Anatomy_Key Terms_Ch19 Flashcards
embryonic sinus venosus
”"”of the vein””, this chamber, which initially receives all blood from the veins of the embryo, will become the smooth-walled part of the right atrium and the coronary sinus; it also gives rise to the sinoatrial node. recent evidence indicates that it also contributes to the back wall of the left atrium (which mostly derives from the bases of the developing pulmonary veins).”
embryonic atrium
this embryonic chamber eventually becomes the ridged parts of the right and left atria–specifically, the parts line by pectinate muscles
embryonic ventricle
the strongest pumping chamber of the early heart, the embryonic ventricle gives rise to the left ventricle
embryonic bulbus cordis
this chamber and its most cranial extension, the truncus arteriosus, give rise to the pulmonary trunk and first part of the aorta. it also gives rise to the right ventricle
ventricular septal defect
the superior part of the intterventricular septum fails to form; thus, blood mixes between the two ventricles. more blood is shunted from left to right because the left ventricle is stronger.<br></br>occures in about 1 in every 500 births
transposition of the great vessels
aorta comes from right ventricle; pulmonary trunk from left. results when the bulbus cordis does not divide properly. unoxygenated blood passes repeatedly around systemic circuit, while oxygenated blood recycles around the pulmonary circuit.<br></br>occurs an about 1 in every 1000 births
coarctation of the aorta
a part of the aorta is narrowed, increasing the workload of the left ventricle.<br></br>occurs in about 1 in every 1500 births
tetralogy of Fallot
multiple defects: 1) pulmonary trunk too narrow and pulmonary valve stenosed, resulting in 2) hypertrophied right ventricle; 3) ventricular septal defect; 4) aorta opens from both ventricles.<br></br>occurs in about 1 in every 2000 births
apex (heart)
heart assumes an oblique position in the thorax, with its pointed _ lying to left of the midline and anterior to the rest of the heart
base (of the heart)
“the heart’s broad posterior surface”
pericardium
”"”around the heart””, triple-layered sac that encloses the heart”
fibrous pericardium
outer layer of the pericardium, strong layer of dense connective tissue, acts as a tough outer coat that holds the heart in place and keeps it from overfilling with blood
serous pericardium
deep to the fibrous pericardium, double-layered, a closed sac sandwiched between the fibrous pericardium and the heart
parietal layer of the serous pericardium
outer layer, adheres to the inner surface, continuous with the epicardium
visceral layer of the serous pericardium
aka epicardium, lies on the heart and is considered a part of the heart wall
pericardial cavity
a division of the embryonic coelom, slitlike space between the parietal and visceral layers of serous pericardium
epicardium
”"”over the heart”” visceral layer of the serious pericardium, often infiltrated with fat especially in older people”
myocardium
”"”muscle heart””, forms the bulk of the heart, consists of cardiac muscle tissue and is the layer that actually contracts”
endocardium
”"”within the heart””, deep to the myocardium, sheet of simple squamous epithelium resting on a thin layer of connective tissue, lines the heart chambers and covers the heart valves”
interatrial septum
partition between the atria that divids the heart longitudinally
interventricular septum
partition between the ventricles that divide the heart longitudinally
oronary sulcus
(corona=crown), extends horizontally, circling the bondary between the atria and the ventricles, external groove
anterior interventricular sulcus
external groove extends vertically, marking teh anterior position of the interventricular septum
posterior interventricular sulcus
“external groove, extends vertically, separating the two ventricles on the heart’s inferior surface”
right atrium
forms the entire right border of the human heart, receiving chamber for oxygen-poor blood returning from the systemic circuit, receives blood from three veins (superior vena cava, inferior vena cava, coronary sinus)
right auricle
“(auricle=little ear), external small flap shaped like a dog’s ear, projects anteriorly from the superior corner of the atrium”
pectinate muscles
(pectin=comb), horizontal ridges than line the anterior part of the right atrium
crista terminalis
”"”terminal crest””, large C-shaped ridge that seperates the posterior and anterior parts of the right atrium”
fossa ovalis
a depression in the interatrial septum that marks the spot where an opening existed in the fetal heart (foramen ovale)
pulmonary trunk
artery that passes blood from the right atrium into the pulmonary circuit
right ventricle
forms most of the anterior surface of the heart, receives blood from the right atrium and pums it into the pulmonary circuit
trabuculae carneae
