Glandular Epithelia
Objectives
 Define gland
 Differentiate between exocrine and endocrine glands, and differentiate between multicellular and
unicellular glands
 Describe how multicellular exocrine glands are classified structurally and funcitonally
Glandular Epithelia
 A gland is one or more cells that makes and secretes an ___________________________________.
 Glandular cells obtain needed substances from blood and transform them chemically into a product that
is then released from the cell.
Classified by:
 Site of product release—_______________________(internally secreting) or
________________________ (externally secreting)
 Relative number of cells forming the gland—unicellular (e.g., goblet cells) or multicellular
Endocrine Glands
 _____________________________ glands
 Secrete _____________________________ that travel through lymph or blood to target organs
Exocrine Glands
 More numerous than endocrine glands
 Secrete products into ___________________
 Secretions released onto ___________________________________ (skin) or into body
________________________
 Examples include: mucous, ________________________, oil, and _________________________ glands
Unicellular Exocrine Glands
 The only important unicellular glands are _______________ cells and _______________________cells.
 Goblet cells- look like a glass with a stem due to the accumulation of ___________________ at
the top of the cell.
 Both produce mucin that dissolves in water when secreted and forms _______________________- a
slimy protective and lubricating coating found within the human body.
Multicellular Exocrine Glands
 Multicellular exocrine glands are composed of a duct and a secretory unit
 Classified according to:
 Duct type
 _________________________: unbranched duct
 _________________________: branched duct
 Structure of their secretory units
 ______________________________: secretory cells form tubes.
 ______________________________ (acinar): secretory cells form small sacs.
 _______________________________: have both types of secretory units.
 Modes of Secretion
 Merocrine
 Products are secreted by ____________________________
 Examples: _________________________________________________________
 Holocrine
 Products are secreted by rupture of gland cells
 Example: _______________________________________________
Connective Tissue
 Most abundant and widely distributed tissue type
Four classes
 Connective tissue proper
 Cartilage
 Bone tissue
 Blood
Major Functions of Connective Tissue
 Binding and support
 Protection
 Insulation
 Transportation (blood)
Characteristics of Connective Tissue
 Connective tissues have:
 Mesenchyme (embryonic tissue) as their common tissue of origin
 Varying degrees of vascularity (supply of blood vessels)
 Cells separated by nonliving extracellular matrix (ground substance and fibers)
 This is what enables the connective tissue to bear weight, withstand great tension, and
endure physical trauma. (think of rebar and concrete sidewalks that are connecting
pathways between buildings)
Structural Elements of Connective Tissue
Ground substance
 Unstructured material that fills the space between the cells and contains the
___________________
 Functions as a molecular sieve through which nutrients and other dissolved substances diffuse
between blood capillaries and cells.
 Components:
 Interstitial fluid
 Adhesion proteins (“glue”)
 Proteoglycans
 Protein core + large polysaccharides (chrondroitin sulfate and hyaluronic acid)
 Trap water in varying amounts, affecting the thickness of the ground substance
Fibers
 provide support
 ________ types of fibers
 _____________________________ (white fibers)
 Strongest and most abundant type
 Provides high tensile strength
 ______________________________
 Networks of long, thin, elastin fibers that allow for _________________
 ______________________________

Short, fine, highly branched collagenous fibers
Cells
 Mitotically active and secretory cells = “blasts”
 Mature cells = “cytes”
 Fibroblasts in connective tissue proper
 Chondroblasts and chondrocytes in ___________________________
 Osteoblasts and osteocytes in ____________________________
 Hematopoietic stem cells in ____________________ _________________________
 Fat cells, white blood cells, mast cells, and macrophages
Connective Tissue: Embryonic
 Mesenchyme—________________________________ connective tissue
 Gives rise to all other connective tissues
 Gel-like ground substance with fibers and star-shaped mesenchymal cells
Connective Tissue Proper:
Types:
 Loose connective tissue
 ____________________________________
 ____________________________________
 ____________________________________
 Dense connective tissue
 _____________________________________
 _____________________________________
 _____________________________________
Connective Tissue: Cartilage
 _______ types of cartilage:
 _______________________________ cartilage
 _______________________________cartilage
 _______________________________
Homeostatic Imbalance
 Cartilage
 Aging cartilage cells lose their ability to ____________________  injure cartilages heal slowly.
 During later life cartilages tend to calcify or ossify (___________________________________).
Other tissues…
 Osseus (bone) Tissue
 Nervous Tissue
 Muscle Tissue
 Muscle Tissue
 Muscle Tissue
 Epithelial Membranes
 Cutaneous membrane (skin)
 Consists of keratinized stratified squamous epithelium (epidermis) firmly attached to a thick
layer of dense irregular connective tissue (dermis)
 Epithelial Membranes
 Mucous membranes
 Mucosae
 Line body cavities open to the exterior (e.g., digestive and respiratory tracts)
 Epithelial Membranes
 Serous Membranes
 Serosae—membranes (mesothelium + areolar tissue) in a closed ventral body cavity
 Parietal serosae line internal body walls
 Visceral serosae cover internal organs
 Steps in Tissue Repair
 Steps in Tissue Repair
 Steps in Tissue Repair
 Homeostatic Imbalance
 Scar Tissue
 Scar tissue that forms in any muscular organ- heart or urinary bladder can severely impair the
function of that organ.
 Scars reduce the internal volume of the organ and block movement of substances through the
hollow organ.
 Can hamper the muscle’s ability to contract.
 Heart = progressive heart failure.
 Visceral organs = adhesions connect organs together and prevent normal shifting about
 ex. Intestines: adhesions obstruct the flow of foodstuffs.
 Tissue Damage-Snake Bite
 Developmental Aspects
 Primary germ layers: ectoderm, mesoderm, and endoderm
 Formed early in embryonic development
 Specialize to form the four primary tissues
 Nerve tissue arises from ectoderm
 Muscle and connective tissues arise from mesoderm
 Epithelial tissues arise from all three germ layers