Muscles

Question 1

Striated muscle

Answer 1

cardiac

skeletal

Question 2

Smooth

Answer 2

blood vessels, vas deferens, airways, uterus

Question 3

Skeletal muscles

Answer 3

multi-nucleated

increase fibre size during growth

Question 4

muscle cells are replaced after injury by

Answer 4

satellite cells

Question 5

Myosin

Answer 5

Thick

Z line/ cross bridge movement

Question 6

Actin

Answer 6

thin filament

Question 7

Cross bridge binds to actin

cross bridge moves

Answer 7

ATP binds to Myosin causing cross-bridge to detach

hydrolysis of ATP energizes cross-bridge

Question 8

What covers the myosin binding site

Answer 8

tropomyosin

Question 9

Tropomyosin is held in place by

Answer 9

troponin

Question 10

Calcium can bind to troponin and..

Answer 10

alter its shape - troponin will pull tropomyosin away

Question 11

If calcium is removed, tropomyosin will be able to…

Answer 11

block the myosin binding site again

Question 12

Motor unit =

Answer 12

Motor neurones + motor fibres

Question 13

Contraction with constant length

Answer 13

isometric

Question 14

contraction with shortening length

Answer 14

isotonic

Question 15

contraction with increasing length

Answer 15

lengthening

Question 16

Latent period is the

Answer 16

time before excitation-contraction occurs

Question 17

contraction time occurs between

Answer 17

start of tension and time when we have peak tension

Question 18

Contraction time depends on

Answer 18

calcium

Question 19

less overlap of filaments = less

Answer 19

tension

Question 20

too much overlap of filaments =

Answer 20

they begin to interfere with each other

Question 21

hydrolysis of ATP energises

Answer 21

X-bridges

Question 22

ATP in contractions

Answer 22

ATP binds to myosin

dissociated bridges bound to actin

new cycle may begin

Question 23

Fatigue prevents muscles using up

Answer 23

ATP - which could cause rigor (muscles would not be able to activate new X-bridge cycles)

Question 24

Factors causing fatigue

Answer 24

contraction failure

increase in lactic acid

increase in ADP and Pi inhibiting the X-bridge cycle (delaying myosin detachment from actin filaments)

Question 25

FAST fibres means myosin has

Answer 25

high ATPase

slow = low ATPase

Question 26

oxidative fibres have…

Answer 26

lots of mitochondria

therefore increased oxidative phosphorylation

Question 27

Glycolytic fibres have…

Answer 27

few mitochondria

lower blood supply

Question 28

3 types of muscle fibre

Answer 28

slow oxidative
fast oxidative
fast glycolytic

Question 29

Slow oxidative

Answer 29

resist fatigue

Question 30

fast oxidative

Answer 30

intermediate resistance to fatigue

Question 31

fast glycolytic

Answer 31

fatigue quickly

Question 32

an increase in load gives a need for an increase in

Answer 32

activation of more motor units

Question 33

exercise causes

Answer 33

hypertrophy

Question 34

aerobic exercise gives an increase in

Answer 34

mitochondria
fibre diameter
vascularisation

Question 35

exercise type determines the..

Answer 35

type of muscle fibres you have

Question 36

Smooth muscle

Answer 36

spindle-shaped

mononucleated

myosin and actin - like skeletal muscle

HOWEVER

filaments are arranged diagonally across cells and are anchored to membranes

Question 37

Smooth muscle X-bridge cycle activation

Answer 37

increase in calcium

calcium binds to calmodulin

calcium-calmodulin binds to Myosin Light Chain Kinase

kinase phosphorylates myosin X-bridges with ATP

phosphorylated X-bridges bind to actin filaments

CONTRACTION AND TENSION

Question 38

Sources of Cytosolic Ca2+

Answer 38

Sarcoplasmic reticulum

extracellular calcium

calcium removed from cytosol by pumping back into SR and out of cell by calcium ATPases

Question 39

in skeletal muscle one action potential releases enough calcium to…

Answer 39

saturate all troponin sites