A&P Lecture Exam 2

Medullary Cavity

Hollow cylindrical space in diaphysis Kids have red bone marrow Adults have yellow bone marrow

Amphiarthrosis

Slightly mobile joint movement classification

Synchondrosis

Cartilaginous joint No cavity Epiphyseal platr

Bone Repair

1. Fracture hematoma (blood clot) 2. Fibrocartilaginous (soft) callus is formed cartilage (fibrocartilage) fills in 3. Hard (bony) callus forms. Osteoblast produce spongy bone 4. Bone is remodeled. Osteoblast from compact bone. Osteoclast absorb spongy bone

Zone of calcified cartilage

2-3 layers of chondrocytes Minerals deposited into matrix between columns of lacunae Calcification destroys chondrocytes Chondrocytes die

Symphysis

Cartilaginous joint No cavity Intervertebral joint

Epiphyseal Line

Adult thin layer of compact bone

Lacunae

Body of "bug"

Osteoblast Cells

Bone forming Make bone matrix Formed from osteoprogenitor cells Form osteocyte cells Immature, build and create

Osteoporosis

Bone loss is not osteoporosis Osteoporosis is extreme loss of bone mass Osteoporosis is always loss of bone mass to the extreme

Diaphysis

Bone shaft that contains medullary cavity

Endrochondrial Ossification Step 5

Bones replaces all but articular cartilage and epiphyseal plate cartilage Bone is highly active and lengthens bone.

Osteoclast

Breaks down Remodels Reabsorbs Derived from fused bone marrow

Endrochondrial Ossification

Cartilage model is replaced by bone Occurs in long bones, pelvis, vertebrae

Hydroxyapatite

Calcium and phosphate 2:1

Endochondrial Ossification Step 2

Cartilage calcified and periosteal bone collar forms around diaphysis. Chondrocytes hyper trophy Osteoblasts create bone collar

Bone formation cells

Chondroblast - lays down matrix Chondrocytes - grow, gets larger, resorbs matrix to create holes, hardens and dies Osteoblast - builds Osteoclast - breakdown minerals

Zone of hypertrophic cartilage

Chondrocytes stop dividing Chondrocytes hypertrophy (enlarge) Chondrocytes resorb matrix

Zone of proliferating cartilage

Chondrocytes undergo rapid mitotic cell division Align like a stack of coins into longitudinal columns of flattened lacunae. Columns are parallel to diaphysis.

Osteoclast Cells

Derived from fused bone marrow cells Breakdown bones Remodel bones Reabsorb minerals

Epiphysis

End of long bones Thick layer of hyaline cartilage (articular) covering surface

Primary ossification center forms in diaphysis

Endochindrial Ossification Step 3 Periosteal bud forms - capillaries and osteoblasts Cartilage completely calcify (bone template) Osteoblasts forms osteitis (bone matrix) Primary ossification center - eventually makes diaphysis.

Secondary ossification center in epiphysis

Endrochondrial Ossification Step 4 Blood vessels enter epiphysis Forms as bone displaces cartilage Osteoclasts resorb bone matrix in diaphysis - creates medullary cavity.

Bones replaces all but articular cartilage and epiphyseal plate cartilage

Endrochondrial Ossification Step 5 Bone is highly active and lengthens bone.

Lengthwise growth continues until epiphyseal plate ossified and forms epiphyseal line.

Endrochondrial Ossification Step 6

Two places for hyaline cartilage

Epiphyseal Plate Articulating surface (epiphysis)

Long bone anatomy

Epiphysis Diaphysis Periosteum Endosteum Epiphyseal plate/line Articular cartilage

Zone of resting cartilage

Farthest from medullary cavity and nearest to epiphysis Composed of small Chondrocytes distributed throughout cartilage matrix Resembles mature and healthy hyaline cartilage Secures epiphysis to epiphyseal plate

Endochondrial Ossification Step 1

Fetal hyaline cartilage model develops Chondroblasts Perichondrium is formed

Structure Joint Classification

Fibrous - no joint cavity Cartilaginous joint - no joint cavity Synovial - fluid filled joint cavity

Suture

Fibrous joint No cavity Cranial bones

Syndesmosis

Fibrous joint No cavity Radius to ulna Tibia to fibula

Gomphosis

Fibrous joint No cavity Tooth to jaw

Synovial Joint

Fluid filled joint cavity Plane - intercarpal Hinge - elbow Pivot - radius/ulna Condylar - metacarpal/phalangeal Saddle - carpal/metacarpal Ball and Socket - hip

Bone Formation

Formation and development of new bone connective tissue. Chondroblast Chondrocyte Osteoblast Osteoclast

Intramembranous Ossification

Formation in a membrane Occurs in flat bones, facial bones, inner clavicles

Diarthrosis

Freely mobile joint movement classification

Osteon

Haversian Central Canal (center) lamellae (in-between circles) lacunae (bug body) canaliculi (bug legs)

Articular cartilage

Hyaline cartilage covering epiphysis Reduces friction

Osteoblast

Immature Builds Bone matrix

Synarthrosis

Immobile joint movement classification

Lamellae

In between circles surrounding haversion canal on osteon

Interstitial lamellae

Incomplete leftover in-between osteons some parts have been partially reabsorbed

Arthritis

Inflammation of a joint Osteoarthritis - from trauma, infection, aging Rheumatoid arthritis - autoimmune disease

Endosteum

Inner layer covering inside of long bone Protects inside of bone

Compact Bone

Lamellar matrix laid down in layers White smooth solid Osteons

Canaliculi

Legs of lacunae

Endrochondrial Ossification Step 6

Lengthwise growth continues until epiphyseal plate ossified and forms epiphyseal line.

