Lecture one-MSK (Houston) Flashcards

1
Q

Structure of long bone

  • What is at the end of long bones (bone and cartilage type)?
  • What is the epiphyseal line?
  • What is at the middle of the long bone (bone type and cavity)?
  • What is lining and contained in medullary cavity?
A
  • Proximal/distal epiphysis that is spongy bone+red bone marrow and articular cartilage to decrease friction of bone on bone
  • Epiphyseal line or plate is a thin layer of cartilage that lies between the epiphyses and metaphyses, and is where the growth of long bones takes place
  • Middle is the diaphysis that is made up compact bone with a medullary cavity
  • Medullary cavity is lined by endosteum and has yellow bone marrow
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2
Q

What is the diaphysis? What does it contain?

A

shaft that provides leverage
* Medullary cavity (marrow cavity)—space in the diaphysis of a long bone that contains bone marrow

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3
Q

What are the epiphyses? waht does it provide?

A

enlarged ends of a long bone
* Strengthen joint and anchor ligaments and tendons

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4
Q
  • What is articular cartilage?
  • What is the nutrient formina?
A
  • Articular cartilage: layer of hyaline cartilage that covers joint surface; allows joint to move more freely
  • Nutrient foramina: minute holes in bone surface that allows blood vessels to penetrate
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5
Q

What is the periosteum? What are the two layers?

A

external sheath covering most of bone

Outer fibrous layer of collagen
* Some fibers continuous with tendons
* Perforating (sharpey’s) fibers—penetrate into bone matrix to give the tendons something to adhere to

Inner osteogenic layer of bone-forming cells
* Important to bone growth and healing of fracture

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6
Q

What is the endosteum? What does it have?

A

thin layer of reticular connective tissue lining marrow cavity
* Has cells that dissolve (reabsorb) osseous tissue and others that deposit it

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7
Q
  • What is the epiphyseal plate (growth plate)? What does it enable?
  • What is the epiphyseal line?
A
  • area of hyaline cartilage that separates epiphyses and diaphyses of children’s bones. Enables growth in length
  • Epiphyseal line—in adults, a bony scar that marks where growth plate used to be
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8
Q

What is the histology of compact bone?

A
  • Spongy bone has trabeculae and spicules (thinner)
  • Perforating canals go off at a 90 degree angle
  • Compact bone is made up of osteon
  • The osteon has oseocytes that is stuck in their own secretion (within lacunae)
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9
Q

Histology of compact bone reveals osteons (haversian systems):

  • How does osteons surround central canals run? What runs through the central canal?
  • Bone matrix deposited in what?
  • What are perforation canals?
  • What is circumferential lamellae?
  • What is interstitial lamellae?
A
  • Osteons surround central canals that run longitudinally through shafts of long bones. Blood vessels and nerves travel through central canal
  • Bone matrix deposited in concentric lamellae. Onion-like layers around each central canal
  • Perforating canals — transverse or diagonal passages
  • Circumferential lamellae fill outer region of dense bone
  • Interstitial lamellae fill irregular regions between osteons
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10
Q

What is the ratio of the matrix of osseous tissue?

A

by dry weight, about one-third organic and two-thirds inorganic matter

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11
Q

For the organic matter part of the matrix of osseous tissue:
* Synthesized by what?
* What is secreted?

A
  • synthesized by osteoblasts (then will be trapped in their secretations)
  • Collagen, carbohydrate–protein complexes, such as glycosaminoglycans, proteoglycans, and glycoproteins

CARBON BASED

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12
Q

For the inorganic matter part of the matrix of osseous tissue:
* What are the components?

A
  • 85% hydroxyapatite (crystallized calcium phosphate salt)-> Need or will have soft bones
  • 10% calcium carbonate
  • Other minerals (fluoride, sodium, potassium, magnesium)
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13
Q

For spongy bone:
* Lattice of bone is covered with what?
* What are spicules?
* What are thin plates of bones?
* What are the spaces filled with?
* What is there a few of?
* What developes along bone’s lines of stress?
* What does it provide?

