40A - Lecture - Chapter #10

Question 1

Function of muscle tissue

Answer 1

1. Produce motion
2. Stabilize body position
3. Storing and moving substances within body

Question 2

Entire Skeletal Muscle

Answer 2

Connective Tissue is epimysium

Question 3

Fascicles

Answer 3

Connective Tissue is Perimysium

Question 4

Muscle Fiber

Answer 4

(Also known as muscle cell)

Connective Tissue is Endomysium

Question 5

Myofibrils

Answer 5

Inside cell
No connective tissue
Contains fillaments (think and thin)

Question 6

Fascia

Answer 6

Holds muscles with similar functions together

Question 7

3 Layers that extend from fascia

Answer 7

1. Epimysium
2. Preimysium
3. Endomysium

Question 8

Sarcolemma

Answer 8

Plasma membrane of muscle fiber, goes / extends around myofibrils

Question 9

Transverse Tubule (T-Tubules)

Answer 9

Inward continuation of sarcolemma inside the cell

Question 10

Sarcoplasm

Answer 10

Cytoplasm of muscle fiber
Contains:
1. Glycogen
2. Myoglobin

Question 11

Sarcomere

Answer 11

Z disc to Z disc

Question 12

Fillaments

Answer 12

All proteins; contractile elements

Thick (myosin) and thin (actin + regulatory proteins (tropomyosin and toponin))

Question 13

Sarcoplasmic Reticulum

Answer 13

Function:

1. Store Ca+2 when muscle is relaxed
2. Release Ca+2 when muscle contracts

Question 14

Contractile Protein (within Myofibril)

Answer 14

Generate force during contraction. Thick fillament (myosin) and thin fillament (action, troponin, and tropomyosin)

Question 15

Structural Protein (within Myofibril)

Answer 15

Titan and Dystrophin

Question 16

Titan

Answer 16

Gives elasticity, resembles a coiled spring, hold sarcomere together

Question 17

Dystrophin

Answer 17

Link to sarcolemma to strengthen it; transmit tension generated by sarcomere to the tendon

Question 18

Contraction Cycle

Answer 18

1. ATP hydrolysis
2. Attachment of myosin to actin
3. Power Stroke
4. Detachment of myosin from actin

Question 19

ATP hydrolysis (from contraction cycle)

Answer 19

Myosin heads hydrolyze ATP and become reoriented and energized. Uses E2 to pivot myosin tail so head can reach the thin fillament

Question 20

Attachment of myosin to actin ( from contraction cycle)

Answer 20

Myosin binds to actin, forming a cross-bridge. Phosphate drops from myosin

Question 21

Power Stroke (from contraction cycle)

Answer 21

Myosin moves actin / thin fillament in incraments.

Myosin head pivots to move towards center of sarcomere

Question 22

Detachment of myosin (from contraction cycle)

Answer 22

As myosin heads bind ATP, the cross-bridge detach.

Uses ATP to disconnect myosin and actin

Question 23

4 functions of ATP in muscle contraction

Answer 23

1. ATP hydrolysis
2. Detachment of myosin and action
3. Drive the Ca+2 active transport pumps. Brings Ca+2 back inside sarcoplasmic reticulum
4. Runs the Na+/K+ ATPase pump. Helps maintain the resting membrane potential

Question 24

Hypertrophy

Answer 24

Increase size and mass of muscle fiber by making more myofibrils

Question 25

Atrophy

Answer 25

Decrease in size due to decrease in muscle mass which decreases myofibril

Question 26

Why do the Ca+2 channels open?

Answer 26

Muscle action potential along tubules open channels

Question 27

Relaxation of muscle

Answer 27

1. Break down Ach in synaptic cleft
2. Block Ach release from motor neuron
   Ex: Botox
3. Block Ach receptor on motor end plate of sarcolemma
4. Black nerve action potential

Question 28

Contraction of muscle

Answer 28

1. Nerve action potential of somatic motor neuron then Ach is released
2. Ach binds to Ach receptor
3. Muscle action potential
4. Ach esterase inhibitor
   Anticholinesterase will knock out Ach esterase