Lec 2 - The Heart

Question 1

list the differences between excitation of vertebrate striated muscle and cardiac muscle

Answer 1

initial cause of depolarisation, time course of AP, propagation of AP along sarcolemma, cellular origins of Ca2+

Question 2

voltage gated ca2+ channels open to cause an increase in cytoplasmic Ca2+ only in

Answer 2

cardiac cells

Question 3

what is special about the refractory period in cardiac muscle

Answer 3

it is a prolonged effective refractory period to allow full emptying of the heart

Question 4

what does myogenic mean

Answer 4

that it is beginning in the muscle, spontaneous

Question 5

list two properties of pacemaker cells

Answer 5

they depolarise fastest and have an unstable resting potential

Question 6

neurogenic means

Answer 6

beginning in the nerve

Question 7

what are neurogenic neurons excited by

Answer 7

neurotransmitters from motor nerves

Question 8

what two types of innervation sites can skeletal muscles have

Answer 8

multiple (tonic) or single (twitch)

Question 9

muscle contraction depends upon

Answer 9

intracellular calcium

Question 10

skeletal muscle sarcoplasmic reticulum can be described as being

Answer 10

highly developed

Question 11

cardiac myocyte sarcoplasmic reticulum t tubules are not so well developed because

Answer 11

the signal travels through gap junctions