602 Flashcards
In a single muscle fiber, sarcomeres are arranged:
a. In parallel (side-by-side) b. In series (end-to-end) c. Partially overlapping d. Two or more of the above
D
What must be the physical relationship of actin to myosin for cross-bridges to form? How does this relationship affect the ability of the sarcomere to produce tension?
Overlapping
Must have an optimal length to work (z-lines can’t be too close or too far to work)
Which way do myosin head groups pull on the actin during an eccentric contraction? What ultimately determines whether an active muscle does a concentric, isometric or eccentric contraction?
Eccentric: head groups pull away from myosin
If the resistance force/effort force wins
What does the muscle look like when the parallel passive elastic elements are contributing most to the pull of that muscle on the tendon or bone?
When passive Is most relevant, it’s lengthened
When active is most relevant, it’s shortened
When a single alpha motor neuron fires in the anterior horn cell of the spinal cord:
a. One sarcomere depolarizes.
b. One myofibril depolarizes.
c. One fiber depolarizes.
d. Some of the fibers within the motor unit depolarize
while others rest.
e. All the fibers within the motor unit depolarize.
E
Muscle fibers within a motor unit fire synchronously
You are going to lift a box off the table that you anticipate is quite heavy. What motor units will you tend to recruit first and what characteristics do they have?
What if the box turns out to be empty?
What if you don’t know?
Larger
Smaller
Start with smaller then work up
If the shoulder flexion force generated by the anterior deltoid is inadequate to flex the shoulder, what options are available to you (or, more correctly, to your nervous system) to increase the force of shoulder flexion?
o Increase frequency
o Recruit another muscle
o Increase the other muscles (coracobrachialis)
o Motor units
o Larger motor units
o Type of fiber
o It would recruit surrounding motor units to compensate
Given the Physical Stress Theory (Mueller and Maluf), what is the response of a tendon to rapidly repeated forceful muscle contractions several hours a day for one or more weeks?
Injury
What structure contributes to the passive stiffness of a muscle?
Titin
What structure(s) is mainly responsible for extensibility or flexibility of a resting muscle?
Endomysium, perimysium
If you had prolonged muscle soreness of a muscle, the day after a workout. What type of muscle contraction would the muscle tolerate well?
Concentric high velocity or eccentric high velocity and why?
Concentric and high velocity
There is more tension during an eccentric contraction, so it wouldn’t make sense
Concentric produces less tension (because of Titin slack/tightening)
Is Titin slack/taut during concentric contraction?
Slack
Which has more Type I collagen? (Ligament or Tendon)
Tendon
Which is under more tensile stress at END ROM?
Under muscle contraction?
Ligament
Tendon
In which are collagen fibers parallel/same direction as force?
Densely packed in direction of many different forces?
(Ligament or Tendon)
Tendon
Ligament
Which has more elastin? (Ligament or Tendon)
Ligament
Enthesis
Fibrocartilaginous attachment of tendon/ligament that attaches to the bone
Sharpey’s fibers
The roots of the entheses
Importance of the 4 zones of Enthesis
Gradual change in tissue composition
Function goes from tendon resisting tensile forces»_space; bone resisting compressive forces
4 zones of enthesis
- Tendon proper
- Uncalcified fibrocartilage
- Calcified fibrocartilage
- Bone
Endotenon
Internal to tendon
Peritendon is…
aka. ..
fx. ..
Epitenon + Paratenon
aka “Tendon Sheath” (when filled with synovial fluid)
protects tendon by allowing slide over tendon
Fx of bursa
Reduce friction between moving tissues (bw skin/bone, tendon/bone, ligament/bone, muscle/bone)
Where is fibrocartilage found?
What type of cartilage does it have?
What forces does it resist?
In cartilaginous joints
Type I cartilage
Resist tensile AND compressive forces
Where is hyaline cartilage found?
What type of cartilage does it have?
What forces does it resist?
In synovial joints
Type II cartilage
Resist compressive forces
How does hyaline cartilage get nutrients?
Compression of joint from PGs and H2O leads to nutrients diffusing into the space after the load is removed
4 zones of hyaline cartilage:
- (Tangential) resists parallel movement, reduces friction between joints
- (Middle/Transitional) Type II collagen forms meshwork, keeps H2O + PGs contained, absorbs compressive forces
- (Radial) Perpendicular collagen fibers hold onto bone
- (Bone) Calcified cartilage layer that is impervious and prevents nutrients from crossing into bone
What is responsible for bone synthesis?
Bone resorption?