”"”little beams of flesh””, irrigular ridges of muscle that mark the internal ventricular walls”
papillary muscles
(papilla=nipple), cone-shaped, project from the walls into the ventricular cavity
cordae tendineae
”"”tendinous cords”” (““heart strings””), thin strong bands that project superiorly from the papillary muscles to the flaps (cusps) of the tricuspid (right atrioventricular) valve”
left atrium
“makes up most of the heart’s posterior suface or base, receives oxygen-rich blood returning from the lungs”
pulmonary veins
two right and two left, pass oxygen-rich blood returning from the lungs to the left atrium; tributaries generally lie anterior to the corresponding bronchi within the lungs
left ventricle
“forms the apex of the heart and dominates the heart’s inferior surface, pumps blood into the sytemic circuit”
right atrioventricular (tricuspid) valve
has three cusps, located at the junction of the atria and ventricle
left atriovenricular (bicuspid) valve
aka mitral valve, has two cusps, located at the junction of the atria and ventricle
aortic and pulmonary (semilunar) valves
three pocketlike cusps shaped roughly like cresent moons, located at the junctions of the ventricles and the great arteries
cardiac skeleton
lies in the plane between the atria and the ventricles and surrounds all four heart valves rather like handcuffs, composed of dense connective tissue
heartbeat
a single sequence of atrial contraction followed by ventricular contraction
systole
”"”contraction””, the contraction of a heart chamber”
diastole
”"”expansion””, the time during which a heart chamber is relaxing and filling with blood”
cardiac muscle tissue
forms the thick myocardium of the heart wall, contains cardiac muscle cells and the connective tissues that surround these cells, striated, contracts by the silding filament mechanism
intercalated discs
”"”inserted between””, complex junctions that join cardiac muscle cells, sarcolemmas of adjacent cells interlock through meshing ““fingers”””
fasciae adherens
desmosome-like junctions contained in transverse regions of intercalated discs, function to bind adjacent cells together and transmit the contractile force to adjacent cells
conducting system
series of specialized cardiac muscle cells that carries impulses throuhout the heart musculature, signaling the heart chambers to contract int he proper sequence; it also initiates each contraction sequence, thereby setting basic heart rate
sinoatrial (SA) node
“crescent-shaped mass of muscle cells that lies in the wall of the right atrium just inferior to the entrance of the superior vena cava; impulse that signals each heartbeat begins at the _; sets the basic heart rate by generating 70-80 electrical impulses per minute (heart’s pacemaker)”
internodal pathway
some impulses travel along an _ from the SA node; impulses spread in a wave along the caridac muscle fibers of the atria, signaling the atria to contarct
atrioventricular (AV) node
in the inferior part of the interatrial septum, some impulses travel along an internodal pathway to the _ where they are delayed for a fraction of a second
antriventricular (AV) bundle
after the AV node delay, the impluses race through the _ which enters the interventricular septum
bundle branches
”"”legs”” (crura), AV bundle enters the interventricular septum and divides into right and left _”
subendocardial conducting network
aka Purkinje fibers, about halfway down the septum, the bundle branches terminate in the _, which aprroach the apex of the heart and then turn superiorly into the ventricular walls
parasympathetic nerves to the heart
arise as branches of the vagus nerve in the neck and thorax, innervation decreases heart rate and is restricted to the SA and AV nodes and the coronary arteries
sympathetic nerves to the heart
travel from the cervical and upper thoracic chain ganglie, innervate the SA node, AV node, and coronary arteries, project to the cardiac musculature throughout the heart, increases heart rate and strength of contraction
cardioinhibitory center
in the medulla, influences parasympathetic neurons
cardioacceleratory center
in the medulla, influences sympthatetic neurons
left coronary artery (LCA)
arises from the sleft side of the aorta, passes posterior to the pulmonary trunk, then divides into two branches: the anterior interventricular and circumflex arteries
atnterior interventricular artery
aka left anterior descending artery (LAD), descends in the anterior interventricular sulcus toward the apex of the heart, sends branches into and supplies the interventricular septum and anterior walls of both ventricles
circumflex artery (Cx)
follows the coronary sulcus posteriorly and supplies the left atrium and the posterior part of the left ventricle
right coronary arter (RCA)
emerges from the right side of the aorta and descends in the coronary sulcus on the anterior surface of the heart, between the right atrium and right ventricle
