The document outlines the levels of organization in animals, detailing the protoplasmic, cellular, tissue, organ, and organ-system grades of organization, along with specialized tissues including epithelial, connective, muscular, and nervous tissues. It explains the structure and function of these tissues, their classifications, and their roles in various bodily functions. Additionally, the document discusses animal symmetry types such as spherical, radial, and bilateral symmetry, highlighting their significance in animal evolution and adaptation.

1. Architectural
Pattern of an
Animal

2. Levels of Organization in Organismal Complexity
Protoplasmic grade of organization.
Found in unicellular organisms. All life functions are confined within the boundaries of
a single cell. Within the cell, protoplasm is differentiated into organelles capable of
performing specialized functions.
Cellular grade of organization.
Aggregation of cells that are functionally differentiated. Such cells have little tendency to
become organized into. Some flagellates, such as Volvox, that have distinct somatic and
reproductive cells might be placed at the cellular level of organization.
Cell-tissue grade of organization.
A step beyond the preceding is the aggregation of similar cells into definite patterns or
layers, thus becoming a tissue. The jellyfishes and their relatives (Cnidaria) more clearly
demonstrate the tissue plan. An excellent example of a tissue in cnidarians is the nerve net,
in which nerve cells and their processes form a definite tissue structure, with the function of
coordination.

3. Levels of Organization in Organismal Complexity
Tissue-organ grade of organization.
Organs are usually composed of more than one kind of
tissue and have a more specialized function than tissues.
The first appearance of this level is in flatworms
(Platyhelminthes), in which there are well-defined organs
such as eyespots, proboscis, and reproductive organs. In
fact, the reproductive organs are well organized into a
reproductive system.
Organ-system grade of organization.
When organs work together to perform some function, we have
the highest level of organization—the organ system. Systems are
associated with the basic body functions—circulation,
respiration, digestion, and the others. Most animal phyla
demonstrate this type of organization.

4. A tissue is a group of similar cells
(together with associated cell
products) specialized for the
performance of a common function.
Types of Tissues
The study of tissues is called histology
.
During embryonic development, the
germ layers become differentiated
into four kinds of tissues. These are
epithelial, connective, muscular,
and nervous tissues.

5. Epithelial Tissue
An epithelium (pl., epithelia) is a sheet of cells that covers an external or internal surface.
Outside the body, the epithelium forms a protective covering. Inside, the epithelium lines
all organs of the body cavity, as well as ducts and passageways through which various
materials and secretions move. On many surfaces epithelial cells are modified into glands
that produce lubricating mucus or specialized products such as hormones or enzymes.
Functions:
-Cover external body surfaces and cavities, and line other internal body cavities.
- form necessary portions of glands
- forms a protective covering of all body surfaces against mechanical injury and loss
of water.
- may be modified to carry out special functions of absorption, secretion, excretion,
sensation and respiration.
All types of epithelia are supported by an underlying basement membrane,
which is a condensation of the ground substance of connective tissue.

6. Epithelial Tissue
Classifications:
Simple epithelium
Made up of only one layers, and are
found in all metazoan animals.
Stratified epithelium
Made up of two or more layers of the cell,
and are mostly restricted to vertebrates

9. Combination of several shapes of cells

12. Connective tissues are a diverse group of tissues that serve various binding and
supportive functions. They are so widespread in the body. It is composed of
relatively few cells, many extracellular fibers, and a ground substance (also called
matrix), in which the fibers are embedded.
Connective Tissue
Classifications:
-Connective Tissue Proper
- Cartilage
- Bone (Osseous Tissue)
- Blood (Vascular Tissue)
Connective Tissue Proper
Fibers form the main bulk of the tissue embedded within the matrix.
3 kinds of intercellular fiber
-Collagenous fibers – colorless, fine & flexible protein fibers lying parallel forming
bundles
- Elastic fibers – fibrillar branched & elastic protein fibers forming irregular network.
- Reticular fibers – extremely fine & highly branched forming networks
-Collagenous and reticular fibers may
simply be diff. morph. expressions of a
single fibrous protein.

13. Made up of highly elastic fibers w/ few
scattered thin collagen fibers. This tissue fills
the space between organs & serves as
packing materials surrounding elements of
other tissues. Binds muscle cells together &
binds skin to underlying tissues.
2 Kinds of Connective Tissue Proper
Loose Connective Tissue Dense Connective Tissue
Made up of thick collagen fibers and dark,
compressed cells between the fiber bundles.
This tissue occurs in tendons, ligaments, dermis
of the skin, and submucous layer of the intestine
and urinary tract.

