Vertebrate Tissues
Mrs. Stahl
Zoology
Tissue
• A group or mass of similar cells working
together to perform a common function.
• The study of tissues= Histology
• Animal Tissues:
– Epithelial
– Connective
– Muscle
– Nervous
Epithelial Tissue
• Covers or lines something and typically consists of
sheets of cells that have surface specializations
adapted for their specific roles.
• Functions: Size, shape, and arrangement directly
relate to these specific functions
– Absorb- lining of the intestines
– Transport- Kidney tubules
– Excrete- Sweat and Endocrine Glands
– Protect- The Skin
– Contain nerve cells for sensory reception- taste buds on
the tongue.
Classified
based on
thickness
and shape
to protect
Classification of epithelia
• According to thickness
– “simple” - one cell layer
– “stratified” – more than one layer of cells
(which are named according to the shape
of the cells in the apical layer)
• According to shape
– “squamous” – wider than tall
– “cuboidal” – as tall as wide
– “columnar” - taller than wide
Epithelial Tissue
Epithelium-Human Stomach
Simple Squamous
• Single layer, simple, flattened.
• Function- diffusion and filtration
• Location- air sacs of lungs, walls of capillaries,
covering visceral organs (hollow organ), lining
body cavities
Simple Cuboidal
• Single layer, cube shaped
• Function- secretion / absorption
• Location- Lining of kidney tubules,
ducts of glands (salivary and
pancreatic), cover the surface of the
ovaries
Simple Columnar
• Single layer, elongated cells with the nucleus
located in the same spot
• Function- protection, absorption, secretion
• Location- lining of the digestive tract and uterus,
gall bladder
– Some have fingerlike projections called microvilli
which increase surface absorption
– Contains scatter goblet cells functioning in the
secretion of mucus
“ciliated” literally =
(see next page)
eyelashes
Stratified Squamous
• Multi-layered, thicker
• Function- protection
• Location- lining of body cavities like the
mouth and outer layer of the skin, nasal
cavity, esophagus, vagina, and anal canal
(non-keratinized). Keratinized -> epidermis of
the skin
Stratified: regenerate from below
Pseudostratified Columnar
• Stratified appearance but really a single
layer with nuclei at various levels giving
the layered look, ciliated, have goblet
cells
• Function- secretion and cilia aided
movement
• Location- lining air passages -> trachea,
auditory tubes of the reproductive
system
Transitional Epithelium
• Thick, layered cuboidal cells,
stretchable forms a barrier to block
diffusion
• Location- lining of urinary bladder
Special Features of Epithelium
• Cilia- hair-like appendages attached to the apical
surface of cells that act as sensory structures or to
proton movement
• Goblet Cells- specialized cells that produce mucus to
lubricate and protect the surface of the organ.
• Villi- fingerlike projections that arise from the
epithelial layer in some organs. Increase surface area
allowing for faster and more efficient absorption
• Microvilli- smaller projections that arise from the cells
surface. Increased surface area, bushy appearance.
Connective Tissue
• Characteristics:
– Most abundant tissue in your body (made up of ground
substance (fluid and semi-solid) and fibers
– Binds structures together, stores nutrients, cells
reproduce
– Provides support, protection, framework, fills space,
stores fat, produces blood cells, fights infection
– Extracellular matrix- a bed of secreted organic material
of varying composition that binds separated cells of
tissue. Nonliving material between cells.
Classes of Connective Tissue: note the cell types
and great variety of subclasses
2 General Types
• 1. Loose Connective Tissue: strong, flexible fibers
of the protein collagen are interwoven with fine,
elastic, and reticular fibers, giving its elastic
consistency and binding capabilities.
• 2. Fibrous Connective Tissue: Densely packed
collagen fibers and they may lie parallel to one
another creating very strong cords (ex- tendons
and ligaments)
– Tendons- connect muscles to bones
– Ligaments- connect bones to bones
Connective Tissue
• Originate from embryonic tissue
called mesenchyme-> rises from
the mesoderm, an embryonic germ
layer (stem tissue)
Common Cell Types
• Adipocytes- adipose tissue cells
• Fibroblasts- most common, secrete collagen
proteins that are used to maintain a structural
framework, play an important role in healing
wounds.
• Osteocytes- bone cells, are trapped within the
bone matrix (the hard part of the bone), has
tentacle like dendrites that allow it to maintain
contact with neighboring cells / communicate.
• Mast cells- tissue of the immune
system of vertebrate animals.
Mediate inflammatory responses->
allergic reactions. They are
scattered all over the connective
tissue. Chemical mediators
produce responses->
inflammation, swelling,
contraction of smooth muscles,
increased mucus production
Adipose
• Large cells
• Function= protection, insulation,
stores energy
• Location= beneath the skin, around
kidneys, eyeballs, abdominal
membranes
Cartilage
• Cells= chondrocytes
• Hard, flexible, supports ears, skeleton of sharks
and rays
• Hyaline- most common, covers ends of bones
and joints, respiratory passages
• Elastic- flexible and elastic, external ear, larynx
• Fibrocartilage- very tough , large, menisci
(cartilage where two bones meet),
intervertebral disks
Bone Cells
• Osteocytes
• In the lacunae (cavity or depression,
especially in bone)
• Support and protection
• Surrounded by calcium phosphate
and calcium carbonate= making the
tissue really hard
Blood
• Plasma-> made up of mostly water but
suspends red blood cells , white blood cells,
and platelets.
• Transports various substances throughout
the body of an animal.
Nervous Tissue
• Found in the brain, spinal cord and nerves
• Composed of:
– Neurons- impulse conducting cells
– Neuroglia- protection, support, and nourishment
– Peripheral Glial Cells- form sheaths and help
protect, nourish, and maintain cells of the
peripheral nervous system (outside the brain and
spinal cord)
Muscle Tissue
• Muscle cells= myofibers
• Function: movement, digestion,
organ function
• 3 kinds: Skeletal, Smooth, and
Muscle
Skeletal
• Attached to bones and makes body
movement possible in vertebrates
• Smooth-
Smooth
• Rhythmic contractions create a
churning action (stomach), help
propel material through tubular
structures (intestines), and
control size changes in hollow
organs (uterus, urinary bladder)
Cardiac
• Wall of the heart
• Results in the heart beating
Tissue Repair
• Regeneration- replaces dead or
damaged cells with the same type
of cell, restoring normal function
• Fibrosis- replaces damaged tissue
with scar tissue, which holds the
tissues together but does not
restore normal functions.