McAuliffe Flashcards
The three layers of the heart:
- epicardium: outer; contains coronary blood vessels.
- myocardium: myocytes.
- endocardium: endothelium
Cardiac myocytes communicate via:
gap/communicating junctions.
The heart twists when it contracts (wrings itself out) due to:
spiral arrangement of cardiac muscle fibers.
Three functions of the cardiac fibrous skeleton:
- attachment site for cardiac muscle
- reinforces bases of valves
- insulates ventricles from electrical activity in atria
In response to volume expansion atrial myocytes secrete ____ from granules stored in their cytoplasm.
atrial natriuretic peptide (ANP)
Function of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP):
-
Hypotensive hormones released by atrium and ventricles.
- lower blood volume and BP by promoting the excretion of salt (natriuresis) and water by the kidneys.
Volume expansion and pressure overload cause the ventricles secrete:
- a precursor to B-type natriuretic peptide, proBNP.
- cleaved in the blood stream to active BNP.
Which hormone secreted by the heart is not stored in granules so its production must be
up-regulated before synthesis and secretion can occur?
- pro-BNP from ventricles.
- ANP levels change faster in blood.
Blood levels of what hormone can be used as an important diagnostic sign of congestive heart failure?
BNP
Role of C-type natriuretic peptides released from vascular endothelium:
promotes clearance of ANP and BNP
Bundles of Purkinje fibers run in _____ to the apex of the ventricles and then fan out into the myocardium.
subendocardial connective tissue
The three layers of arteries:
- tunica intima (innermost)
- tunica media (smooth muscle layer)
- tunica adventitia (outermost)
How are the endothelial cells of the tunica intima oriented?
- with their long axes parallel to direction of blood flow.
- 2 to 3 times as long as they are wide.
Contents of the arterial tunica media:
- circularly arranged smooth muscle.
- circularly arranged elastic tissue.
Contents of the tunica adventitia:
- connective tissue with:
- vaso vasorum (vessels of the vessels)
- nervi vascularis (ANS; innervate smooth muscle)
The elastic tissue in large elastic arteries are made by:
smooth muscle cells in the tunica media
As arteries get smaller they have:
- more smooth muscle and less elastic tissue in tunica media.