Order Excitation Contraction and Relaxation

Order Excitation Contraction and Relaxation
Order 59809192
Order Excitation Contraction and Relaxation
12.1 Vascular myocytes
a. are spindle-shaped cells aligned longitudinally along the vessel axis.
b. form homocellular gap junctions that provide electrical coupling.
c. are striated due to the presence of myosin and actin.
d. have actin filaments that are rooted in Z lines.
e. store Ca2 in the sarcoplasmic reticulum.
12.2 Vascular contraction differs from cardiac contraction in that
a. vascular contraction does not always depend on depolarization, unlike
cardiac contraction.
b. vascular contraction requires myosin activation, as opposed to actin
filament activation in cardiac myocytes.
c. vascular contraction can be maintained despite a fall in cytosolic free Ca2.
d. cardiac contraction lasts much longer than vascular myocyte contraction,
in general.
e. sympathetic fibres can initiate vascular contraction, but not cardiac contraction.
For a change, here is a ‘choose the right phrase’ question.
Order Excitation Contraction and Relaxation
12.3 The ion channels of vascular myocytes
Vascular myocytes typically have a basal membrane potential of around ______.This is
generated in part by an ______ current of ______ through the abundant ______. Other
channels that can increase the membrane potential (hyperpolarize it) include ______, which
help prevent vasospasm, and ______, which contribute to vasodilatation in ischaemic tissue.
When the sympathetic fibres to a resistance vessel are activated, a slow depolarization called
a slow ______ may arise due to the activation of two currents – an ______ current carried
by ______ composed of TRP proteins, and an outward movement of negative charge
through ______. In resistance vessels, the slow depolarization activates the abundantly
expressed ______.The latter may result in an ______ in some vessels.
Insert the right word or phrase from the list below.A word can be used more than once or
not at all.
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