Download File - Donabel M. Germino

MULTICELLULAR ORGANIZATION
Bodies of multicellular organisms are organized on the basis of cells, tissues,
organs and organ systems. A tissue is composed of cells with similar structures and
functions. An organ is composed of several tissues grouped together into a structural
unit. And an organ system is a group of organs that work together in the performance of
a specific function.
TISSUES
PLANT TISSUES
I. Meristematic Tissues. These are composed of embryonic cells capable of
cell division.
Location: growing tips of roots and stems.
Apical meristems – responsible for the increase in
length of the plant
Lateral meristems – for the increase in girth
II. Permanent Tissues. These are composed of mature, differentiated cells
A. Surface Tissue – form the protective outer covering of the plant
Epidermis – the principal surface tissue of roots, stems and all
leaves.
B. Fundamental Tissues – simple tissues composed of a single type of
cells.
Kinds :
Parenchyma Cells.
In leaves, site of photosynthesis because of the chloroplasts
present.
In stems and roots, for the storage of nutrients and water.
Collenchyma Cells
Supporting tissue in young plants, in stem and in leaves.
Sclerenchyma Cells
Give strength to the plant body.
C. Vascular Tissues – or conductive tissue function as tubes or ducts
through which water and food substances move from one part of the plants to
another.
Xylem
Transports water and dissolved substances upward in the
plant body
Phloem
Transports food substances both up in down in the plant
body
Figure 1. Plant Tissue
ANIMAL TISSUES
I. Epithelial Tissues
 Forms the covering or lining of all free body surfaces, both external and internal.
 Outer portion of the skin, linings of the digestive tract, lungs, blood vessels,
various ducts, body cavity etc.
Types of Epithelium According to Shape
1. Squamous – contain flat cells arranged like tiles.
2. Cuboidal – consists of cube-shaped cells arranged in a very regular pattern.
3. Columnar – looks like rectangles set on end.
Types of Epithelium According to Cell Layers
1. Simple – cells are arranged in a single layer
2. Stratified – cells are arranged in more than one layer.
Glandular Epithelium – masses of epithelial cells which have become specialized
into secreting organs.
Types of Gland
1. Endocrine Gland – ‘ductless gland’. It releases specific substances directly
into the bloodstream for transport to the target organ
2. Exocrine Gland – ‘duct gland’. It has a duct which brings the secretion from
the secreting cells to the specific target organ.
II. Connective Tissue
 connect and bind parts together;
 provides the framework that supports epithelial and other tissues;
have an essential role in transport, protection and repair.
Types of Connective Tissue
1. Adipose – consists largely of flat cells
 Fat cells beneath skin and on surface of heart and other internal organs
for insulation, food and energy storage and support for breast and
kidneys.
2. Cartilage - A tough, elastic, fibrous connective tissue found in various parts of
the body, such as the joints, outer ear, and larynx.
3. Fibrous – consist of dense, wide and strong fibers with cells aligned between
them.
Locations:
 Tendons – attach muscle to bones
 Ligaments – bind bones together at joints
 Fasciae – hold bundles of muscles together
4. Bone – The dense, semirigid, porous, calcified connective tissue forming the
major portion of the skeleton of most vertebrates. It consists of a dense organic
matrix and an inorganic, mineral component.
III. Muscle Tissue

consist of elongated cells which have greater capacity for contraction. This tissue
is responsible for movement
Types of Muscle According to Striation
1. Striated – has striations in the muscle cells
2. Non-striated – has no striations in the muscle cells
Types of Muscle According to Control of the Will
1. Voluntary – under the control of the will
2. Involuntary – not under the control of the will
Types of Muscle According to Striation and Control of the Will
1. Smooth Muscle – non-striated and involuntary.
Location : walls of the blood vessels and intestines
Function: rhythmic contractions
2. Skeletal Muscle – striated and voluntary
Location: voluntary muscles of the body
Function: Voluntary movement
3. Cardiac Muscle – striated and involuntary
Location: heart
; Function: beating of the heart
IV. Nervous Tissue

receives stimuli from the environment or from the various organs of the body;
transmit impulses to the nerve centers in the brain and spinal cord and bring
appropriate motor responses.
Neurons – the cells making up the nervous tissue
Animal Tissues