Decrease, vasodilation

Increase, vasodilation

Increase, vasoconstriction

Decrease, vasoconstriction

Stay the same, vasoconstriction

increases cardiac output.

increases the ‘firing rate’ of the pacemaker cells.

causes bradycardia.

increases the force of ventricular contraction.

has the same effect as adrenaline.

48%

10%

34%

19%

59%

decrease pre-load and stroke volume.

decrease pre-load and increase arterial blood

pressure.

increase pre-load but not alter stroke volume or

arterial blood pressure.

increase pre-load and decrease arterial blood

pressure.

increase

pre-load and stroke volume.

Smooth muscle myosin is inactivated when myosin-light-chain phosphatase

removes the phosphate residue attached by myosin-light-chain kinase

Intracellular calcium binds to calmodulin (CaM) and the Ca-CaM complex activates a kinase.

An increase in cytosolic calcium induces calmodulin binding to myosin-light chain kinase.

The regulation of the actin-myosin interaction occurs by calcium binding to troponin.

Phosphorylation of the myosin light chain converts the myosin into its active form which can then bind to F-actin.

Isotonic contraction.

Isometric contraction.

Isometric concentric contraction.

Eccentric contraction.

Isotonic concentric contraction.

Sliding is caused by the cross-bridges formed between the myosin head and specific sites on the actin molecule

ATP hydrolysis provides the energy for the myosin head to unbind from the actin binding site.

Every cycle, four molecules of ATP are used by each myosin head.

The cross-bridges are activated once during a contraction.

The troponin complex is an ATP sensor.

The amplitude of the action potentials coming from the motor neuron is larger during a tetanus.

In a twitch (which occurs when a muscle is activated by a single action potential) there is not enough time to take up all the elastic tension before the muscle starts to relax again.

The myosin heads move more slowly during a twitch.

The CaATPase pumps on the sarcoplasmic reticulum work faster during a single twitch, lowering the calcium concentration more quickly than in the case of the larger tetanus.

The rate of diffusion of Ca²⁺ molecules from the sarcoplasmic reticulum to the contractile proteins is slower during a single twitch.

Myosin and Titin

Collagen and Troponin

Actin and Myosin

Tropomyosin and Alpha-actinin

Actin and Titin

Whole muscle is surrounded by the TENDOPIMYSIUM, fascicles by the PERIMYSIUM and individual fibres by the ENDOMYSIUM.

Whole muscle is surrounded by the EPIMYSIUM, fascicles by the ENDOMYSIUM and individual fibres by the PERIMYSIUM.

Whole muscle is surrounded by the EPIMYSIUM, fascicles by the PERIMYSIUM and individual fibres by the ENDOMYSIUM.

Whole muscle is surrounded by the PERIMYSIUM, fascicles by the EPIMYSIUM and individual fibres by the ENDOMYSIUM.

Whole muscle is surrounded by the ENDOMYSIUM, fascicles by the PERIMYSIUM and individual fibres by the EPIMYSIUM.