Osteoblasts
Osteoclasts
Where is Trabeculae found?
In cancellous/spongy bone
Cortical bone aka
compact bone
Cancellous bone aka
spongy
How are trabeculae organized
direction of stress/strain on bone
Fx of periosteum
1) Attaches ligaments, tendons, cartilage to deeper bone
2) Houses precursors to osteoblasts/clasts
3) Blood nutrients
Wolff’s law
What does it say about someone who is overweight?
Change in bone matches fx
Bone will be denser/thicker
SAID principle
Specific Adaptation to Imposed Demand
Load
Stress
Strain
Force applied
Force applied to a cross-sectional area
% in length/cross section of a structure
What happens to the stiffness of a tissue if it has bigger cross sectional area?
Increases stiffness
What happens to the stiffness of a tissue if it is longer?
Decreases stiffness
What is the inverse of stiffness
Compliance
How do you describe ultimate failure for:
- Ligament
- Tendon
- Cartilage
- Bone
- Sprain
- Tear
- Tear
- Fracture
How would you classify these joints by movement?
- Fibrous
- Cartilaginous
- Synovial
- Synarthrosis (little/no mvmt)
- Amphiarthrosis (some mvmt)
- Diarthrosis (free mvmt)
What are common features of synovial joints?
- Joint capsule
- Synovial membrane/fluid
- Hyaline cartilage
What are the 2 layers of synovial joint capsule?
What are their fx?
1) Fibrous
Encloses cavity, stability, sensory endings
2) Synovial
Lubrication, vascularized
What kind of joints are:
- Uniaxial
- Biaxial
- Triaxial
- Hinge/pivot joints
- Condyloid/saddle joints
- Plane + ball/socket joints
Convex on concave rule
Concave on convex rule
Roll and glide occur in opposite direction
Roll and glide occur in same direction
What affect do these have on joint mobility?
1) Large bony prominence
2) High elastin content
3) Hypertonic muscles
4) Joint capsule in plastic range
1) No effect
2) Hypermobility
3) Hypomobility
4) Hypermobility
What is the membrane that covers a muscle cell?
Sarcolemma
What is the contractile unit of a muscle? And how are they separated?
Sarcomere
Z discs
Which protein moves on which in contraction?
Myosin pull on actin
What direction do the myosin head groups pull actin in…
1) Concentric contraction
2) Eccentric contraction
1) Pull actin towards myosin (shortened)
2) Pull actin away (cross bridges broken, reformed, lengthening)
How are sarcomeres arranged in a myofibril?
in series
How are myofibrils organized in a muscle fiber?
in parallel
can be of different lengths and generate different amounts of tension
How do muscle fibers fire in motor unit?
What do motor units fire?
Synchronously
Asynchronously
What are limiting factors for motor unit to fire repeatedly?
Refractory period
Availability of calcium at junction
Size of motor unit
Fiber type
Are pennate fibers better or worse for force production?
Why?
Better
Have bigger CSA, numerous
What is the order of connective tissue in a muscle?
Titin > Tendon > Sarcolemma > Endomysium > Perimysium > Epimysium
What does Titin do during:
Concentric exercise?
Eccentric exercise?
Slacks
Tenses (would overstretch without)
Total tension when…
Muscle fiber lengthened beyond optimal length?
Muscle fiber shortened beyond optimal length?
- reduces active tension (passive tension may increase because they are stretched aka will increase total tension)
- reduces active tension (passive elements are slack aka total muscle tension is least in a shortening fiber)
Why would you want to bend your knees/hips when you’re about to jump?
So the parallel elastic tissues are stretching creating more tension and contribute to force produced by active contraction of the sarcomeres
Would the rotational velocity of a limb segment remain constant if a muscle was contracting with a constant number of motor units as a joint moves through its range of motion?
There would be the same amt of muscle tension applied over changing moment arms which would change torque production
More torque = more acceleration
Less torque = less acceleration
During shoulder flexion…
- Anterior deltoid
- Coracobrachialis
- Rotator cuff
- Posterior deltoid
- Quads + Hamstrings during leg press
- Agonist
- Co-agonist
- Synergist
- Antagonist
- Synergist
The following options are available to you to increase the force generated for elbow flexion to lift a box except?
a. Recruit more motor units
b. Increase the frequency of firing of the motor units
c. Recruit larger sized motor units
d. Increase the tension in the endomysium
Increase the tension in the endomysium
there would be a decrease in tension because passive structures are being used less
A tendon will permit more force to be utilized for the movement of a bone more if:
a. It has more compliance b. It is longer c. It is shorter and thicker d. It has less stiffness
It is shorter and thicker
The following are true of a motor unit except?
a. Includes the cell motor neuron/cell body
b. Contains both small and large muscle fibers
c. Includes a myelin covered axon
d. When larger fires more rapidly
Contains both small and large muscle fibers
During an eccentric contraction, all are true except
a. The muscle is lengthening b. The resistance force is the muscle c. Z-lines are moving apart d. Positive work is being done
Positive work is being done
Where is active muscle tension less, fully shortened position or fully lengthened position?
