Chapter 18 Flashcards
Apex of Heart
inferior end formed by left ventricle
Base of Heart
Is superior/posterior portion formed by the atria; points to right shoulder
Pericardium Main Functions
1) Protects and anchors heart 2) Prevents heart from overfilling with blood 3) Allows the heart to work in a relatively friction free environment.
Coverings of the Heart (4)
1) Fibrous pericardium 2) Parietal Pericardium 3) Pericardial Cavity 4) Visceral / Epicardium
List the three layers of the heart wall
1) Epicardium (visceral pericardium) outer layer
2) Myocardium: cardiac muscle, bulk of the heart
3) Endocardium: endothelial layer of the inner myocardial surface
Where is the right ventricle located
(looking at piece of paper straight on) its on the left bottom side of the heart.
Where is the right Atrium
on the left upper side of heart
Where is the left ventricle/ atrium
ventricle = right, lower side of heart, atrium = right upper side of heart
Define Sulci (sulcus)
Groove on the surface of the heart
Define Coronary Sulcus
a depression surrounding the heart at the atrioventricular junction and giving passage to coronary arteries, coronary veins, and the coronary sinus.
Define Anterior Interventricular Sulcus
shallow groove between left and right ventricles on anterior surface (over septum)
Define Posterior Interentricular sulcus
siilar landmark but on the posteroinferior surface
Name the two vessels returning blood to the heart
Superior/ Inferior Venae cavae, Right/Left pulmonary veins
Name the two vessels conveying blood away from the heart
Pulmonary Trunk (left/right pulmonary arteries) Ascending aorta ( Brachiocephalic, left common, left subclavian arteries)
Compare the Atrias’ of the heart to the ventricles
-Atrias are the receiving chambers, and ventricles are the discharging chambers
What is a pectinate muscle
a combed muscle in the atrial walls
what three veins give blood to the right atrium
1) superior venae cavae (drains body superior to diaphragm)
2) Inferior venae cavae (drains body inferior from diaphragm)
3) Coronary sinus (drains myocardium) (is a vein attached to heart)
Where do the 4 pulmonary veins drain their blood to
the Left atrium
Describe Ventricles
pump blood away from the heart
where and what do papillary muscles and trabecular carneae muscles do
they mark the ventricular walls and prevent Artrioventricular valves from everting (going in or out on themselves)
which ventricle pumps blood into the pulmonary trunk
Right ventricle
where does the left ventricle pump blood to
the aorta
What is the function of heart valves
ensure unidirectional blood flow
Antrioventricular (AV)
prevents back flow from ventricles to atria
Right side = tricuspid
Left side = Mitral valvue (bicuspid)
Chordae Tendineae
Anchores AV valves to papillary muscles
Where do the two semilunar vales flow to and from
1) aortic semilunar: from left ventricle to aorta
2) pulmonary semilunar: from right ventricle to pulmonary trunk
how many nuclei can a heart muscle have
one or two
how do heart muscles behave
as a single coordinated unit (functional syncytium)
How does a heart muscle contract
1) stimulated by nerves
2) self-excitable (autorythmic: generates its own rhythmic action potentials independent of the nervous system).
Describe the function of Senatorial Nodes
a small group of cells in the walls of the right atrium that control the rhythmic beating of the heart. (SA nodes)
Does the heart have a long or short refractory period
A long one. (becomes unresponsive to further stimuli after a stimulation)
Briefly describe the 3 phases of action potentials in the cardiac muscle cells
1) Depolarization: na+ influx through fast na+ voltage gated channels. Channel inactivation ends this phase
2) Plateau Phase: due to Ca2+ influx through slow Ca2+ channels. this keeps the cell depolarized because few K+ channels are open
3) Repolarization: due to Ca2+ channels inactivating and K+ channels opening. allows K+ efflux, which brings the membrane potential back to its resting voltage.
Does nervous input modify cardiac conduction
Yes, but cardiac muscles can initiate action potentials on their own
what cells can depolarize spontaneously
pacemaker cells, (unstable resting potentials = pacemaker potentials)
what does calcium influx represent
the rising phase of the action potentials in the cardiac system
Where does Purkinje Finbers carry an impulse to
the heart apex and ventricular walls
Where do bundle branches carry an impulse to
the apex of the heart
what does p wave correspond to
depolarization of SA nodes
QRS complex corresponds to
ventricular depolarization
T wave corresponds to
ventricular depolarization
Lub Lub =
closing of the heart
sounds occur when
1) AV valves close
2) SL valves close
What does a cardiac cycle refer to
all events associated with blood flow through the hear
Systole =
contraction of heart muscle
Diastole =
relaxation of heart muscle
What does cardiac output mean
the amount of blood pumped by each ventricle in one minute
CO is the product of what
Heart reate (HR) and stroke volume (SV)
