University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2023
Views:

262

Pages:

61
Author:

Kundulu8mbj

CARTILAGE, BONE AND OSTEOGENESIS Objectives • Histologically identify and functionally characterize each of the various forms of supporting connective tissue. • Recognize the structure and characterize the function of cells, fibers and ground substance components of each of the supporting connective tissues examined. • Describe the cellular mechanisms that provide for intramembranous and endochondrial bone development. • Compare and contrast the structure and function of compact and sponge bone. FUNCTIONS OF CARTILAGE FLEXIBLE SUPPORT - RETURN TO ORIGINAL SHAPE (EARS, NOSE, AND RESPIRATORY) FUNCTIONS OF CARTILAGE SLIDES ACROSS EACH OTHER EASILY WHILE BEARING WEIGHT (JOINTS, ARTICULAR SURFACES OF BONES) CUSHION - CARTILAGE HAS LIMITED COMPRESSIBILITY (JOINTS) No nerves and, thus, no pain during compression of cartilage. CONNECTIVE TISSUE CELLS OF CT FIBROBLASTS MESENCHYMAL CELLS and RBC ADIPOSE CELLS MACROPHAGE PLASMA CELLS MAST CELLS and WBC CHONDROBLASTS CHONDROCYTES OSTEOBLASTS OSTEOCYTES OSTEOCLASTS GENERAL ORGANIZATION OF CARTILAGE PERICHONDRIUM CAPSULE-LIKE SHEATH OF DENSE IRREGULAR CONNECTIVE TISSUE THAT SURROUNDS CARTILAGE (EXCEPT ARTICULAR CARTILAGE) FORMS INTERFACE WITH SUPPORTED TISSUE HARBORS A VASCULAR SUPPLY GENERAL ORGANIZATION OF CARTILAGE MATRIX TYPE II COLLAGEN (LACK OF OBVIOUS PERIODICITY) GENERAL ORGANIZATION OF CARTILAGE MATRIX TYPE II COLLAGEN (LACK OF OBVIOUS PERIODICITY) SULFATED PROTEOGLYCANS (CHONDROITIN SULFATE AND KERATAN SULFATE) - STAIN BASOPHILIC CAPABLE OF HOLDING WATER / DIFFUSION OF NUTRIENTS AVASCULAR - GETS NUTRIENT/WASTE EXCHANGE FROM PERICHONDRIUM GENERAL ORGANIZATION OF CARTILAGE MATRIX TYPE II COLLAGEN (LACK OF OBVIOUS PERIODICITY) SULFATED PROTEOGLYCANS (CHONDROITIN SULFATE AND KERATAN SULFATE) - STAIN BASOPHILIC CAPABLE OF HOLDING WATER / DIFFUSION OF NUTRIENTS AVASCULAR - GETS NUTRIENT/WASTE EXCHANGE FROM PERICHONDRIUM GENERAL ORGANIZATION OF CARTILAGE CHONDROCYTES / CHONDROBLASTS GENERAL ORGANIZATION OF CARTILAGE CHONDROCYTES / CHONDROBLASTS GENERAL ORGANIZATION OF CARTILAGE CHONDROCYTES / CHONDROBLASTS GENERAL ORGANIZATION OF CARTILAGE CHONDROCYTES / CHONDROBLASTS Type II Cartilage 040 • Hyaline cartilage • Glassy matrix (GAGs, proteoglycans, collagen II) devoid of blood vessels, surrounded by fibrous sheath perichondrium • Elastic cartilage 037 • Similar to hyaline except chondrocytes become trapped in their secretions (enmeshed within the matrix, lacunae), has elasticity thus maintains its shape • Fibrocartilage • Course collagen I fibers form dense bundles to withstand physical stresses, strengthen hyaline cartilage 017 Developing Cartilage 040 Cartilage grows by both interstitial growth (mitotic division of preexisting chondroblasts) and by appositional growth (differentiation of new chondroblasts from the perichondrium). perichondrium Slide 40: Trachea Perichondrium Chondrogenic region Chondroblasts Hyaline cartilage C-ring Isogenous group of Territorial matrix chondrocytes in Inter-territorial matrix individual lacunae Slide 40: Trachea Perichondrium Staining variations within the matrix reflect local differences in its molecular composition. Immediately surrounding each