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Flashcards in excitation and contraction Deck (41):
1

myofibril

- longitudinally with in the muscle fibers
- Z line
- ACH in the neuromuscular junction releases CALCIUM

2

sarcomeres

- composed of this and thick filaments

3

contraction

- causes no change in A BAND
- shortening of I an H BAND

4

I BAND

- ACTIN

5

H ZONE/BAND

- MYOSIN

6

A BAND

- ACTIN and MYOSIN

7

ACH in the neuromuscular junction releases CALCIUM
CALCIUM descends into

- T-tubule

8

sarcolemma

- covering of myofibril

9

sarcoplasmic reticulum

- dumps calcium into the T-tubules

10

T- tubules take calcium into the

- muscles

11

ACTIN

- THIN filaments

12

MYOSIN

- THICK filaments

13

tropomyosin

- covers the binding site
- blocks the myosin head for attachment
- prevents cross linking to actin

14

calcium binds to

- troponin

15

troponin

- functions is to move tropomyosin

16

hydrolysis of ATP causes

- cross bridge to gain energy and affinity for actin
- loss of affinity for actin

17

SARCOPLASMIC RETICULUM

- STORAGE SITE FOR CALCIUM

18

2 ATP's are needed

- to start mechanical contraction

19

ATP split are needed for

- relaxation and contraction

20

skeletal muscle action potential

- SHORT
- causing multiple action potential

21

complete TETANUS is obtained

- when sufficient free calcium is available
- everything is engaged

22

complete tetanus vs rigor mortis

- tons of calcium , actin and myosin are engaged (TETANUS)
- no ATP it doesn't detached (RIGOR MORTIS)
- SAME

23

ABSOLUTE REFRACTORY PERIOD

- is already depolarized
- -70mV
- happening

24

relative refractory period

- going back to normal
- earliest time that can have a new stimulus
- can get new depolarization

25

preload

- load on a muscle in a relaxed state prior to contraction
- causes muscle to STRETCH
- causes muscle to develop PASSIVE TENSION

26

AFTERLOAD

- how much effort to push to get the blood out 100lb
- the HIGHER THE BLOOD PRESSURE the MORE THE LOAD

27

drugs that decrease renin angiotensin aldosterone (CHF)
decrease AFTERLOAD (lowers amount of ischemia, arrhythmias, and death)

- spironolactone
- ACE inhibitors
- beta blocker
- ARB

28

more preload

- more passive tension

29

stretch too much loose (DILATED CARDIOMYOPATHY)
over stretch the actin and myosin filaments
PASSIVE

- FORCE
- cannot generate force of contraction
- causing low EF

30

no stretch

- straight contractility

31

muscle contract when

- they are moderately streched

32

active

- actin, myosin filaments are contracting
- consuming ATP

33

passive, more stretch more passive

- pulling muscles apart
- loosing active

34

FORCE- VELOCITY CURVE

- preload can go up

35

Vmax is determined by

- muscle ATPase activity

36

maximum force generated

- is determined by muscle mass

37

white muscle

- large
- powerful muscles
- utilized short term
- LEG muscle of a sprinter, ocular muscles
- large mass
- high ATPase activity
- high capacity for anaerobic glycolysis
- low myoglobin
- fast energy

38

red muscle

- smaller
- less powerful muscle
- utilized long term
- for endurance
- postural muscles
- small mass
- lower ATPase activity
- slower
- high capacity for aerobic metabolism
- high myoglobin (red color) provide O2 to the cell

39

skeletal muscle

- striated (Z lines)
- actin myosin form sarcomeres
- sarcolemma lacks junctional complexes bet fibers
- each fiber innervated
- must be separately/ individually innervated
- one muscle at a time
- troponin to bind to calcium
high ATPase activity
- fast muscle
- extensive sarcoplasmic reticulum inside the sarcomere
- T-tubules form TRIADIC at A I junctions
- lack Ca channels

40

cardiac muscle

- actin myosin form sarcomeres
- striated (Z lines)
- junctional complexes bet fibers including Gap junctions
- electrical syncytium
- troponin to bind to calcium (MI increase troponin)
- intermediate ATPase activity
- intermediate sarcoplasmic reticulum
- T tubules form dyadic contact near Z lines
- voltage gated calcium channels
- plateau phase 200 msec

41

smooth muscle

- non striated (no Z lines, no sarcomeres)
- actin myosin not organized into sarcomeres
- gap junctions ( fast bidirectional)
- electrical syncytium
- detrusor, esophagus, diaphragm
- calmodulin ( calcium modulation)to bind Ca2+
- low ATPase activity
- slow muscle
- limited sarcoplasmic reticulum
- lack T- tubules because their is a electrical syncytium to deliver electricity to the whole muscle simultaneously
- sarcoplasmic reticulum controlled by 2nd messenger
- voltage gated calcium channels