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Principles of Biology
By
Frank H. Osborne, Ph. D.
Cells and Tissues
Cells and Tissues
• Living things exhibit structure and
organization. The basic unit of structure and
function is the cell.
• Cells are organized into units containing
similar cells. These are called tissues.
• Different types of tissues are found in an
organ. Organs are organized into units of
structure called organ systems.
Cells and Tissues
A living creature,
such as a human, is
an organism
containing various
organ systems with
their component
organs.
PLANT TISSUES
I.
II.
Meristematic tissues
A. Shoot tip
B. Root tip
C. Cambium
Permanent tissues
A. Surface tissues
1. Epidermis
2. Periderm
PLANT TISSUES
B.
C.
Fundamental tissues
1. Parenchyma
2. Collenchyma
3. Sclerenchyma
4. Endodermis
Vascular tissues
1. Xylem
2. Phloem
PLANT TISSUES
Meristematic Tissues
•Meristematic tissues have embryonic,
undifferentiated cells. Undifferentiated means
that these cells have not changed into other cells
yet. When they do change, the process is called
differentiation because the cells become different.
• The shoot tip meristem is found on the end of
each branch. It is protected by a bud. This
meristem produces all the tissues in the branch.
The Shoot Tip Meristem
The Root Tip Meristem
Meristematic Tissues
• The root tip meristem is found on the tip of
each root. It divides and produces all the
cells found in the root.
• The cambium is found between
the xylem (wood) and phloem
(bark) of the tree. It is active only
during the growing season,
producing new xylem and phloem
cells. This annual growth forms in
rings.
Permanent Tissues
• Epidermis contains living cells and is found
on the surfaces of young stems and leaves.
• The lower epidermis of leaves contains
specialized occlusive cells called guard cells
that surround openings in the leaves called
stomates.
•The stomates permit exchange of gases
(carbon dioxide and oxygen) with the air
outside of the leaf. The guard cells prevent
loss of water.
Onion skin epidermis
Low Power (100x)
High Power (400x)
Permanent Tissues
• Periderm contains non-living cells that have
thick secondary walls. The walls are made
waterproof with a material called suberin.
• Periderm tissue replaces epidermis on older
stems of the plant. It prevents loss of water.
Periderm
Fundamental Tissues
• Parenchyma contains living cells that are
capable of cell division. It is the least
specialized of the plant tissues. These
cells have thin primary walls. Parenchyma is
used as a filler tissue in such plant structures as
corn stalks.
Fundamental Tissues
• Collenchyma cells are usually alive. They have
cell wall material that is deposited in the corners
giving them a characteristic microscopic
appearance. It serves as a support tissue in
certain types of stems.
Parenchyma and Collenchyma
Fundamental Tissues
• Schlerenchyma cells are dead. They have thick
secondary walls.
–Fibers are very long with thick walls and very small
lumens. They provide vertical support structure in
stems.
–Sclereids are also dead. They have thick walls with
very tiny interior spaces. They are parts of such
plant structures as peach pits.
Sclerenchyma cells
Sclerenchyma fibers
Sclereids
Fundamental Tissues
• Endodermis is a layer of living cells found in
the root. It has a waterproofing layer known as
the Casparian strip containing lignin and
suberin.
• The plant uses the endodermis to regulate what
materials enter the plant and are transported up
to the stem and leaves.
Endodermis
Endodermis
Vascular Tissues
Vascular tissues are specialized
transport tissues. There are two kinds:
xylem and phloem.
• Xylem cells are dead. Xylem transports water
and nutrients upward in the plant.
• Phloem has living cells. Phloem cells come in
pairs, the sieve tube and the companion cell. The
sieve tube transports conducts materials both
upwards and downwards in the plant. Phloem is
the major component of the bark of the tree.
Xylem
Phloem
ANIMAL TISSUES
I.
Epithelium
A. Simple epithelium
1. Simple squamous epithelium
2. Simple cuboidal epithelium
3. Simple columnar epithelium
B. Stratified epithelium
1. Stratified squamous epithelium
2. Stratified cuboidal epithelium
3. Stratified columnar epithelium
ANIMAL TISSUES
II.
Connective tissue
A. Tissues that connect body structures
1. Loose connective tissue (areolar)
2. Dense connective tissue
3. Adipose (fat) tissue
4. Cartilage
B. Bone
C. Vascular tissue
1. Blood
2. Lymph
ANIMAL TISSUES
III. Muscle
A. Smooth muscle
B. Striated muscle
C. Cardiac muscle
IV.
Nerve
Simple Epithelium
Simple epithelium always contains a single layer
of cells attached to a membrane. As this
membrane is underneath the cells, it is called the
basement membrane. There are three kinds of
epithelium that differ in their shapes.
Simple Epithelium
Simple Squamous Epithelium
"Squamous" means flat. Simple squamous
epithelium contains a single layer of flat cells
attached to a basement membrane. An example
is peritoneum, the tissue that surrounds and
suspends the digestive organs in the abdominal
cavity.
Simple Epithelium
Simple Cuboidal Epithelium
"Cuboidal" means having the shape of a cube.
This tissue contains a single layer of cube-shaped
cells on a basement membrane. An example of
this type of tissue is the lining of the collecting
duct in the kidney.
