Week 1 Flashcards
(166 cards)
1
Q
What are the properties of the calcified cartilage layer of articular cartilage?
A
- rests on underlying cortex of bone
- stains slightly darker
2
Q
What are the layers of spinal meninges?
A
- Dura mater (spinal dural sheath)
- Arachnoid
- Pia mater
2
Q
What is the role of estrogen in bone strength?
A
- prevents accelerated bone loss
- act to reduce bone resorbing actions of PTH
- increases blood levels of calcitrol but doesnt stimulate its production
3
Q
Describe Psoriasis
A
- accerlerated keratinocyte mitosis in stratum basale and spinosum
- turnover happens in 1 week instead of 4
- leads to thickening of epidermis
- red, itchy, plaques of thickened skin
- autoimmune
4
Q
Describe the function and physiology of myosin V
A
- has a very long lever arm in order to take larger steps
- one arm has to be attached at least 50% of the time
- relate to monkey bar climbing
- myosin V transports vesicles in cells
5
Q
What is an isogenic group?
A
- Represent mitotic division of chondroblasts (stem cells)
- responsible for intersititial growth
- sit within holes of hyaline cartilage in groups of single, doubles, or quadruples
5
Q
How do glucocorticoids affect bones?
A
- inhibit vitamin D intestinal Ca2+ transport
- able to reverse hypercalcemia
- can cause steroid induced osteoporosis
- decrease osteoblasts and cytes
- increase osteoclasts
- muscle weakness
- increased risk of fracture
6
Q
Describe the properties of Langerhans’ cells
A
- originate in bone marrow
- antigen-presenting cells
- capable of phagocytosis
- mainly found in stratum spinosum
- oral, esophageal, rectal, and vaginal epithelium
7
Q
What is the yield point/stress?
A
- The point where a material goes from the elastic region to the plastic region on the stress/strain curve
- structural changes occur to the specimen
7
Q
What are the keratinized cells characteristics?
A
- loss of organelles
- thickened plasma membrane
- bundles of tonofilaments
8
Q
What is appositional growth and who can do it?
A
- Hyaline and elastic cartilage
- chondrogenic cells from inner layer of perichondrium become chondroblasts to add new layers onto those previously formed
- newly forming cartilage has lots of appositional growth
- older cartilage has few chondrogenic cells so appositional growth less common but occurs
9
Q
What role does the cerebrum in pain processing?
A
- Sensory cortex
- Limbic system
10
Q
Name these ligaments
A
10
Q
What is the function of eccrine sweat glands?
A
- responds to heat and nervous stress
- purpose
- cooling/thermoregulatory
- excretion (urea/ammonia)
- emotional sweating
11
Q
Function of hyaline cartilage
A
- resistant to compression
- provides cushioning
- smooth and low friction surface for joings
11
Q
What is the function of bone?
A
- Protects internal organs
- support and movement
- hemopoiesis (red marrow)
- energy storage (yellow marrow -fat)
- mineral reservior (Ca2+ and phosphate)
12
Q
What is contained within a tendon structure?
A
- water
- Type I and III collagen
- tenocytes
- proteoglycans
13
Q
Why are there enlargements at the cervical and lumbosacral levels?
A
- enlargement because it gives rise to the innervation of the limbs
14
Q
What is hysteresis?
A
- Energy lossed due to internal friction during cyclic differences between loading and unloading
- Tendon with repetitive loading, hysteresis will become mnimal
15
Q
What is the biophyschosocial model?
A
- Health and illness is the result of the interaction of mechanisms
- cellular
- tissue
- organismic
- interpersonal
- environmental
15
Q
What are the Erector Spinae muscles>
A
- Spinalis - spine to spine
- Longissimus - sacrospinous to ribs and transcerse processes
- Iliocostalis - from sacral area
powerful extenders, innervated by dorsal rami
15
Q
What is a motor unit?
