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BIO 171 prof. Evans > Exam #3 > Flashcards

Exam #3 Flashcards

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Biology 101 flashcards
1
Q

What are two methods used to classify joints? What are the subclasses and descriptions?

A

Structural Classifications:

Fibrous = fibrous connective tissue
Cartilaginous = cartilage
Synovial = not joined directly

Functional Classifications:

Synarthrosis = immovable
Amphianthrosis = slightly movable
Diarthrosis = freely movable
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2
Q

What is the function of synovial fluid?

A

Synovial fluid is held in the cartilage, mechanically squeezed out, and lubricates the surface to reduce friction

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3
Q

What are the types of synovial joints? Axial? How do they move? Where are they found?

A

Plane joint = non-axial, slipping/gliding movement only (intracarpal joint)

Hinge joint = uniaxial, convex cylinder in one bone articulates with that of another (elbow joint)

Pivot joint = uniaxial, rotation on a single axis (proximal radiolnar joint)

Condyloid joint = biaxial, ovoid articulation (metacarpophangeal joint)

Saddle joint = biaxial, opposing surfaces are reciprocally concave-convex (carpometacarpal joint of thumb)

Ball & socket joint = multiaxial, one rounded bone fits into the cup-like depression of another bone (shoulder joint)

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4
Q

Muscle functions?

A

Movement of bones/blood

Maintaining posture and body position

Control of body openings and passages (vasodilation & vasoconstriction)

Heat generations (esp. in skeletal muscle) (vasoconstriction)

Glycemic control (reg. blood sugar levels)

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5
Q

What are the characteristics of muscle tissue?

A

Excitability (responsiveness or irritability): ability to receive and respond to stimuli

Contractility: ability to shorten when stimulated

Extensibility: ability to be stretched

Elasticity: ability to recoil to resting length

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6
Q

Organization of skeletal muscle?

A

Muscle tissue (cells / fibers)

Connective tissues

Nerves

Blood Vessels

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7
Q

Organization of connective tissue?

A

epimysium

perimysium

endomysium

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8
Q

What’s the role of the sarcomere?

A

… the functional unit of muscle contraction, separated by a dense material called Z lines.

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9
Q

What is the Z-line?

A

A dark thin protein band to which actin filaments are attached in myofibrils

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10
Q

What is the M-line?

A

runs through the exact center of the sarcomere

provide elasticity to the muscle

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11
Q

What are the binding sites on a myosin head? What do they do?

A

Binding site for actin to convert chemical energy, in the form of ATP, to mechanical energy.

Binding site for ATP (ATP hydrolysis, performs a power stroke associated with release of hydrolysis products, and detaches from actin upon binding with new ATP. )

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12
Q

What are the requirements for skeletal muscle contraction?

A

Activation: neural stimulation at a neuromuscular joint (NMJ)

Excitation-contraction coupling:
• Generation and propagation of an action potential along the sarcolemma

• Final trigger: a brief rise in intracellular Ca2+ levels

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13
Q

What are the steps of muscle relaxation?

A
  • Ach is broken down by AChE
  • SR recaptures Ca2+
  • Active sites covered, no cross-bridge formation
  • Contraction ends
  • Relaxation occurs, passive return to resting length
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14
Q

What are the steps in initiating muscle contraction?

A
  • Ach released, binding to receptors
  • Action potential reaches T-tubule
  • SR releases Ca2+
  • Active site exposure, cross-bridge formation
  • Contraction begins
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15
Q

Describe the sliding filament theory

A
  • In the relaxed state, thin and thick filaments overlap only slightly
  • During contraction, myosin heads bind to actin, detach, and bind again, to propel the thin filaments toward the M line
  • As H zones shorten and disappear, sarcomeres shorten, muscle cells shorten, and the whole muscle shortens
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16
Q

Define motor unit (diff. between small and large motor units)

A
  • Motor unit = a motor neuron and ALL (four to several hundred) muscle fibers it supplies
  • Small motor units in muscles that control fine movements (fingers, eyes) 1 neuron : 4-6 fibers
  • Large motor units in large weight-bearing muscles (thighs, hips) 1 neuron : 1000s fibers
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17
Q

Define muscle twitch. What are the phases?

