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Question Bank
- 1Types of muscle cells
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skeletal, cardiac, smooth - 2Which type of muscle tissue is responsible for involuntary movements?
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Cardiac and smooth - 3Which type of muscle tissue is responsible for voluntary movements?
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Skeletal - 4Type of muscle that connects skeleton to other structures
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skeletal - 5What type of muscle tissue are the walls of the heart made from?
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Cardiac contract to pump blood - 6What are the primary functions of smooth muscle tissue in the body?
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contract walls, control blood flow and move contents of organs involuntary - 7Types of joints
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fibrous, synovial, cartilaginous - 8What type of joints are generally immobile?
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Fibrous joints - 9WHat joints are freely movable
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synovial joints - 10What joints allow some movement?
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cartilaginous - 11How many bones are in the adult human skeletal system?
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206 - 12Where do All the bones in the appendicular and most axial skeleton develop from?
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mesoderm - 13Which type of cells develop into the facial bones and rostral skull bones?
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neural crest cells - 14What process is responsible for the development of cartilage from the mesoderm layer?
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chondrogenesis - 15What is the primary function of cartilage?
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Structurally support soft tissues and provide cushioned, low-friction surface within joints. - 16What is chondrogenesis?
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embryonic development of cartilage from the mesenchyme - 17What type of tissue is cartilage?
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Tough, flexible connective tissue Avascular Lacks lymphatic vessels and nerves - 18Cartilage =
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chondrocytes + chondroblasts embedded in the extracellular matrix (ECM). - 19What does ECM include
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collagen and proteoglycans that can bind a large amount of water - 20Which cells in cartilage produce the ECM and maintain the cartilage long term?
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chondrocytes - 21What process do chondroblasts undergo to contribute to the ECM?
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mitosis - 22What are the main types of cartilage
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Elastic, hyaline, fibrocartilage - 23What type of collagen is primarily found in elastic cartilage?
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Type II Collagen - 24Which type of cartilage contains more chondrocytes?
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Elastic Cartilage - 25What type of collage is found in fibrocartilage?
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Type I Collagen - 26What type of collage is found in hyaline cartilage?
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type II - 27Elastin cartilage characteristics
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• least common • most elastic type • abundant network of elastic fibers • type II collagen - 28What is the most common type of cartilage?
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Hyaline cartilage - 29Where is hyaline cartilage commonly found?
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articular surfaces of movable joints, respiratory passages, and rib ends - 30What type of cartilage forms the temporary skeleton in the embryo?
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Hyaline cartilage, later gradually replaced by bone - 31Hyaline cartilage density?
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medium chondrocyte density - 32What is osteoarthritis
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gradual loss or changed physical properties of the hyaline cartilage that lines the joints - 33What type of cartilage is characterized by the highest tensile strength but the least chondrocyte density?
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Fibrocartilage - 34Where is fibrocartilage commonly found?
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Meniscus of knee, spinal intervertebral discs, tendon insertion (e.g. TMJ) - 35What type of protein fiber is predominant in fibrocartilage?
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Type I collagen, highest protein fiber density - 36Fibrocartilage function
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Provides tough and cushioning support for the bone - 37What is bone classified as?
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supportive connective tissue with calcified extracellular matrix - 38What type of matrix is found in bone?
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Type I collagen matrix • provides network for hydroxyapatite crystals - 39How do bones contribute to the process of blood cell formation?
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Bones enclose the bone marrow which is essential for blood cells formation. - 40Types of bones by shape
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• long • short • flat • sesamoid • irregular (vertebra, facial) - 41What type of bone is characterized by a long, cylindrical shape?
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Long bone - 42Which bone shape is typically associated with the skull?
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Flat bone - 43What comprises the periosteum?
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outer fibrous layer + inner cellular layer - 44Function of the outer fibrous layer?
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• protects bone • provides attachment for ligaments and tendons - 45What does the inner cellular layer do?
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• osteoblasts: secret bone matrix • chondroblast: produce cartilage - 46Parts to a long bone
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epiphysis metaphysis diaphysis (shaft) - 47What is the name of the part of a long bone where growth occurs?
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Epiphysis - 48What is the term for the growth plate in bones?
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Epiphyseal Plate - 49What type of bone is closer to the surface and is denser?
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Compact (cortical) bone - 50Which bone type has interconnecting cavities and is deeper?
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Cancellous (trabecular) bone - 51What are the two main components of bone structure?
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Bone Matrix and Bone Cells - 52What is the primary component of the bone matrix?
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Type I collagen framework infused with hydroxyapatite crystals Ca10(PO4)6(OH)2 + cells (osteocytes, osteoblasts and osteoclasts) - 53Which cells are found within the bone structure?
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osteocytes, osteoblasts, and osteoclasts - 54Inorganic components of bone matrix?
