NURS 5315 UTA (Cardiac And Pulmonary) EXAM 3 – Q&A
Question : How does blood flow through the heart
chambers/valves?
CORRECT ANSWER : Superior vena cava to inferior vena
cave. Blood then enters the right atrium and passes through the tricuspid valve to the right ventricle. The right ventricle pumps the blood to the lungs through the pulmonary valve to the pulmonary arteries where it becomes oxygenated. The oxygenated blood is brought back to the heart by the pulmonary veins which enter the left atrium. From the left atrium blood flows through the bicuspid (mitral) valve into the left ventricle.
Question : Which coronary arteries provide blood to which
part of the heart?
CORRECT ANSWER : a. ) Left coronary artery
i.) Left anterior descending artery:widow maker
LV and RV, intraventricular septum
ii. ) Circumflex: LA and left lateral wall of LV.
- ) Right coronary artery
RV, intraventricular sulcus and small vessels of the RV and LV
Question : What factors contribute to blood flow in a vessel?
CORRECT ANSWER : Pressure difference between two
ends of a vessel
Resistance: r/t diameter of a vessel
Viscosity (n) of the blood Length (l) of the vessel
Question : What does QP: QS mean and what factors alter a normal ratio?
CORRECT ANSWER : Q=blood flow
QP= blood flow to the lungs (pulmonary) : QS= blood flow to
the body (systemic) i ) Vascular resistance =measures in woods units ii) Pulmonary vascular resistance (PVR)
) <8 weeks of age: 8-10 woods units/m2
) >8 weeks of age: 1-3 woods units/m2
iii) Systemic vascular resistance
- Infant 10-15 woods units/m2
2.) 1-2 years old: 15-20 woods units/m2
3.) Child to adult: 15-30 woods units/m2
a) Factors affecting resistance
i.) Compliance-ease that blood travels through the arteries
Constriction and relaxation of smooth muscle of arteries and arterioles
- ) Sympathetic nervous system
b.) Local tissue metabolism c.) Hormone responses d.) Changes in chemical environment
Question : Explain the process of cardiac contraction and
relaxation. What are the roles of actin, myosin, and troponin in this process?
CORRECT ANSWER : At rest, active sites on actin are
blocked by troponin and tropomyosin complexes. During action potential, troponin C binds with calcium and moves the complexes off the actin active site. Actin and myosin interact (contract).
"Walk-along" theory:
Head of myosin cross-bridge attached to the actin filament at the active site.Intra molecular forces cause the myosin head to tilt forward on a flexible hinge and drag the actin filament with it (power stroke) Myosin head breaks away and interacts with the next actin active site.Z disc pulls filaments together at the sarcomeres= muscle contraction.
Question : What is the effect of Epinephrine on the
cardiovascular system?