Muscle Physiology Flashcards Preview

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Flashcards in Muscle Physiology Deck (32):
0

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

Z-line

1

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

M line

2

Major protein in M line?

Myomesin

3

Dark area of myosin

A band

4

Light area of actin, thin myofilaments

I band

5

Myosin

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

6

Actin (f-actin)

Makes up thin myofilaments

Contain G actin, tropomyosin, and troponin

G actin twists in a double helix

7

Tropomyosin

Long thin stringlike molecule
Blocks myosin binding sites

8

Troponin

3 subunit complex

TnT attaches to tropomyosin
TnC binds calcium ions
TnI binds actin

9

Sarcoplasmic reticulum

Stores and regulates intercellular calcium

10

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

Terminal cisternae

11

T tubules? Why and what?

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.

12

Sliding filament model of contraction

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

13

Motor end plate

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

14

Neurotransmitter at myoneural junctions?

Acetylcholine

15

Junctional folds

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

16

Epicranius

Raises eyebrows

17

Characteristics of Muscle tissue

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

18

Epimysium

Dense irregular ct

19

Perimysium

Dense regular connective tissue

20

Endomysium

Areolar

21

Origin

Point of attachment to to immovable or less moveable bone

22

Insertion

Point if attachment to moveable bone

23

Direct and indirect origins and insertions

Direct- epimysium fused to periosteum or perichondrium
Indirect- via tendons or aponeuroses

24

Aponeuroses

Sheet like fibrous membrane

25

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

Glycosomes granules of stored glycogen

Myoglobin red pigment that carries oxygen

26

Sarcoplasmic reticulum does what important job?

Stores regulates and releases calcium

27

Power levers

Load is closer to the fulcrum than effort applied
Small effort can move a large load, but not very far proportionally

28

Speed levers

Effort is closer to the fulcrum than the load
Effort must be greater than the load to move it

29

First class lever

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

30

Second class levers

Fulcrum load effort
Always mechanical advantage by definition
Power lever

31

Third class lever

Load effort fulcrum
Speed lever
Mechanical disadvantage