A
  • Lattice of bone covered with endosteum
  • Slivers of bone called spicules
  • Thin plates of bone called trabeculae
  • Spaces filled with red bone marrow
  • Few osteons and no central canals
  • Trabeculae develop along bone’s lines of stress
  • Provides strength with **minimal weight. **

Think about skull: the middle is spongy bone so that way it is lighter

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14
Q

Explain the process of bone repair

A

Old bone removed/resorbed (broken down) before new tissue replaces it
1. Osteoblasts sense microcracks, secrete recpetor activator of nuclear factor KB ligand (RANKL)
2. RANKL binds to RANK receptors on monocytes-> causes them to fuse, form multinucleated osteoclast cells
3. Osteoclasts secrete lysosomal enzymes (mostly collagenase)-> digest collagen in bone matrix-> create surface holes (Howship’s lacunae), hydrochloric acid-> dissolves hydroxyapatite into soluble calcium, phosphate
4. Osteoblasts secrete osteoprotegerin-> Deactivates RANKL, slows down osteoclast activity (before osteoclast apoptosis), osteiod seam (mostly collagen)-> fill in Howship’s lacunae
5. Calcium, phosphate deposit on seam forming hydroxyapatite
6. Some osteoblasts get trapped within lacunae-> turn into osteocytes

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15
Q
  • What does the achieving maximus peak bone mass depend on?
  • What are all negative impact on the acquisition of peak bone mass?
  • After bone growth is completed, bone mass is determined by what?
  • What is also very important in determining bone mass?
A
  • Achieving maximum peak bone mass depends on optimal nutrition, physical activity, general health, and hormonal exposure throughout childhood and adolescence.
  • Inadequacies in nutrition, weight-bearing exercise, and gonadal steroid exposure all have a negative impact on the acquisition of peak bone mass.
  • After bone growth is completed, bone mass is determined by the level of peak bone mass attained and the subsequent rate of loss.
  • Genetics are very important in determining bone mass.
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16
Q

What are the different hormones that are important in Calcium balance?

A
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17
Q

What is wolff’s law?

A

Tension and compression cycles create a small electrical potential that stimulates bone depostiion and increased density at points of stress
* Adopt to stress so increase stress, add bone and decrease stress, decrease bone

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18
Q
  • What are the three functional classification of joints?
  • What are the three structural classifications of joints?
A

Three functional classifications
* Synarthroses: no movement -> Symphyses, first rib to sternum+ growth plate (hyaline cartilage)
* Amphiarthroses: a little movement
* Diarthroses: free movement
Three structural classifications
* Fibrous
* Cartilaginous
* Synovial

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19
Q
  • What is articular cartilage?
  • What is the small potential space in synovial joints?
  • What are the layers of articular (joint) capsule?
  • What is the synovial fluid made up of and what does it do?
A

Articular cartilage: hyaline cartilage

Joint (synovial) cavity: small potential space

Articular (joint) capsule
* Outer fibrous capsule
* Inner synovial membrane

Synovial fluid
* Viscous slippery filtrate of plasma + hyaluronic acid
* Lubricates and nourishes articular cartilage

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20
Q

What are the three possible types of reinforcing ligaments?

A
  • Capsular (intrinsic) — part of the fibrous capsule
  • Extracapsular — outside the capsule
  • Intracapsular — deep to capsule; covered by synovial membrane
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21
Q

What is the synovial joint rich nerve and blood vessel supply>

A
  • Nerve fibers detect pain, monitor joint position and stretch
  • Capillary beds produce filtrate for synovial fluid
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22
Q
  • What is a bursa?
  • What the tendon sheath?
  • What is the meniscus?
A
  • Bursa: fibrous sac filled with synovial fluid, located between muscles, where tendons pass over bone, or between bone and skin
  • Tendon sheath: elongated cylindrical bursa wrapped around a tendon
  • Meniscus: moon-shaped cartilage in knee; in each knee. Absorb shock and pressure. Guide bones across each other and improve their fit together. Stabilize the joints, reducing the chance of dislocation
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23
Q

Dense packed, parallel collagen fibers:
* What are the characteristics?
* What do tendons attach? Ligament?

