Striated Muscle

Question 1

Does cardiac muscle need nerves for contraction?

Answer 1

no, as the cells are electrically connected to one another

Question 2

The process by which an outside signal is translated into activation of a muscle cell. This mechanism is very different between the different types of muscles.

Answer 2

excitation contraction coupling

Question 3

Describe the arrangement of skeletal muscle.

Answer 3

bundles of myofibrils make up a muscle fiber (aka, muscle cell), which bundle up to form a fasciculus

Question 4

What is the function of a DHPR vs. a RyR in skeletal muscle?

Answer 4

DHPR is the voltage sensor and RyR is the calcium release channel; the two are physically connected, allowing for the mechanical coupling seen in skeletal muscle (DHPR does not allow for calcium flux in skeletal muscle)

Question 5

What is the function of a DHPR vs. a RyR in cardiac muscle?

Answer 5

DHRP is a calcium channel that allows flux of calcium and RyR is a calcium release channel that releases calcium in response to calcium stimulation (from calcium flowing through DHPR); this is the mechanism for calcium-induced calcium release

Question 6

How does calcium affect the sarcomere?

Answer 6

It binds to troponin C, which causes movement of tropomyosin away from myosin binding sites on underlying actin molecules; this allows contraction to occur

Question 7

An increase in the force of contraction at a given intracellular [Ca++].

Answer 7

calcium sensitization