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Anatomy Lecture 5

Chapter 6: Cartilage and Bone Tissue
5 types of connective tissue
Blood, Bone, Cartilage, Connective tissue proper (loose CT and Dense CT)
Types of Cartilage
Hyaline, Fibrocartilage, Elastic
Hyaline Cartilage
Most abundant type. Provides support through resillience and flexibility. Found at the end of bones.

EX: trachea, articular cartilage, epiphyseal plate, fetal skeleton, costal cartilage, nose
Contains thinck collagin fibers. Acts as a shock absorber.

EX:Intervertebral disk, menisci of knee, pubic symphasis
contains highly branched elastic fibers. Provdes flexibility.

Ex: Epiglottis, auricle of the ear
Charateristics of cartilage
1. semigrid, weaker than bone.
2.Flexible and resillient bc of elastic fibers and water content
3. Avascular
-get nutrients through diffusion
Functions of cartilage
1. support soft tissues
2.articular surface for joints
2. Provide a modle for enchondral bone formation
*Endochondral (within cartilage). "Chon" = w/ cartilage
Strcture fo cartilage
Chondroblast, chondrocytes, extracellular matrix, perichardium
produce matrix of cartilage
marture cartilage cells. Reside in lacunae. Alive, but not doing much.
Extracellular MAtrix (ECM)
any substance produced by cells and excreted to the extracellular space within the tissues, serving as a scaffolding to hold tissues together and helping to determine their characteristics.
made of dense CT. Provides mechanical support and protection.
1. Osseous CT
2.Clacified ECM (Calcium phosphate
Bone functions
1. support and prtect
2. Movement
-attchment site for muscles
3. hemopoiesis: red bone marrow
-especially in long bones such as the femur
4. Storage of mineral and energy reserves
-calcium phosphate and yellow bone marrow
Bone types
1. Long
2. short
3. Flat
4. Irregular
Long bones
Conatin diaphysis and epiphysis
EX: Humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals
Short bones
EX: Carpals, tarsals, sesamoid bone (platella)
Flat Bones
EX: skull, scapulae, sternum, ribs
Irregular bones
EX: vertabrae, sacrum, coccyx, Os, Coxa, Ethmoid, Sphenoid
Structure of long bones Part 1 (See diagram on pg 150 of TB)
1. Compact bone
-superficial bone tissue
2.Spongy Bone
-dense bone tissue
3. Epiphysis
-ends of long bones
4. Diaphysis
5. Metaphysis
-contains the epiphyseal plate
6. Aricular Cartialge
-hyaline cartialge covering the ends of bones within a joint
Structure of long bones Part 2 (See diagram on pg 150 of TB)
7. Medullary Cavity
-contains yellow bone marrow in adults and red in children
8. Endosteum
-layer of cells lining the spongy bone and medullary cavity
9. Periosteum
-dense CT outer covering of the bone
10. perforating fibers
-attach the periosteum to the compact bone
11. nutrient foramen
-conatins nutrient artery
Cells of Bone
Osteoprogenitor (See Pictures on TB pg. 152)
Stem cells derived from the mesenchyme that becomes osteoblast
Immature osteocytes that BUILD bone by secreting osteoid (organic part of ECM)
Mature bone cells that maintain bone matrix. Reside in the lacunae
1. cells that CONSUME bone (bone reabsorption)
2. Phagocytic cells using hydrochloric acid and lysosomes
3.Increase blood Calcium levels
Classification of bone by Histoology
Compact VS Spongy bone
Compact bone
1. AKA cortical bone
2. solid, dense
3. lined by periosteum
4. found in the superficial regions of bone
5. contains osteons
Spongy bone
1. AKA cacellous or trabecular bone
2. porous
3. lined by endosteum
4. Found in deeper regions of the bone
Structure of compact bone Part 1 (see diagrams on TB Pg. 154/156)
1. Osteon (haversian system)
-basic structural and functional unti
2. Central canal (Haversian Canal)
3.Concetric Lamellae
-concetric rings of osseous CT that surround the central canal
4. Osteocytes
-mature bone cells
Structure of compact bone Part 2 (see diagrams on TB Pg. 154/156)
5. Lucanae
-cavities which house osteocytes
6. Canaliculi
-connect neighboring lacunae
-allows nutrients to travel btw the cental canal and the osteocytes
7. Perforating ccanals (Volkmann's canals)
-connect blood and nerve supply to central canal
Structure of spongy Bone (Pic. on TB Pg. 154)
1. Trabeculae
-main structural/ functional component
-form criss crossing bars and plates for strength
2. Parallel Lamellae
3.Osteocytes within lacunae
-provides nutrients to cells through diffusion
1.Intermembranous ossification
2. Enchondral ossification
Intermembranous ossification
bone growth wi membrane (mesenchyme)
-forms flat bones of the skull, some facial bones, mandible, and clavical
Enchondral ossification (Diagram on TB Pg. 159)
Bone growth with in cartilage
-turns fetal frmawork of hyaline cartilage into bone
- formation of most bones
-Primary ossification center in diaphysis and secondary in epiphysis
Bone Growth
1. Occurs during childhood and adolesence
2. Intersitial gowth (length) VS. Appositonal Growth (thickening)
Intersitial Growth
Occurs at Epiphysil plates:
1.Chonfroblast neart he epiphysil plate multiply, pushing the epiphysis away from the diaphysis
2. Chondrocytes enlarge; matrix calcifies
3. Chondrocytes die and disentigrate
4. Remodeling by osteoclast
Bone Fractures
Simple fracture
Bone doesn't perice skin
Open/Compound fracture
bone pierces the skin
Stress fracture
thin break from repetitive loads
Patholigic Fracture
Disease weakens the bones
Fracture Repair (Pic TB Pg. 166)
1. Fracture hematoma forms
2. Fibrocartilage (soft) callus forms
3.Hard (bony) callus forms
4. Bone remodeled
Called rickets in small children
-Soft bones
-leads to bowed legs
excessive bone reabsorptipon. Aged and post menopause.
Other Bone disorders
-Vitamin D deficency
-Calcium Deficency
Osteitis Deformans
*AKA Paget's disease
*Excessive osteoclast and osteoblast function
*Bone is unstable and Immature
*most common in os coxa, skull, vertebrae, femure, and tibia
What is the function of red bone marrow? Yellow?
Red blood cells, platelets and most white blood cells arise in red marrow; some white blood cells develop in yellow marrow. The color of yellow marrow is due to the much higher number of fat cells. Both types of bone marrow contain numerous blood vessels and capillaries.
In what region of the long bone is the epiphysis plate found?