Placed in the thoracic medial cavity (mediastinum)
Extends obliquely, tilted left, for 12 to 14 cm from the second rib to the fifth intercostal space
It rests on the superior surface of the diaphragm and
Lies anterior to the vertebral column and posterior to the sternum.
The lungs are on the lateral side
It's Tip (called apex), is the point of maximal intensity
The heart wall is a double-walled sac called
The loosely fitting superficial part of the sac is call fibrous pericadium: Is tough, dense connective tissue layer designed to do three things
1. Potects the heart
2. anchors it to surrounding structures
3. prevents overfilling of the heart with blood
The loosely fitting superficial part of the sac is called
The heart wall composed of three layers
epicardium, myocardium and the endocardium
The superficial epicardium is the visceral layer of what? Often filtrated with fat, especially in older people.
The heart wall is rich in blood supply, and made up of what kind of tissue?
the heart wall middle layer, has cardiac muscle, involved in contraction, form crisscrossing tissue fibers and arranged in spiral or circular bundles
Located in the heart wall is a sheet of squamous epithelium on a thin connective tissue layer.
Located on the inner myocardial surface of the heart wall
Located on the inner myocardial surface
•covers the fibrous skeleton of the valves.
The layer lines the heart chambers
Part of the heart wall this layer covers the fibrous skeleton of the valves.
How many chambers of the heart
What are the 4 chambers of the heart
two superior atria and (artium - single)
two inferior ventricles
This separates the atria longitudinally L and R
This separates the ventricles.
This ventricle forms most of the anterior surface
The right ventricle
This ventricle dominates the inferoposterior aspect of the heart and forms the heart apex.
The left ventricle
Otherwise known as the Receiving Chambers
it's Left and Right chambers, are small and thin-walled
In this chamber is pushes blood "downstairs" into the ventricles, low pressure
Blood enters the right atrium via these three veins
superior vena cavareturns, the inferior vena cavareturns, and the coronary sinus
This vein returns blood to the heart from the body regions superior to the diaphragm
superior vena cavare
The vein returns blood to the heart from body areas below the diaphragm
inferior vena cava
This vein collects blood from the myocardium.
the coronary sinus
How many pulmonary veins enter the left atrium, transporting blood from the lungs back to the heart
What veins enter the left atrium? transporting blood from the lungs back to the heart
Using the pulmonary veins blood enter the left atriumfrom where?
Also know as the Discharging Chambers
make up most of the volume of the heart
It's internal walls have irregular ridges of muscle trabeculae carneae "crossbars of flesh", massive
Cone-like papillary muscles play a role in valve function, project into this cavity
The Left ventricle contracts to propel blood out of the heart into circulation via the?
this is the largetst artery
Which chamber pumps blood into the pulmonary trunk?
The right ventricle pumps blood into this; which routes the blood to the lungs where gas exchange occurs.
The R ventricle pumps blood into the pulmonary trunk, to the lungs for this reason?
The blood vessels that carry blood to and from the lungs for gas exchange is called what circuit
The blood vessels that carry blood supply to and from all body tissues is part of what circuit.
The functional blood supply to the myocardium; is the shortest circulation in the body
Function of the left side of the heart
This pathway of Oxygenated blood from the lungs to the LA to LV, pumped into the aorta
The systemic circulation
From the Aorta to smaller systemic arteries to the body tissues, where gases and nutrients are exchanged across the capillary walls support what pathway
Blood loaded with CO2 and depleted of O2, returns through the systemic veins to the R side of the heart
Through the superior and inferior venae cavae, the RA receives blood from what circuit
smaller systemic arteries carry to the body tissues, where gases and nutrients are exchanged across the capillary walls. As blood loaded with CO2 and depleted of O2, returns through the systemic veins to the R side of the heart, entering the RA through the superior and inferior venae cavae. This happens how often?
This cycle repeats itself continuously.
Function of the right side of the heart
Blood returning from the body is O2 poor and CO2 rich in what circuit
From RA to RV, then to lungs the blood uses this
the pulmonary trunk
In the lungs, the blood unloads CO2 and picks up O2 during this circulation
The freshly oxygenated blood is carried by the pulmonary veins back to the left side of the heart during this circulation
True or false: the Pulmonary circulation pumps handles more blood volume than the Systemic Circulation
False they have Equal volumes of blood handle however they have unequal workloads.
