Connective Tissues
What do all connective tissues have in common?
• Made up of 3 components:
1) Specialized cells
2) Protein fibers
3) A fluid known as ground substance
• Protein fibers and ground substance= Matrix
• The matrix makes up most of the volume of connective
tissues
3 Major Types of Connective Tissue:
•1) Connective Tissue Proper
•2) Fluid Connective Tissue
•3) Supporting Connective Tissue
Cells of Connective Tissue Proper
• Fibroblasts: most abundant type; produce fibers and
ground substance.
• Macrophages: these cells “eat” or phagocytize damaged
cells or pathogens. Release chemicals that mobilize the
immune system.
• Fat cells or adipocytes: contain large droplets of lipids
(fat)
• Mast Cells: found near blood vessels; have vesicles filled
with chemicals released to defend the body after
injury/infection.
Connective Tissue Fibers:
• Collagen fibers: Most common type; long,
straight, unbranched- Strong and flexible.
• Elastic fibers: contain protein Elastin. They are
branched, wavy,and stretchy.
• Reticular fibers: least common type; thin,
branched and interwoven like a web.
Ground Substance
• Fills the spaces
between cells and
surrounds the
connective tissue
fibers.
• Clear, colorless and has
a maple-syrup
consistency ( slows
down pathogens)
Types of Connective Tissue Proper:
Loose
Connective
Tissue
Dense
Connective
Tissue
Loose Connective Tissue or “Areolar Tissue”
• “packing material of
the body”
• Fill spaces between
organs, provide
cushioning, and
support epithelia,
anchor blood vessels
and nerves, store
lipids.
Adipose Tissue ( Fat)
• Loose connective
tissue is called
Adipose tissue if
dominated by fat
cells (adipocytes).
Dense Connective Tissues:
• Consists mostly of collagen
fibers.
• Types:
1) Tendons: attach skeletal
muscles to bones
2) Ligaments: connect bones to
each other. Have some
elastic fibers ( a little more
stretchy than tendons).
Fluid Connective Tissues
• 2 Types: Blood and Lymph
• Contain cells in a watery matrix.
• Unlike other connective tissues, the
proteins are dissolved in the matrix and do
not form insoluble fibers.
Blood- A fluid Connective Tissue
Consists of:
Red blood cells:
transport
Oxygen(O2)
White blood cells:
fight infection
Platelets: clot
blood
Lymph- A fluid Connective Tissue
• Lymph: forms as
interstitial fluid ( fluid
within the body’s tissue)
enters small passageways
, or Lymphatic vessels that
eventually return it to the
cardiovascular system.
Supporting Connective Tissues:
• Includes: Cartilage and Bone
• Provide a strong framework that
supports the body
Cartilage
• The matrix is a firm gel containing embedded fibers.
• Contains Chondrocytes: cartilage cells found within
the matrix that live in small pockets called lacunae
• Is avascular
• Separated from surrounding tissues by
perichondrium.
• 3 major types: Hyaline, Elastic, Fibrous
Hyaline Cartilage
• Most common type
• Matrix contains closely
packed collagen fibers
• Tough but flexible.
Found: between joints,
connecting ribs to
sternum, supporting the
larynx and trachea.
Elastic Cartilage
• Matrix contains
numerous elastic fibers
• Resilient and flexible
• Found: external flap of
ear (auricle), the
epiglottis, and airway to
the middle ear.
Fibrous Cartilage or Fibrocartilage
• Matrix contains little
ground substance and is
dominated by collagen
fibers that are densely
interwoven.
• Tough and durable
• Found: pads between
vertebrae, between
pubic bones of pelvis.
Bone ( Osseus tissue)
• Matrix consists of little ground substance containing collagen
fibers . It is calcified with calcium compounds
• Strong and resistant to shattering.
• Contain osteocytes( bone cells) found in lacunae
• Lacunae are found surrounding blood vessels .
• Cytoplasmic extensions from osteocytes reach blood vessels- form
a network called the canaliculi
Bone
•
Contain osteocytes( bone cells)
found in lacunae
•
Lacunae are found surrounding blood
vessels .
•
Cytoplasmic extensions from
osteocytes reach blood vessels- form
a network called the canaliculi
(little canals)
•
Outer layer of bone surrounded by a
fibrous covering called periosteum