Fully shortened
Sarcomeres have reduced potential for cross-bridge formation AND passive elastic components are slack
Your patient is barely able to initiate abduction of his arm from his side because of weakness (can only abduct about 10°). What exercise might your patient be able to do to strengthen the abductors?
a. Passively position the shoulder in some abduction to improve the length-tension relationship and allow for greater cross-bridge formation. Then, ask for eccentric contraction as arm is lowered back to side at a fairly rapid pace. These conditions advantage the abductor muscles for improved tension production.
b. Exercise the abductor muscles in other motions for which they serve as synergists. For example, the deltoid is a prime move in abduction, but the anterior deltoid will also be active in flexion while the posterior deltoid will also be active in extension. The rotator cuff muscles participate in abduction, but will also be active in external rotation.
c. Perform shoulder abduction in gravity-eliminated supine or prone position
In which position would the rectus femoris be likely to generate the greatest torque at the knee joint?
a. 90° of hip flexion and 0° knee flexion.
b. 90° of hip flexion and 135° knee flexion.
c. 90° of hip flexion and 45° of knee flexion.
d. 45° of hip flexion and 45° of knee flexion.
e. 45° of hip flexion and 0° knee flexion.
45° of hip flexion and 45° of knee flexion.
A muscle performing an eccentric contraction using a constant number of motor units is approaching optimal length while opposing a constant torque. As the contraction continues:
a. The acceleration of the lever will decrease. b. The acceleration of the lever will increase. c. The total muscle tension in the eccentric contraction will increase. d. The parallel elastic elements will contribute less to total muscle tension e. A and C
A and C
A muscle performing an eccentric contraction must be the:
a. Agonist b. Synergist c. Antagonist
Synergist
Does the CNS get information from the muscle spindle during an active muscle contraction (when the muscle spindle is slack)?
Yes
CNS sends info via gamma neurons to the spindle to CONTRACT which stretches the center of the spindle slightly
Then spindle is able to respond to length change in a shorter muscle
This is the reason why the CNS is always able to get info from the muscle spindle
A muscle spindle informs the CNS (central nervous system) about:
a. Stretch in an active muscle only (not in a passive
muscle).
b. Unloading (loss of tension) in the spindle in an
actively shortened muscle.
c. Anticipated stretch in a joint capsule.
d. An anticipated muscle contraction.
Unloading (loss of tension) in the spindle in an actively shortened muscle.
Muscle hypertrophy with resistance training is primarily due to:
a. Increase in the number myofibrils
b. Increase in conduction velocity of the nerve of the
muscle.
c. Increase the number of motor units in the muscle.
d. Increase in the number of Type I muscle fibers.
Increase in the number myofibrils
Well-applied resistance training in typical adults can be expected to do which of the following:
a. Increase tolerance to stress of tendons, ligaments, and muscle connective tissue. b. Decrease tolerance to stress of ligaments. c. Decrease is size of the muscle connective tissue in response to muscle fiber hypertrophy. d. Increase normal levels of bone mineral density.
Increase tolerance to stress of tendons, ligaments, and muscle connective tissue.
- Bone trabeculae will increase most in response to:
a. Compressive stresses in line with the long axis of the bone.
b. Stresses on the bone in a variety of directions.
c. Typical aging.
d. Excessive compressive stresses heading to injury.
Stresses on the bone in a variety of directions.
- Which of the following is associated with “feed-forward control” of movement?
a. Firing of the muscle spindle’s intrafusal fibers in
response to stretch
b. Firing of the extrafusal muscle fibers in response to
muscle spindle firing
c. Inhibition of GTO sensitivity
d. Shortening of the intrafusal fibers in response to
unloading (reduced firing)
Inhibition of GTO sensitivity
Tension in the parallel elastic elements of a muscle will be greatest when:
a. The muscle is actively contracting. b. The muscle is passive. c. The muscle is longest. d. The speed of a concentric contraction is slow.