A
- its all the muscle cells that a motor neuron innervates
- the more motor units recruited, the more force generated known as **recruitment **
- interneuron in the spinal cord helps recruit more units
16
Q
What muscles make up the suboccipital triangle?
A
- Rectus Capitis major
- C2 spine to occipital bone
- litt bit of rotation and good extender
- Superior oblique
- C1 trans to occipital bone
- extension
- Inferior oblique
- C2 spine to C1 trans
- rotation
17
Q
Describe stress/strain curve of a tendon
A
- Toe region
- uncrimping of collagen fibers
- Linear Region
- slope is eleastic modulus of tendon
- Failure region
- permanent stretching
18
How does the spinous processes differ between the different vertebrae levels?
* Cervical - horizontal
* Thoracic - points inferiorly
* Lumbar - large squarish spinous process
18
What are the properties of the papilary layer of the dermis?
* dermal papillae interdigitate with epidermal ridges
* superficial layer
* contains meisners corpuscles (fine touch receptors)
* type III collagen fibers and elastic fibers
* Type VII ifbers to anchor epidermis to dermis
18
What does peritrichial nerve ending sense and where is it located?
* located
* wrapped around the base and shaft of hair follicle
* stimulated by hair movement
19
What is the IASP definition of pain?
* an unpleasant sensory and
* emotional experience associated with
* actual or potential tissue damage or
* described in terms of such damage
20
What is Wolff's law?
* Bone remodels in response to stress placed on it
20
What is the fundamental contractile unit of muscle?
* muscle sacromere
* contracts when myosin and actin slide past each other
21
Function and disease of Myosin V
* Involved in melanosome transport and certain neurological functions
* Disease
* Griscelli's Syndrome - point mutation leads to hypopigmentations and neurological defects
22
What are the properties of the tangential layer of articular cartilage?
* chondrocytes (maintain cartilage), small and flat, lay parallel to the surface
* lamina splendens (most superficial) has no cells
* very fine collagen fibersrun parallel to surface
22
What are the properties of the arrector pili muscle?
* SM
* elecates hair and causes goose bumps depressions of skin where the muscle attaches to dermis
23
What is osteomalacia?
* decreased mineralization of new bone matrix
* commonly caused by Vit D deficiency, chronic renal failure
* Clinical features
* Children: failure to grow, rickets
* Adults: bone pain, proximal myopathy or fractures with minor trauma
23
What are the properties of spinosum?
* several layers thick
* tonofibrils
* bundles of cytokeratin + desmosome = spiny processes
* prickle cells with intracellular bridges
* kertinocytes in deeper layers and they divide
* melanocytes and langerhans cells
24
How do you diagnosis osteoporosis?
* Dual energy X-ray absorptiometry (DEXA or DXA) test for
* woman age 65 older
* patients aged 60 and increased risk for osteoporosis
* T score
* -1: normal bone density
* -1 and -2.5: sign of osteopenia
* -2.5: bone density indicates osteoporosis
24
What are the functions of integument (skin)?
* Protection
* sensory receptor
* role in secretion (urea/NH4+)
* Vit D metabolism
* regulation of blood pressure and body temp
25
What are the splenius muscles?
* Splenius capitis - spinous processes to skull
* Splenius cervicis - spinous processes to transverse processes of cervical vertebrae
25
What is viscoelastic?
* properties sensitive to how fast and how long strain rate is applied
* bone ductile with slow loading, brittle with rapid loading
25
What does Ruffini end organ sense and where is it located?
* sensitive to pressure and responds to pacinian corpuscle stretching
* location
* skin and joint capsule
* pacinian corpuscle found in hypodermis and deep fascia tissues
26
What are the structural features of hair follicles?
* hair follicles formed by epidermis and dermis together
* no hair follicles are formed after birth
* comprised of hair shaft and a hair bulb
28
What is allodynia?
* pain resulting from normally painless stimuli
28
What is the Haversian system or osteon?
