Tissues - Midlandstech

Dr. Gerald Brasington
Histology: The study of microscopic
structure of tissues.
 Integumentary System: The skin and its
 Every tissue of the body falls into one of
4 main categories:
Epithelial Tissue
Distinguished by its close association of
cells  epithelial cells are packed close
together with little material between
 Epithelium is avascular.
 Epithelial tissue covers body surfaces,
lines inside of body cavities and organs,
and forms glands.
Epithelial tissue (continued)
3 main functions:
◦ 1. Protection
◦ 2. Control of permeability
◦ 3. Secretion of needed substances from glands
Epithelial tissue (continued)
Arrangement of cells results in clumps or
◦ Sheet- like: covering or lining epitheliumCovers the body and organ surfaces.
◦ Lines all hollow structures.
 Often protective  form a barrier  regulates
movement of substances
Epithelial tissue (continued)
Clump- like  Glandular epithelium
◦ Form glands
Glands- 2 types
◦ Exocrine: Secrete products into body cavities
and surfaces by way of tubular ducts.
◦ Endocrine: Secretions diffuse into
bloodstream for transport throughout body.
 Hormones
Epithelial tissue (continued)
Epithelial tissue usually has connection tissue
under it.
 Often borders a hollow space (cavity or
 The side exposed to a body space  apical
(free) surface.
 The side exposed to connective tissue is the
basal surface.
 Basement membrane- layer of protein fibers
anchor epithelial sheet to connective tissue.
Classification of epithelial tissue
Cell shape
◦ Squamous- Flat with a thin nucleus
◦ Cuboidal- Cube-shaped with round nucleus near
the center of the cell
◦ Columnar- Tall with an oval nucleus near the basal
◦ Transitional- Shape changing from round when
tissue is relaxed to flat when tissue is stretched.
organization (layers)
◦ Simple- One layer
◦ Stratified- Multiple layered.
Connective Tissue
Arises from Mesenchyme
 Embryological Mesenchyme
 5 types of connective tissue:
Loose Connective Tissue
Dense Connective Tissue
Connective Tissue (Continued)
General function is to connect and
support the tissues and organs of the
Muscle Tissue
Specialized cells containing molecular
filaments of protein (Myosin and Actin)
arranged in parallel bundles.
 The filaments enable the cells to shorten
in length (contract).
 Contraction of many cells in a
coordinated manner cause body
 Also aids in temperature regulation.
Muscle Tissue (Continued)
3 types of muscle
◦ Skeletal: attached to bones; Main type;
Voluntary; cells and very long & cylindrical.
Striped appearance  striations.
◦ Smooth: Sheets that contribute to the walls of
hollow organs blood vessels, Stomach, Small
intestines. Cells are spindle shaped, lack
striations, involuntary control.
◦ Cardiac: Forms the wall of the heart.
Branched, contain striations. Intercalated
Nervous Tissue
Neural tissue is specialized cells that
“communicate” with each other through
electrochemical signals (conductivity).
 The cells are called Neurons. Found in
brain, spinal cord, and nerves.
 Contain a large axon  conducts signal to
other cells.
 Numerous, smaller dendrites  receive
signals from other cells.
 Neuroglia: small non-conductive support
The End