Term
| What are the three types of muscles? |
|
Definition
| skeletal, cardiac, and smooth muscle |
|
|
Term
| What two structural groups can the three types of muscle be placed into? |
|
Definition
| striated and unstriated muscle |
|
|
Term
| What type(s) of muscle are striated? |
|
Definition
|
|
Term
| What type(s) of muscle are unstriated? |
|
Definition
|
|
Term
| What type(s) of muscle are voluntary? |
|
Definition
|
|
Term
| What type(s) of muscle are involuntary? |
|
Definition
|
|
Term
| Skeletal muscles fall under the ________ nervous system. |
|
Definition
|
|
Term
Cardiac and smooth muscles fall under the ________ nervous system.
|
|
Definition
|
|
Term
| What does skeletal muscle look like? |
|
Definition
| it is long, straited, and has multiple nuclei |
|
|
Term
| What is the most common location of skeletal muscle? |
|
Definition
|
|
Term
| What is the function of skeletal muscle? |
|
Definition
| contraction for voluntary movements |
|
|
Term
| What does smooth muscle look like? |
|
Definition
| it is long, has spindle-shaped cells, and each cell has a single nucleus |
|
|
Term
| What is the most common location of smooth muscle? |
|
Definition
| in hollow organs such as the stomach and intestines |
|
|
Term
| What is the main function of smooth muscle? |
|
Definition
| propulsion of substances along internal passageways |
|
|
Term
| What does cardiac muscle look like? |
|
Definition
| it branches and it has striated cells that are fused at the plasma membranes, also has more than one nucleus per cell |
|
|
Term
| What is the most common location of cardiac muscle? |
|
Definition
|
|
Term
| What is the main function of cardiac muscle? |
|
Definition
| pumping of blood in the circulatory system |
|
|
Term
| What is the activity of skeletal muscles like? |
|
Definition
| strong, quick, discontinuous voluntary contraction |
|
|
Term
| What is the activity of cardiac muscle like? |
|
Definition
| strong, quick, continuous involuntary contraction |
|
|
Term
| What is the actvity of smooth muscle like? |
|
Definition
| weak, slow, involuntary contraction |
|
|
Term
| Can muscle cells be regenerated? Explain. |
|
Definition
| smooth muscle can be regenerated but skelatl and cardiac muscle cannot be regenerated |
|
|
Term
|
Definition
| a connective tissue that connects skeletal muscle to bone |
|
|
Term
|
Definition
| fibrous connective tissue around the belly of skeletal muscle |
|
|
Term
|
Definition
| a single skeletal muscle cell |
|
|
Term
|
Definition
| the membrane surrounding the muscle fiber |
|
|
Term
|
Definition
| the specialized cytoplasm of muscle fiber containing multiple nuclei and mitochondria |
|
|
Term
|
Definition
| a contarctile protein that forms the backbone of the thin filaments in the muscle fiber |
|
|
Term
|
Definition
| a contractile protein that forms the backbone of the thick filaments in muscle fiber |
|
|
Term
|
Definition
| it is the smallest contarctile unit of skeletal muslce; an individual cell is made up of many sarcomeres |
|
|
Term
|
Definition
| it's the end of a sarcomere |
|
|
Term
|
Definition
| its the beginning of myosin to the end of the myosin held together by the M line |
|
|
Term
|
Definition
| the end of one actin filament to the beginning of the next actin filament in the same sarcomere |
|
|
Term
|
Definition
| it bisects the sarcomere and anchors two adjacent myosing myofilaments together (center of H zone) |
|
|
Term
|
Definition
| it is an area in two adjacent sarcomere that only contain actin myofilaments |
|
|
Term
|
Definition
| rod-like structures running through the middle of muscle fibers that contain the contractile proteins actin and myosin that give the skeletal muscles the striated appearance |
|
|
Term
| How long and wide are myofibrils? Give an example. |
|
Definition
- it depends on the size of the muscle fiber and the muscle fibers location; there is a wide range of lengths and diameters
- for ex, in the retina the myofibrils are very small because the retina requires precise control
|
|
|
Term
| What are actin myofilaments? |
|
Definition
| they contain actin with actin binding sites that are covered by tropomyosin that has strategically located sites of troponin protein onto which calcium ions have high affinity for |
|
|
Term
| What do myosin filaments look like? |
|
Definition
| they contain globular heads with two binding sites |
|
|
Term
| What are the two binding sites that myosin filaments have? |
|
Definition
| actin and ATPase binding sites |
|
|
Term
| What are thick filaments made out of? |
|
Definition
|
|
Term
| What are thin filaments made up of? |
|
Definition
| primarily actin (and a little troponin and tropomyosin) |
|
|
Term
| What are the levels of organization in a skeleatl muscle going from largest to smallest? |
|
Definition
| whole muscle, muscle fiber, myofibril, thick and thin filaments, and myosin and actin |
|
|
Term
| What part of the myofibril makes up the dark band? |
|
Definition
|
|
Term
| What part of a myofibril makes up the light band? |
|
Definition
|
|
Term
| One thick filament is surrounded by _____ thin filaments. |
|
Definition
|
|
Term
| One thin filament is surrounded by _______ thick filaments. |
|
Definition
|
|
Term
Myosin is _________ shaped and have two ___________.