* around each capillary canal lamella of bone surrounds it in a circular fashion
* lamella can be inner, outer circumferential, interstitial
* lacuane contain osteocytes that are interconnected by canaliculi
29
Clinical features and pathogenesis of muscle myopathy?
* mutations to MyHC II a
* Clinical features
* muscle weakness
* trophy near shoulders, hand and thigh muscles
* Pathogenesis
* mutations to SH1 helix in myosin
* alters actin-myosin ATPase activity
30
What are the properties of the stratum basale?
* rest on basal lamina
* keratinocytes
* divide continuously
* desmosome (each other), hemidesmosomes (basement membrane)
* cytokeratin increases going towards surface
* melanocytes, Merkel's cells
32
According to the biopsychosocial perspective what is pain influenced by?
* Biological/physical
* tissue damage, tension, sleep, overuse
* inappropriate medications
* physical deconditioning
* Psychological/emotional
* mood (depression, anxiety, anger)
* personal ideas about pain
* avoidance
* Social factors
* impact of others, cultural issues, past learning history
33
What role does thalamus play in pain processing?
* all sensory (not olfactory) systems send signals to the thalamus they are directed to the specific cortical representation areas
* lateral and medial pain systems
33
Clinical features and pathogenes to Distal arthrogryposis, Freeman-Sheldon syndrome, Sheldon Hall syndrome
* mutations to embryoni MyHC 3
* Clinical features
* joint conractions with predominant distal involvement
* Pathogenesis
* mutations in troponin I, troponin T, tropomyosin, perinatal myosin and embryonic myosin
* thought to disrupt development
33
Describe apocrine sweat glands
* large specialized sweat glands
* axilla, areola of nipple, and perianal glands of Moll in eyelids and ceruminous (wax) glands of ear
* scent glands
* release by merocrine process
* dont function until puberty
* response to hormonal influences
* respond to emotional and sensory stimuli but no heat
34
Describe the metaphyseal-epiphyseal system
* supplies the metphyseal part of the long bones (tips)
* anastomose with nutrient arterial system
35
Describe graph
* isometric
* muscle length remains static as tension increases
* concentric
* muscle contracture with decreasing muscle length
* eccentric
* muscle contracts with stimultaneous lengthening
36
What are the effects of Fibroblast growth factor 23 (FGF23)?
* inhibits calcitrol production and phosphate reabsorption in kidney
* made by
* osteoblasts and osteocytes in bone
* stimulated by calcitrol production
38
What level does the spinal cord end?
* L2
* transition into the cauda equina
38
What are the properties of osteoclasts?
* large, motile, multinucleated and have acidophilic cytoplasm
* bone marrow precursor
* stimulated by calcitonin, osteoclast stimulating factor from osteoblasts
* occupy Howship's lacunae (shallow depressions)
* attach to bone to create a microenvironment and acidify this area
40
What are the extrinisic back muscles?
* Levator scapulae
* Trapezius
* Rhomboids - minor,major
* Latissimus Dorsi
* Serratus posterior S/I
40
What are the two different bone formation processes?
* Inramembranous
* direct mineralization of matrix secreated
* most flat bones are formed this way
* Endochondral
* deposition of bone matrix on a preexisting cartilage matrix
41
What do muscles attach to on the lateral surface of each superior marticular facet?
* Mammillary processes
42
What are the cells located within bone?
* osteoprogenitor cells - mesenchymal
* osteoblasts - osteoprogenitor
* osteocytes - osteoprogenitor and osteoblasts
* Bone lining cells
* osteoclasts - bone marrow precursor
43
What are the effects of raloxifene?
* increases bone density and appears to decrease number of fractures
* decreases total cholesterol
* decreases incidence of cancer
* side effects
* increased thromboembolic events
44
What is the nerve supply to the bones?
* vasomotor innervates blood to the interior of bone
* periosteal nerves are sensory nerves
* some are pain
* periosteum is sensitive to tearing or tension
45
What is the lymphatic drainage of bones?