chondrocyte, the ECM is relatively rich in GAGs causing these areas of territorial matrix to stain differently from the intervening areas of interterritorial matrix. Territorial matrix Inter-territorial matrix Slide 37: Epiglottis Fold artifact Elastic cartilage Perichondrium Elastic cartilage has obvious elastic fibers in an otherwise heterogenous matrix with more individual cells and fewer isogenous groups. Slide 16: External auditory tube (Verhoff’s stain for elastin) Elastic fibers Perichondrium Chondrocyte Lacunae FIBROCARTILAGE INTERMEDIATE BETWEEN DENSE REGULAR CONNECTIVE TISSUE AND HYALINE CARTILAGE NO PERICHONDRIUM FIBROCARTILAGE FOUND IN : • INTERVERTEBRAL DISCS • ATTACHMENT OF LIGAMENTS TO CARTILAGINEOUS SURFACE OF BONES Type I collagen of tendon Type II collagen around each condocyte Slide 17: Vertebra Hyaline cartilage Fibrocartilage Chondrocyte in lacunae Dense connective tissue Fibrocartilage Hyaline cartilage Bone 194 Fibrocartilage of Fetal elbow Fibrocartilage Fibrocartilage 194Fibrocartilage of Fetal elbow Fibrocartilage 220 Fetal finger – fibroblasts in tendon Tendon 220 Fetal finger – fibroblasts in tendon Tendon Fibrocartilage SUMMARY OF CARTILAGE HYALINE ELASTIC FIBROCARTILAGE SUMMARY OF CARTILAGE HYALINE ELASTIC FIBROCARTILAGE FUNCTIONS OF BONE SKELETAL SUPPORT LAND ANIMALS PROTECTIVE ENCLOSURE SKULL TO PROTECT BRAIN LONG BONE TO PROTECT HEMOPOIETIC CELLS FUNCTIONS OF BONE CALCIUM REGULATION Parathroid hormone (BONE RESORPTION) FUNCTIONS OF BONE CALCIUM REGULATION Parathroid hormone (BONE RESORPTION) Calcitonin (PREVENTS RESORPTION) These HORMONES are INVOLVED IN TIGHT REGULATION as 1/4 OF FREE CA++ IN BLOOD IS EXCHANGED EACH MINUTE. FUNCTIONS OF BONE CALCIUM REGULATION Parathroid hormone (BONE RESORPTION) Calcitonin (PREVENTS RESORPTION) These HORMONES are INVOLVED IN TIGHT REGULATION as 1/4 OF FREE CA++ IN BLOOD IS EXCHANGED EACH MINUTE. HEMOPOIESIS CELLS OF BONE OSTEOBLASTS - SECRETE OSTEOID - BONE • EXPAND BONE BY APPOSITIONAL GROWTH CELLS OF BONE OSTEOBLASTS - SECRETE OSTEOID - BONE • EXPAND BONE BY APPOSITIONAL GROWTH OSTEOCYTE = OSTEOBLAST TRAPPED IN MATRIX OF BONE CELLS OF BONE OSTEOBLASTS OSTEOCYTES – OSTEOBLASTS TRAPPED IN MATRIX OF BONE CELLS OF BONE OSTEOCLASTS - MULTINUCLEATED PHAGOCYTIC CELLS FROM MONOCYTES CELLS OF BONE OSTEOCLASTS - MULTINUCLEATED PHAGOCYTIC CELLS FROM MONOCYTES Slide 17: Vertebra Fibrous periosteum containing fibroblasts Cancellous bone Osteocyte in lacunae Osteoblasts lining bony trabeculae Developing Bone Methods of bone development • Endochondrial ossification: formation within cartilage model with • Intramembranous: formation within distinct zones of development, fibrous/collagenous membranes formation fibroblast like precursor cells formation by replacing cartilage cells and matrix Copyright McGraw-Hill Companies Copyright McGraw-Hill Companies HISTOGENESIS OF BONE INTRAMEMBRANOUS OSSIFICATION DIRECT MINERALIZATION OF MATRIX SECRETED BY OSTEOBLAST WITHOUT A CARTILAGE MODEL HISTOGENESIS OF BONE INTRAMEMBRANOUS OSSIFICATION FLAT BONES OF SKULL Slide 36: Nasal septum (intramembranous osteogenesis) Osteoblasts Osteoclasts in Howship’s lacunae Bone spicule HISTOGENESIS OF BONE ENDOCHONDRAL OSSIFICATION DEPOSITION OF BONE MATRIX ON A PREEXISTING CARTILAGE MATRIX CHARACTERISTIC OF