Their _______ are intertwined around eachother. |
|
Definition
| golf club, identical subunits, tail ends |
|
|
Term
| What is the function of tropomyosin? |
|
Definition
| it keeps out muscles in a blocked state by blocking the binding site for myosin |
|
|
Term
| What is the main mechanism behind muscle contraction? |
|
Definition
| cycles of cross-bridging binding and bending which pull the thin thin filaments closer together between the stationary thick filaments, causing shortening of the sarcomeres |
|
|
Term
| During muscle contraction, does the H zone change in length? Explain. |
|
Definition
|
|
Term
| During muscle contraction does the A band become shorter? Explain. |
|
Definition
| no, it stays the same width |
|
|
Term
| During muscle contraction, does the I band change width? Explain. |
|
Definition
|
|
Term
| During muscle contraction, what happens during the binding phase? |
|
Definition
| the myosin cross bridge binds to an actin molecule |
|
|
Term
| During muscle contraction, what happens during the power stroke phase? |
|
Definition
| the cross bridge bends towards the center of the sarcomere, pulling the thin myofilament inward |
|
|
Term
| During muscle contraction, what happens during the detachment phase? |
|
Definition
| the cross bridge detaches at the end of the power stroke and returns to its original conformation |
|
|
Term
| During muscle contraction, what happens during the second binding phase? |
|
Definition
| the cross bridge binds to a more distal actin molecule and the cyle repeats |
|
|
Term
| How is complete shortening of the sarcomere accomplished? |
|
Definition
| by repeated cycles of cross bridge binding and bending |
|
|
Term
| ________ is the link between excitation and contraction. |
|
Definition
|
|
Term
| What is needed in order for the ATP to detach from the ATPase binding site on the myosin head? |
|
Definition
|
|
Term
| If cattle don't have enough magnesium in their diet what can happen? Explain. |
|
Definition
| grass tetany; if a cow is put out on a fresh spring pasture there may not be enough magnesium in the grass so the cattle will be unable to relax their muscles because there will be no way to detach ATP from the ATPase binding site |
|
|
Term
| What causes rigor mortis? |
|
Definition
| after death, the cells stop making ATP so the cytosolic concentration of calcium begins to rise as calcium leaks in which cause the actin binding sites to be exposed so that myosin binds to them and begins muslce contractions |
|
|
Term
| What is the organelle that stores calcium in muscle cells? |
|
Definition
| the sarcoplasmic reticulum |
|
|
Term
| Are myosin, troponin, tropomyosin, and actin located in other cells aside from muscle cells? |
|
Definition
| yes, just in smaller amounts |
|
|
Term
| What does calcium bind with in order to start cross bridging? |
|
Definition
|
|
Term
| What are the steps involved in muscle contraction from the iniation of an action potential to binding of the calcium? |
|
Definition
- action potential arrives at the terminal button of the neuromuscular junction which stimulates release of acetylcholine, which diffuses across the cleft and triggers an action potential in the muscle fiber
- the new action potential moves across the surface of the membrane and into the muscle fiber's interior through T tubules. An action potential at the T tubule triggers the release of calcium from the sarcoplasmic reticulum into the cytosol
- the calcium binds to troponin on the thin filamnents
|
|
|
Term
| What are the steps involved in muscle contraction from calcium binding to the power strokes? |
|
Definition
- binding of calcium to troponin causes tropomyosin to change shape uncovering the actin binding sites for the myosin cross bridges
- myosin cross bridges attach to the actin binding site
- the binding triggers the cross bridge to bend, pulling the thin filament over the thick filament toward the cneter of the sarcomere . Thsi power stroke is powered by ATP
|
|
|
Term
| What are the steps involved in muscle contraction from after the power stroke to relaxation? |
|
Definition
- after the power stroke, the cross bridge detaches from the actin. If calcium is still present, the myosin bridges reattach to another actin binding site