* abundant in periosteum
* Absent in the medulla of the bone
46
What are the 5 layers of the epidermis?
* Stratum basale (closest to the basement membrane)
* stratum spinosum
* stratum granulosum
* stratum lucidum
* stratum corneum
47
What is endosteum?
* lines the central cavity within a bone
* CT composed of monolayer of osteoprogenitor, osteoblasts, and endosteal cells
* during injury will differentiate into osteoblasts to repair damage
49
Does cartilage have a b lood flow?
* no, cartilage does not have a blood supply
* everything has to flow through ECM
* acts as a selective filtration system
50
What are the effects of PTH?
* Decreased Ca2+ excretion by kidneys, increased excretion of phosphate
* conversion Vit D to calcitriol causes
* increased Ca2+ absorption in intestine
* mobilizes Ca2+ from bone
* stimulates osteoblasts which stimulate osteoclasts to release Ca2+ into the blood
50
What is melanins?
* contribute to skin, eye and hair color
* differences in between light/dark is rates of melanin synthesis, accumulation and degradation
* freckles
* patches of epidermal melanin
* made by melanocytes
* in keratinocytes they surround nuclei
* protect DNA from sun rays and absorbs free radicals
* eventually keratinocytes will degrade melanin
51
Describe the triple Jeopordy of bone aging
* Reduction in vertical trabecula
* reduction in thickness of trabeculae
* increased length of traveculae
53
What are the three components of the cruciate liagment?
* Superior longituidinal band
* Transverse ligament of Atlas
* Inferior longitudinal band
covered posteriorly by tectorial membrane from posterior longitudinal ligament
54
Describe Creep
* Continued deformation of tissue
* result of constant stress for an extended period of time
* for tendons creep will result in elongation
55
What does the plastic region imply?
* Region is from yield point to ultimate tensile stress (failure point)
* structural changes are irreversible in the specimen
55
What are the features of the epidermis?
* keratinized stratified squamous epithelium
* made from ectoderm
* regenerated every 30 days
* keratinocytes divide at night
* overlies projections of dermis (dermal papillae) to form epidermal ridges
* has 5 layers
57
How are bones classified?
* According to their shape
* long, short, flat, irregular
58
Describe the annulus fibrosis
* part of IV disc
* peripheral ring of fibrocartilage
* runs oblique
59
What are the structural properties of musle myosin II?
* myosin is a dimer
* each heavey chain has a motor domain and a tail
* myosin are actin based motors
* able to detect direction of actin molecule
60
What is hyperhidrosis?
* excessive sweating
* sweating of hands most distressing
* treatment
* antiperspirants
* lontophoresis
* drugsn (lots of side effects)
* surgery for axillary glands
61
What is the perichondrium?
* a layer of dense irregular connective tissue that surrounds the cartilage of developing bone. - made by fibroblasts
* Contains two layers
* outer fibrous layer - fibroblasts to make collagenous fibers
* inner chondrogenic layer - undifferentiated to make chondroblasts or chondrocytes
62
What are two important questions you should ask patients when assessing their pain and its disruption of their life?
* How much does pain interfere with your activity levels?
* How much does you avoid activities because of pain?
63
What is contained within the hypodermis (subcutaneous fascia)?
* not part of skin
* thickness will vary
* loose CT and adipose tissue
* panniculus adiposus = really thick
* contains large blood vessels (subcutaneous plexus)
64
Describe the bisphasic nature of articular cartilage
* Two phases: fluid and solid
* Type II collagen with proteoglycans to strength and attract water
* when load is applied fluid exudate is created
64
What forces affect muscles ability to generate force and contraction?
* myosin isoforms: SM myosin is much slower
* frequency of stimulation
* number of motor unit stimulated
* degree of stretch
* whether muscle is allowed to shorten
64
Describe length-tension relationship
* altering the starting length of the muscle affects the strength of the muscle contraction
* either completely streched out or complete overlap will generate much less force
65
What are the properties of stratum lucidum?
