Exam 2 Flashcards
1
Q
Entire muscle surrounded by
A
Epimysium
2
Q
Fascicle surrounded by
A
Perimysium
3
Q
Muscle fibers surrounded by
A
Endomysium
4
Q
Smallest functional unit of SkM
A
Sarcomere (made up of myofilaments - actin and myosin)
5
Q
Calsequestrin
A
Protein in SR that regulates Ca
6
Q
Tropomyosin function
A
Blocks myosin binding site on actin at rest
One Tm runs 7 G-actin (1 F actin)
Lies within actin groove
7
Q
Troponin function
A
Regulates tropomyosin
8
Q
Troponin subunit Tc
A
Binds Ca
9
Q
Troponin subunit Ti
A
Inhibits tropomyosin movement off of myosin binding site
10
Q
Troponin subunit Tt
A
Binds troponin to tropomyosin
11
Q
Proteins that anchor myosin
A
Titin and M-line proteins
12
Q
Proteins that anchor actin
A
Alpha actinin and Dystrophin
13
Q
“power stroke”
A
Repetitive crossbridges –> continued force generation
14
Q
Relaxation of SkM (3 steps)
A
ATPase pumps pump Ca back into SR
Tc no longer bound to Ca, Tropomyosin slides over myosin binding site
Ti becomes active again
15
Q
Serial/Vertical orientation of sarcomeres
A
Facilitate velocity of contraction (greater shortening)
E.g. hamstring
16
Q
Parallel/ Pennate orientation of sarcomeres
A
Facilitate force generation (packing of more sarcomeres)
E.g. quads, gastrocnemius
17
Q
Torque- velocity relationship
A
Takes eccentric phase into account
Force generation ability: E>I>C
18
Q
Why do eccentric contractions generate the most force?
A
- Myosin heads ripping
- CT resists lengthening
19
Q
Which type of activation do we maintain best with age?
A
Eccentric
20
Q
Size of motor unit defined as
A
Number of fibers innervated by one nerve
Smaller = greater control
21
Q
Structural changes of muscle with aging
A
Fast twitch motor units die, fibers are rescued by slow twitch motor units
–> Fewer, slower, larger motor units overall
Increased tensile ability in CT
Fewer muscle fibers
Possibly more precipitous in females
22
Q
Alpha motor neuron
A
Efferent neuron to SkM (from muscle spindle reflex)
23
Q
Gamma motor neuron
A
Efferent neuron to muscle spindle
24
Q
Muscle spindle afferent neurons (1a and II endings)
A
Sense passive elongation of muscle
25
Golgi Tendon Organs
Lie within tendon, respond to increases in tension.
Muscles with increased tension inhibited
Input is conscious level?
26
Afferent neurons in golgi tendon reflex sense
Tension in golgi and in extrafusal fibers
27
Smooth muscle differences from skeletal
3rd filament (intermediate) --> No striation
Dense bodies instead of sarcomeres (actin approximates dense bodies) - analogous to z line approximation
Muscle shortens and widens (nonlinear contractions)
Wider length-tension relationship
28
Multiunit Smooth Muscle contractions
"Neurogenic" - innervated by ANS
| e.g. blood vessels
29
Single Unit Smooth Muscle contractions
"Myogenic" - activated by stretch
| e.g. visceral organs
30
Atrial muscle
Bilayer - deep fibers specific to one atrium
31
Ventricular muscle
Coil-like fibers
32
Hierarchical structure of muscle
Muscle, fascicles, fibers (cell), myofibrils (organelles), myofilaments
33
Sarcopenia
Age related muscle loss - greatest decline occurs with inactivity
34
Bone density peaks ____, remains stable for____
After 3rd decade; 20 years
35
Preclinical disability
Progressive and detectable, but unrecognized decline in physical function (65+ y.o.)
Pt says they can still do everything they want, but objective measures show that their function has declined
--> Increased risk for severe disability. Early intervention important (EXERCISE- both strength and endurance)
36
Which type of bone is osteoporosis more common in?
Trabecular (vertebrae, epiphysis) - common in hips
37
Which type of bone is osteoporosis more common in?
