Aminals Ii (8)

Front 1

Contraction

Back 1

conversion of chemical energy to mechanical energy

-allows locomotion, propulsion through body

Front 2

myofibers/muscle fibers

Back 2

cells that make up skeletal muscle, large, elongted cylinders; multiple nuclei, run in parallel

Front 3

myofibrils

Back 3

bundle up to make muscle fibers; made of myofilaments; the greater the density of myofibrils, the greater the force that can be generated

Front 4

components of myofibrils

Back 4

myosin(thick) and actin(thin) filaments>>myosin has big head with actin-binding site and myosin atpase

-actin strands have sites for myosin attachment, which are covered by tropomyosin when fiber is relaxed.

Front 5

troponin

Back 5

attaches to tropomyosin, contains Ca2+ binding site that alter configuration.

-when site is vacant, troponin stabilizes tropomyosin in blocking position

-when bound, troponin initiates atwist in tropomyosin that exposes myosin head attachment sites

Front 6

sarcomere

Back 6

repeating series of contractile segments within myofibrils

Front 7

sliding filament model of myofiber contraction

Back 7

actin filaments pulled by myosin heads toward center of sarcomere, resulting in contraction.

Front 8

4 step contraction cycle

Back 8

1) binding: myosin cross bridge binds to actin molecule

2) power stroke: cross bridge bends, pulling thin myoilament inward

3) detachment: cross bridge detatches at end of power stroke and returns to original conformation

4) binding cross bridge binds to more distal actin molecule; cycle repeats

Front 9

t tubules & contraction

Back 9

-t tubules are membrane proections between muscle fibers

-action potential enters fiber interior along t tubules

-action potential triggers release of Ca2+ from sarcoplasmic reticulum (SR) into cyosol; myofibrils flooded in Ca2+

-Ca2+ sequestered back into SR by Ca2+ ATPase pumps when AP stimulus subsides

-Ca2+ binds troponin, moving tropomosin and allowing cross bridge cycling during contraction

Front 10

endoskeleton

Back 10

tendons attack muscle to bones for leverage

Front 11

exoskeleton

Back 11

muscles attach directly to apodemes proecting from inner face of exoskeleton on overlying bone

Front 12

hydrostatic skeleton

Back 12

manipulation of fluid provides for tension generation and a dynamic form of leverage

Front 13

vertebrate v invertebrate tension control

Back 13

muscle fibers innervated by 1 motor neuron v muscle fibers innervated by more than one motor neuron

Front 14

2 stereotyped portions

Back 14

action potential strength, muscle fiber contractile strength

Front 15

motor unit size

Back 15

delicate movements: small motor unit; few fibers/motor unit

powerful movements: large motor unit; more fibers/motor unit

Front 16

tetanus

Back 16

smooth, sustained contraction - rapid ap firing; relaxation can't occur

Front 17

energy storage: vert v invert

Back 17

creatine phosphate; arginine phosphate

Front 18

fatigue

Back 18

typical stimulation produces decreased contractile response; fuel depletion(glycogen), increased adp, lactate, extracellular K+

Front 19

oxygen debt

Back 19

deep breathing after activity occurs; o2 is needed for energy systems (anabolism)

-conversion of lactate into pyruvate and two pyruvate into glucose

-replenish creatine phosphate

-replenish glycogen stores

Front 20

dark meat

Back 20

slow twitch oxidative fibers

-long lateny to peak tension

-high aerobic capacity; myoglobin, blood supply, mitochondira

-low glycogen

-high fatigue resistance

Front 21

white meat

Back 21

fast twitch glycolitic fibers

-short latency to peak tension

-low aerobic capacity

-low myoglobin, blood supply, mitochondira

-high glycogen and low resistance to fatigue

Front 22

effects of high intensity activities

Back 22

-increased synthesis of myosin and actin filaments

-increased size and %muscle mass of fast twitch fibers

Front 23

corticospinal motor systems

Back 23

fine motor control and conscious movement

Front 24

brainstem motor systems

Back 24

regulation of overall body posture, involuntary movements of trunk and limbs

Front 25

smooth muscle

Back 25

single long nucleus, no striations, does not contract all in one direction

Front 26

smooth muscle contraction

Back 26

when ca2+ binds to calmodulin, activates myosin light chain kinase that phosphorylates myosin and promotes cross bridge cycling

Front 27

catch state

Back 27

smooth muscle; tethered to maintain tension with low atp consumption; occurs after ACh withdrawn, serotonin relaxes catch

Front 28

multi-unit smooth muscle

Back 28

multiple neurons stimulating same organ; phasic

Front 29

single-unit smooth muscle

Back 29

1 neuron for entire smooth muscle, tonic with phasic "burts"; always partially contracted to some egree

Front 30

cardiac and skeletal similarities

Back 30

striated

t-tubules and SR

aerobic activity

Front 31

cardiac and smooth similarities

Back 31

self-excitable with basal tonic state

interconnected by gap junctions

innervated by autonomic nervous system