- when the action potentials stop, calcium is taken back up by the sarcoplasmic reticulum. With no calcium, troponin recovers the actin binding sites so contraction stops and the thin filaments passively slide back to their original relazed positions
|
|
|
Term
| Explain the steps involved with muscle contraction in terms of the ATPase binding site. |
|
Definition
- ATP is split by myosin ATPase; ADP and P remain attached to the myosin and this energy is stored in the cross bridge
- when calcium is released the cross bridge binds with the actin
- during cross bridging P is released and ADP is released after the stroke
- the linkage between actin and myosin is then broken as a fresh molecule of ATP bind to the myosin cross bridge; the cross bridge then assumes the original conformation
- ATP is hydrolyzed again and the cycle repeats
|
|
|
Term
| What does the sarcoplasmic reticulum look like? |
|
Definition
| it looks like weebing that surrounds the myrofibrils; it has lateral sacs and surrounds the transverse (T) tubules |
|
|
Term
| Where are T tubules located? |
|
Definition
| on both ends of the A band (inbetween the A bands and I bands) |
|
|
Term
| How does the calcium get back into the sarcoplasmic reticulum? What part of the sarcoplasmic reticulum does it return to? |
|
Definition
| via active transport (Ca2+ ATPase pump); it returns to the lateral sacs |
|
|
Term
| What is key to muscle relaxation? |
|
Definition
|
|
Term
| In high speed muscles how does relaxation occur? Give an example of an animal that this happens in? |
|
Definition
| calcium binding proteins attach to the calcium and make it unavailable so the muscle can relax; hummingbird wings |
|
|
Term
| How many axons are there per muscle fiber? |
|
Definition
|
|
Term
| What is the name of the theory that describes how actin slides over myosin during muscle contraction? |
|
Definition
|
|
Term
| How does the duration of contarctile activity compare to the electrical activity that initiated it? |
|
Definition
| contractile activity far outlasts the electrical activity |
|
|
Term
| Whole muscles are groups of _________ bundled together by _____________, often attached to _______ elements in ____________ pairs. |
|
Definition
| muscle fibers, connective tissue, skeletal, antagonistic |
|
|
Term
|
Definition
| connective tissue that connects muscle to bone |
|
|
Term
| What are antagonistic pairs? Give an example. |
|
Definition
| two muscles that oppose eachother to move the body in opposite directions; biceps and triceps- when the bicep is contracted, the tricep must be relaxed |
|
|
Term
| What affects the strength of whole muscle contractions? |
|
Definition
| the number of muscle fibers contracting within a muscle and the tension developed by each contracting fiber |
|
|
Term
| What does the number of fibers contracting within a vertebrae muscle depend on? |
|
Definition
| the extent of motor unit recruitment |
|
|
Term
|
Definition
| it is made up of concurrently activating muscle fibers that are all innervated by the same motor neuron |
|
|
Term
| If there are less fibers per motor unit, what kind of muscle control does this result in? Give and example. |
|
Definition
| weak, precise control; retinal muscles (few dozen fibers) |
|
|
Term
| If there are more fibers per motor unit, what does this result in? Give an example. |
|
Definition
| strong, rough control; mammalian legs (150- 2000 fibers) |
|
|
Term
| What four things influence the tension developed by each vertebrae skeletal muscle fiber? |
|
Definition
- frequency of stimulation
- length of fiber at onset of contraction
- extent of fatigue
- thickness of fiber
|
|
|
Term
|
Definition
| smooth, sustained contraction of maximal strength (not the disease) |
|
|
Term
| When the cross bridges unbind from the actin sites so that further contraction can occur, how come the whole muscle doesn't go back to its original conformation? |
|
Definition
| because cross bridging of different motor units occurs at alternating times so that there is always cross bridging occuring |
|
|
Term
| What provides the energy for the power stroke of the cross bridge? |
|
Definition
| splitting of ATP by myosin ATPase |
|
|
Term
| What permits detachment of the cross bridge from the actin filament at the end of the power stroke? |
|
Definition