Via the RV, this is a short, low-pressure circulation
via the LV, the blood takes a long pathway, encounters 5x friction, or resistance to blood flow in what circuit
The walls of the LV (which are nearly circular) are how many time as thick as compared to the wall of the RV
Which ventricle generates much more pressure than the other and is a far more powerful pump
The arterial supply of the coronary circulation is by which arteries, both arising from the base of the aorta and encircling the heart in the coronary sulcus
the R and L coronary arteries
The LCA toward the L side of the heart and then divides into its major branches:
the anterior interventricular artery (aka left anterior descending artery) and the circumflex artery
follows the anterior interventricular sulcus and supplies blood to the interventricular septum and anterior walls of both ventricles
left anterior descending artery (aka anterior interventricular)
Supplies blood to the left atrium and the posterior walls of the left ventricle.
The RCA courses to the right side of the heart, where it also divides into two branches
the marginal artery and the posterior interventricular artery
the artery that supplies blood to myocardium of the lateral right side of the heart
the marginal artery
this artery runs to the heart apex and supplies the posterior ventricular walls
The posterior interventricular artery
Near the apex, this artery merges (anastomoses) with the anterior interventricular artery
posterior interventricular artery
Together these branches of the RCA supply the right atrium and nearly all the right ventricle with blood
the marginal artery and the posterior interventricular artery
Blood flows in how many directions through the heart.
one: from atria to ventricles and out the great arteries leaving the superior aspect of the heart
how many valves in the heart
There are 4 valves that open and close in response to what on their two sides?
differences in blood pressure
Two of the four vales are located where?
The two valves at the Atrial-ventricular junction are designed to do what?
prevent backflow into the atria when the ventricles are contracting
the right AV valve (Atrial-ventricular) has three flexible cusps (flaps of endocardium reinforced by connective tissue cores) the valve is called what?
The left AV valve (atrioventricular), with two flaps, is called
mitral or the bicuspid valve
Two semilunar valves (half-moon)
The aortic and the The pulmonary
The valve that guards the bases of the aorta and prevent backflow into LV.
This valve guards the bases of pulmonary artery and prevent backflow into RV
What is the role of Cardiac skeletal muscles?
Large mitochondria account for how much of the volume of cardiac cells (only 2% in skeletal muscle)
25–35% of the volume of cardiac cells
What gives cardiac cells a high resistance to fatigue.
Cardiac muscle cells are self-excitableand can initiate their own what
Cardiac muscle cells initiate their own depolarization in a spontaneous and rhythmic way called what
automaticity or autorhythmicity
In cardiac muscle, the heart either contracts as a unit or what happens?
doesn’t contract at all
The ability of cardiac muscle to depolarize and contract is
The depolarization wave travels across the heart from cell to cell via ion passage throught what type junction
An impulse (electrical excitation) located in the RA wall, excites ~ 75 times every minute
Sinoatrial node (SA)
Sinoatrial node (SA) sets the pace for the heart (pacemaker) and its rhythm is called?
Sinus rhythm determines what
From the SA node, the depolarization wave spreads via atrial gap junctions to the what?
Atrioventricular node (AV)
From the AV node, the impulse sweeps to this in the superior part of the interventricular septum (leads into the R and Left bundle branches)-apex.
impulse passes through long strands of barrel-shaped cells, penetrate into the heart apex, and then turn superiorly into the ventricular walls.
is a tracing of a single action potential of heart activity
Electrocardiogram(ECG or EKG)
ECG has three distinguishable waves or deflections, what are they
P Wave, QRS complex and the T wave
This wave lasts 0.08s, movement of the depolarization wave from the SA node through the atria
0.1 s after the P wave begins, what contracts?
This results from ventricular depolarization and precedes ventricular contraction, lasts 0.08 s.
This is caused by ventricular repolarization and lasts 0.16 s.
Why is theT wave more spread out and has a lower amplitude
because Repolarization is slower than depolarization
What is the time called (about 0.16 s) from the beginning of atrial excitation to the beginning of ventricular excitation