Phys: Muscle Phys.

Question 1

where is the sarcolemma?

Answer 1

cell membrane found in skeletal & cardiac muscle

Question 2

what does the sarcoplasmic reticulum do?

Answer 2

stores Ca++ to be released by skeletal muscle

Question 3

T-tubules function?

Answer 3

“telephone” line to send the AP into th emuscle to cause Ca++ release from sarcoplasmic ret.

Question 4

what are the 2 types of myofibril? ratio?

Answer 4

Actin- thin
Myosin- thick
2:1

Question 5

where is the Myosin?

Answer 5

H zone- thick
cross bridges (ATPase attach to the myosin head)

Question 6

Where is Actin? types?

Answer 6

i bands- thin
F-actin filament- contains the binding sites
Tropomyosin “mom”- covers the f-actin binding sites
Troponin “Dad”- binds Ca++ and moves tropomysosin off the binding sites- found in both sk. & cardiac

Question 7

what does smooth muscle have?

Answer 7

actin
myosin
sarcoplasmic reticulum

Question 8

__ is needed for smooth muscle contraction?

Answer 8

calmodulin

Question 9

what is the organization of a sarcomere?

Answer 9

sarc.- Z line approximates to Z line
A- band- contains both actin & myosin
H- band- myosin only
I band- actin only
Z-H-IZI-A-Z

Question 10

what does eccentric mean?

Answer 10

muscle lengthens while it contracts

Question 11

what does concentric mean?

Answer 11

muscle shortens while it contracts

Question 12

what does isometric mean?

Answer 12

muscle contracts w/o joint movement or muscle lengthening (push a wall)

Question 13

what is iostonic?

Answer 13

load remains the same

Question 14

what is ioskinetic?

Answer 14

speed of contraction remains the same throughout the contraction

Question 15

what is the motor unit?

Answer 15

single motor neuron & all the muscle fibers it innervates

Question 16

what do fast twitch muscle fibers do?

Answer 16

split the ATP rapidly

Question 17

ventral root fibers are considered?

Answer 17

Alpha-extrafusal

Gamma- Intrafusal

Question 18

how is the strength of a muscle determined?

Answer 18

by the number of muscle fibers recruited

Question 19

what is the sequence for an AP?

Answer 19

AP by T-tubules> SR becomes more permeable to Ca++ ions & diffuse into sarcoplasm around myofibril> Ca++ binds to troponin> troponin- tropomyosin complex moves to expose active sites.

Question 20

what happens to the i-band when a muscle contracts?

Answer 20

the i-band will get smaller; whereas the A-band will stay the same

Question 21

how does rigor mortis happen?

Answer 21

it takes place after death bc crossbridges will form (myosin), but then are unable to release bc Actin is not activated by the AP

Question 22

Slow twitch fiber characteristics:

Answer 22

type 1
RED fibers
LOng distance runners
Smaller fiber size
uses LESS glycogen
Many MITOchondria
MORE myoglobulin

Question 23

Fast twitch fiber characteristics:

Answer 23

Type 2
WHITE fibers
Sprinters
Large fiber size (for greater contraction)
uses MORE glycogen
less mitochondria
LESS myoglobin

Question 24

what is the smooth muscle actin:myosin ration?

Answer 24

20:1

Question 25

what is the flexor withdrawal reflex?

Answer 25

a painful stimulus causes a flexor muscle to withdraw the affected limb on side of stimulus

Question 26

what is the crossed extensor reflex?

Answer 26

is activated by a noxious stimulus to the skin
causes extensors to be activated on opposite side of stimulus
it provides support of the body during withdrawal of the affected limb as a righting reflex

Question 27

what is the deep tendon reflex?

Answer 27

striking a muscle with a reflex hammer causes the muscle spindle in the muscle to be suddenly stretched

Question 28

how is an UMN lesion characterized:

Answer 28

Spastic paralysis
hyperreflxia
babinski sign
no atrophy
no fasciculations

Question 29

what will result with repetitive stimulation without relaxation?

Answer 29

tetany of the skeletal muscle