SHUPA Physiology - Cardiac Muscle

What chemicals are used in cardiac dysrhythmias due to electrolyte abnormalities?

• Something with K

• Something with Na

• Something with Ca

• Something with Au

What substance is measured in the blood of myocardial infarct is suspected?

• Calcium

• Magnesium

• Troponin

• Myosin

Which of the following appear to have a striated muscle pattern?

• Skeletal muscle

• Smooth muscle

• Cardiac muscle

• Precapillary sphincters

Similar to smooth muscle, a signal travels through the whole muscle at the same time.

• True

• False

Cardiac muscle is unique in the fact that they have these channels…

• Na+

• Na+/K+

• Na+/Ca++

• Ca++

These channels act slower in cardiac muscle, causing a plateau during Repolarization

• Ca++

• Na+

• K+

• H+

Ventricular muscle fibers have a slightly higher resting membrane potential of…

• -70mV

• -80mV

• -90mV

• -100mV

Put the following in order, starting from depolarization and ending at resting:

1. Ca channels open

2. Fast Na channels open

3. Ca channels close, slow K channels open

4. Return to -90mV

5. Fast Na channels close

• 2, 5, 3, 1, 4

• 2, 5, 1, 3, 4

• 1, 3, 2, 5, 4

• 1, 2, 3, 5, 4

Extracellular Ca++ is signaled by an AP to enter the T-tubules, causing an influx of Ca++ into this intracellular structure during excitation

• Granular Endoplasmic reticulum

• Smooth Endoplasmic reticulum

• Sarcoplasmic reticulum

• Golgi apparatus

The influx of Ca into the Sarcoplasm activates THESE receptors which then release the Ca ions from the SR, causing a contraction

(a)