Question

Which of the following is the muscle action that results in exhalation and causes the air pressure inside the lungs to be higher than outside the chest cavity? Contraction of external intercostals Contraction of the diaphragm Relaxation of the external intercostals Relaxation of the diaphragm

A biology class wants to perform an experiment to investigate the effect of different colors of light of green, yellow, red and clear cellophane and plant three seeds in each one. The colors of cellophane acts as the light source for the set up.Three colors would give off different wavelengths of light to the sample in the jar.

Which of the following occurs in the cardiac cycle if the impulse triggered at the sinoatrial node never close?

Diastole will shorten in duration

The ventricles will not contract

There will be an absence of systole

The atria will not contract.

Answer 1

Answer a)  muscle action that results in exhalation and causes the air pressure inside the lungs to be higher than outside the chest cavity results in relaxation of diaphragm.

Answer b) if the cardiac cycle if the impulse triggered at the sinoatrial node never close then:

the ventricles and atria will not contract.

because SA node cells have the ability to spontaneously produce an electrical impulse (action potential), that travels through the heart via the electrical conduction system causing it to contract.