Download ANIMAL CELLS AND TISSUES Literacy Lesson

ANIMAL CELLS AND TISSUES
by Michael J. Farabee, Ph.D., Estrella Mountain Community College, updated 12/06.
http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookanimalts.html [edited S. Dillery 4/13]
Animals are multicellular heterotrophs whose cells lack cell walls. Organs are
composed of tissues, which are in turn composed of cells.
Animals have four [types of tissue]: epithelial, connective, muscle, and
nervous.
Epithelial Tissue
Epithelial tissue covers body surfaces and lines body cavities. Functions
include lining, protecting, and forming glands. Three types of epithelium
occur:
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Squamous epithelium is flattened [irregular disk-shaped] cells.
Cuboidal epithelium is cube-shaped cells.
Columnar epithelium consists of elongated cells.
Functions of epithelial cells include:
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movement materials in, out, or around the body.
protection of the internal environment against the external
environment.
Secretion of a product.
1.Squamous Epithelial Cells
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2. Cuboidal Epithelial Cells
3. Columnar Epithelial Cells
Connective Tissue
Connective tissue serves many purposes in the body:
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binding
supporting
protecting
forming blood
storing fats
filling space
Connective cells are separated from one another by a non-cellular matrix. The
matrix may be solid (as in bone), soft (as in loose connective tissue), or liquid
(as in blood). Two types of connective tissue are Loose Connective Tissue (LCT)
and Fibrous Connective Tissue (FCT). Adipose tissue has enlarged fibroblasts
storing fats and reduced intracellular matrix. Adipose tissue facilitates energy
storage and insulation.
Bone has calcium salts in the matrix, giving it greater rigidity and strength
[than cartilage]. Bone also serves as a reservoir (or sink) for calcium. Protein
fibers provide elasticity while minerals provide [strength]. [Bone cells have a
central canal.]
Blood is a connective tissue of cells separated by a liquid (plasma) matrix. Two
types of cells occur. Red blood cells (erythrocytes) carry oxygen. White blood
cells (leukocytes) function in the immune system. Plasma transports dissolved
glucose, wastes, carbon dioxide and hormones, as well as regulating the water
balance for the blood cells. Platelets are cell fragments that function in blood
clotting.
4. Red Blood Cells
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5. Bone Cells
6. Adipose Cells
Muscle Tissue
Muscle tissue facilitates movement of the animal by contraction of individual
muscle cells (referred to as muscle fibers). Three types of muscle fibers occur
in animals (the only taxonomic kingdom to have muscle cells):
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skeletal (striated)
smooth
cardiac
Muscle fibers are multinucleated, with the nuclei located just under the
plasma membrane. Most of the cell is occupied by striated, thread-like
myofibrils.
Skeletal (striated) muscle fibers have alternating bands perpendicular to the
long axis of the cell. These cells function in conjunction with the skeletal
system for voluntary muscle movements.
Smooth muscle fibers lack the banding. These cells function in involuntary
movements and/or autonomic responses (such as breathing, secretion,
ejaculation, birth, and certain reflexes). Smooth muscle fibers are spindle
shaped cells that form masses. These fibers are components of structures in
the digestive system, reproductive tract, and blood vessels.
Cardiac muscle fibers are a type of striated muscle found only in the heart.
The cell has a bifurcated (or forked) shape, usually with the nucleus near the
center of the cell. The cells are usually connected to each other by
intercalated disks.
7. Skeletal Muscle Cells
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8. Smooth Muscle Cells 9. Cardiac Muscle Cells
Nervous Tissue
Nervous tissue functions in the integration of stimulus and control of response
to that stimulus. Nerve cells are called neurons. The neuron is the functional
unit of the nervous system. Humans have about 100 billion neurons in their
brain alone! While variable in size and shape, all neurons have three parts.
Dendrites receive information from another cell and transmit the message to
the cell body. The cell body contains the nucleus, mitochondria and other
organelles typical of eukaryotic cells. The axon conducts messages away from
the cell body.
10. Neuron Cell
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