LONG BONE FORMATION Slide 20: Long bone (longitudinal section; epiephysial plate) Zone of resting/ Zone of reserve cartilage proliferation Zone of hypertrophy bone Epiphysial plate Zone of calcification Zone of ossification EXTRACELLULAR MATRIX OF BONE OSTEOID - MIXTURE OF TYPE I COLLAGEN AND COMPLEX MATRIX MATERIAL TO INCREASE THE AFFINITY AND SERVE AS NUCLEATION SITES FOR PARTICIPATION OF CALCIUM PHOSPHATE (HYDROXYAPATITE) EXTRACELLULAR MATRIX OF BONE SECRETED by POLARIZED OSTEOBLASTs CALCIFICATION ADDS FIRMNESS, BUT PREVENTS DIFFUSION THROUGH MATRIX MATERIAL EXTRACELLULAR MATRIX OF BONE FORMS LACUNAE AND CANALICULI - EXTRACELLULAR MATRIX OF BONE FORMS LACUNAE AND CANALICULI - CAUSES THE NEED FOR NUTRIENTS TO PAST THROUGH THE MANY GAP JUNCTIONS BETWEEN OSTEOCYTES VIA CANALICULI COMPACT BONE - SHAFT AND OUTER SURFACE OF LONG BONES COMPACT BONE-SHAFT AND OUTER SURFACE OF LONG BONES PERIOSTEUM FIBROBLAST create CIRCUMFERENTIAL LAMELLAE • APPOSITIONAL GROWTH COMPACT BONE-SHAFT AND OUTER SURFACE OF LONG BONES PERIOSTEUM FIBROBLAST create CIRCUMFERENTIAL LAMELLAE • APPOSITIONAL GROWTH (NOTE: BONE HAS NO INTERSITIAL GROWTH AS DOES CARTILAGE) COMPACT BONE-SHAFT AND OUTER SURFACE OF LONG BONES ENDOSTEUM INSIDE COMPACT BONE, SURFACES OF SPONGY BONE, INSIDE HAVERSIAN SYSTEMS COMPACT BONE HAVERSIAN SYSTEMS LAMELLAE OF BONE AROUND HAVERSIAN CANAL LINKED BY VOLKMANN’S CANAL Slide 19: Compact bone (ground cross section) Volkmann’s canal Canaliculli Concentric lamellae Osteon/ Haversian systems Haversian canal Lacunae containing osteocyte Interstitial lamellae Slide 19: Compact bone (ground cross Connecting adjacent osteons, section) Volkmann’s canal perforating (Volkmann’s) canals provide communication for osteons and another source of microvasculature for the central canals of osteons (nutrients, blood, etc.). Clinical Correlation An elderly patient is diagnosed with osteoporosis. Describe the cells involved that produce this imbalance in bone production and resorption. Which of these cell types would be more active and which would be less active? What is the difference between osteoporosis and osteomalacia? p143&151 FUNCTIONS OF BONE CALCIUM REGULATION Parathroid hormone (stimulates osteoclast production) FUNCTIONS OF BONE CALCIUM REGULATION Parathroid hormone (stimulates osteoclast production) Calcitonin (removes osteoclast’s ruffled boarder which PREVENTS RESORPTION FUNCTIONS OF BONE CALCIUM REGULATION Parathroid hormone (stimulates osteoclast production) Calcitonin (removes osteoclast’s ruffled boarder which PREVENTS RESORPTION Osteoporosis is an imbalance in skeletal turnover so that bone resorption exceeds bone formation. This leads to calcium loss for bones and reduced bone mineral density. FUNCTIONS OF BONE CALCIUM REGULATION Parathroid hormone (stimulates osteoclast production) Calcitonin (removes osteoclast’s ruffled boarder which PREVENTS RESORPTION Osteoporosis is an imbalance in skeletal turnover so that bone resorption exceeds bone formation. This leads to calcium loss for bones and reduced bone mineral density. Osteomalacia is characterized by deficient calcification of recently formed bone and partial decalcification of already calcified matrix.

Cartilage, Bone and Osteogenesis

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