* seen only in thick skin
* acidophilic
* contains immature keratin called eleidin
66
What are the two components of the intervertebral discs?
* Annulus fibrosis
* Nucleus pulposis
68
Posterior longitudinal ligament
* Narrow and somewhat weaker muscle on posterior side of vertebrae
* limits flexion
70
What is the movement around the anteroposterior axis?
* Lateral Bending
72
What is the blood supply to the long bones?
* Nutrient Arterial System
* Metaphyseal-epiphyseal system
* Periosteal systemones
Bones recieve 5-20% of cardiac output
73
What are the components of the ECM of bone?
* organic components 35%
* Type 1 collagen
* Proteoglycans
* Multi-adhesive glycoprotein
* Inorgnaic components 65%
* hydroxyapatite crystals (Ca2+ and phosphorus)
73
Where is and what does Meissner corpuscle sensory receptors receive?
* present in the dermal papilla of
* fingers, hand, food, front of forearm, lips and tongue
* tactile receptor - fine touch
73
What are the 3 types of skin cancer and which one is the worst?
* basal cell carcinoma
* most common from stratum basale, high cure rate with early Dx
* squamous cell carcinoma
* 20% of cancers from stratum spinosum, high cure rate with early Dx
* melanoma
* 5% of cancers but causes 75% of skin cancer deaths
* grows rapidly and metastasizes quickly
74
What is anisotrophy?
* mechanical propeties different in all directions of loading
* orthotropy
* mechanical properties symmetric within two planes
* ie long bone: Axial and transverse loading
76
What is the blood supply to the spinal cord?
* Aorta
* posterior radicular artery \> posterior spinal artery
* anterior medullary artery \> anterior spinal artery (only present at specific levels)
77
How is smooth vs skeletal muscle regulated?
* Thin filament (skeletal and cardiac)
* Thick filament (SM)
* myosin light chain kinase creates an active myosin
* myosin light chain phosphatase inactivates myosin
78
What are the sources for ATP in muscle?
* ATP
* Creatine phosphate
* glycogen (anaerobic/aerobic)
* lipolysis
79
Describe cancellous, spongy, or traveculated bone
* mature spongy bone is arranged as trabeculae
* found in all bone types, cavity of diphysis and epiphysis
* possess lamellae, but no osteons
* covered by an endosteum
80
Describe the properties of Merkels Cells
* found in stratum basale
* most numerous in thick skin
* derived from neural crest
* have desmosomes and tonofilaments
* **sensory mechanoreceptors **
81
What occurs to tendon strength in regards to age and immbilization?
* tendon strength increases to maturity then remains constant
* physiological strain on tendons 2-5% but can handle up to 25%
* Weeks after immobilization period, losses 40% of strength and even after a year, near normal but not perfect
83
What factors interfere with movement of the spine?
* thickness of intervertebral discs
* orientation of articular facets
* attachment of ribs
* size, elasticity and orientation of muscles of back and abdominal wall
85
What is the stress strain differences between cortical and travecular bone?
* Trabecular
* lower ultimate stress
* ductile
* can absorb significant energy with minimal mass
* Cortical Bone
* high ultimate stress - strongest in compression, weakest at transverse
* brittle
86
What are the transcersospinae muscles?
* semispinalis 6-8 to skull
* multifidus 3-5
* long rotators 2
* short rotators 1
87
What is the movement around the transverse axis?
* Flexion
* Extension
88
What is the function of cartilage?
* provies shape and flexibility
* shock absorber
* facilitates smooth movement of joints
90
How do ventral and dorsal rami exit the sacrum?
* Ventral - anterior sacral foramina
* Dorsal - posterior sacral foramina
91
What is an important note about the internal vertebral venous plexus?
