Physiology: Muscle Contraction (Schuske Block I)

Front 1

Skeletal muscle cells are _________ as a result of several cells fusing during develpment.

Back 1

Multinucleated

Front 2

Cardiac cells communicate directly with one another through __________.

Back 2

Gap Junctions

Front 3

______ ________ cells may contract individually or as whole units depending on their location and function.

Back 3

Smooth muscle

Front 4

Name the three components of the thin muscle filaments.

Back 4

1. Actin
2. Tropomyosin
3. Troponin

Front 5

The ________ protein binds to both the actin and tropomyosin, positioning the tropomyosin over the actin active sites.

Back 5

Troponin

Front 6

The ___________ stabilize the head region of the heavy chains and regulate ATPase activity.

Back 6

Light Chains

Front 7

This is a structure unique to skeletal muscle that converts the electrical action potential from the CNS to a chemical signal and then back to an electrical signal causing an AP across the muscle cell membrane.

Back 7

Myoneural Synapse

Front 8

Specialized region on the muscle cell sarcolemma with a high conc. of ACh receptors.

Back 8

Motor End Plate

Front 9

Only neurotransmitter of the skeletal muscle myoneural synapse.

Back 9

ACh

Front 10

The skeletal muscle AP takes longer than the nerve cell AP because the ______________ takes longer to completely repolarize.

Back 10

T-Tubule System

Front 11

The ___________ stabilize the head region of the heavy chains and regulate ATPase activity.

Back 11

Light Chains

Front 12

This is a structure unique to skeletal muscle that converts the electrical action potential from the CNS to a chemical signal and then back to an electrical signal causing an AP across the muscle cell membrane.

Back 12

Myoneural Synapse

Front 13

Specialized region on the muscle cell sarcolemma with a high conc. of ACh receptors.

Back 13

Motor End Plate

Front 14

Only neurotransmitter of the skeletal muscle myoneural synapse.

Back 14

ACh

Front 15

The skeletal muscle AP takes longer than the nerve cell AP because the ______________ takes longer to completely repolarize.

Back 15

T-Tubule System

Front 16

The skeletal muscle ______ are located in the regions where the A and I bands overlap in the sarcomere.

Back 16

Triads- so that calcium is released where the cross bridges form

Front 17

In both skeletal and cardiac muscle, an action potential depolarizes ________ channels in the T-tubule membrane.

Back 17

L-Type Calcium (Ryanodine Receptors)

Front 18

The RYR open after the ______ are depolarized and Calcium stores in the SR are released into the cytoplasm.

Back 18

DHPR

Front 19

________ muscle is able to contract without extracellular Ca2+ because the DHPR acts as a voltage senseor.

Back 19

Skeletal Muscle

Front 20

Fewer direct mechanical connections occur in the ______ muscle and CICR is essential for contraction.

Back 20

Cardiac

Front 21

Binds calcium to the thin filaments in both skeletal and cardiac muscle.

Back 21

Toponin C

Front 22

Complexes with Ca2+ and acivates MLCK to increase the force of contraction in heart cells. It is also the regulatory protein in smooth muscle.

Back 22

Calmodulin

Front 23

_______ binds calcium and its concentration is related to the speed of the muscle.

Back 23

Parvalbumin

Front 24

Binds Calcium and localizes it in the JSR.

Back 24

Calsequestrin

Front 25

Is a SR protein that, when phosphorylated, increases the SR Ca2+ ATPase activity.

Back 25

Phospholamban

Front 26

Two proteins important for Ca2+ resequestration into the SR.

Back 26

Calsequestrin and Phospholamban

Front 27

Ca2+ is sequestered into the SR by a Ca-ATPase pump, aka:

Back 27

SERCA

Front 28

When the SR calcium stores are exhausted the SR can signal the ______________ to increase influx of Ca2+.

Back 28

Store operated membrane channels.

Front 29

Calmodulin, not TnC is the calcium binding protein responsible for regulating ______ muscle contraction.

Back 29

Smooth (through activation of MLCK)

Front 30

In __________ contraction occurs when the contraction does not result in anatomical shortening of the muscle.

Back 30

Isotonic

Front 31

What happens to the tension in a muscle when it overcomes the load?

Back 31

Once it is great enough to overcome the load, no more tension develops.

Front 32

The increase in a load on a cross-bridge causes a decrease in the rate of ___________ and thus a slowing of the rate of cross bridge cycling.

Back 32

ATP hydrolysis

Front 33

What are the two mechanisms underlying summation of muscle contraction in skeletal muscle?

Back 33

1) less time for calcium to be re-sequestered so intracellular Ca2+ remains high
2) The muscle's elastic elements stay stretched

Front 34

Which muscle type has low amounts of myoglobin, few mitochondira, fast myosin ATPase, and fast SERCA

Back 34

Type II- Fast

Front 35

Which muscle type has high amounts of myoglobin, many mitochondira, slow myosin ATPase, and Slow SERCA

Back 35

Type I- Slow