Muscle 2 (Brief)

Question 1

Where does the energy for muscle contraction come from?

Answer 1

Hydrolysis of ATP

Question 2

What is muscle fatigue?

Answer 2

A state that Is caused by repeated muscle stimulation

Question 3

What is muscle fatigue dependent on?

Answer 3

Fibre type

Length of contraction

Fitness of individual

Question 4

What does muscle fatigue prevent?

Answer 4

Prevents muscles using us vast amounts of ATP which would cause rigor

Question 5

Myosin has high ATPase activity in

Answer 5

Fast shortening skeletal muscle fibres

Question 6

Myosin has low ATPase activity in

Answer 6

Slow shortening skeletal muscle fibres

Question 7

Describe oxidative fibres. (4)

Answer 7

These fibres have more mitochondria for oxidative phosphorylation

They are more vascular to allow for the delivery of oxygen and nutrients

They contain myoglobin to help with oxygen delivery

Red fibres with low diameters

Question 8

Describe glycolytic fibres. (4)

Answer 8

Few mitochondria

Higher concentration of glycolytic enzymes and glycogen

Lower blood supply

White fibres with low diameters

Question 9

Describe the 3 specific types of skeletal muscle fibres.

Answer 9

Slow oxidative (I) - resist fatigue

Fast oxidative (IIa) - intermediate resistance to fatigue

Fast glycolytic (IIb) - Fatigue quickly

Question 10

State the order of activation of specific skeletal muscle fibres.

Answer 10

Slow oxidative

Fast oxidative

Fast glycolytic

Question 11

Describe smooth muscle. (6)

Answer 11

Mononucleate

Divide throughout life

Non-straited

Exist in hollow organs (airways, bladder, GI tract)

Also has a cross bridge cycle and uses calcium ions

Innervated by ANS

Question 12

How are myosin and actin filaments different in smooth muscle when compared to skeletal muscle?

Answer 12

The filaments are arranged diagonally across cells and are anchored to membranes and cell structures by dense bodies

Question 13

What does smooth muscle lack that skeletal muscle have

Answer 13

Troponin

Question 14

Describe the process of smooth muscle contraction. (6)

Answer 14

Ca2+ is released from the sacroplasmic reticulum/ECF

Ca2+ binds to calmodulin

Ca2+ - calmodulin binds to myosin light chain kinase (activating MLCK)

Active MLCK phosphorylates the myosin cross bridges with ATP

The phosphorylates myosin cross bridges then bind to actin filaments

Contraction + Tension occurs