Animal Organization
Levels of biological organization
cells
tissues
organs
organ system
Tissue
• Groups of cells that have the same structural
characteristics and perform the same functions
• Four major types of tissue:
• Epithelial tissue
• Connective tissue
• Muscular tissue
• Nervous tissue
Epithelial tissue
• Epithelial tissue: forming a continuous layer, or sheet
over the entire body surface and most of the body’s
inner cavities; it forms a covering that protects the
animal from infection, injury, and drying out;
producing and releasing secretions; absorbing
nutrients.
• Two descriptive terms
—shape: squamous, cuboidal, columnar
—layer: simple, stratified
Simple squamous Epithelium
• Structure: Thin, Flat,
many-sided, a central
nucleus
• Function: Filtration,
diffusion, osmosis
• Location: Walls of
capillaries, lining of blood
vessels, air sacs of lungs,
lining of internal cavities
Stratified Squamous Epithelium
• Structure: Innermost layers
are cuboidal or columnar;
outermost layers are
flattened
• Function: Protection, repel
water
• Location: Skin, linings of
mouth, throat, anal canal,
vagina
Esophagus
Simple Cuboidal Epithelium
• Structure: Cube-shaped
• Function: Secretion, absorption
• Location: Surface of ovaries,
linings of ducts and glands,
lining of kidney tubules
Simple Columnar Epithelium
• Structure: Column like—
tall, cylindrical cells,
nucleus at base
• Function: Protection,
secretion, absorption
• Location: Lining of uterus,
tubes of digestive tract
Pseudostratified Ciliated Columnar
Epithelium
• Structure: Looks layered
but is not; ciliated
• Function: Protection,
secretion, movement of
mucus
• Location: Linings of
respiratory passages
Trachea
Connective tissue
• Connective tissue joins different parts of the body
together.
• All types of connective tissue consist of cells
surrounded by a matrix that usually contains fibers.
• Loose fibrous connective tissue
• Dense fibrous connective tissue
• Adipose tissue
• Bone
• Cartilage
• Blood
Loose fibrous connective tissue
• Structure: Fibers are widely
separated
• Function: Binds organs
together
• Location: Between the
muscles; beneath the skin;
beneath most epithelial
layers
Loose fibrous connective tissue
Dense fibrous connective tissue
• Structure: Fibers are closely
packed
• Function: Binds organs
together, binds muscle to
bones, binds bone to bone
• Location: Tendons, ligaments
Dense fibrous connective
tissue
Adipose tissue
• Structure: Large cell with
fat-filled vacuole; nucleus
pushed to one side
• Function: Insulation, fat
storage, cushioning, and
protection
• Location: Beneath the
skin; around the kidney
and heart; in breast
Adipose tissue
Compact Bone
• Structure: Concentric
circles
• Function: Support,
protection
• Location: Bones of
skeleton
Compact bone
Hyaline Cartilage
• Structure: Cells
(chondrocytes) in
lacunae
• Function: Support,
protection
• Location: Nose, ends of
bones, rings in walls of
respiratory passages;
between ribs and sternum
Hyaline cartilage
Blood
• Structure: Red and white cells floating in plasma
• Function: RBCs carry oxygen and hemoglobin
for respiration; WBCs fight infection
• Location: Blood vessels
Blood
Muscle tissue
• Muscular tissue is composed of cells called
muscle fibers.
• Skeletal muscle
• Cardiac muscle
• Smooth muscle
Muscle tissue
Skeletal muscle
Smooth muscle
Cardiac muscle
Type
• Skeletal
• Smooth
• Cardiac
Striations
(yes/no)
Branching
(yes/no)
Yes
No
Yes
No
No
Yes
Conscious Control
(yes/no)
Yes
No
No
Nervous tissue
• Nervous tissue is found in brain, spinal cord
and nerves.
• Neurons: transmitting messages
• Neuroglia: supporting and nourishing the
neurons
Nervous tissue
dendrite
nucleus
astrocyte
Microglia
cell body
Oligodendrocyte
axon
Organ Level of Organizations
• Organs are structures composed of two or more
types of tissue that work together to perform
particular functions.
Intestinal Wall
Skin
• Prepared slides