Vascular Anatomy Flashcards
where is the SA node located
located in the intra-atrial wall of the right atrium near vena cava and intravenous tubercle
function of the SA node
pacemaker - controls heart rate
location of the AV node
caudal right atrium near septum
function of the AV node
ensures atrium is completely filled before conducting the signal to the ventricles
location of the purkinje fibers
subendocardial layer
(between endocardium and myocytes/myocardium)
function of Purkinje fibers
specialized cardiac cells that allow for synchronized contraction
fossa ovale
remnant of the foramen ovale during development
located in the right atrium
coronary sinus
opening for venous return from coronary circulation; receives deoxygenated blood from coronary veins –> empties into R atrium
located in the right atrium
moderator band (septomarginal trabeculae)
allows purkinje fibers to extend to the right lateral heart
located in the right ventricle
annulus fibrosus
skeletal component of the heart; provides structural separation between the atrium and ventricles
fibrous rings surrounding all 4 valves to act as an anchor
prevents most connections between atrium and ventricles
what is the only thing that can cross from atrium to ventricles
purkinje fibers
chordae tendinae
fibrous strands that attach the valves to the papillary muscles of the ventricle wall
prevents valves from inverting into atrium while closing to prevent back flow
atrioventricular (AV) valves
separate atrium and ventricle
left side: mitral
right side: tricuspid
semilunar (SL) valves
separate ventricles and great vessels
left side: aortic valve
right side: pulmonary valve
coronary arteries
first branches off of the aorta; supplies oxygenated blood to the heart
travels in the coronary groove around the heart between atria and ventricles
right C.A.: supplies the right side of the heart
left C.A.: supplies the left side of the heart
interventricular subsinuosal groove
groove that the right coronary artery travels in
interventricular paraconal groove
groove that branches from the left coronary artery travel in
how does sympathetic innervation affect the heart
increases HR, contractility, and conduction velocity
what node(s) does the sympathetic nervous system innervate
AV node only
sympathetic trunk
dorsal chain of sympathetic ganglia that runs from head to tail alongside the spine
cervicothoracic ganglia
“stellate” ganglia
extends nerve fibers down to middle cervical ganglia via ansa subclavia
middle cervical ganglia
innervates the heart and lungs
origination point of the vagosympathetic trunk
vagosympathetic trunk
combined sympathetic and parasympathetic nerve fibers that run within the same nerve sheath
sympathetic: extends cranially from middle cervical ganglia to innervate the head
parasympathetic: extends caudally from middle cervical ganglia as the vagus nerve
how does parasympathetic innervation affect the heart
decrease HR, contractility, and conduction velocity
what node(s) does the parasympathetic nervous system innervate
SA and AV node
is SNS or PNS the predominant innervation at rest
parasympathetic - keeps HR low
vagus nerve
cranial nerve 10
extends to thorax via vagosympathetic trunk until the level of the middle cervical ganglia –> continues caudal as only vagus nerve
branches into dorsal and ventral at the level of the base of the heart
the L and R dorsal & ventral branches merge to form dorsal or ventral vagal trunks
species variations in aortic branches
carnivores: 2 branches - L subclavian and brachiocephalic trunk
herbivores: 1 branch - brachiocephalic trunk
how do you identify branches off the subclavian
named based off of where they terminate
ex. internal thoracic, superficial cervical, vertebrae, cervical, scapula, intercostal, etc
what are the three layers of the vessels
tunica externa
tunica media
tunica intima
tunica externa
adventitia; connective tissue surrounding the vessel
contains nerves and vasa vasorum
tunica media
smooth muscle
+ elastin in arteries
tunica intima
endothelium and basement membrane
characteristics of arteries
thick walled
high pressure
no valves
THICK tunica media
wave endothelium
characteristics of veins
thin walled
low pressure
valves present
THIN tunica media
smooth endothelium
histological layers from inside –> outside of cardiac vessels
- endothelium
- sub endothelial CT
- myocardium
- subepicardial CT
- epicardium (mesothelium)
cardiomyocyte characteristics
cardiac muscle cells
central nuclei
intercalated discs between cells
branching of individual cells
