e109 Weekly quizzes exam 2

The purpose of transverse tubules is to

rapidly conduct action potentials to the interior of the muscle fiber.

What gets shorter when a skeletal muscle contracts?

Sarcomeres

In a muscle, maximal force is generated by a sarcomere length that

optimizes the overlap between thick and thin filaments, allowing the most cross-bridges to form.

Which of the following is true?

answer choices:

• Both smooth and skeletal muscles attach to bones, while cardiac muscle is only found in the heart. 

• An increase in Ca++ concentration inside a muscle cell occurs during contraction in all muscle cell types. 

• Only a small fraction of skeletal muscles are under voluntary control. 

• Cardiac muscle is the muscle type that fatigues most quickly. 

• Smooth muscle is the most rapidly-contracting muscle.

An increase in Ca++ concentration inside a muscle cell occurs during contraction in all muscle cell types.

Smooth muscle is usually

the muscle type found in the walls of hollow organs.

Which of these synapses does NOT have acetylcholine as its main neurotransmitter?

synapse of a postganglionic sympathetic neuron onto a smooth muscle cell

“Hyperkalemic periodic paralysis”  is caused by a genetic defect in the voltage-gated Na+ channels on cell membranes of skeletal muscle cells. Paralysis is not constant but happens occasionally.    When paralysis is occurring, the voltage-gated Na+ channels remain open for an abnormally long amount of time. What is logical to expect during this time  (while the voltage-gated Na+ channels are remaining open)?

voltage-gated K+ channels will remain open

Right atrium, right ventricle, pulmonary artery, pulmonary vein, left atrium, left ventricle

A system of valves in the heart and veins

A decrease in the rate of action potential in pacemaker cells, which will slow down heartbeat rate

An unusually long delay at the AV node

Volume of blood pumped out of either ventricle per unit of time

The coronary arteries branch from…

Aorta

At an intercalated disc…

Two cardiac muscle cells are connected by gap junctions

Blood cells are primarily produced in

Bone marrow

You are able to detective pulse in an artery, but not a vein because

The pulsatile nature of blood flow has dissipated or diminished by the time the blood has reached the veins