A
  • Densely packed, parallel collagen fibers (uniform structure)
  • Compressed fibroblast nuclei
  • Elastic tissue forms wavy sheets in some locations
  • Tendons attach muscles to bones and ligaments hold bones together
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24
Q

Hyaline Cartilage:
* What are the characteristics?
* What are the functions?
* What are the locations?

A
  • Hyaline cartilage: Clear, glassy appearance because of fineness of collagen fibers
  • Eases joint movement, holds airway open, moves vocal cords, growth of juvenile long bones
  • Locations: articular cartilage (long bone), costal cartilage, trachea, larynx, fetal skeleton
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25
Q

What is the skeletal muscle anatomy? (layers)

A
  • Most outer layer: Epimysium which is around the muscle
  • Middle: Perimysium which wraps perimysium
  • Inner: Endomysium which wraps muscle fibers
  • All of them come together to form tendon
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26
Q

What is the muscle fiber made up of?

A

Myofibril which has sacromeres. Sacromeres are made up of protein filaments

27
Q

Skeletal muscle:
* What are the characteristics

A
  • Made of muscle fibers (long thin cells)
  • Most skeletal muscles attach to bone
  • Contains multiple nuclei adjacent to plasma membrane
  • Striations (alternating dark and light bands)
  • Voluntary control
28
Q
  • How many actin encircle each myosine thick filament?
A

6

29
Q

What are the different lines, band and zones of a sarcomeres?

A
30
Q

How is actin formed?

A
31
Q

What are the components of thick filament

A
32
Q

What is a crossbrigde?

A

“head” portion of the myosin Irenefilament that “bridges” the gap between myosin and actin during contraction

33
Q

What is the excitation-contraction coupling process (6 steps)?

A
34
Q

Explain the cross bride cycling?

A
35
Q

Discuss the effects of aging on the musculoskeletal system:
* What is it called with bone, joints and muscle?

A

Bone
* Osteoporosis

Joints
* Osteoarthritis

Muscle
* Sarcopenia

36
Q

What is osteoporosis?

A

A state of low bone mass with microarchitectural deterioration of bone structure leading to compromised bone strength with an attendant propensity to fragility fracture. The bone is normal in composition but reduced in amount.

37
Q

What is The most important etiologic factor in osteoporosis? Explain

A

gonadal steroid deficiency
* The estrogen deficiency that occurs after menopause accelerates the loss of bone mass; postmenopausal women consistently have lower bone mass than men and a higher incidence of osteoporotic fractures.

38
Q

With respect to bone remodeling in men, testosterone serves as what? What does this help?

A

With respect to bone remodeling in men, testosterone serves some of the same functions as estrogen in women, but estradiol generated from the peripheral aromatization of testosterone is the critical gonadal steroid mediating the development and preservation of male bone mass. Hypogonadal men experience accelerated bone loss.

39
Q

Explain how bone mass when it comes to menopause and when addeded with inadequate nutrition and physical activity

A
40
Q
  • When does the accelerated phase of estrogen-deficient bone loss begin?
  • Where is bone loss most evident?
  • Where do fractures happen?
A
  • The accelerated phase of estrogen-deficient bone loss begins immediately at the time of menopause (natural or surgical).
  • It is most evident in trabecular bone, the compartment remodeled most rapidly.
  • As much as 5–10% of spinal trabecular bone mineral is lost yearly in early postmenopausal women; osteoporotic fractures in such early postmenopausal women are often in the spine, a site of primarily trabecular bone.
41
Q

What happens in estrogen deficient state?

A
  • Clearly, it involves an increased release of cytokines such as (eg, interleukin-6) from cells in the bone microenvironment in estrogen deficiency.
  • These cytokines increase the expression of RANK-L and decrease the expression of OPG on stromal cells and osteoblasts - favors increased osteoclastogenesis and bone resorption.
42
Q
  • One important factor in the pathogenesis of age-related bone loss is what?
  • Because renal losses of calcium are obligatory, a decreased efficiency of calcium absorption means what?
A
  • One important factor in the pathogenesis of age-related bone loss is a relative deficiency of calcium and 1,25-(OH)2D. The capacity of the intestine to absorb calcium diminishes with age
  • Because renal losses of calcium are obligatory, a decreased efficiency of calcium absorption means that dietary calcium intake must be increased to prevent a negative calcium balance
43
Q

Osteoarthritis (OA):
* Attributed as what?
* What is now thought to have what?
* What happens to articular cartilage?
* What is it accompanied by?
* What may develop?

