Dr. Chakraborty
A&P I
Review: Tissue: Tissues are collections of cells and cell products that perform specific, limited
functions.
Types of tissue
Epithelial tissue: Covers exposed surfaces; Lines internal passageways; Forms glands
Connective tissue: Fills internal spaces; Supports other tissues; Transports materials;
Stores energy
Muscle tissue: Specialized for contraction; Skeletal muscle, heart muscle, and walls of
hollow organs
Neural tissue: Carries electrical signals from one part of the body to another
Epithelial Tissues: Layers of cells covering internal or external surfaces and Glands -structures
that produce secretions
Characteristics of Epithelia
Cellularity (cell junctions) Functions of Epithelial Tissue
Polarity (apical and basal surfaces) Provide physical protection
Attachment (basal lamina) Control permeability
Avascularity Provide sensation
Regeneration Produce specialized secretions
(glandular epithelium
Specializations of Epithelial Cells: Move fluids over the epithelium (protection). Move fluids
through the epithelium (permeability). Produce secretions (protection and messengers)
Attachments: Maintaining the Integrity of Epithelia - intercellular connections and attachment to
basal lamina: two layers. top layer (clear layer) secreted by epithelial tissue known as lamina
lucida and the bottom layer secreted by connective tissue known as lamina densa.
CAMs (cell adhesion molecules): transmembrane proteins; Intercellular cement: proteoglycans
Cell junctions: Form bonds with other cells or extracellular material:
i) tight junctions: between two plasma membranes that prevents passage of water and solutes
ii) gap junctions: allow rapid communication; held together by channel proteins (junctional
proteins, connexons)
iii) desmosomes: button, belt and hemi desmosomes
Classification of Epithelia
Based on shape Based on layers
Squamous epithelia: thin and flat Simple epithelium: single layer of cells
Cuboidal epithelia: square shaped Stratified epithelium: several layers of cells
Columnar epithelia: tall, slender rectangles
** Read all the locations that are mentioned in the slide (important)
Two additional epithelial tissues are:
Transitional Epithelium: Tolerates repeated cycles of stretching and recoiling and returns to its
previous shape without damage- situated in regions of the urinary system (e.g. urinary bladder)
Pseudostratified columnar epithelium – trachea
Glandular Epithelia: Endocrine glands and Exocrine glands
Endocrine gland - release hormones into interstitial fluid and have no ducts
Exocrine glands- produce secretions onto epithelial surfaces through ducts
Classification of Exocrine glands:
A&P I
Review: Tissue: Tissues are collections of cells and cell products that perform specific, limited
functions.
Types of tissue
Epithelial tissue: Covers exposed surfaces; Lines internal passageways; Forms glands
Connective tissue: Fills internal spaces; Supports other tissues; Transports materials;
Stores energy
Muscle tissue: Specialized for contraction; Skeletal muscle, heart muscle, and walls of
hollow organs
Neural tissue: Carries electrical signals from one part of the body to another
Epithelial Tissues: Layers of cells covering internal or external surfaces and Glands -structures
that produce secretions
Characteristics of Epithelia
Cellularity (cell junctions) Functions of Epithelial Tissue
Polarity (apical and basal surfaces) Provide physical protection
Attachment (basal lamina) Control permeability
Avascularity Provide sensation
Regeneration Produce specialized secretions
(glandular epithelium
Specializations of Epithelial Cells: Move fluids over the epithelium (protection). Move fluids
through the epithelium (permeability). Produce secretions (protection and messengers)
Attachments: Maintaining the Integrity of Epithelia - intercellular connections and attachment to
basal lamina: two layers. top layer (clear layer) secreted by epithelial tissue known as lamina
lucida and the bottom layer secreted by connective tissue known as lamina densa.
CAMs (cell adhesion molecules): transmembrane proteins; Intercellular cement: proteoglycans
Cell junctions: Form bonds with other cells or extracellular material:
i) tight junctions: between two plasma membranes that prevents passage of water and solutes
ii) gap junctions: allow rapid communication; held together by channel proteins (junctional
proteins, connexons)
iii) desmosomes: button, belt and hemi desmosomes
Classification of Epithelia
Based on shape Based on layers
Squamous epithelia: thin and flat Simple epithelium: single layer of cells
Cuboidal epithelia: square shaped Stratified epithelium: several layers of cells
Columnar epithelia: tall, slender rectangles
** Read all the locations that are mentioned in the slide (important)
Two additional epithelial tissues are:
Transitional Epithelium: Tolerates repeated cycles of stretching and recoiling and returns to its
previous shape without damage- situated in regions of the urinary system (e.g. urinary bladder)
Pseudostratified columnar epithelium – trachea
Glandular Epithelia: Endocrine glands and Exocrine glands
Endocrine gland - release hormones into interstitial fluid and have no ducts
Exocrine glands- produce secretions onto epithelial surfaces through ducts
Classification of Exocrine glands:
