AP 150: Heart Questions

During a cardiac cycle, how many of the four chambers contract at any one time?

2

Parasympathetic innervation of the heart occurs via

CN X

Cardiac muscle tissue contains fewer mitochondria than are found in skeletal muscle tissue.

False

Match the branch of the nervous system with its effect on heart rate and output. Increases rate and force of contractions

Sympathetic innervation

Though the autonomic innervation by autonomic centers in the brainstem cannot initiate a heartbeat, it can increase or decrease the heart rate.

True

The external layer of the heart wall is the

epicardium

Match the chamber of the heart with the structure(s) from which it receives blood. pulmonary veins

left atrium

Match the chamber of the heart with the structure(s) from which it receives blood. left atrium

left ventricle

The serous fluid within the pericardial cavity works to

lubricate the membranes of the serous pericardium.

The layer of the heart wall composed of cardiac muscle tissue is the

myocardium

The fibers that extend through the walls of the ventricles and allow the rapid, immediate spread of the impulse throughout the ventricular myocardium are called _______ fibers.

purkinje

Match the chamber of the heart with the structure(s) from which it receives blood. coronary sinus

right atrium

Match the chamber of the heart with the structure(s) from which it receives blood. Right atrium

right ventricle

The internal wall surface of each ventricle displays large, smooth, irregular muscular ridges called

trabeculae carneae.

Unidirectional flow in the heart is ensured because the heart contains __________ that prevent backflow.

valves

Match the branch of the nervous system with its effect on heart rate and output. Decreases the heart rate

Parasympathetic innervation

The cardiac cycle is

all the events involved with a single heart beat

The valve that prevents backflow of blood into the right ventricle is the _______ _______ valve.

pulmonary semilunar