Chapter 19: Heart

what does the second heart sound represent?

-closing of semilunar valves during ventricular diastole

What are the 3 layers of the heart?

-epicardium: outer protective layer -myocardium: thickest layer -endocardium: lines chambers where blood circulates and covers the heart valves

How do gap junctions and intercalated disks aid contraction of the heart?

-gap junctions allow impulses to spread from one cardiac muscle cell to another -allows for Na+,K+,Ca2+ ion to flow btw adjacent cells to propagate an action potential so contraction can happen

what is isovolumic contraction?

-initial phase of ventricular systole -no blood is being ejected from ventricles -volume of blood stays constant

what is the pulmonary circuit?

-transports blood to and from the lungs, where it picks up oxygen and delivers co2 for exhalation

what is the systemic circuit?

-transports oxegenated blood to all tissues of body and returns deoxygenated blood and co2 to heart to be sent back to pulmonary circulation

what are the 5 points on the EKG?

1. P wave: represents depolarization of atria 2. QRS complex: 3.T wave: repolarization of ventricles

what are the 2 major cardiac cells?

1. myocardial contractile cells: responsible for contractions that pump blood through the body 2. myocardial conducting cells: triggers the contractions that propel the blood

The cardiovascular centers are located in which area of the brain? a. medulla oblongata b. pons c. mesencephalon (midbrain) d. cerebrum

a. medulla oblongata

Which valve separates the left atrium from the left ventricle? a. mitral b. tricuspid c. pulmonary d. aortic

a. mitral

Which of the following lists the valves in the order through which the blood flows from the vena cava through the heart? a. tricuspid, pulmonary semilunar, bicuspid, aortic semilunar b. mitral, pulmonary semilunar, bicuspid, aortic semilunar c. aortic semilunar, pulmonary semilunar, tricuspid, bicuspid d. bicuspid, aortic semilunar, tricuspid, pulmonary semilunar

a. tricuspid, pulmonary semilunar, bicuspid, aortic semilunar

The force the heart must overcome to pump blood is known as ________. a. preload b. afterload c. cardiac output d. stroke volume

b. afterload

Most blood enters the ventricle during ________. a. atrial systole b. atrial diastole c. ventricular systole d. isovolumic contraction

b. atrial diastole

The ________ layer secretes chemicals that help to regulate ionic environments and strength of contraction and serve as powerful vasoconstrictors. a.pericardial sac b. endocardium c. myocardium d. epicardium

b. endocardium

The myocardium would be the thickest in the ________. a. left atrium b. left ventricle c. right atrium d. right ventricle

b. left ventricle

Which of the following is unique to cardiac muscle cells? a. Only cardiac muscle contains a sarcoplasmic reticulum. b. Only cardiac muscle has gap junctions. c. Only cardiac muscle is capable of autorhythmicity d. Only cardiac muscle has a high concentration of mitochondria.

c. Only cardiac muscle is capable of autorhythmicity

In which septum is it normal to find openings in the adult? a. interatrial septum b. interventricular septum c. atrioventricular septum d. all of the above

c. atrioventricular septum

The first heart sound represents which portion of the cardiac cycle? a. atrial systole b. ventricular systole c. closing of the atrioventricular valves d. closing of the semilunar valves

c. closing of the atrioventricular valves

Of the three germ layers that give rise to all adult tissues and organs, which gives rise to the heart? a. ectoderm b. endoderm c. mesoderm d.placenta

c. mesoderm

Which chamber initially receives blood from the systemic circuit? a. left atrium b. left ventricle c. right atrium d. right ventricle

c. right atrium

Which component of the heart conduction system would have the slowest rate of firing? a. atrioventricular node b. atrioventricular bundle c. bundle branches d. Purkinje fibers

d. Purkinje fibers

The two tubes that eventually fuse to form the heart are referred to as the ________. a. primitive heart tubes b. endocardial tubes c. cardiogenic region d. cardiogenic tubes

d. cardiogenic tubes

Which of the following is not important in preventing backflow of blood? a. chordae tendineae b. papillary muscles c. AV valves d. endocardium

d. endocardium

The earliest organ to form and begin function within the developing human is the ________. a. brain b. stomach c. lungs d. heart

d. heart

The cardiac cycle consists of a distinct relaxation and contraction phase. Which term is typically used to refer ventricular contraction while no blood is being ejected? a. systole b. diastole c. quiescent d. isovolumic contraction

d. isovolumic contraction

Which portion of the ECG corresponds to repolarization of the atria? a. P wave b. QRS complex c. T wave d. none of the above: atrial repolarization is masked by ventricular depolarization

d. none of the above: atrial repolarization is masked by ventricular depolarization

The influx of which ion accounts for the plateau phase? a. sodium b. potassium c. chloride d. calcium

d.calcium

what is systole?

period of contraction that the heart undergoes while it pumps blood into circulation

what is diastole?

period of relaxation that occurs as chambers fill with blood

Why is afterload important to cardiac function?

represents the resistance w/in the arteries to the flow of blood ejected from the ventricles

what occurs during isovolumic contractions?

ventricular contractions while no blood is being ejected