Skeletal Muscles

Question 1

Skeletal Muscles

Answer 1

Intrafusal (5%)

Extrafusal (95%)

Question 2

detects changes in muscle LENGTH

Answer 2

Intrafusal

innervation: GAMMA motorneurons

Question 3

for VOLUNTARY MUSCLE CONTRACTION

Answer 3

Extrafusal

innervation: ALPHA motorneurons

Question 4

2 types of Extrafusal

Answer 4

TYPE I

TYPE II

Question 5

slow twitch
red fiber
greater myoglobin and mitochondria
oxidative phosphorylation --> sustained contraction
for ENDURANCE training

Answer 5

TYPE I

postural muscles of the back

Question 6

fast twitch
white fiber
anaerobic glycolysis
less myoglobin and mitochondria
for WEIGHT/RESISTANCE training, SPRINTING

Answer 6

TYPE II

Question 7

(+) gap junctions, (+) syncytium for GROSS motor movement

Answer 7

UNITARY SMOOTH MUSCLES

i.e. uterus

Question 8

(-) gap junctions, for FINE motor movement

Answer 8

MULTI UNIT SMOOTH MUSCLES

i.e. pupil cells

Question 9

Functional, structural and contractile unit of skeletal and cardiac muscles

area b/w 2 Z lines

Answer 9

sarcomere

Question 10

Contains MYOSIN that act as CROSS BRIDGES of the sarcomeres

Answer 10

THICK FILAMENTS

1 pair of heavy chains
2 pairs of light chains

Question 11

Contains ACTIN, TROPOMYOSIN AND TROPONIN

Answer 11

THIN ILAMENTS

Question 12

“relaxing protein’ that covers actin binding sites at rest

Answer 12

Tropomyosin

Question 13

3 subunits of Troponin

Answer 13

T - attached troponin complex to tropomyosin

I - inhibits actin-myosin binding

C - calcium binding protein

Question 14

Part of sarcomere

borders

Answer 14

Z lines (“Zwischenscheibe”)

Question 15

Part of sarcomere

midline

Answer 15

M line (“Mittelscheibe”)

Question 16

entire length of the myosin

Answer 16

A band (Anisotropic)

Question 17

inside A band, PURELY MYOSIN no actin interspersed

Answer 17

H band (Heller)

Question 18

inside H band; no myosin heads

Answer 18

bare zone

Question 19

PURELY ACTIN no myosin interspersed

Answer 19

I band

Question 20

Invagination of the Sarcolemma

Spreads AP to all parts of the muscles

Answer 20

Transverse Tubules

Question 21

Voltage sensitive receptor that is found in the Transverse Tubules

Answer 21

dihydropyridine receptors (DHPRs)

activates ryanodine receptors

Question 22

Contains calcium needed for contractions

Answer 22

Sarcoplasmic Reticulum (SR)

amt of calcium released by SR depends on the amount of stored calcium

Question 23

Calcium release channel in the SR ACTIVATED by DHPR

Answer 23

Ryanodine

Question 24

Protein that stores Ca2+ in the SR

Answer 24

Calsequestrin

Question 25

Pumps Ca from ICF to the SR

Answer 25

SERCA

Question 26

Binds myosin to Z lines, binds Z lines to M line

Answer 26

TITIN determines the normal stiffness of the ventricular muscles

Question 27

Stabilizes sarcolemma and prevents contraction induced rupture

Answer 27

DYSTROPHIN binds actin to beta dystroglycan in the sarcolemma

Question 28

Binds actin to Z lines

Answer 28

Actinin, CapZ protein

Question 29

Binds Z lines to sarcolemma

Answer 29

Desmin

Question 30

Acts as molecular rulers that sets the LENGHT of ACTIN

Answer 30

Nebulin

Question 31

PARTIAL hydrolysis of ATP

Answer 31

RECOCKING of myosin heads

Question 32

COMPLETE hydrolysis of ATP

Answer 32

POWER STROKE

Question 33

Blocks REUPTAKE of choline into presynaptic terminal

Answer 33

Hemicholinium

Question 34

INHIBITS acetylcholinesterase

Answer 34

Neostigmine

Question 35

COMPETES with Ach for receptors on Motor End Plate

Answer 35

Curare

Question 36

BLOCKS RELEASE of Ach from pre-synaptic terminals

Answer 36

Botulinum Toxin

Question 37

LENGTH is CONSTANT while muscle contracts force generated is not enough to move or lift an object NO muscle shortening/lengthening

Answer 37

ISOMETRIC CONTRACTION i.e. pushing against a wall

Question 38

LOAD is CONSTANT while muscle contracts

Answer 38

ISOTONIC CONTRACTION CONCENTRIC - (+) muscle SHORTENING (i.e. pulling a weight up) ECCENTRIC - (+) muscle LENGTHENING (i.e lowering a weight down)

Question 39

Muscle length

Answer 39

PRELOAD

Question 40

Load against which muscle contracts

Answer 40

AFTERLOAD

Question 41

Tension d.t. muscle STRENGHT

Answer 41

Passive tension

Question 42

Tension d.t. muscle CONTRACTION

Answer 42

Active tension proportional to the number of cross bridges formed

Question 43

Occurs 3-6 hrs after death d.t. lack of ATP

Answer 43

Rigor Mortis

Question 44

Happens when ALL CALCIUM from SR has been RELEASED; no further increased in muscle strength

Answer 44

Tetanus/Tetanic Spasm

Question 45

Relies PURELY on INTRACELLULAR CALCIUM

Answer 45

Skeletal Muscles