS OF STRUCTURAL ORGANIZATION
• 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.
LEVELS OF STRUCTURAL ORGANIZATION
• 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.
LEVELS OF STRUCTURAL ORGANIZATION
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.
LEVELS OF STRUCTURAL ORGANIZATION
• 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.
LEVELS OF STRUCTURAL ORGANIZATION
•
•
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.
LEVELS OF STRUCTURAL ORGANIZATION
•
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.
LEVELS OF STRUCTURAL ORGANIZATION
• 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 .