Trabecular (vertebrae, epiphysis) - common in hips
| Pain is severe and localized
38
Osteoporosis Treatment
Try to stop progression of disease:
Promote weight bearing
Meds, supplemental Ca
39
Paget's disease
High bone turnover, but new bone is weakened (fibrous tissue)
Osteoclasts gone wild
40
Paget's disease Sxs
Bowing of legs, bone pain, fx, OA
| *slow progression, often not caught early
41
Paget's disease Tx goal:
Normalize bone activity
| Note: Avoid high impact exercise
42
Osteomyelitis
Inflammation of bone due to infection - usually Staph
| Becoming more common due to bacterial resistance and prosthetic implants
43
Acute vs. chronic osteomyelitis
Acute: Children, spreads through bloodstream from other infection site
Chronic: Adults, esp. immunosupressed
44
Osteomyelitis sxs
Fever, pain, erythema (children)
Vague sxs, back pain (adults)
Pain with weight bearing
Sausage toe
45
Dx of Osteomyletis
- Systemic signs (fever, WBC increase)
- Only 50-80% have positive bacterial culture
- MRI, bone scans (X-rays only effective after 10 days)
46
Osteomyelitis treatment
IV Antibiotics for 3-4 weeks
| Acute: good prognosis. Chronic: Poor
47
Infectious (Septic) Arthritis
Infection in joint
Happens at any age
Either due to direct infection (bacterial, viral, fungal) or reactive from infection elsewhere in body.
48
Infectious (Septic) Arthritis Treatment
Medical emergency - IV antibiotics
49
Muscular dystrophy
X-linked recessive error in dystrophin
50
Spinal Muscular Atrophy
Autosomal recessive reduced number of anterior horn cells
| Marked hypotonia and weakness
51
Spinal Muscular Atrophy diagnosis
EMG studies to check nerve conduction
52
Plagiocephaly
Mishapen head, can be side effect of torticollis
53
Callous formation stage of bone healing
Cartilage replaced with bone
54
Strongest predictor of mortality in older adults with surgery to repair hip fx
Inability to stand up, sit down, walk after 2 weeks
55
Most common intervertebral discs for DDD
L4-L5
56
Greatest risk factor for DDD
Family history
| age, overweight, underweight also risk factors
57
3 stages of age-related disc degeneration
1. Dysfunction (tear in annulus, hypermobility of facter jts)
2. Instability (degeneration of facet jts, subluxation)
3. Stabilization (spinal stenosis)
58
DDD symptoms
LBP - but many cases asymptomatic
Slow progression of pain
Worse with activity and prolonged static position, better with rest
Disc herniation common
59
DDD diagnosis and treatment
Xray and MRI findings poorly coordinate with symptoms
Conservative vs. surgery: = outcomes
NSAIDs, PT, weight loss
60
Signs of disc herniation
Ankle dorsiflexion, great toe extensor weakness
| Impaired ankle reflexes, loss of sensation in foot
61
Osgood- Schlatter
Mechanical problem related to extensor mechanism of knee - fibers of patellar tendon pull immature bone from tibia
Occurs before complete fusion of epiphysis
62
Osgood-schlatter treatment
Rest from painful activities until sxs abate - no immobilization
NSAIDs and ice
Address inefficient extensor mechanism, stretch and strengthen
-90% respond well to above treatment
63
Arthrogryposis Multiplex Congenita
Non-progressive disease characterized by severe muscle contractures, weakness, fibrosis at birth. (Sometimes have muscles missing).
64
Osteogenesis Imperfecta
Non progressive, diffuse osteoporosis (both types of bone)
Autosomal dominant
Bowing of long bones, extremities appear small compared to trunk
65
Osteogenesis Imperfecta pathology
Defect in collagen synthesis (dysplasia) --> Bone, ligament, muscle weakness
66
Differentiating child abuse from osteogenesis imperfecta
Epiphyseal fractures common in abuse, rare in OI
67
Developmental Hip Dysplasia
Congenital abnormal growth, dislocation, or sublaxation of hip (shallow acetabulum)
68
To develop normally, hip needs:
Muscle balance
Bony congruence
Weight bearing forces through joint
^ Wolfe's Law
69
Developmental Hip Dysplasia clinical presentations
Decreased hip ROM, especially ABD
| Asymmetrical gait, posture, muscle bulk
70
Developmental Hip dysplasia, diagnosis needed before
18-36 months
71
Legg-Calve-Perthes Disease
Avascular necrosis of femoral head (medial femoral circumflex artery)
Predictable, self limiting course
72
4 Stages of Perthes disease
Takes 1-3 years
73
Incidence of Perthes disease
4-8 year old thin, active boy
Caucasian
20% bilateral
Often associated with learning disability
74
Clinical presentation of Perthes disease
```
Limp, Trendelenburg gait
Limited ABD and ER
Pain: Groin, knee, anterior medial thigh
Buttock and thigh atrophy
No history of obvious injury
```
75
Steps to take if you find a case of Perthes
Refer to a surgeon (not and emergency)
76
Slipped Capital Femoral Epiphysis Incidence
African american males around puberty
75% obese
25-33% bilateral
77
Slipped Capital Femoral Epiphysis clinical presentation
Antalgic limp
Held in ER
Decreased ABD, flex, and IR
Pain: Groin, knee, anteromedial thigh
78
What to do if you suspect a SCFE
Medical emergency - send to surgeon
79
SCFE vs. Perthes
SCFE: Overweight, puberty, african american, held in ER, limited ABD, flex, IR
Perthes: Thin, active, 4-8 y.o., cuacasian, limited ABD and ER
Both have increased risk of degenerative arthritis as adults
80
Club foot clinical presentation
Forefoot adduction
Hindfoot varus, small calcaneus
Hypoplastic muscles
Ankle equinus - unable to DF
81
Club foot treatment
Medical emergency
Serial casting immediately
Surgery, PT, taping, manipulation
82
Kyphosis -->
SC compression
83
Scoliosis -->
Spinal nerve compression
84
Fetal age when terratogens --> Limb deficiencies
3-8 weeks
85
Complications of Myelography
HA, meningitis, allergic reaction to dye
| What is myelography?