Simple Epithelium
Simple Columnar Epithelium
"Columnar" means that the cells are tall like
columns. This tissue contains a single layer of
tall cells on a basement membrane. An example
of this type of tissue is the intestinal lining.
Stratified Epithelium
"Stratified" means that the cells of the tissues
are found in layers. All three types of stratified
epithelium start out as several layers of cuboidal
cells on a basement membrane. The other layers
determine which type of tissue it is.
Stratified Epithelium
Stratified Squamous Epithelium
Stratified squamous epithelium contain several
layers of cuboidal cells that flatten as you
proceed away. An example is skin.
Stratified Epithelium
Stratified Cuboidal Epithelium
In stratified cuboidal epithelium, the cells in all
layers of the tissue are cuboidal. An example is
the lining of the ducts of the sweat glands.
Stratified Epithelium
Stratified Columnar Epithelium
In stratified columnar epithelium, all layers are
cuboidal except for the top layer which contains
tall cells. An example is the lining of the ducts of
the mammary glands.
Connective Tissue
Connective implies holding things
together or joining things. Thus we
expect to find tendons, ligaments and cartilage
classified as connective tissue. In addition, the
category of connective tissue also contains bodywide tissues such as bone, blood and lymph.
In most cases, the cells that make up the tissue
are surrounded by some kind of matrix or
material characteristic of the tissue.
Connective Tissue
Areolar (Loose) Connective Tissue
Loose connective tissue contains cells
surrounded by a matrix of collagenous fibers,
elastic fibers and lymph. Collagenous fibers are
made of collagen, a type of structural body
protein. Lymph is also called tissue fluid. It is a
liquid that is found in between the different
parts of the body in the spaces known as
connective tissue spaces.
Connective Tissue
Areolar (Loose) Connective Tissue
Elastic fiber
Collagenous fiber
Fat cell
Lymphoblast
Lymph
Loose Connective Tissue
Connective Tissue
Dense Connective Tissue
Dense connective tissue is made of
collagenous fibers. It is found in the dermis of
the skin, tendons and ligaments. A tendon
connects a muscle to a bone while a ligament
connects one bone to another bone.
Dense Connective Tissue
Connective Tissue
Adipose Tissue (= Body Fat)
Adipose tissue is made of fat cells.
Each cell has a thin ring of cytoplasm that
surrounds a large vacuole containing a fat
droplet.
Connective Tissue
Connective Tissue
Cartilage
There are three kinds of cartilage. Each consists
of cells surrounded by a matrix of small fibers.
• Yellow elastic cartilage is found in the arteries
and between the rungs of the trachea.
• Hyaline cartilage forms the ridge of the nose
and the rungs of the trachea.
• Elastic cartilage is found in the external ear,
the epiglottis and the Eustachian tube.
Elastic Cartilage
Connective Tissue
Cartilage
• Hyaline cartilage
forms the ridge of
the nose and the
rungs of the
trachea.
Connective Tissue
Bone
Bone cells are surrounded by a matrix of
calcium phosphate. There are tunnels in the
bone called Haversian canals that contain the
blood supply. Bone has the most mineral
matter.
Connective Tissue
Bone
There are two types of bone called spongy bone
and compact bone.
• The ends of the long bones are made of spongy
bone. "Spongy" means having the appearance
of a sponge.
• Compact bone does not have spaces in it that
give it a spongy appearance. The long parts of
the long bones are made of compact bone tissue.
Connective Tissue
Vascular Tissue
Vascular tissue consists of cells surrounded by a
liquid matrix. There are two types of vascular
tissue called blood and lymph.
• Blood is found in blood vessels. It is carried by
the circulatory system.
• Lymph consists of fluid that is found outside of
the blood vessels. It is also known as tissue fluid.
It is collected via the lymphatic system and
eventually returns to the circulatory system.
Blood
Muscle
Smooth Muscle
Smooth muscles are found in all involuntary
organs except the heart. Examples of organs
include the diaphragm and the arteries. Smooth
muscle does not contain striations.
Smooth Muscle
Muscle
Striated Muscle
•Striated muscles are attached to the bones of
the skeleton. Each striated muscle cell is
multinucleate because it has many nuclei.
• Striated muscles contain striations, which are
lines that produce a cross-banding effect. These
lines result from the orientation of the muscle
proteins within the cells. The striated muscle
cells are also known as voluntary muscles.
Muscle
Striated Muscle
Striated muscles contain striations, which are
lines that produce a cross-banding effect.
Nucleus
Striation
Striated Muscle
Muscle
Cardiac Muscle
The heart is the only organ that contains cardiac
muscle. This muscle cell type has distinct cells
that are separated by intercalated discs. The
intercalated discs partition the muscle into cells.
Cardiac muscle cells also contain striations.
Muscle
Cardiac (Heart) Muscle
Properties
• One nucleus per
cell
• Striations
• Involuntary
Nucleus
Striation
Intercalated disc
Cardiac Muscle
Nerve
Nerve cells
The neuron is the cell of the nervous
system. Each axon is surrounded by a sheath
of membranes.
Axon
Dendrites
Terminal
Sheath
Cell Body
Branches
Nucleus
Nerve Tissue Art
Nerve Tissue
The End
Principles of Biology
Cells and Tissues