| binding of a fresh molecule of ATP to myosin |
|
|
Term
| What are the three different steps of contraction-relaxation that require ATP? |
|
Definition
- splitting of ATP by myosin ATPase which indirectly provides the energy for the power stroke of the cross bridge
- binding of a fresh molecule of ATP to myosin to permit detachment. This ATP is subsequently split to provide energy for the next power stroke
- the active transport of calcium back into the sarcoplasmic reticulum
|
|
|
Term
| What happens to the fresh molecule of ATP that binds to myosin to permit detachment? |
|
Definition
| it is subsequently split to provide energy for the next stroke of cross bridge |
|
|
Term
| What are the three alternate pathways that muscle fibers have for producing ATP? |
|
Definition
| phosphogens, oxidative phosphorylation, and glycolysis |
|
|
Term
| What are the two types of phosphogens? Which one is used by vertebrates? |
|
Definition
| creatin phosphate and arganine phosphate; creatine phosphate is used by vertebrates |
|
|
Term
| How do phosphogens create ATP? |
|
Definition
creatine phosphate + ADP →(via creatin kinase) creatin + ATP
this reaction is reversible |
|
|
Term
| How long does the ATP from phosphogens last? |
|
Definition
|
|
Term
| What is an advantage and disadvantage of using phosphogens? |
|
Definition
| it is the quickest way to get ATP but we don't store much creatine phosphate so it doesn't last very long |
|
|
Term
| What is required for oxidative phosphoyrylation? Why? |
|
Definition
| oxygen because it an aerobic process |
|
|
Term
| What steps of cellular respiration involve oxidative phosphorylation? |
|
Definition
| citric acid cycle and the ETC |
|
|
Term
| What type of process is glycolysis? Why? |
|
Definition
| anaerobic because it doesn't require oxygen |
|
|
Term
| How does glycolysis produce ATP? |
|
Definition
|
|
Term
| What is a by-product of anearobic respiration? How does this happen? |
|
Definition
| lactic acid; pyruvic acid + NADH → lactic acid + NAD+ |
|
|
Term
| What is an advantage and disadvantage of glycolysis? |
|
Definition
| it is the fastest way to produce ATP because there are fewer steps but it produces lactic acid which can contribute to muscle fatigue |
|
|
Term
| What are the three main causes of muscle fatigue? |
|
Definition
- a local increase of phosphate (may interfere with cross bridging or calcium release/reuptake by the sarcoplasmic reticulum)
- accumulation of lactic acid
- depletion of energy reserves
|
|
|
Term
| What is necessary to recover from activity? |
|
Definition
| increased oxygen concumption |
|
|
Term
| Why do many animals pant? |
|
Definition
| it helps increase oxygen consumption |
|
|
Term
| What does lactic acid do? |
|
Definition
|
|
Term
| What happens to the lactic acid that is produced during anearobic glycolysis? |
|
Definition
| it is converted back to pyruvic acid which can be used to make ATP or be converted back into glucose |
|
|
Term
| What are the three types of skeletal muscle fibers? |
|
Definition
- slow oxidative fibers (Type I)
- fast oxidative fibers (Type IIa)
- fast glycolytic fibers (Type IIb, IId, or IIx)
|
|
|
Term
| What color are slow oxidative fibers (Type I)? |
|
Definition
|
|
Term
| What two factors determine the speed at which a muscle contracts? |
|
Definition
| the load and the myosin ATPase activity of the contracting fibers |
|
|
Term
| What color are fast oxidative muscle fibers? |
|
Definition
|
|
Term
| What color are fast glycolytic muscle fibers? |
|
Definition
|
|
Term
| What type of muscle fiber is being used when a horse trots? What is the energy source for this? |
|
Definition
|
|
Term
| What type of muscle fiber is used when a horse walks? What is the energy source for this? |
|
Definition
|
|
Term
| What type of muscle fiber is used when a horse gallops? What is a by-product of this? |
|
Definition
| Type IIb, d, & x; lactic acid |
|
|
Term
| Why are Type II muscle fibers used when the horse does higher energy work? |
|
Definition
| because they can produce ATP faster |
|
|
Term
| What is the difference between fast and slow fibers? |
|
Definition
| in fast fibers there is more myosin ATPase activity |
|
|
Term
| What is the structural difference between oxidative and glycolytic fibers? |
|
Definition