A

… response of a fiber to a single stimulus

  • latent period = delay between activation of nerve and activation of muscle
  • contraction phase = cross-bridge formation, creates tension
  • relaxation phase = reabsorption of Ca into SR
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18
Q

What’s the difference between fused and unfused tetanus?

A

fused tetanus = force of contraction is smooth and constant because of very frequent APs (until fatigued)

unfused tetanus = force of contraction varies

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19
Q

Define tetanus

A

contraction of a muscle caused by stimuli (AP)

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20
Q

Define muscle tension

A

force of a muscle contraction

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21
Q

What is length-tension relationship?

A

amount of overlap between actin and myosin

too much overlap = not much force/tension

too little overlap = decreased froce/tension

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22
Q

How does the length of a sarcomere differ in the heart?

A

sarcomere length is shorter in the heart than in skeletal muscle, allowing heart to pump blood

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23
Q

What is motor unit recruitment?

A

same muscle to lift different masses (small mass = 5 fibers // large mass = 12 fibers)

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24
Q

What are the many differences between slow and fast twitch muscle fibers?

A 
large red slow twitch = 
(2 low glyco, 4 highs)
• low glycogen content
• low glycolytic capacity
• high fatigue resistance
• high capillary supply
• high mitochondria
• high myoglobin (carries oxygen)
• aerobic
• steady power
small white fast twitch =
(2 high glyco, 4 lows)
• high glycogen content
• high glycolytic capacity
• low fatigue resistance
• low capillary supply
• low mitochondria
• low myoglobin (carries oxygen)
• anaerobic
• explosive power

Most human muscles are mixed fibers, pink

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25
Q

Know the types of muscle contractions

A

Isotonic:
• concentric = muscle contracts, muscle opposes load (lifts)
• eccentric = muscle elongates, muscle holds load

Isometric = muscle contracts, cannot oppose load (cannot lift)

26
Q

What is Myostatin?

A

inhibits muscle differential, muscles stay are normal size

Myostatin deficiency, muscles get super toned without any regulation by Myostatin

27
Q

What is muscle metabolism for?

What are the types?

Sources of energy?

Time?

A

muscle metabolism is for the energy used in muscle contraction

  • Direct phosphorylation = coupled reaction of creatine phosphate and ADP. Anaerobic. 15s
  • Anaerobic respiration = glycolysis and lactic acid formation. Anaerobic (no O2 needed). 30-60s
  • Aerobic respitation = glucose, pyruvic acid, fatty acid. Aerobic (O2 required). Hours
28
Q

Describe muscle fatigue

A

Physiological inability to contact

Occurs when:
• Ionic imbalances (K, Ca, Pi) interfere with E-C coupling
• Prolonged exercise damages the SR and interferes with Ca regulation and release
• Total lack of ATP occurs, during states of continuous contraction

29
Q

Describe oxygen deficit/debt

A

Extra oxygen needed after exercise for:
• oxygen reserves
• glycogen stores
• ATP and CP reserves

Conversion of lactic acid to pyruvate acid, glucose, and glycolygen

30
Q

Describe heat production

A

~40% of the energy released in muscle activity is useful as work

remaining 60% given off as heat

dangerous heat levels prevented by radiation of heat from skin and sweating

31
Q

What does muscle performance depend on?

A

the distribution of muscle fibers

32
Q

ID the structure that coordinates skeletal movement

A

golgi tendon organ = prevents overstretching and tearing of tendon

muscle spindles (in muscle itself)

un-stretched muscle: APs are generated at a constant rate

stretched muscle: APs are generated at a high rate

33
Q

What are the two types of muscle pathology?

A

Neurogenic diseases
• Muscular Sclerosis = degeneration of myelin sheath
• Spinal muscular atrophy = degeneration of spinal muscle

Myopathic diseases:
• Muscular dystrophy
• Mitochondrea Myopathy

34
Q

What is eburnation?

A

the rubbing/friction of bone-on-bone

35
Q

What is atrophy?

A

shrinkage of muscle due to lack of use

36
Q

What is hypertrophy?

A

enlargement of muscle due to overuse

37
Q

What is Rigor Mortis?

A

no ATP to release myosin heads, muscles stay contracted as the cross-bridge formation remains

38
Q

What’s the difference between smooth and skeletal muscle contraction?

