TissuesTissuesDr. Gerald Brasington
TissuesTissuesHistology: The study of
microscopic structure of tissues.Integumentary System: The skin
and its appendages.Every tissue of the body falls into
one of 4 main categories:◦Epithelial◦Connective◦Muscle◦Nervous
Epithelial TissueEpithelial TissueDistinguished by its close
association of cells epithelial cells are packed close together with little material between them.
Epithelium is avascular.Epithelial tissue covers body
surfaces, lines inside of body cavities and organs, and forms glands.
Epithelial tissue Epithelial tissue (continued)(continued)3 main functions:
◦1. Protection◦2. Control of permeability◦3. Secretion of needed substances
from glands
Epithelial tissue Epithelial tissue (continued)(continued)Arrangement of cells results in
clumps or sheets◦Sheet- like: covering or lining epithelium- Covers the body and organ surfaces.
◦Lines all hollow structures. Often protective form a barrier
regulates movement of substances
Epithelial tissue Epithelial tissue (continued)(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 Epithelial tissue (continued)(continued)Epithelial tissue usually has
connection tissue under it.Often borders a hollow space
(cavity or lumen)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 Classification of epithelial tissuetissueCell 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 surface◦Transitional- Shape changing from
round when tissue is relaxed to flat when tissue is stretched.
organization (layers)◦Simple- One layer◦Stratified- Multiple layered.
Connective TissueConnective TissueArises from MesenchymeEmbryological Mesenchyme5 types of connective tissue:
◦Loose Connective Tissue◦Dense Connective Tissue◦Cartilage◦Bone◦Blood
Connective Tissue Connective Tissue (Continued)(Continued)General function is to connect
and support the tissues and organs of the body.
Muscle TissueMuscle TissueSpecialized 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 movements.
Also aids in temperature regulation.
Muscle Tissue (Continued)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 Discs.
Nervous TissueNervous TissueNeural 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 cells.
The EndThe End