Quickly need it in 10 mins as many as you can Skeletal muscle can reach tetanus whereas cardiac muscle cannot because...

Group of answer choices

skeletal muscle depolarizes with sodium, wheras cardiac muscle requires calcium

cardiac muscle runs out of ATP more quickly than skeletal muscle

skeletal muscle has more stamina than cardiac muscle

skeletal muscle AP's have short refractory periods whereas cardiac muscle AP's have long refractory periods

What is the location and function of the NCX pumps?

Group of answer choices

SR of contractile cells; pump calcium back into SR

intercalated disks; pump calcium into cell and sodium out of cell

t-tubules and sarcolemma of contractile cells, pump calcium out to ECF

sarcolemma of autorhythmic cells; open calcium channels for depolarization

Which of the answer choices has the correct sequence of structures for blood flow through the heart & body one time?

(Structures may be missing in the sequence choices, but you can still figure out the correct sequence.)

Group of answer choices

vena cavae, pulmonary valve, pulmonary veins, lungs

lungs, left ventricle, pulmonary arteries, right atrium

aortic valve, tricuspid valve, right ventricle, vena cavae

right ventricle, bicuspid valve, aorta, right atrium

During the isovolumic (AKA isovolumetric) relaxation period, the pressure in the ventricles is and the AV valves are .

Group of answer choices

increasing; closed

decreasing; closed

constant; open

constant: closed

decreasing; open

Which two waves are coupled together in an ECG, given a consistent pattern on the ECG?

Group of answer choices

P and T

QRS and T

P and QRS

The autonomic nervous system can influence heart rate . The mechanism for changing heart rate is by .

Group of answer choices

sympathetic decrease of potassium current or parasympathetic decrease of sodium current.

sympathetic decrease of sodium current or parasympathetic decrease of potassium current.

sympathetic increase of potassium current or parasympathetic decrease of sodium current.

sympathetic increase of sodium current or parasympathetic increase of potassium current.

True/False: Your stroke volume would increase if sympathetic output increased on the veins of your body.

Group of answer choices

True

False

AND.. Muscle mass usually reflects the relative strength of the muscle. Which chamber in the heart has the thickest walls & the most muscle mass?