Muscle Physiology

Question 0

Anchor for thick filaments (myosin) that lies between the h-zone, a lighter staining area in the midst of the dark A band

Answer 0

M line

Question 1

Anchor for thin filaments (actin). A dark line in the light-colored I band.

Answer 1

Z-line

Question 2

Major protein in M line?

Answer 2

Myomesin

Question 3

Dark area of myosin

Answer 3

A band

Question 4

Light area of actin, thin myofilaments

Answer 4

I band

Question 5

Myosin

Answer 5

Makes up thick myofilaments
Rodlike tail, 2 globular heads
Heads contain binding sites for actin and ATP

Question 6

Actin (f-actin)

Answer 6

Makes up thin myofilaments

Contain G actin, tropomyosin, and troponin

G actin twists in a double helix

Question 7

Tropomyosin

Answer 7

Long thin stringlike molecule

Blocks myosin binding sites

Question 8

Troponin

Answer 8

3 subunit complex

TnT attaches to tropomyosin
TnC binds calcium ions
TnI binds actin

Question 9

Sarcoplasmic reticulum

Answer 9

Stores and regulates intercellular calcium

Question 10

What is at the junction of A bands and I bands?

Answer 10

Terminal cisternae

Question 11

T tubules? Why and what?

Answer 11

Finger like invaginations of the sarcolemma form a complex network of tubules that encircle every myofibril near the (A-I) band boundaries aka terminal cisternae of each sarcomere. Why? Uniform release of calcium ions to promote uniform contraction of the muscle. The myoneural junction is only at one spot, but the transverse tubule system helps with uniformity.

Question 12

Sliding filament model of contraction

Answer 12

Thin filaments slide past thick filaments.
I band size decreases as thin filaments penetrate the a band.
H band nearly disappears
Sarcomere a shorten
A bands move closer together but length is the same

Question 13

Motor end plate

Answer 13

On the muscle, a structure if muscle
The axon meeting here is only covered by a thin cytoplasmic extension from a Schwann cell

Junctional folds

Question 14

Neurotransmitter at myoneural junctions?

Answer 14

Acetylcholine

Question 15

Junctional folds

Answer 15

The wrinkly area of the ms plate, sarcoplasmic wrinkles increase surface area

Question 16

Epicranius

Answer 16

Raises eyebrows

Question 17

Characteristics of Muscle tissue

Answer 17

Excitability(receive and respond to stimuli)
Contractility (can shorten when stimulated)
Extensibility (can stretch)
Elasticity (can return to original shape)

Question 18

Epimysium

Answer 18

Dense irregular ct

Question 19

Perimysium

Answer 19

Dense regular connective tissue

Question 20

Endomysium

Answer 20

Areolar

Question 21

Origin

Answer 21

Point of attachment to to immovable or less moveable bone

Question 22

Insertion

Answer 22

Point if attachment to moveable bone

Question 23

Direct and indirect origins and insertions

Answer 23

Direct- epimysium fused to periosteum or perichondrium

Indirect- via tendons or aponeuroses

Question 24

Aponeuroses

Answer 24

Sheet like fibrous membrane

Question 25

Special organelles within the muscle fiber (cell) sarcoplasmic contains…

Answer 25

Glycosomes granules of stored glycogen

Myoglobin red pigment that carries oxygen

Question 26

Sarcoplasmic reticulum does what important job?

Answer 26

Stores regulates and releases calcium

Question 27

Power levers

Answer 27

Load is closer to the fulcrum than effort applied

Small effort can move a large load, but not very far proportionally

Question 28

Speed levers

Answer 28

Effort is closer to the fulcrum than the load

Effort must be greater than the load to move it

Question 29

First class lever

Answer 29

Fulcrum in middle

Advantage or disadvantage, depends on location of the in-between lever

Question 30

Second class levers

Answer 30

Fulcrum load effort
Always mechanical advantage by definition
Power lever

Question 31

Third class lever

Answer 31

Load effort fulcrum
Speed lever
Mechanical disadvantage