A

smooth = muscle contraction regulated by MLCK complex

skeletal = muscle contraction regulated by TTC complex

39
Q

Describe how mature muscle fiber becomes multinucleated

A

muscle fibers develop through the fusion of mesodermal cells called myoblasts

40
Q

What forms the triad?

A

T-tubule & 2x terminal cisternae

41
Q

What is transmembrane potential?

A

difference in electrical potential (voltage) across the membrane of a lining cell

42
Q

What is action potential (AP)?

A

nerve impulses that allow for muscle contraction

43
Q

Where are neurotransmitters found?

A

in vesicles in the motor neuron axon

44
Q

What is a threshold stimulus?

A

minimum strength (mV) to initiate a contraction

45
Q

What does “all-or-none response” mean?

A

the muscle fibers either contract or do not, there is no partial contraction

46
Q

What does a partial but sustained contraction describe?

A

muscle tone

47
Q

What attributes to the striated appearance of skeletal muscles?

A

repeating sarcomere units

48
Q

What transmits muscle impulses into the cell interior?

A

T-tubules

49
Q

What regulates Ca2+ levels? What is it called with Ca gates are opened/closed?

A

SR & T-tubules

open Ca gate = depolarization

closed Ca gate = repolarization

50
Q

What happens to muscle when there is no Ca present? … and with Ca present?

A

Without Ca, the muscle is relaxed because myosin heads cannot form cross-bridge

With Ca, the binding of Ca to troponin causes a shift in the TTC allowing cross-bridge formation

51
Q

What are the 7 steps of the NMJ?

A
  1. ) AP travels the length of the axon of a motor neuron to the axon terminal
  2. ) voltage gates Ca channels open, and Ca ions diffuse into the terminal
  3. ) Ca entry causes synaptic vesicles to release ACh via exocytosis
  4. ) ACh diffuses across synaptic cleft and binds to ACh receptors on ligand-gated cation channels
  5. ) ligand-gated cation channels open
  6. ) Na ions enter muscle fiber, K+ ions exit, causing AP to become less negative
  7. ) once the membrane potential reaches threshold value, an AP propagates along sarcolemma
52
Q

What are the 4 steps of the cross bridge cycle?

A
  1. ) cross-bridge formation = ATP hydrolysis to ADP, cocks myosin head
  2. ) cross bridge formation = myosin head attaches to actin in presence of Ca
  3. ) power stroke = shortening of sarcomere, pulling actin towards center (M-line)
  4. ) cross bridge detachment = ATP releases myosin from actin (Ca is then reabsorbed into SR)
  5. ) reactivation of myosin head =
53
Q

What is bronchoconstriction?

A

constriction of the airways in the lungs due to the tightening of surrounding smooth muscle

54
Q

What is bronchodilation?

A

expansion of bronchial air passages

55
Q

Describe smooth muscle contraction

A

slow, sustained contractions

non-voluntary

contain actin and myosin filaments

no striations, no sarcomeres

56
Q

What are the 4 steps in excitation-contraction coupling?

A
  1. ) Ca comes in from the ECF & SR
  2. ) Ca binds to calmodulin, making it active
  3. ) Calmodulin activates MLCK, giving it energy
  4. ) MLCK phosphorylates and cocks myosin head
57
Q

Describe the force of muscle contraction

A

force is affected by the relative size of the fibers (fiber diameter)

cell hypertrophy: increase of size and force of contraction)

cell hyperplasia (more cells)

58
Q

What are the 4 common muscle disorders?

A

Tetanus - permanent contraction

Botulism - no AP

Myasthenia gravis - low nerve stimulation

Lou Gehrig’s - ALS, degeneration of motor neurons

59
Q

What are the 5 ligaments in the shoulder joint?

A

coracoacromial

coracoclavicular

coracohumeral

glenohumeral

acromioclavicular

60
Q

What are the 5 ligaments in the knee joint?

A

fibular collateral

tibial collateral

posterior cruciate

anterior cruciate

patellar ligament

61
Q

What are the three different layers of connective tissue in a muscle?

A

perimysium

epimysium

endomysium

BIO 171 prof. Evans (12 decks)

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