Interstitial growth

Long bones grow in length Zone of resting cartilage Zone of proliferating cartilage Zone of hypertrophic cartilage Zone of calcified cartilage Zone of ossification

Tissue bone composed of

Mainly connective tissue (also epithelia and nervous) CT: bone, hyaline cartilage, fibrocartilage, dense fibrous adipose

Bone Storage

Matrix - calcium and phosphate Bone Marrow - Yellow (adults) Red (Children)

Osteocyte

Mature Maintain bone

Osteocyte cells

Mature Maintain the bone matrix Derived from osteoblasts

Haversion Canal

Middle of osteon

Fibrous Joint

No Joint Cavity Gomphosis - tooth to jaw Suture - cranial bones Syndesmosis - tibia to fibula

Cartilaginous Joint

No Joint Cavity Synchondrosis - epiphyseal plate Symphysis - intervertebral joint

Bone blood supply

Nutrient foramen - arteries and veins enter/exit Arteries carry nutrients to bone Veins carry waste away from bone Nerves supply bones - go in through nutrient foramen

Bone Remodeling Cells

Osteoblasts - increase osteoid synthesis Osteoclasts - resorption (takes calcium and phosphate out of bone and puts into blood) Occurs at periosteal and endosteal

Bone cells

Osteogenic - stem cells (give rise to others) Osteocytes - mature, maintain Osteoblast - immature, builds bone matrix Osteoclast - breakdown, remodel, reabsorb, derived from fused bone marrow cells

Bone Growth Cells

Osteoprogenitor cells Osteoblast Osteocyte Osteoclast

Circumferential lamellae

Outer rings of compact bone surrounding all osteons internal to periosteum or endsteum

Spongy Bone

Porus Red or yellow bone marrow No osteons Lacunae are present Trabeculae - lattice, narrow rods, plates of bones

Endochondrial Ossification Step 3

Primary ossification center forms in diaphysis. Periosteal bud forms - capillaries and osteoblasts Cartilage completely calcify (bone template) Osteoblasts forms osteitis (bone matrix) Primary ossification center - eventually makes diaphysis.

Bone Resorption

Process by which osteoclasts break down bone and release minerals. Osteoclast.

hematopoiesis

Production of blood cells. Occurs in red bone marrow connective tissue.

Concentric lamellae

Rings of compact bone surrounding central canal - bulk of osteon

diploe

Sandwich of compact and spongy bone Compact on outer surface Found in short, irregular and flat bones

Endrochondrial Ossification Step 4

Secondary ossification center in epiphysis Blood vessels enter epiphysis Forms as bone displaces cartilage Osteoclasts resorb bone matrix in diaphysis - creates medullary cavity.

Osteogenic

Stem cell

Osteoprogenitor Cells

Stem cells Mature to become osteoblast

Fetal hyaline cartilage model develops

Step 1 for endrochondrial ossification Chondroblasts: makes cartilage matrix for format, makes cartilage model Peri hindering is formed - this surrounds hyaline cartilage model

Cartilage calcified and periosteal bone collar forms around diaphysis

Step 2 for endrochondrial ossification Chondrocytes hyper trophy (divide) and resort matrix to create holes then harden and die. Blood vessels enter holes to make vascularization. Osteoblasts create periosteal bone collar. Perichondrium become periosteum.

Skeletal System Functions

Support Protection Storage Produce blood cells Movement

Movement Joint Classification

Synarthrosis - immobile Amphiarthrosis - slight mobile Diarthrosis - freely mobile

Saddle

Synovial joint Fluid filled cavity Carpal/metacarpal

Hinge

Synovial joint Fluid filled cavity Elbow

Ball-and-socket

Synovial joint Fluid filled cavity Hip

Plane

Synovial joint Fluid filled cavity Intercarpal

Condylar

Synovial joint Fluid filled cavity Metacarpal/phalangeal

Pivot

Synovial joint Fluid filled cavity Radius/ulna

Epiphyseal plate

Thin layer of hyaline cartilage Lengthwise growth Grows from end towards middle

Periosteum

Tough health covering long bones Anchor for tendons, blood, lymph, nerves 2 layers: outer dense irregular fibrous CT, inner osteogenic cells (makes new bone)

Factors to counteract bone loss

Vitamin D Calcium Bisphosphonates Estrogen Therapy Exercise

Zone of ossification

Walls breakdown between lacunae in columns and this forms longitudinal channels Spaces invaded by capillaries and osteoprogenitor cells from medullary cavity New matrix of bone is deposited on remaining calcified cartilage matrix

Appositional Growth

Widening of the bones at the periosteum Osteoblasts produce and deposit bone matrix within layers parallel to the surface. As rings increase, strength increases. As new bone lays down, osteoclasts resorb bone matrix along medullary cavity. More exercise/force - wider bone gets.

Bone loss factors

With age, more resorption, less formation Vitamin D Calcium from diet Sex steroids Exercise - stimulates formation and bones get bigger

Bone matrix

hydroxyapatite (calcium and phosphate 2:1)