Circulatory System Flashcards
Which heart valves are not actively closed by the contraction of muscular structures?
Semilunar valves
The first heart sound, “Lub,” indicates the heart
Entering systole
Systole is typically defined as
Ventricular contraction
The first heart sound indicates the
Closure of both mitral and tricuspid valves
The second heart sound indicates the
Beginning of diastole
The second heart sound, “Dup,” is due to the
Closure of the semilunar valves
What phase is the heart in between the first and second heart sounds?
Systole
During systole, the heart pumps blood from the
Ventricles
Which valves are closed during systole?
Atrioventricular valves
The closure of the semilunar valves is the start of
Isovolumetric relaxation
At the instant following the second heart sound, all valves are
Closed
All blood vessels have a
Tunica intima
The tunica intima is made of
Endothelial cells
What is the cellular messenger that results in the contraction of smooth muscle?
Intracellular calcium
The tunica media is a
Muscular layer
How does the tunica media change blood pressure?
It can be contracted and relaxed
Blood pressure is highest at the
Aorta
What has lower pressure, capillaries or veins?
Veins / venules
What layer of the heart would be most immediately susceptible to infections caused by bacteria circulating in the blood?
Endocardium
What is the muscular portion of the heart?
Myocardium
What is the pericardium?
A double walled sac which encloses the heart
What is the function of the pericardium?
- Structural support
- Lubrication
The epicardium is where the
Pericardium contacts the heart wall at the myocardium
What is the function of the endocardium?
It lines the inside of the heart
The endocardium is in direct contact with
Circulating blood
What vessel carries deoxygenated blood away from the heart?
Pulmonary artery
What are the coronary arteries?
Vessels which supply the heart itself with oxygen and nutrients
The pulmonary artery brings blood from the
Right ventricle of the heart to the lungs
How can the circulatory system promote heat retention/conservation?
Vasoconstriction
Vasodilation results from a
Decrease in smooth muscle contraction