* communicates with both venous sinues of brain and venous plexus of the plevis
* possivle for prostate cancer to metastasize in CNS
92
What does the substantia gelatinosa contain?
* located in the dorsal horn of spinal cord
* contains excitatory neuropetide input from primary afferent neurons
94
How is trabeculated or spongy bone formed?
* mesenchymal cells \> osteoblasts
* bone matrix creates a randomly orientated network of spicules and traveculae
* calcification occurs
* osteoblasts get stuck in matrices and become osteocytes
95
What are the intrinsic back muscle layers?
From superficial to deep
* Splenius muscles
* Erector spinae muscles
* Transversospinae muscles
97
What is a feature between nerve root length and vertebral column?
* as you move closer to the cauda equina each successive nerve root gets longer and longer to reach its intervertebral foramen
* dural sac ends around S2
98
Describe the sebaceous glands
* embedded in dermis all over the body expects palms and soles.
* most abundant on face
* secretions empty at neck of hair follicle
* holocrine glands make sebum that in puberty would lead to acne
99
What is Paget's disease?
* excessive bone resorption and formation
* clinical features
* bone pain
* skeletal deformity
* neurological complications or fractures
101
Anterior longitudinal ligament
* Anterior portion of the vertebral column, thick ligament
* limits extension
* prevents herinated discs
101
Describe periosteal system
* low pressure system
* supplies outer 1/3 cortex
102
What is the conus medullaris?
* inferior, tapered end of spinal cord
103
What are the properties of elastic cartilage?
* has perichondrium
* does not undergo calcification
* chondroblasts, chondrocytes in much higher number than hyaline
* has type II collagen but masked by lots of elastic fibers
* very limited repair
104
What is the movement around the vertical axis?
* Rotation
105
Describe the nutrient arterial system to long bones
* High pressure from systemic
* enter through nutrient foramina
* divide into ascedning and descending medullary branches
* supplies
* medullary cavity
* inner 2/3 of cortex via Haversian system
107
What is periosteum?
* covers the external surface of bone
* consists of an outer layer of dense fibrous CT and inner cellular layer that has osteoporgenitor cells and periosteal cells
* during injury will differentiate into osteoblasts to repair damage
108
What is hyperalgesia?
* heightened sense of pain to noxious stimuli
109
What are the properties of stratum granulosum?
* lamellar bodies (granules)
* release GAGs and phospholipids into intracellular space
* membrane-less keratohyalin granules
* contain histidine and cystine rich proteins that will bind to tonofilaments
* bundles of tonofilaments
* attachment of proteins to tonofilaments is the first step in keratinization
* this layer is critical to water proofing the deeper layers
110
What are the properties of stratum corneum?
* Most superficial layer
* dead, platelike, enucleated kertinocytes
* contain mature keratin
* keratin birefringent scleroprotein
* made of at least 6 polypeptides + tonofilaments
111
How does time effect the second contraction of muscle?
* the shorter the time between each contraction signal it will cause the second peak to be higher
* additional influx of Ca2+ promotes a second contraction which is added to the first = **temporal summation**
* if signal is frequency limitlessly you get **complete tetanus** until muscle fatigue
112
Describe eccrine sweat glands
* simple coiled tubular gland, located nearly everywhere
* secretory unit
* dark cells - secrete glycoproteins
* clear cells - secrete water and electrolytes
* myoepithelial cells
* ducts lined with stratified cubodial epithelium
* modifies sweat absorbing electrolyes
* excretes ions, urea, lactic acid
113
What is the gate control theory?
* sensory inputs to spinal cord start to interact at very first steps of transmission
* theory suggests non-painful input (rubbing or massaging) closes the gates to painful input, preventing if from traveling to CNS
114
Function of myosin IIa
* involved in cell division
115
What are the properties of the dermis?
* contains collagen and elastic fibers
* derived from mesoderm
* contains two layers
* papillary layer (superficial)
* recticular layer
116
What are selective estrogen receptor modulators (SERMs)?