The muscle is longest.
Which of the following would be likely to result in the MOST structural and functional changes to a muscle?
a. Performing periodic moderate resistance eccentric
contractions through the muscle’s full contractile
range.
b. Performing periodic moderate resistance
concentric contractions through the muscle’s full
contractile range.
c. Consistently using and maintaining a muscle in its
lengthened range.
d. Consistently using and maintaining a muscle in its
shortened range.
Consistently using and maintaining a muscle in its shortened range.
Which of the following situations (assuming constant speed through use of something like an isokinetic device) would produce the least muscle tension in the tested muscle that is using a constant number of motor units?
a. Slow eccentric contraction b. Slow concentric contraction c. Fast eccentric contraction d. Fast concentric contraction
ast concentric contraction
Motor units composed of Type IIb (IIx) fibers will have all of the following characteristics EXCEPT:
a. Large diameter axons.
b. High oxidative capacity.
c. High conduction velocity.
d. Rapid loss of tension.
High oxidative capacity.
If abduction flexion of the GH joint is limited in range of motion to a max of 60 degrees of abduction (due to a tight capsule), what would the maximum active composite GH and scapulothoracic abduction be?
a. 60 degrees b. 90 degrees c. 120 degrees d. 180 degrees
120 degrees
Which axis of motion does clavicular rotation occur in anatomically?
a. Anterior posterior
b. Longitudinal
c. Vertical
d. None of the above
Longitudinal/mediolateral
The cardinal signs of inflammation EXCEPT:
a. Erythema
b. Heat
c. Loss of function
d. Infection
Infection
Granulation tissue forms at what stage of healing
a. Inflammatory
b. Proliferative
c. Remodeling
d. Maturation
Proliferative
Tensile strength of collagen reaches 20% of normal in the healing process
a. Day 12
b. Day 21
c. 6 weeks
d. 8 weeks
Day 21
All of these factors can lower threshold for subsequent injury except
a. Inflammation
b. Atrophy
c. Previous injury
d. Hypertrophy
Hypertrophy
The typical order of sensations a patient will feel when performing an ice massage is:
a. intense cold, aching, burning, numbness, analgesia b. intense cold, burning, aching, analgesia, numbness c. intense cold, aching, burning, analgesia, numbness d. intense cold, burning, aching, numbness, analgesia
b. intense cold, burning, aching, analgesia, numbness
You have a patient with tight or shortened hamstrings. Along with other treatments you have decided to use heat as part of your plan of care. When in the treatment session would it be most beneficial to use the hot pack?
a. At the beginning of your treatment session b. In the middle of your treatment session between stretching techniques c. At the end of the treatment session d. It doesn’t matter when the hot pack is applied
a. At the beginning of your treatment session
You have a patient who presents with an acute tear of the plantaris muscle in the R calf (1 day ago). Acutely the patient has swelling, pain, and stiffness in the calf and has some difficulty walking without an assistive device. Initially you advise the patient to use a cold pack to help with the swelling and pain. The patient asks when they can switch to heat as opposed to using the cold pack. When is it appropriate to switch to heat?
a. You advise the patient to use cold for 24 hours before switching to heat
b. You tell the patient it does not matter whether they use heat or cold
c. You advise the patient to stay with the cold pack and you will advise them when they can switch to heat based on the end of the acute inflammation
d. You advise the patient to only use cold for 1 month and then switch to heat.
c. You advise the patient to stay with the cold pack and you will advise them when they can switch to heat based on the end of the acute inflammation
You have a patient you are going to treat with cryotherapy but you also need to do some strength testing of muscles in the same area. Why should strength testing be performed before the application of cryotherapy?
a. Because the patient may be uncomfortable after the application of cryotherapy b. Because muscle strength may be temporarily influenced by cryotherapy c. Both A and B d. None of the above
b. Because muscle strength may be temporarily influenced by cryotherapy
When using cryotherapy to control inflammation on the extremities, the time recommendation for the application of a cold pack is:
a. 5 or less minutes
b. 6-10 minutes
c. 10-14 minutes
d. 15-20 minutes
c. 10-14 minutes
Why is it important to screen a patient’s sensation before you apply a physical agent?
a. The screening helps you determine how to set specific parameters for the physical agent. b. The screening helps you determine if the patient’s sensations are impaired which presents a safety concern for the application of several physical agents. c. The screening helps you determine how long to apply the physical agent. d. None of the above
b. The screening helps you determine if the patient’s sensations are impaired which presents a safety concern for the application of several physical agents.
