Download Connective Tissue

Classification of Exocrine Glands:Type
of Secretions Produced
Type of secretion produced
 Serous secretions
 Watery
 Contain a high concentration of enzymes
 Pancreatic secretion
 Mucous secretions
 Thick, viscous
 Composed of glycoproteins
Mucus membranes (GI and respiratory tracts)
 Mixed exocrine glands contain both mucous and serous components
 Salivary glands
Connective Tissue
 Forms metabolic and structural connections between tissues
 Found ___________ in the body and represents most abundant tissue by weight.
 Examples: Blood, tendons, fat, cartilage, bone
 Some systems are almost exclusively composed of connective tissue
 Skeletal, integumentary
 Derived from _____________
 Is vascularized.
 Loose & Adipose = good supply, Dense = poorly supplied
 Form and function may vary
 can be elastic and flexible, rigid, semisolid, liquid
 Reserve for energy, protective sheath, provides framework of structural support, transport
medium, promotes healing, controls foreign invaders
Connective Tissue Components
 3 major components of connective tissue:
 Extracellular fibers, Ground substance, Cells
 Extracellular Matrix = Extracellular fibers + Ground substance
 Matrix surrounds and separates the cells, providing important structural and nutritional
support to them, allowing them to be farther apart than epithelial cells.
 1. Extracellular fibers
 Collagenous, Reticular, Elastic
 2. Ground substance
 Liquid, solid, or gel
 3. Cells
 Fixed cells
Fibroblasts, Adipocytes (fat cells), Reticular cells
 Wandering cells
 Mast cells, Leukocytes (white blood cells), Macrophages (fixed and
wandering)

Connective Tissue Components: Ground Substance
 An amorphous, homogenous material that ranges
from ______ to _____ to _______.
 Composed of glycoproteins called
__________________ (GAGs)
 hyaluronic acid
 Help to orient fiber formation in connective tissue.
 Is medium through which cells exchange nutrients
and waste with the bloodstream.
 Acts as ______ absorbing cushion and helps to
protect the delicate cells that it surrounds.
 Serves as obstacle for invading microorganisms.
Fibers of Connective Tissue
 Collagenous:
 Most common fiber found in the body
 Strong, thick bands composed of collagen (structural protein).
 Organized into bundles
 Resist pulling forces, so they are found in tendons and ligaments that are
continuously being pulled and stretched.
 wavy appearance when not stretched
 Sometimes called white fibers
 Density and arrangement can vary
depending on tissue function.
 Loose around organs to dense within
tendons.
Fibers of Connective Tissue
 Reticular:
 Composed of collagen, but are not thick
 Thin, delicate, branched into complicated networks.
 Form support for around highly cellular organs
 endocrine glands, lymph nodes, spleen, bone marrow, liver
 Found around blood vessels, nerves, muscle fibers, capillaries
 Elastic:
 Composed primarily of protein elastin.
 Are branched and form networks
 Can stretch and contract.
 Found in tissues that stretch: vocal cords, lungs, skin, blood vessel walls.
 May be referred to as yellow fibers.
Major Cell Types of Connective Tissue
Fixed Cells:
 Remain in the connective tissue
 Produce and maintain the matrix
 Fibroblast:
secrete fibers and ground substance of the matrix
 Can reproduce and are metabolically active.
 Name is based on location

o Chondroblast (cartilage), osteoblast (bone), etc.

As the cells mature and the matrix is formed, cells become less active and are
called –cytes.
o Chondrocyte, osteocyte, fibrocyte
o Can revert back to blast if more matrix is needed.
Major Cell Types of Connective Tissue
 Fixed cells continued.
 Adipose cells/Adipocytes:
 Found throughout connective tissue
 Resemble fibroblasts early on, but as they age they
become filled with lipid and swell.
 nucleus gets pushed to the side
 Adipocytes clustered together form adipose tissue.
 found all over, but is prominent under the skin,
behind the eyes, around the kidneys, and in the
abdomen
 Reticular Cells:
 Flat, star-shaped cells that form net-like connections
with other cells
 Manufacture of reticular fibers.
 Found in tissues of the immune system: lymph
nodes, spleen, bone marrow
Major Cell Types of Connective Tissue
 Wandering Cells:
 Move in and out of connective tissue as needed.
 Leukoctyes: (white blood cells)
 Found in blood and move into connective tissue during periods of infection.
 Squeeze through the simple squamous epithelium of blood vessels (diapedesis)
 Important in immune function- engulf and digest invaders or produce antibodies against
them
 Mast cells
 Carry histamine and heparin granules which initiate inflammatory response when
released into tissue
 Usually found near blood vessels
Major Cell Types of Connective Tissue
 Wandering cells continued..
 Macrophages:
 Phagocytotic scavengers that may be either fixed or transient in connective
tissue.
 Engulf microbes, dead cells and debris that are digested by the macrophage’s
lysosomes
 drawn to sites of infection where they engulf invaders
 Given different names depending on locations
 Kupffer cells in liver, microglial cells in brain