* drugs that have tissue specific effects
* function as competitive inhibitors in tissues with alpha estrogen receptors
* agonists with beta estrogen receptor
* two examples
* tamoxifen
* raloxifene
118
What are the stages of myosin attachment?
* attached
* locked tightly to actin
* released
* ATP binds to back of head to cause the myosin to have lower affinity for the actin and release
* cocked
* ATP is hydrolyzed as the head moves forward but ADP and Pi stay attached
* force-generating
* weak binding occurs between the myosin and actin
* ADP and Pi dettach and its at its original position
* attached
119
What are secondary curvatures?
* Cervical
* Lumbar
121
What are the primary curvatures?
* Thoracic
* Sacral
122
What are the layers of articular cartilage?
* Tangential layer (closest to joint space)
* Transitional zone
* Radial Zone
* Calcified cartilage layer
123
How do local anesthetics and lidoderm patches work?
* in nociceptor signaling to the CNS it blocks the transformation of the pain signal
* prevents action potential generation
125
What are the properties of fibrocartilage?
* resists deformation under stress
* no perichondrium
* Type 1 collagen is dominent with some type II
* parallel columns of chondrocytes, fibroblasts
* located in IV discs, pubic symphysis
126
What is stress relaxation?
* Over time the force necessary to maintain deformation of a structural decreases
127
What is isotrophy?
* Uniformity in all orientations
* ie sphere
129
Function and disease myosin VI and VII
* involved in maintaining orgnization of actin-filled stereocilia
* Disease
* mutations associated with hearing loss
* certain myosin VII mutations associated wiht Usher syndrome
130
What is structures are contained within the axial skeleton?
* Skull
* Vertebral column 33 vertebrae
* 7 cervical
* 12 thoracic
* 5 lumbar
* 5 sacral
* 4 coccygeal
* Ribs
* Sternum
131
Clinical features and pathogenesis of laing myopathy
* mutations to B-cardiac myosin (MyHC7)
* clinical features
* weakness of ankle dorsiflexion
* hanging big toe
* Pathogenesisi
* mutations in LMM region of myosin
* disrupt myosin filament formation or interactions with myosin binding proteins like titin
132
How is structural strength defined?
* Brittle
* Glass
* Ductile
* able to absorb more energy before it breaks
133
Describe the function and physiology of myosin II
* low duty motor
* arm has to be attached about 10% of the time
* short arms
* drives muscle contraction
* functional unit is ~20 heads
* many myosin II molecules are required to propel actin filament to create thick filament
134
What are the effects of bisphosphonates?
* reduces turnover of bone
* prevents the number and activity osteoclasts
* takes 48 hours to block bone resorption
* should not be taken with milk products
* side effects
* GI
* gastric ulcers
* take with water and dont lay down for 30 mins
135
Hormone replacement therapy
* estrogen at menopause inhibits effect of oestoclasts on bone resorption
* increased cardiovascular events with women with a history of heart disease
* increased risk of breast cancer and harder to find tumors
137
What is spondylolithesis?
* forward displacement of a vertebrae
* most commonly occurs after a fracture or break but doesnt have to
138
What is the periaqueductal Grey (PAG)?
* target of the spinomesencephalic neurons
* very important in regulation of nociception
* relays descending pain modulation
139
What is intersititial growth and who uses it?
* occurs in all cartilages
* growth starting in different centers within a structure that is already formed
* important for growth of long bones at epiphyseal plate
141
What does lamina V contain?
* receives input from Adelta and C-fiber nociceptors
* key neurons responsible for central sensitization
142
What are the structural properties of myosin?
* many different types of myosin not all involved in muscle
* Have similar motor domains
* Have different tail lengths
* differences correspond to differences in cargo and regulation
* tail acts as a lever, bigger tail bigger steps
143
What are the structural features of hyaline cartilage?