14. - not covered by
perichondrium found in
intervertebral discs,
symphysis pubis, and in
mandibular joints
Cartilage
Elastic cartilageHyaline cartilage
Made up of cartilage cells, chondrocytes, lodged in cavities or spaces called lacunae
scattered irregularly in the matrix that appears transparent and homogenous but composed
of dense collagen fibers and elastic fibers embedded in a rubbery ground substance. It is
produced by the chondroblast in a process called chondrification.
3 types of cartilage
-Covered by a fibrous layer,
perichondrium
- found in nose, larynx,
trachea, bronchi, ends of
ribs, surfaces of bones w/in
cavities
- yellow in color, greater
flexibility and elasticity due
to prominince of elastic
fibers.
- enveloped by
perichondrium found in
external ear, eustachian
tube & epiglottisFibrocartilage
Cartilage facilitate
movements of joints,
provide flexibility and
support

16. Bone (Osseous) Tissue
A hard specialized connective tissue w/ its collagenous matrix impregnated w/ mineral salt
deposits, including calcium and phosphorus. Consists of cells called osteocytes & masked
collagenous fibers embedded in a matrix containing ostein. Derived from ossein, bone
collagen. Fibrous CT covering the bone is periosteum, while endosteum lines the bone
marrow cavity. Bone is produced by osteoblast in a process called ossification. Functions
for support, protection, assisting for movement and storage of minerals.
Classification according to shape
Long bone
Composed of middle portion, the diaphysis or
shaft, and the epiphysis or ends of the bone.
Bones of legs and arm.
Flat bone
Lacks a bone marrow. Bones of skull and
scapula.
Irregular bone
Neither long nor flat & also lacks bone
marrow. Bones of wrist and ankle.

18. Bone (Osseous) Tissue
Lamellae
Series of concentric rings/circles arround a
central Haversian canal
Lacunae
Small spaces in between the Lamellae w/c
contain the osteocytes.
Osteocytes
Bone cells
Canaliculi
Minute channels that linked lacunae together
w/c provides routes by w/c nutrients can
nutrients can reach the osteocytes & removal of
waste materials
Haversian canals
Central tubes w/c contain
blood vessels and nerves
Bone marrow
Responsible for production of blood cells
and storage of chemical energy.

20. Blood (Vascular) Tissue
Consists of cells, matrix, and fibers. Functions in transporting gases, nutrients, hormones,
enzymes and other substances to and from different parts of the body; in blood clotting;
defense of the body; regulating body fluid electrolytes; in controlling pH (7.4); & in
maintaining body temperature.
Components of the blood
Red Blood Cells (Erythrocytes)
Most numerous. Disc shape containing large amounts of hemoglobin. Tend to
adhere one another by thin flat or broad surfaces and form rows resembling
piles of coins known as Ruoleaux formation.
White Blood Cells (Leucocytes)
Generally bigger, nucleated, w/out hemoglobin, fewer in number w/c
originates from bone marrow, spleen, & lymphatic tissues. Do not exhibit
Ruoleaux formation. Functions in body defense against microorganisms by
their phagocytic action & antibody production
Granulated (granulocyte)
w/ granules on cytoplasm & w/ 1 or
more nucleus
-Eosinophil – two lobed nucleus
-Basophil – S-shaped nucleus
-Neutrophil – w/ 3 or 4 nuclei
Agranulated (agranulocyte)
w/out granules on cytoplasm & with only 1 nuclei
-Lymphocyte – the smallest; produces antibody
- Monocyte – mono-nucleated cell; transformed into
macrophage

21. Blood (Vascular) Tissue
Components of the blood
Platelets (Thrombocytes)
Small, non-nucleated, colorless, round/ovel biconcave corpuscle produced by a
giant cell called megakaryocyte found in bone marrow. Plays vital role in blood
clotting.
Plasma
Liquid component of blood (90% water) w/c contains numerous cells, organic
& inorganic salts, hormones, nitrogenous wastes and other substances like
prothrombin and fibrinogen, and antibodies against infection.
Hemoglobin
Protein constituent of the blood responsible for the attachment of oxygen and
for the red coloring of the blood.

22. Hemostasis: Prevention of Blood Loss

24. Muscular Tissue
Responsible for body’s movement, heat production, and posture maintenance. Displays
excitability, contractility in response to stimulation due to the presence of numerous fine
fibers, myofibrils.
Muscle fibers
Consist of myofibrils, composed chemically of a protein called actomyosin. Each myofibril
is made up of alternating myofilaments, the thin actin and the thick myosin filaments.
Myofibril exhibits alternate anisotropic (A) & isotropic (I) striations. A relaxed myofibril
has A and I bands approximately of equal width. The I band transverse at the middle by a
thin zigzag line, Z disk (darker zone), while A band is transversed by a thin M-line & H-zone
(central light area). The segment between the two Z-disks represents sarcomere,
functional unit of muscle contraction. Contraction of muscle is the result of the sliding of
two sets of myofilaments w/ respect to each other, wherein A band remains constant but I
band shortens. With relaxation, the original arrangement of disks returns.