| glycolystic fibers contain fewer mitochondria but more glycolytic enzymes |
|
|
Term
| What is the speed of contraction like in slow oxidative, fast oxidative, and fast glycolytic fibers like? |
|
Definition
|
|
Term
| How does the resistance of fatigue compare in slow, oxidative, fast oxidative, and fast glycolystic? |
|
Definition
|
|
Term
| How does the amount of anaerobic glycolytic enzymes compare in slow oxidative, fast oxidative, and fast glycoytic fibers? |
|
Definition
|
|
Term
| How does the amount of capillaries compare in slow oxidative, fast oxidative, and fast glycolytic muscle fibers? |
|
Definition
|
|
Term
| How does the myoglobin content compare in slow oxidative, fast oxidative, and fast glycolytic muscle fibers? |
|
Definition
|
|
Term
| How does the glycogen content compare in slow oxidative, fast oxidative, and fast glycolytic muscle fibers? |
|
Definition
|
|
Term
| Why do slow and fast oxidative muscle fibers appear to be red? |
|
Definition
| because they have a high myoglobin content |
|
|
Term
| Through what mechanism do muscles enlarge? What is this? |
|
Definition
| hypertrophy; growth by increasing cell size |
|
|
Term
| What is hyperplasia? Does this happen in muscles? |
|
Definition
| growth by increased cell number; no |
|
|
Term
| Do all muscle types (skeletal, smooth, cardiac) use the sliding filament mechanism? |
|
Definition
|
|
Term
| Do hormones affect all three muscle types? Explain. |
|
Definition
| no; hormones do not affect skeletal muslce |
|
|
Term
| Are all muscle types made up of thin and thick filaments? |
|
Definition
|
|
Term
| Is there troponin and tropomyosin in all muscle types? |
|
Definition
| there is both in skeletal and cardiac muscles but smooth muscles only have tropomyosin |
|
|
Term
| Do all muscle types have T tubules? Explain. |
|
Definition
| no, smooth muscle does not |
|
|
Term
| What is the source of increased cytosolic concentration in the muscle types? |
|
Definition
skeletal: sarcoplasmic reticulum
smooth and cardiac: sarcoplasmic reticulum and extracellular fluid |
|
|
Term
| Because smooth muscle has only tropomyosin and not troponin what is the cite of calcium regulation? |
|
Definition
| myosin in the thick filaments |
|
|
Term
| Because there is only tropomyosin in smooth muscle, what is the mechanism of calcium action in smooth muscle? |
|
Definition
| the calcium chemically brings about phosphorylation of myosin cross bridges so they can bind with actin instead of physically repositioning the troponin-tropomyosin complex |
|
|
Term
| How does the myosin ATPase activity compare in skeletal, smooth, and cardiac muscles? |
|
Definition
| depends on fiber, very slow, slow |
|
|
Term
| How does the length of a skeletal muscle fiber compare to the length of the muscle as a whole? |
|
Definition
|
|
Term
| Smooth muscle filaments do not form _________. What doe this result in? |
|
Definition
| myofibrils; unstriated muscle |
|
|
Term
| What is the primary difference between miltiunit smooth muscle and single unit smooth muscle? |
|
Definition
| multiunit smooth muscle contracts in a way as if it had motor untis like skeletal muscle but single unit smooth muscle contracts as a single unit |
|
|
Term
| Multiunit smooth muscle is neurogenic. What does this mean? |
|
Definition
| it means that it must recieve an electrical impulse in order to contract |
|
|
Term
| Single unit smooth muscles are myogenic. What does this mean? |
|
Definition
| it means it is self-excitable and does not need nervous stimulation for contraction because they generate their own |
|
|
Term
| Is the initiation of contraction in skeletal muscles neurogenic or myogenic? |
|
Definition
|
|
Term
| Is the initiation of contraction in cardiac muscle neurogenic or myogenic? |
|
Definition
| myogenic (own pace maker) |
|
|
Term
| Does skeletal muscle have gap juntions? |
|
Definition
|
|
Term
| Does smooth muscle have gap junctions? |
|
Definition
|
|
Term
| Does cardiac muscle have gap junction? |
|
Definition
|
|
Term
| What mechanism is the presence of gap junctions in different muscle types likely related to? |
|
Definition
| myogenic initiation of contraction because groups of muscle cells need to talk to eachother |
|
|
Term
| Is ATP used by all muscle types? |
|
Definition
|
|