* ECM has Type II collagen firbrals and aggrecan to make it absorb water
* components of hyaline matrix are not evenly distributed
* Growth and repair is very limited so scar tissue forms
144
Why is the TRPV1 receptor important?
* nociceptor that its stimulate by capsaicin
146
Where is hyaline cartilage located?
* fetal skeletal tissue
* epiphyseal plates
* articular surface of synovial joints
* costal cartilages of rib cage
* rings of trachea
147
Describe the properties of the reticualr layer of the dermis
* thicker
* follicles, sweat and sabaceous glands
* dense irregular CT
* elastic fibers and bundles of collagen (type I)
* contains many sensory fibers
148
What is Anterior spinal artery syndrome?
* blockage of anterior segmental medullary arteries
* T8-L2 region most clinically important because aortic aneurysm
* damages motor neurons and can cause level loss
150
Describe compact bone
* structural unit: called osteons (Haversian system)
* Voklmann's canal: horizontal channels containing blood vessels from bone marrow
* different kinds of lamellae
* endosteum
* periosteum
152
What are the structural features of nociceptor?
* usually unmyelinated axons (C-fiber and Adelta-fiber)
* small cell body diameters
* encode stimulus intensity into noxious range
153
What is failure strength?
* Structures because of progressive structural damange from cyclic loading will approach a fatigue limit
* results in a stress fracture
154
Properties of melanocytes
* from neural crest cells
* located in stratum basale
* highly mobile because they have no desmosomes
* inject melanin into keratinocytes
155
Function of tropomyosin
* Wraps around actin filament blocking myosin from binding sites
* Ca2+ binding to troponin C results in tropomyosin moving away from myosin binding sites
* cooperative binding of Ca2+, creating a steep binding curve
156
What are the properties of the radial zone of chondrocytes?
* Fairly large condrochytes
* form raidial columns, perpendicular to surface
* collagen fibers follow the columns
157
What are the three phases of a muscle twitch?
* Latent period
* Ca2+ activation
* difference between signal and muscle reaction
* Contraction
* actin-myosin cycle
* cycling of cross linking
* Relaxation
* pumping Ca2+ out of muscle
158
Describe the nucleus pulosis
* Part of the IV discs
* Gelatinous core
* able to deform
* most common area for stress L5/S1 and L4/L5
159
What is spondylolysis?
* stress fracture of pars interarticularis of the vertebrae
* can be the result of repeated stress to hte spine
* Shows up as Scotty Dog with a collar in an X-ray
160
What is osteoporosis?
* thinning of bone
* common in post-menopausal women
* increased morbidity and mortality
* accelerated by
* premature or surgical loss of ovarian function
* drugs (corticosteriods)
* lifestyle (alcohol or smoking)
161
What are the effects of Tamoxifen?
* blocks estrogen receptor in breast cancer cells
* may prevent breast cancer
* used in conjuction with surgery or chemotherapy
* side effects
* hot flashes
* nausea/vomiting
162
What does free nerve endings sense and where are they located?
* respond to pain and temperature
* lack myelin or Schwann cells
* found in
* epidermis
* corneal epithelium
163
What are the effects of Denosumab?
* Human monoclonal antibody against RANKL
* treats osteoporosis
* inhibits the maturation of pre-osteoclasts into osteoclasts
* side effects
* increased urinary and respiratory tract infections
* joing pain
* eczema
164
What is the properties of the transitional zone of articular cartilage?
* Chrondocytes slightly larger
* occur single and in isogenous groups
* Collagen fibers run oblique
165
What are the features articular cartilage?
* subset of hyaline cartilage
* sits on the ends of bones to lubrricate, prevent wear and be slighlt compressible
* does not have a perichondrium, poorly vascularized
166
Properties of Herniated discs
* occurs when there is excessive pressure on the disc
* impinges the root below the herniating level
* occurs posterolateral direction
* Most common at L4/L5 and L5/S1