25. Muscular Tissue

26. Classification
Muscular Tissue
Consist of long, cylindrical muscle fibers w/
crossbanded or striated appearance. Found
attached to skeleton, voluntary in action
because movement is the result of impulses.
Skeletal Muscle
Cardiac Muscle
Striated, branched muscle fibers (Y-shaped),
has single central nucleus. Multifibers are
attached by intercalated discs. Formed by
myocardium (middle, thicker layer).
Involuntary.

27. Classification
Muscular Tissue
Consist of spindle shaped cells w/c are thickened at the middle but tapered towards the
ends. An oval or rod-shaped nucleus occupies in the central, thickest portion of the cell
body. Consist of unstriated muscle. Capable of peristalsis, contractions on the walls of the
digestive tract. Involuntary in action.
Visceral/Smooth Muscle

29. Nervous Tissue
Specialized for conduction of nerve impulses.
Consists of 2 specialized elements, neurons, w/c is
the functional/structural units capable of receiving &
conducting impulses; neuroglia, composed of glial
cells & fibers, w/c serve support & bind together the
component nervous elements.
Cell body (Cyton)
Composed of central nucleus w/in the protoplasmic
fluid called neuroplasm.
Cell processes
Cytoplasmic extensions that continue for a
considerable length from the cell body.
Dendrite/Dendron
One or more process; Short; carries impulses
towards cell body
Axon/axis cylinder
Single process; Long; do not branch near cell body.
Conveys impulses away from cell body

30. Nervous Tissue
During the nerve impulse transmission, association of
processes of two nuerons forms a synapse (junction
between two successive neurons). Dendrites of one neuron,
associated through synapse with axon endings of
functionally related neurons, receive the nerve impulse from
another neuron. Neurons are sensitive to different types of
stimuli s.a temperature, pressure, light, etc. These nerve cells
transmit electrical nerve impulses thereby moving
information around the body.
Nervous tissue is specialized for reception of stimuli and
conduction of impulses from one region to another. Two basic
types of cells in nervous tissue are neurons (nerve), the basic
functional unit of the nervous system, and neuroglia, a variety of
non-nervous cells that insulate neuron membranes and serve
various supportive functions.

31. Type of Neurons according to function
Sensory (Afferent Neuron)
conducts impulses towards CNS
Motor (Efferent neuron)
conducts impulses away from the
CNS
Association (Interneuron)
conducts impulses w/in CNS
Type of Neurons according number of cell
processes
Myelin sheath
Covers axon of a neuron

33. Animal Body Plans

34. Animal Symmetry
Symmetry refers to balanced proportions, or correspondence in size and shape of parts
on opposite sides of a median plane.
Spherical symmetry means that any
plane passing through the center
divides the body into equivalent, or
mirrored, halves.
This type of symmetry is found chiefly
among some unicellular forms and is
rare in animals. Spherical forms are
best suited for floating and rolling.

35. Radial symmetry applies to forms that can be divided into similar halves by more than
two planes passing through the longitudinal axis. These are tubular, vase, or bowl shapes
found in some sponges and in hydras, jellyfish, sea urchins, and related groups, in which
one end of the longitudinal axis is usually the mouth.
The two phyla that are primarily radial,
Cnidaria and Ctenophora, are called the
Radiata.
Animal Symmetry
Echinoderms (sea stars and their kin) are
primarily bilateral animals (their larvae are
bilateral) that have become secondarily
radial as adults.

36. Bilateral symmetry applies to animals that can be divided along a sagittal plane into two
mirrored portions— right and left halves.
Animal Symmetry
The appearance of bilateral symmetry in animal evolution was a major advancement,
because bilateral animals are much better fitted for directional (forward) movement
than are radially symmetrical animals.
Bilateral animals form a monophyletic group
called the Bilateria. Bilateral symmetry is
strongly associated with cephalization.

37. Animal Symmetry
Invertebrates pectoral refers to the chest
region or the area supported by the
forelegs, and pelvic refers to the hip region
or the area supported by the hind legs.
Terms used for locating regions of bilaterally-symmetrical animals:
anterior, used to designate the head end
posterior, the opposite or tail end
ventral, the front or belly side
Medial refers to the midline of the body
dorsal, the back side
lateral, to the sides
Distal parts are far from the middle of the
body
proximal parts are nearer
frontal plane (coronal plane) divides a bilateral
body into dorsal and ventral halves.
Sagittal plane the plane dividing an animal into
right and left halves
transverse plane (cross section) would cut
through a dorsoventral and a right-left
axis at right angles to both the sagittal
and frontal planes and would result in
anterior and posterior portions.

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