WEEK 2 Flashcards
(256 cards)
WHAT Two sounds are associated with closing of heart valves?
First sound (LUB ~ S1) AND Second sound (DUB ~ S2)
when does First sound (LUB ~ S1) occur?
occurs as atrioventricular valves close
what does First sound (LUB ~ S1) signify?
signifies the beginning of systole (ventricles contracting and pumping blood)
auscultation points of First sound (LUB ~ S1)
auscultation points are between the left 5th and 6th ribs (L)
when does Second sound (DUB ~ S2) occur?
occurs when semilunar valves close at the beginning of ventricular diastole (relaxed and filling with blood)
auscultation points of Second sound (DUB ~ S2)
auscultation points are between 2nd and 3rd ribs (L & R)
Arteries functions
carry blood away from the heart
branch and diverge as they form smaller vessels
carry oxygenated blood (except for pulmonary arteries- which carry deoxygenated blood)
blood flow order of arterioles, capillaries and arteries.
arteries —>arterioles —>capillaries
Veins function
carry blood toward the heart
join, merge and converge into larger vessels
have valves
carry deoxygenated blood(except for pulmonary veins (which carry oxygenated blood)
blood flow order for veins, capillaries, venules
capillaries—>venules—>veins
Three main layers found in all arteries
Tunica Intima/Interna (innermost layer), Tunica Media (middle layer), Tunica Externa (outermost layer)
Tunica Intima/Interna (innermost layer) Contacts ….
Contacts the vessel lumen
Tunica Intima/Interna (innermost layer) consists of
consists of endothelium (↓fluid friction)
the basement membrane and the internal elastic lamina
what is Tunica Media (middle layer) innervated by?
Innervated by the sympathetic nervous system – e.g. ↑ stim. = vasoconstriction and ↓ stim. = vasodilation (due to the recoil of the wall)
what does Tunica Media (middle layer) consist of?
consists of a muscular layer and external elastic lamina
what does Tunica Externa (outermost layer) consist of?
connective tissue.
larger arteries contain vasa vasorum (small blood vessels that supply tunica externa) contain nerves which pass to the tunica media
Tunica Externa (outermost layer) provides
provides anchorage and protection
what artery is the closest to the heart?
Elastic artery
functions of Elastic artery:
delivers blood to regions
largest lumen diameter (~ low resistance)
more elastic
act as pressure reservoirs: expand and recoil as blood is ejected from the heart blood flows smoothly rather than in a pulsatile manner.
Elastic artery examples
e.g. Aorta, Pulmonary trunk, etc.
Muscular Artery delivers
delivers blood to organs
Muscular Artery consists of
more smooth muscle in tunica media (which means more active in vasoconstriction and less distensible)
Muscular Artery examples
e.g. brachial arteries, radial arteries, femoral arteries, etc
Arteriole delivers
delivers blood to tissues