86
DEXA t scores and z scores
T-score: Compared to healthy young adults (peak BMD)
| Z-score: Compared to age-matched controls
87
Complications of Arthrocentesis
Infection, hemorrage
88
Contraindications of arthrography
Active arthritis, joint infection
89
Complications of arthroscopy
Infection, hemarthrosis, swelling, synovial rupture
90
Contraindications for EMG
Anticoagulant meds, skin infection
91
Inner layer of periosteum
Cambrium - precursor cels to osteoblasts
92
Osteocytes
Mature osteoblasts surrounded by the collagen matrix they secrete
93
Increase in bone thickness
Osteoblast activity - add new bone to cambrium
94
Increase in bone length
Chondrocyte activity -
Chondrocytes near epiphysis multiply
Chondrocytes on epiphyseal side of line multiply
Older chondrocytes near diaphysis hypertrophy and are ossified
95
Growth hormone
Promotes growth in both length and thickness of bone
96
Bones most susceptible to effects of DID
Weight bearing bones of lower extremity, pelvis, lumbar spine
-Demineralization occurs in trabecular bone - not externally apparent
97
What type of cartilage forms growth plate?
Hyaline
98
Proteoglycans
Protein + GAG, syrupy substance that hold cartilage cells together.
e.g. hyaluronic acid, chondroitin and keratan sulphate
99
Superficial layer of cartilage
Fibers horizontal, easily compressed, resist friction
100
Middle layer of cartilage
Increases tensile strength and compression resistance
| Fibers oblique to superficial layer
101
Deep layer of cartilage
Greatest resistance
| More proteoglycans, less water
102
Calcified layer of cartilage
Anchors cartilage to bone
103
2 classes of ligaments
Capsular and non capsular (non capsular can be internal and external)
104
Most common IV General anesthetic
Propofol
105
Most common inhaled general anesthetic
Nitrous oxide
106
Types of neuromuscular junction blockers
```
Non depolarizing (iums) - block ACh receptors
Depolarizing (succinyl-choline) - Prevent re-polarization
```
107
General anesthetics mechanism of action
1. Stimulate GABA receptors - hyperpolarize cell
| 2. Inhibit ACh receptors
108
Local anesthetic mechanism of action
Bind Na chanels in membrane of afferent neuron --> blocks depolarization, no pain sensation sent to brain
109
Typical level of epidural or spinal block
L3-4 or 4-5, to avoid spinal chord
110
Order of anesthesia
Small, unmyelinated nerves first, then larger, myelinated ones.
Pain, temp, pressure, proprio, motor
111
Drugs that treat spasm
Polysynaptic inhibitors
| Receptor specific drugs
112
Polysnaptic inhibitors
Decrease excitatory input at alpha motor neuron to block pain - spasm - pain cycle
(Smooth muscle affected too - constipation)
Tolerance and dependence possible.
Meprobomate - antianxiety
113
Drugs to treat spasticity
```
Diazepam (valium)
Baclofen
Tizanidine/ Clonidine
Gabapentin (neuronin)
Dantrolene Na
```
114
Ascending mechanism of opioids
Block release of pain neurotransmitters; hyperpolarize post-synaptic terminal
115
Descending mechanism of opioids
Bind opioid receptors in brain, activating pain inhibitory pathways
116
Proteins responsible for pain, fever, inflammation, etc.
Prostoglandins (produced via cyclooxygenase pathway)
| *COX 2 is the pathway with the negative products
117
S/s of ASA overdose:
Hearing loss, tinnitus, confusion, HA
