Lecture 3 Tissue COVID (4).pptx PDF

Collagen fibers Most common fibers in CTP Long, straight, and unbranched Strong and flexible Bundle of fibrous protein strands Resist force in 1 direction (along longitudinal axis) e.g., tendons and ligaments Reticular fibers Network of interwoven fibers (stroma) Strong and flexible Resist...

Collagen fibers Most common fibers in CTP Long, straight, and unbranched Strong and flexible Bundle of fibrous protein strands Resist force in 1 direction (along longitudinal axis) e.g., tendons and ligaments Reticular fibers Network of interwoven fibers (stroma) Strong and flexible Resist force in many directions Stabilize functional cells (parenchyma) and structures e.g., sheaths around organs Elastic fibers Contain elastin protein Branched and wavy Flexible: return to original length after stretching e.g., elastic ligaments of vertebrae & ear lobe Ground Substance of Connective Tissue Proper Fills spaces between cells Clear and colorless Viscous and dense slows down pathogens Categories of Connective Tissue Proper Loose connective tissue: more ground substance, less fibers e.g., fat (adipose tissue) Dense connective tissue: more fibers, less ground substance e.g., tendons Categories of Connective Tissue Proper Loose connective tissue: more ground substance, less fibers e.g., fat (adipose tissue) Dense connective tissue: more fibers, less ground substance e.g., tendons Loose Connective Tissues The packing materials of the body 3 types: areolar adipose reticular Areolar Tissue Least specialized Open framework Viscous ground substance Elastic - retains shape after stretch Absorbs shocks Holds blood vessels and capillary beds e.g., subcutaneous tissue (under skin) Adipose Tissue Main cell: adipocytes Types of Adipose Tissue White fat: Brown fat: most common ̶ infants & young stores lipids children absorbs shocks ̶ more vascularized insulator ( heat loss) ̶ adipocytes have many mitochondria ̶ breaks down fat ̶ produces heat Liposuction Surgical removal of unwanted adipose tissue Treatment of obesity & lipodystrophy Problem may recur as tissue regenerates Reticular Tissue Complex, 3-dimensional network Reticular fibers (stroma): support functional cells (parenchyma) Reticular organs: spleen – liver – lymph nodes – bone marrow – kidneys Categories of Connective Tissue Proper Loose connective tissue: more ground substance, less fibers e.g., fat (adipose tissue) Dense connective tissue: more fibers, less ground substance e.g., tendons Dense Connective Tissues Tightly packed with high numbers of collagen or elastic fibers(collagenous tissues) Types: regular connective tissue irregular connective tissue Dense Regular Connective Tissue Attachment and stabilization Tightly packed, parallel collagen fibers: ̶ tendons: attach muscles to bones ̶ ligaments: connect bone to bone and stabilize organs e.g., liver ̶ aponeuroses: CT sheets attached to flat muscles Subtype: ̶elastic tissue … Elastic Tissue Subtype of dense regular CT Made mainly of elastic fibers e.g., elastic ligaments of spinal vertebrae Dense Irregular Connective Tissue Strength in many directions Interwoven networks of collagen fibers Locations: ̶ dermis, perichondrium, periosteum, organ capsules, … Fluid Connective Tissues Include: blood lymph Components: watery matrix of dissolved proteins specific cell types (formed elements) Blood Fluid content (plasma) Formed elements: ̶ red blood corpuscles (RBCs) (erythrocytes) ̶ white blood cells (WBCs) (leukocytes) ̶ platelets (thrombocytes) Lymph Collected from interstitial space Monitored by immune system Transported by lymphatic vessels Returned to venous system Supportive Connective Tissues Support soft tissues and body weight: ̶cartilage:  gel-type ground substance  for shock absorption and protection ̶bone (osseous tissue):  calcified (rigid by calcium salts, minerals)  for weight support Cartilage Structure: ̶ cells: chondrocytes located within lacunae (chambers) ̶ matrix: firm gel No blood vessels Perichondrium: dense irregular CT ̶ covers cartilage surfaces ̶ has 2 layers:  outer, fibrous layer (for strength)  inner, cellular layer (for growth and maintenance) Types of Cartilage Hyaline cartilage Elastic cartilage Fibrocartilage Hyaline Cartilage Tough, flexible support Translucent matrix Reduces friction in joints No predominant fibers e.g., Synovial joints, rib tips, sternum and trachea Elastic Cartilage Flexible support Tightly packed elastic fiber Locations: external ear and epiglottis Fibrocartilage Resists compression Limits movement Prevents bone-to-bone contact Very dense collagen fibers Locations: knee pads, symphysis pubis, intervertebral discs Bone (Osseous Tissue) Strong: calcium salt deposits Resists shattering: flexible collagen Bone Structure: ̶ bone cells (osteocytes):  located within lacunae  arranged around central canals within matrix ̶ canaliculi: small channels through matrix – access blood supply Rich blood supply Periosteum: dense irregular CT ̶ covers bone surfaces ̶ 2 layers:  outer fibrous layer  inner cellular layer Cartilage vs. Bone  Categories of Connective Tissues CT Fluid Supportive proper CT CT Loos Dense Bloo Lymp e d h Bone Cartilag Irregula Regular e r Elastic Hyaline Elastic Fibrocartilag Areola Adipose Reticula e r r