Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SfM > Muscles 2 > Flashcards

Muscles 2 Flashcards

1
Q

Whats ATP used for in muscle contraction?

A

ATP is hydrolysed for energising X-bridges.

Also powers Ca2+ATPase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does fatigue depend on?

A

Fibre type
Length of contraction
Fitness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What can cause fatigue in high-intensity short duration exercise?

A
  • rise in [K+] causes depolarisation and conduction failure
  • Rise in [lactic acid] acidifies proteins
  • Rise in [adp] & [Pi] inhibits X-bridge cycle, delaying myosin detachment from actin filaments.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can cause fatigue in long-term, low intensity exercise?

A
  • drop in muscle glycogen
  • drop in blood glucose
  • Dehydration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Central command fatigue?

A

Cerebral cortex cannot excite motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What characterises skeletal msucle fibre types?

A

Whether theyre fast or slow shortening

Whether they use oxidative or glycolytic ATP forming pathways.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Whats different about oxidative fibres?

A

More mitchondria
More vascularisation
Myoglobin for O2 delivery
Red fibres small diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Whats different about glycolytic fibres?

A

Few mitochondria
more Glycolytic enzymes & glycogen
Low blood supply
White fibres with large diameters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are 3 muscle fibre types?

A 
Slow oxidative (I) - resist fatigue
Fast oxidative (IIa) - some resistance to fatigue
Fast Glycolytic (IIb) - Fatigue quickly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is muscle fibre recruitment?

A

An increase in the number of active motor units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What causes muscle fibre recruitment?

A

And icnrease in load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In what order are muscle fibres recruited?

A

I
then IIa
Then IIb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does exercise type determine the type of fibres you have?

A

Anaerobic exercise increases glycolysis and fibre diameter

Aerobic exercise increases mitochondria and vascularisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is differnet about smooth muscle?

A

No striATIONS
Innervated by ANS not the Somatic NS
Mononucleate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where is smooth muscle found?

A

Hollow organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What shape are smooth muscle cells?

A

Spindle-shaped

17
Q

How is the smooth muscle x-bridge cycle different to skeletal muscle?

A

The Ca2+ binds to calmodulin

  • the complex binds to myosin light chain kinase
  • kinase phosphorylates myosin x-bridges with ATP
  • Phosphorylated X-bridges bind to actin filaments and contract.
18
Q

How is smooth muscle relaxed?

A

Myosin light chain phosphatase dephosphorylates X-bridges

19
Q

What is different about Ca2+ supply in smooth muscle?

A

Little SR with no T-tubules so most Ca2+ is sourced extracellulaly from voltage gated Ca2+ channels.

20
Q

How is Ca2+ removed from smooth muscle

A

Pumped into SR and out of cell by Ca2+ ATPase (slower process than in skeletal muscle)

21
Q

How is contraction graded in smooth muscle cells?

A

1 AP doesnt release enough calcium to saturate all the troponin sites.
So the no of APs can grade the contraction

22
Q

What does the tone of smooth muscle refer to?

A

There is a basal level of Ca2+ in smooth muslce causing a constant level of tension which can be increased or decreased.

23
Q

What factors affect contractile activity in smooth muscle?

A
  • hormones
  • local factors (pH, O2, osmolarity etc)
  • Stretch
  • autonomic neurotransmitters from varicose veins
  • spontaneous electrical activity in muscle membranes
24
Q

Where are single unit smooth muscle types?

A

GI tract, Uterus, small vesells

25
Q

Whats special about single unit muscle smooth muscle?

A
  • many cells linked by gap junctions
  • signals travel between cells
  • May contain pacemaker cells
  • Stetch evokes contraction
  • Contract synchronously
26
Q

Where are multiunit smooth muscle types found?

A

Airways
large arteries
hairs

27
Q

Whats special about multiunit smooth muscle?

A
  • Few or no gap junction
  • richly innervated by ANS
  • Dont respond to stretch

SfM (35 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions