connective tissue. found everywhere in the body includes the most abundant and widely distributed...
TRANSCRIPT
Connective Tissue
Connective Tissue
• Found everywhere in the body• Includes the most abundant and widely
distributed tissues• Functions
– Binds body tissues together– Supports the body– Provides protection
Connective Tissue Characteristics
• Variations in blood supply– Some tissue types are well vascularized– Some have a poor blood supply or are avascular
• Extracellular matrix– Non-living material that surrounds living cells
Extracellular Matrix
• Two main elements• Ground substance—mostly water along with
adhesion proteins and polysaccharide molecules– Fibers
• Produced by the cells• Three types
– Collagen (white) fibers– Elastic (yellow) fibers– Reticular fibers
Connective Tissue Types
• Bone (osseous tissue)– Composed of
• Bone cells in lacunae (cavities)• Hard matrix of calcium salts• Large numbers of collagen fibers
– Functions to protect and support the body
Figure 3.19a
Bone cells inlacunae
(a) Diagram: Bone Photomicrograph: Cross-sectional viewof ground bone (300×).
Lamella
Lacunae
Central canal
Connective Tissue Types• Hyaline cartilage
– Most common type of cartilage– Composed of
• Abundant collagen fibers• Rubbery matrix
– Locations• Larynx• Entire fetal skeleton prior to birth
– Functions as a more flexible skeletal element than bone
Figure 3.19b
Chondrocyte(Cartilage cell)
Lacunae
(b) Diagram: Hyaline cartilage Photomicrograph: Hyaline cartilagefrom the trachea (500×).
Matrix
Chondrocytein lacuna
Connective Tissue Types
• Elastic cartilage– Provides elasticity– Location
• Supports the external ear
• Fibrocartilage– Highly compressible– Location
• Forms cushion-like discs between vertebrae
Figure 3.19c
Chondro-cites inlacunae
Collagenfibers
(c) Diagram: Fibrocartilage Photomicrograph: Fibrocartilage of anintervertebral disc (110×).
Collagen fiber
Chondrocytesin lacunae
Connective Tissue Types
• Dense connective tissue (dense fibrous tissue)– Main matrix element is collagen fiber– Fibroblasts are cells that make fibers– Locations
• Tendons—attach skeletal muscle to bone• Ligaments—attach bone to bone at joints• Dermis—lower layers of the skin
Figure 3.19d
Ligament
Tendon
Collagenfibers
Nuclei offibroblasts
(d) Diagram: Dense fibrous Photomicrograph: Dense fibrous connective tissuefrom a tendon (500×).
Nuclei offibroblasts
Collagenfibers
Connective Tissue TypesConnective Tissue Types
Slide 3.59Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Dense connective tissue Main matrix element
is collagen fibers
Cells are fibroblasts
Examples Tendon – attach
muscle to bone
Ligaments – attach bone to bone
Dermis of skinFigure 3.18d
Two types of Dense Connective Tissue
• REGULARREGULAR• Parallel bundles of collagen;
packed tightly together• Extremely strong & tough• Avascular (why????)• Found in tendons & ligaments
for a strong rope-like connection
• Differentiate: tendon, ligament
• IRREGULARIRREGULAR• Non-parallel bundles of
collagen, arranged in a web like mesh
• Great strength• Vascular (why????)• Composes the dermis of the
skin
Which is which: regular or irregular dense connective tissue?
Connective Tissue Types
• Loose connective tissue types– Areolar tissue
• Most widely distributed connective tissue• Soft, pliable tissue like “cobwebs”• Functions as a packing tissue• Contains all fiber types• Can soak up excess fluid (causes edema)
Figure 3.19e
MucosaepitheliumLaminapropria
Fibers ofmatrix
Nuclei offibroblasts
(e) Diagram: Areolar Photomicrograph: Areolar connective tissue, asoft packaging tissue of the body (300×).
Fibroblastnuclei
Collagenfibers
Elasticfibers
Connective Tissue Types
• Loose connective tissue types– Adipose tissue
• Matrix is an areolar tissue in which fat globules predominate
• Many cells contain large lipid deposits• Functions
– Insulates the body– Protects some organs– Serves as a site of fuel storage
Figure 3.19f
Nuclei offat cells
Vacuolecontainingfat droplet
(f) Diagram: Adipose Photomicrograph: Adipose tissue from thesubcutaneous layer beneath the skin (430×).
Vacuolecontainingfat droplet
Nuclei offat cells
Connective Tissue Types
• Loose connective tissue types– Reticular connective tissue
• Delicate network of interwoven fibers• Locations
– Forms stroma (internal supporting network) of lymphoid organs
» Lymph nodes» Spleen» Bone marrow
Figure 3.19g
Spleen
Reticularcell
Reticularfibers
Bloodcell
(g) Diagram: Reticular Photomicrograph: Dark-staining networkof reticular connective tissue (430×).
White blood cell(lymphocyte)
Reticular fibers
Connective Tissue Types
• Blood (vascular tissue)– Blood cells surrounded by fluid matrix called blood
plasma– Fibers are visible during clotting– Functions as the transport vehicle for materials
Figure 3.19h
Neutrophil(white bloodcell)
Red bloodcells
Monocyte(white bloodcell)
Photomicrograph: Smear of human blood (1300×)(h) Diagram: Blood
Whiteblood cell
Redblood cells
Blood cellsin capillary