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hydroxyapatite crystals - 60% calcium + phosphate with small amount of bicarbonate, citrate, magnesium, potassium, and sodium ions - 55Organic materials found in found in bone matrix?
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Osteoid - 40% • type I collagen, 90% • Ground substance - 56What is ground substance?
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proteoglycans and multi-adhesive glycoproteins like osteonectin - 57What is osteonectin?
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glycoprotein that: • is secreted by osteoblasts • has high affinity for calcium and collagen • is vital for bone mineralization - 58Which protein is vital for bone mineralization?
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Osteonectin - 59Osteoblast Osteoclast Osteocyte
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OB: bone building OC: bone cutting OCy: bone cell - 60Which cell type is responsible for forming the bone matrix?
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Osteoblasts - 61Where do osteoblasts originate from?
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from osteoprogenitor cells under the influence of growth factors (osteoblastogenesis) - 62What materials do osteoblasts produce?
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osteoid protein + chondroitin sulphate (cartilage) + osteonectin - 63Function of osteoblasts
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promote growth and differentiation of osteoclasts • via M-CSF • to maintain the balance between bone formation and resorption - 64What happens to Older osteoblasts?
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small population → differentiate to osteocytes some undergo apoptosis - 65Where are osteocytes primarily found?
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cavities (lacunae) between bone matrix layers (lamellae) most abundant cells in bone - 66What type of cells are osteocytes derived from?
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osteoblasts - 67What network do osteocytes use to contact each other?
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network of canaliculi - 68What are osteoclasts?
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essential for bone resorption and remodeling • "bone cutting" • Large, multinucleated, motile cells • from bone marrow-derived monocytes (WBC) - 69Osteoclast functions
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1. bone turnover 2. involved in ion, nutrient and waste exchange 3. homeostasis: regulating calcium flow in/out of bone 4. express proteins that can regulate bone remodeling - 70Which factors are required for osteoclast production?
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RANKL and M-CSF - 71Define: RANK, RANKL, M-CSF
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RANK = receptor activator of nuclear factor kappa RANKL = RANK ligand M-CSF = monocyte colony stimulating factor. - 72What inhibits the differentiation of osteoclasts?
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Osteoprotegerin (OPG) - 73How do osteoblast regulate osteoclast differentiation?
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Osteoblasts inhibit the formation and activity of osteoclasts via OPG - 74Which factor can promote osteoclastogenesis?
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Interleukin-6 and tumor necrosis factor - 75Which cells are the main source of RANKL in periodontitis?
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B cells and T cells - 76What is the decoy receptor for RANKL?
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OPG OPG inhibits formation of OC from OB RANKL needed for differentiation - 77What molecules mediate RANK signaling?
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TRAF6 and NF-κB ↑ actiavtes RANKL + RANK → OC - 78Which does activated NF-kB induce?
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activated T cells cytoplasmic 1 (NFATc1) - 79What does NFATc1 do?
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induces numerous osteoclast-specific target genes that are responsible for cell fusion and function - 80What does osteoclast-mediated bone resorption release?
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TGF-β and IGF-1 • from bone matrix to induce osteoblast-mediated bone formation • secretes other mediators to promote/suppress OB differentiation - 81Which factors do OB secrete to promote OC development?
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M-CSF, RANKL, WNT5A - 82Which factors do OB secrete to inhibit OC activity?
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OPG and WNT16 - 83What does the balance of RANKL and OPG indicate about bone health?
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RANKL < OPG = homeostatic conditions RANKL > OPG = inflammatory conditions - 84How often is spongy bone replaced?
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Every 3 to 4 years - 85How often is compact bone replaced?
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Every 10 years - 86What does the term 'osteogenesis' refer to?
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bone development - 87Which mechanism involves osteoblasts differentiating directly from osteoprogenitor cells?
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Intramembranous ossification • OB begin secreting osteoid • flat and irregular bones - 88In which type of ossification do osteoblasts invade a preexisting matrix of hyaline cartilage?
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Endochondral ossification begin osteoid production after invasion - 89What is the initial step in intramembranous ossification?
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Mesenchymal cells cluster → develop into OBs → formation of a primary ossification center - 90second step of intramebranous ossification
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OBs deposit osteoid matrix → matrix binds to calcium salts → becomes calcified - 91third step of intramembranous calcification
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Continued matrix secretion + calcification → enlarges calcified areas + fuses w/ nearby ossification centers → formation of bone without cartilage backbone - 92What is the initial structure that forms in the fetal stage of bone development?
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Hyaline cartilage - 93Endochondral ossification - Fetal Stage
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1. Fetal hyaline cartilage model 2. Cartilage calcifies → bone collar forms around diaphysis 3. Primary ossification center forms in diaphysis - 94Endochondral ossification - Childhood Stage
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4. Secondary ossification centers form in epiphyses 5. Bone replaces cartilage (except articular cartilage and epiphyseal plates) - 95Endochondral ossification - Adult Stage
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6. epiphyseal plate ossifies and forms epiphyseal lines - 96What is the term for the thick plate of cartilage found in the growth region of a growing long bone?
