Sketal, Smooth And Cardiac Muscle

Question 0

What is the value in mV of APs in the SAN and and the ventricles

Answer 0

SAN- 70-80

Ventricle- 100-110

Question 1

Way is the term given to the relation shop between cardiac AP and cardiac contraction

Answer 1

Coincident

Question 2

What are the 2 main types of smooth muscle and explain

Answer 2

Single unit- myogenic in origin

Multi unit- neurogenic in origin

Question 3

How are smooth muscle cells connected

Answer 3

Mechanically- intermediate junction

Electrically- gap junction

Question 4

Explain how contraction in smooth muscle is generated

Answer 4

A catecholamine binds to a smooth muscle cell—> PLC—> IP3–> Ca released from SR—> binds to calmodulin–> binds to myosin light chain kinase–> phosphorylates cross bridge region of myosin head–> cross bridge can form with actin

Question 5

How does relaxation after contraction of smooth muscle occur

Answer 5

Removal of Ca due to dephosphorylation of myosin by a phosatase