Cold can affect neuromuscular function in which of the following way(s)?
a. decrease nerve conduction velocity
b. elevate the pain threshold
c. altering muscle force generation
d. all of the aboved. all of the above
Which of the following is a precaution(not a contraindication) for cryotherapy?
a. applying over a regenerating peripheral nerve b. applying on the very young or very old c. cold intolerance d. Raynaud’s disease
b. applying on the very young or very old
11. Contraindications for the use of intermittent compression pumps include which of the following?
a. heart failure
b. pulmonary edema
c. obstructed lymphatic return
d. all of the aboved. all of the above
Effects of heat include which of the following?
a. vasoconstriction b. decrease in nerve conduction velocity c. vasodilation d. all of the above
c. vasodilation
You have a 60 y/o female patient who presents with rheumatoid arthritis. (RA) She reports not being in a flare up of her RA but is experiencing stiffness in her finger joints on both hands. You choose to treat with a paraffin dip and wrap heating technique. How many dips would you recommend prior to wrapping the hands?
a. 6-10
b. 1-5
c. 2-3
d. 11-14
a. 6-10
Which of the following are contraindications for the use of thermotherapy?
a. recent hemorrhage
b. impaired sensation
c. malignant tumor
d. all of the aboved. all of the above
What kind of pain do C fibers transmit?
AD fibers?
Dull, throbbing, aching, burning, tingling, tapping
Sharp, stabbing, pricking
Which type of pain fibers are reduced by opioids?
C fibers
Which pain fibers have a fast transmition of APs?
A-D fibers
Lateral spinothalamic
sharp pain, temperature
what might be touching?
where is it touching?
Anterospinothalamic
relays affective information to limbic + somatosensory for an emotional response
1) Paraesthesia
2) Dyesthesia
3) Hyperesthesia
4) Causalgia
5) Hypoesthesia
6) Allodynia
1) abnormal dermal sensation without cause
2) spontaneous unpleasant sensations
3) abnormal increase in sensitivity to sense
4) burning in limb from nerve damage
5) numbness
6) sensitivity to normally innocuous stimuli
Phases of healing?
Injury > Inflammation > Proliferation > Maturation
Phases of inflammation?
Vasoconstriction > vasodilation > clot formation > phagocytosis
(vascular response, hemostatic response, cellular response, immune response)
What happens during the Vascular Response?
1) Vasoconstriction
2) Vasodilation of non-injured vessels
3) Slowing of blood flow
4) Margination, pavementing, emigration of leukocytes
5) Edema
What is the fx of histamine in the inflammatory phase?
Hageman factor?
- Causes vasodilation and contributes to edema by attracting leukocytes to area
- activates clotting/coagulation to stop bleeding and increased permeability
Where does edema occur during healing phases?
Inflammation stage
What happens during the Hemostatic Response?
(Happens when vessel is damaged)
1) Sealing blood vessels
2) Platelets form clots and build a fibrin lattice
What happens during the Cellular Response?
(Main fx is to deliver leukocytes to clear debris)
1) Neutrophils are the 1st responders and are important in first 24 hrs
- Clears site of debris by eating
- Promotes inflammatory response
2) RBC carry O2
3) Monocytes (Macrophages) are the biggest hero in healing
- produce chemicals that facilitate tissue removal
- enhances collagen deposition
What happens during the Immune Response?
1) Mediated by humoral and cellular factors (b-cells and t-cells)
2) Increase vascular permeability, stimulate phagocytosis, chemotactic stimulus
What’s the function of B-cells?
T-cells?
(Within adaptive immune response)
- B cells: humoral, have antibodies and recognize antigens for binding
- T cells: cause inflammation, kill cells or activate cells that kill, check and balance b cells
What phase of injury is granulation tissue formed?
What type of collagen is it made of?
Proliferation phase
Starts as Type III but becomes Type I
What phase of healing does infection impair?
Inflammatory
When neutrophils die after digestion, become…
slough
What phase of healing is a chronic wound stuck in?
proliferative
What happens during the Proliferative Phase?
1) Collagen is produced in a weakened form (15% tensile strength) and creates Granulation Tissue
2) Fibroblasts produce GAGs and brings in more water
3) Neovascularization (creates new blood supply)
What happens during Maturation Phase?
1) Restoration of prior function
2) ALL ABOUT COLLAGEN ORGANIZATION
3) Decrease in cells that were cleaning debris
4) Need some tension for final tissue structure
Bioavailability
% of drug that reaches its target
