Living things have several levels of structural organization, from lowest to highest: 1) The chemical level includes atoms and molecules like carbohydrates, proteins, vitamins, and minerals that are essential for life. 2) At the cellular level, molecules combine to form cells, the basic units of life. 3) Cells combine to form tissues like muscle and nerve tissues. 4) Tissues combine to form organs like the heart, lungs, and brain. 5) Organs work together in organ systems like the circulatory, respiratory, and nervous systems. 6) All the organ systems function together as a whole organism.

1. LEVELS OF STRUCTURAL
ORGANIZATION

2.  Living things consists of
several levels of structural
organization that are
associated with one another
in various ways.

3. CHEMICAL LEVEL
 It is the lowest level of organization
 It includes atoms and molecules that are
essential in maintaining life.

4. CHEMICAL LEVEL
Atom
 A unit of matter
that comprises a
chemical element.
 It is the smallest
particle of an
element.

5. CHEMICAL LEVEL
Atom
 Elements essential for maintaining life
are:
 Carbon (C)
 Hydrogen (H)
 Oxygen (O)
 Nitrogen (N)
 Calcium (Ca)
 Potassium (K) and
 Sodium (Na)

6. CHEMICAL LEVEL
Molecule
 The chemical combination of two or more
atoms.

7. CHEMICAL LEVEL
Molecule
 Carbohydrates – includes
sugars, starches, glycogen and cellulose
 Plants store carbohydrates as starch and use
the carbohydrates cellulose to build the cell
wall
 In animals, it provide a readily available source
of energy to drive metabolic reactions
 Fats – also provides energy and forms adepose
tissue
 Proteins – for muscle growth and repairs
 Vitamins and minerals – catalyzes metabolic
reactions

8. CELLULAR LEVEL
 The next higher level of
organization.
 It yields from the
combinations of molecules
from the chemical level.
 CELL:
 Is the basic structural and
funcional unit of an organism.
 There are several kinds of cell
in our body, and each has a
different stuctures and each
performs a different function.
 Each cell contain specialized
structures called organelles
that perform specific
functions.

9. TISSUE LEVEL
 It is the level in which
different cell types cells are
joined together to form a
structure called, tissue.
 Tissues – are group of similar
cells (and the substance
surrounding them) that
usually arise from common
ancestor cells and work
together to perform a
particular function. The four
basic types of tissue in the
body are:
 Epithelial tissue
 Muscle tissue
 Connective tissue
 Nervous tissue

10. ORGAN LEVEL
 It is where different kinds of tissues are joined
to form a structure of a body called organ.
 Organs – are structures that are composed of
two or more different tissues, have specific
functions, and usually have recognizable
shapes.
 Some examples of organs are the
heart, liver, lungs, brain and stomach.

11. SYSTEM LEVEL
 The level where different organs are
joined together to form a body
system.
 Consists of several related organs
that have a common function.

12. SYSTEM LEVEL
11 systems in the human body
 Integumentary System – helps regulate
body temperature, protects the body,
eliminates some wastes, helps produce
vitamin D, and receives certain stimuli
such as temperature, pressure, and pain.
 Includes skin, hair, nail, sweat and oil
glands.
 Skeletal System – supports and protects
the body, assist in body movements,
houses cells that give rise to blood cells,
and store minerals.
 Includes all bones of the body, cartillages
and joints.
 Muscular System – participates in
bringing about movement, produces heat,
maintains posture and gives shapes to the
body.
 Specifically refers to skeletal muscle
tissue.

13. SYSTEM LEVEL
11 systems in the human body
 Nervous System – regulates body
activities through action potentials (nerve
impulses) by detecting changes in the
internal and external
environment, interpreting the changes, and
responding to the changes by inducing
muscular contractions or glandular
secretions.
 Includes brain, spinal chord, nerves and
special sense organs such as the eyes and
ears.
 Endocrine System – regulates body
activities through hormones, chemicals
transported in the blood to various target
organs of the body.
 Includes all hormone-producing glands and
cells such as the pituitary gland, thyroid
gland, and pancreas.
 Circulatory System - carries carbon
dioxide and wastes away from cells, helps
maintain the acid-base balance of the
body, protects against disease, prevents
hemorrhage by forming blood clots, and
helps regulate body temperature.
 Includes blood, heart and blood vessels.

14. SYSTEM LEVEL
11 systems in the human body
 Lymphatic and Immune System – returns
proteins and plasma to the cardiovascular
system, transports fats from the
gastrointestinal tracts to the cardiovascular
system, filters body fluid, site of maturation
and proliferation of certain white blood
cells, and helps protect against disease
through the production of proteins called
antibodies, as well as other responses.
 Includes lymph, lymphatic vessels, and
structures or organs ontaining lymphatic
tissue (large numbers of white blood cells
called lymphocytes), such as the spleen,
thymus gland, lymph nodes and tonsils.
 Respiratory System – supplies oxygen,
eliminates carbon dioxide, helps regulate the
acid-base balance of the body, and produces
vocal sounds (phonation).
 Includes lungs and series of associated
passageways leading into and out of them.
 Digestive System – performs the physical
and chemical breakdown and absorption of
food for use by cells and eliminates solid and
other wastes.
 Includes the gastrointestinal tract, salivary
galnds, liver, gallbladder, and pancreas.

15. SYSTEM LEVEL
11 systems in the human body
 Urinary System – regulates the
volume and chemical composition of
blood, eliminates wastes, regulates
fluid and electrolyte balance, helps
maintain the acid-base and calcium
balance of the body, and helps
regulate red blood cell production.
 Includes the kidney, ureters, urinary
bladder, and urethra that together
produce, store, and eliminate urine.
 Reproductive System – reproduces
the organism for continuity.
 Includes the gonads that produce
reproductive cells or gametes, uterine
(Fallopian) tubes and uterus in females,
the epididymis, ductus (Vas) deferens,
and penis in males that transport and
store reproductive cells.

16. 11 Systems of the Human Body
 Integumentary System
 Skeletal System
 Muscular System
 Nervous System
 Endocrine System
 Circulatory System
 Lymphatic / Immune System
 Respiratory System
 Digestive System
 Urinary System
 Reproductive System

17. ORGANISMIC LEVEL
 The highest level of
organizational
structure where all
parts of the body
are functioning with
one another to
comprise the total
organism – one living
individual.

18. LEVELS OF STRUCTURAL
ORGANIZATION
 Chemical Level
 Cellular Level
 Tissue Level
 Organ Level
 System Level
 Organismic Level

19. Up next…
LIFE PROCESSES