List and describe the major functions of connective tissues.
- Binding of organs - tendons and ligaments
- Support - bones and cartilage
- Physical protection —cranium, ribs, sternum
- Movement - bones provide lever system.
- Storage - fat, calcium, phosphorus
- Cushion and insulate -
- Heat production - metabolism of brown fat in infants
- Transportation - blood
- Immune protection —white blood cells attack foreign invaders.
4 Types of Connective Tissues
- Adipose (fad, lipid) (LOOSE)
Special Characteristics of Connective Issues
- Abundance of extracellular matrix (ECM = fibers or fluid) with fewer cells.
- Encloses and separates the tissues
- Highly VASCULAR (blood connections)
- Most abundant & widely distributed
Types of Fibers in Connective Issues
- Reticular (Collagenous)
- Special Characteristics:
- Cell Body Shape: Thin collagen fibers coated with glycoprotein that form networks of fibers.
- Form a sponge like framework for such organs as the spleen and lymph nodes.
- Allows stretch and recoil
- Branch and rejoin each other
- thinner than collagen fibers
- Lungs & Arteries
Most abundant, tough, flexible
Loose Areolar Connective Tissue Location
- Deep to epithelial basement membrane
- Packing between glands, muscles, and nerves
- Dermis of skin (papillary layer)
Loose Areolar Connective Tissue Functions
- Packing, support, vascular support of epithelial tissues (supply nutrients/oxygen and remove wastes)
- Packing and support
- Supportive structure
Loose Adipose Connective Tissue Location
- Subcutaneous fat
- Surrounds and supports Mammary glands
Loose Adipose Connective Tissue Functions
- Thermal insulation, Packing material,
- Energy storage, Protection from injury
Loose Reticular Connective Tissue Location
- Spleen, lymph nodes, & Tonsils
Loose Reticular Connective Tissue Functions
Provides structural support (framework) for lymphatic organs.
Dense Regular (Collagenous) Fibrous Connective Tissue Location
Tendons and ligaments
Dense Regular (collagenous) Fibrous Connective Tissue Functions
Withstand force placed on the tissues in one direction (the direction of the fibers)
Dense Irregular (collagenous) Fibrous Connective Tissue Location
- Deep layer of the dermis of the skin
Organ capsules (covering)
Dense Irregular (collagenous) Fibrous Connective Tissue Functions
Withstands stretching in all directions
Dense Regular Elastic Connective Tissue Functions
- Vocal Folds
- Ligaments between vertebrae
Dense Regular Elastic Connective Tissue Functions
Able to stretch and recoil in the direction of the elastic fibers
Dense Irregular Elastic Connective Tissue Location
Elastic arteries (Aorta, Vena Cava)
Dense Irregular Elastic Connective Tissue Functions
Stretching and recoil in all directions.
Hyaline Cartilage Location
- Growth plates in bones
- Nasal cartilages
- Articular surfaces of bones at joints
Hyaline Cartilage Functions
- Bone growth
- Structural support with flexibility
- Strong, smooth, flexible articular surfaces of joints
Fibrocartilage Connective Tissue Location
- Pubic symphysis
- Intervertebral disks
- Menisci of knee
Fibrocartilage Connective Tissue Functions
- Strong yet slightly flexible connection of pelvis
- Withstands great pressure of moving spine, somewhat flexible
- Shock absorption, somewhat flexible connection
Elastic Cartilage Connective Tissue Location
- External ears
- Epiglottis (tissue that opens and closes when you swallow to divert food away from the trachea)
Elastic Cartilage Connective Tissue Functions
Most flexible yet still rigid of the cartilages because the elastic fibers recoil to original shape after stretching
- In blood vessels
- Transport Oxygen, Carbon dioxide, nutrients, hormones, and waste products
- Protection from infection (white blood cells)
- Temperature regulation
Loose Reticular Characteristics
Cell Body Shape : Loose network
of reticular fibers & cells
- Looks like cherry blossoms or marble
- Infiltrated by lots of WBC (White Blood Cells)
Loose Adipose Characteristics
- Cell Body Shape: Empty-looking (large and open) cells with thin margins.
- Small nucleus pressed against cell membrane.
- Predominant cells are adipocytes.
- Very pale because of scarcity of stained cytoplasm
Loose Areolar Charateristics
- Cell Body Shape: Scatter collagenous, elastic, and reticular fibers.
- Many cells of various types
- Most Abundant
- Numerous blood vessels
Dense Regular Characteristics
- Cell Body Shape: Densely packed, parallel, often wavy sheets collagen fibers, elastic tissue/fibers
- Slender nuclei compressed between collagen bundles
- Few blood vessels.
Dense Irregular Characteristics
- Cell Body Shape: Densely packed collagen fibers going in random directions. Irregular in shape; randomly arranged.
- Few visible cells
- Few blood cells.
Cell Body Shape: Often in small clusters
of 2-4 cells (chondrocytes)
- Chondrocytes make cartilage.
- Looks like eyes or fish eggs.
- Rounded or polygonal chondrocytes
translucent appearance, clear, glassy matrix
- Usually because of fineness of the collagen fibers
- Collagen fibers not obvious
- Cell Body Shape: Fine elastic fibers form weblike mesh-like bundles and lacunae. Round.
- Always covered by perichondrium
- Fibers are fine and dark (elastic fibers)
- Cell Body Shape: Round to oval shaped; bound together orderly.
Contains large, coarse bundles of
- Numerous parallel collagen fibers.
- Rows of unclustered chondrocytes in lacunae between collagens.
- Strongest of the 3 cartilages and most durable.
Cell Body Shape: Osteons are large,
cork-like circles with mineralized concentric rings around central
- Arranged in cylinders (rings of tree)
- Dominated by osteons.
- Tiny dark dots in rings are cells (osteocytes)
- Densely packed
- Blood vessels present.
- Blood vessels and nerves
Cell Body Shape: Numerous tiny,
circular, bell shaped cells (erythrocytes) with thinner margins.
- Often very pale because of scarcity of stained cytoplasm.
- Cells suspended in plasma.
- Typically NO nucleus
Substitution of dead/damaged cells by viable/functional cells
- CAPABLE OF MITOSIS throughout life (skin, bone marrow cells, and mucous membranes)
- NO MITOSIS after growth ends, but can divide after injury (liver, pancreas, and endocrine cells)
- If killed, REPLACED by a different type of cell. Limited regenerative ability (nervous, skeletal, and cardiac muscle)