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Epiphyseal plate - 97In a mature long bone, what replaces the thick epiphyseal plate?
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Epiphyseal line - 98What is the primary function of the epiphyseal plate?
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Longitudinal bone growth - 99Zones of epiphyseal plate
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1. Reserve Zone 2. Proliferative Zone 3. Zone of Maturation 4. Zone of Calcified Matrix - 100Reserve Zone function
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hyaline cartilage layer with chondrocytes - 101Proliferative Zone function
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• next layer toward the diaphysis • contains stacks of slightly larger chondrocyte that are rapidly dividing via mitosis - 102Zone of Maturation and Hypertrophy function
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• chondrocytes undergo final maturation • grow in size (hypertrophy) • chondrocytes secrete type X collagen • calcification of matrix begins → chondrocyte death - 103What happens in Zone of calcified matrix?
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• zone closest to the diaphysis • OBs start ossification process → formation of hydroxyapatite crystals on the calcified cartilage matrix. • bone grows in length, osseous tissue added to diaphysis • longitudinal growth stops when chondrocytes in the epiphyseal plate stop proliferating and bone replaces the cartilage - 104What is appositional growth
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growth in circumference through OBs • form new bone tissue • OCs resorb old bone - 105Where does bone resorption occur in appositional growth?
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medullary cavity - 106What is the primary function of osteoclasts in bone remodeling?
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Osteoclasts erode and absorb previously formed bones. - 107What is the sealing zone
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edge of osteoclast are tightly sealed to the bone via integrins • create bone-resorbing compartmen - 108What enzyme do osteoclasts secrete to break down the collagen matrix?
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lysozymal enzymes, mostly collagenase form Howship's lacunae (sho=allow depression) - 109What pH level do osteoclasts create around the bone to dissolve hydroxyapatite?
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~ 4.0 • secrete HCl to acidify the area • dissolves HA into soluble calcium and phosphate - 110What molecule does osteoptegerin bind to?
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RANKL slows foen activation of OCs - 111What protein does osteoblasts secrete to fill in lacunae?
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Osteoid seam - 112What substance is deposited on osteoid seam made from calcium and phosphate?
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Hydroxyapatite - 113What do trapped OBs become?
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Osteocytes - 114Phases of bone repair
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reactive reparative remodeling - 115What happens during reactive phase of bone remodeling
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1. clot formation 2. replaced by callus with regenerated blood vessels 3. inflammatory reaction 4. release of growth factors - 116What happens during reparative phase?
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1. CB + OB form 2. initial woven bone, named “callus” 3. hard callus from hyaline cartilage (type II collagen) 4. hyaline cartilage replaced by a lamellar bone (type I collagen) - 117What is the final structure formed in the remodeling phase?
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Compact bone at fracture site • takes weeks to months • includes bone resorption by OCs and redeposition by OBs - 118What is the initial tissue that replaces the hematoma in the reactive phase?
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fibrous connective tissue - 119What type of collagen is present in the final compact bone matrix?
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type I collagen - 120What hormone is released by the parathyroid gland to regulate calcium levels?
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PTH (parathyroid hormone) - 121Which cells in bone tissue have receptors for PTH?
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Osteoblasts - 122What effect does high PTH have on bone?
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Catabolic effects - 123What effect does low PTH gave on the bone
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anabolic effects - 124Thyroid Gland and regulation of bone remodeling?
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High calcium: stimulates calcitonin from thyroid → calcitonin binds to OCs → inhibit bone resorption → ↓ blood Ca levels - 125How does estrogen affect bone resorption?
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Inhibiting production of bone-eroding cytokines → slows bone resorption inhibits OB apoptosis, promotes OC apoptosis - 126Lack and excess growth hormone during childhood?
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Lack = pituitary dwarfism Excess = gigantism - 127What is the primary effect of mechanical stress on bone remodeling?
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Increases the rate of bone remodeling • bones that bear more weight, remodel at a higher rate (Wolff's Law) - 128How does active vitamin D affect calcium levels?
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Stimulates calcium absorption from the intestine → increases calcitonin level → inhibit bone resorption - 129What is the role of vitamin C in collagen production?
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Required for collagen production - 130What does PTH primarily affect in hyperparathyroidism?
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calcium levels (increase) - 131What is the relationship between calcium and phosphate levels in primary hyperparathyroidism?
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Calcium increases while phosphate decreases - 132Where is alkaline phosphatase found and indicative of?
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on OBs level is reflective of bone mineralization and formation - 133Composition of enamel?
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95 % mineral, 2% matrix protein and 3 % water - 134Bone, dentin, and cementum composition?
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70 % mineral, 20 % collagen and 10 % water