A
  • Traditionally attributed as “Wear-and-tear arthritis”
  • However, now thought to have an underlying inflammatory component
  • Articular cartilage softens and degenerates
  • Accompanied by crackling sounds called crepitus
  • Bone spurs develop on exposed bone tissue causing pain
44
Q

Explain how the articular cartilage is loss slowly

A

Articular cartilage damage → chondrocytes replace type II (joints) collagen with type I (in skin), ↓ proteoglycans → eventual exhaustion, apoptosis of chondrocytes → ↓ elasticity, ↑ cartilage breakdown → clefts in articular surface (fibrillations), “joint mice” in synovial space with inflammation of synovium → bone exposition → rubbing other bone → eburnation (polished ivory look)

45
Q

What are the causes of sarcopenia?

A
46
Q

What are the causes of fractures?

A

i. Injury
ii. Repetitive stress
iii. Pathological

47
Q

What are the two types of fractures due to injury?

A

Direct and indirect

48
Q

What is direct force fracture

A
49
Q

What is the indirect force fracture?

A
50
Q

What is a fatigue/repetitive stress fracture? (the different grades)

A
51
Q
  • When does a pathological fracture happen?
  • What is osteoporosis?
A
52
Q
  • What is a fracture?
  • When does a fracture occurs?
  • Bone can withstand a lot but it is susceptible when?
A
  • A fracture is defined as a disruption in the continuity or structural integrity of bone.
  • A fracture occurs when stress applied to bone is greater than bone’s intrinsic strength.
  • Bone can withstand very high compressive forces, but it is susceptible to breaks from tension and torsional forces.
53
Q
  • Fractures involve not only injury to bone but also injury to what?
  • A fracture that compromises the skin and overlying soft tissue resulting in what?
A
  • Fractures involve not only injury to bone but also injury to the surrounding soft tissues, including the periosteum, muscles, and surrounding vessels.
  • A fracture that compromises the skin and overlying soft tissue resulting in bone exposure is called an open fracture.
54
Q

Fractures are classified how?

A

location, orientation and extent of fracture lines, amount of displacement, and soft-tissue integrity

55
Q

What is nondisplaced, displaced, angulated, bayonetted, and distracted?

A
56
Q

What is a transverse, comminuted, oblique, segmental, spiral, intra-articular, torus and greenstick fracture?

A
56
Q

What is an impaction, compression, depression, stress (fatigue), stress (insufficiency) and pathologic fracture?

A
57
Q

What is the process of fracture healing?

A
58
Q

What are sprains, strains, subluxation and dislocations?

A
  • Sprains are injuries to ligaments
  • Strains are caused by trauma to the muscle or the musculotendinous unit.
  • Subluxation is defined as a partial or incomplete misalignment of the bones of a joint.
  • Dislocation is a complete misaligned of the bones of a joint.
59
Q
  • Sprain typically occur where?
  • What causes it?
  • Why is classifying sprains useful?
A
  • Sprains typically occur in the ankle, knee, and wrist during sport activities.
  • Collagen fibers that make up a ligament begin to fail as they are stretched beyond their normal limits.
  • Classifying sprains provides useful information concerning the degree of disability, prognosis, and treatments of these injuries.
60
Q

What are the different grades of sprains?

A
61
Q
  • Strains are common sport injuries and usually followed by what?
  • Seen in who?
  • What does aging brin about?
A
  • Strains also are common sports injuries and usually follow forceful eccentric loading of the muscle.
  • These injuries are frequently seen in athletes who run, jump, or kick, and they typically occur at the myotendinous junction of muscles spanning two joints, such as the gastrocnemius, hamstring, and quadriceps muscles.
  • Aging brings about collagen changes, resulting in decreased elasticity, which makes the muscle-tendon unit susceptible to injury.
62
Q

What are the different grades of strains?

A

Strains are graded on the amount of musculotendinous fibers torn. A complete tear of a muscle (grade IV strain) is described as a rupture