06/07/2023 Notes Flashcards
What lines the heart valves and ensures unidirectional blood flow?
Endothelium
What is the fibrous skeleton of the heart?
Irregular dense connective tissue found between the atria and ventricles that separates them from each other, anchors heart valves, provide electrical insulation, and provides a rigid framework for attachment of cardiac muscle tissue
Why is it important to have electrical insulation in the heart?
Ensures that muscle impulses are not spread randomly and prevents the heart chambers from beating simultaneously
Where does the right atrium receive blood from?
Receives venous blood from systemic circulation and from heart muscle itself
Where does the superior vena cava drain blood from?
Head, neck, upper limbs, and upper regions of the trunk
Where does the inferior vena cava drain blood from?
Lower limbs and trunk
What drains blood from the heart wall?
Coronary sinus
What is the interatrial septum?
A thin wall between the right and left atria that contains the fossa ovalis
What is the fossa ovalis?
An oval depression in the interatrial septum that the occupies the former location of the foramen ovale
What is the right atrioventricular (AV) valve?
Tricuspid valve that is forced shut when the right ventricle contracts to prevent backflow of blood into right atrium
Where does deoxygenated blood from the right atrium travel to?
Through the tricuspid valve and into the right ventricle
What is the interventricular septum?
A thick wall between the right and left ventricles
What are trabeculae carneae?
Large, smooth irregular muscle ridges found on the internal walls of each ventricle
What are papillary muscles?
cone-shaped muscular projections that anchor chordae tendineae (thin strands of collagen fibers)
What do chordae tendineae do?
Attach to lower surfaces of cusps on the right AV valve and prevents the valve from everting and flipping into the atrium during contraction
What is the pulmonary semilunar valve?
Marks the end of the right ventricle and entrance into the pulmonary trunk
What are the pulmonary arteries?
Branches of the pulmonary arteries which carry deoxygenated blood to the lungs
semilunar valves are located in the walls of both _____.
Ventricles
What forms semilunar valves?
3 thin, half-moon shaped semilunar cusps
How do the semilunar valves/semilunar cusps work?
As blood is pumped into arterial trunks, it pushes against the cusps and forces the valves open, and when contraction ends, blood is prevented from backflowing by entering the semilunar valves between the cusps and chamber walls which causes the cusps to fill and expand
After gas exchange occurs in the lungs, where does the oxygenated blood travel to?
Left atrium
How many openings are found in the smooth posterior wall of left atrium?
4 (3 if pulmonary veins fuse!)
What are two other names for the left atrioventricular (AV) valve?
Bicuspid valve/Mitral valve
The left ventricle has a muscle wall that is _____ times bigger than the right ventricle.
3
Why does the left atrium have a thick muscle wall?
It is needed to generate enough pressure to force the oxygenated blood into the aorta and throughout the entire systemic circulation
Trabeculae carneae are more prominent in which heart chamber?
Left ventricle
What does the aortic semilunar valve indicate?
End of the left ventricle and entrance to aorta
What supplies blood to the heart?
Left and right coronary arteries that travel in the atrioventricular groove between atria and ventricles that are the only branches of the ascending aorta and exit superior to aortic semilunar valve
Coronary arteries branch into smaller arteries and arterioles to supply what?
Blood with oxygen and nutrients to the capillaries of the myocardium of atria and ventricles
What is ischemia?
Inadequate supply of oxygen to a part of the body
What is silent myocardial ischemia?
Painless myocardial ischemia
What is painful, agonizing myocardial ischemia?
Angina pectoris
What are cardiac veins?
Veins that carry venous blood from myocardial capillaries
Where do ALL cardiac veins drain into?
Coronary sinus that lies in the posterior aspect of the atrioventricular groove that drains directly into the right atrium
When does most coronary blood flow occur?
During diastole (relaxation) when ventricular walls are relaxed
What is tachycardia?
Abnormally high heart rate (above 100 bpm) that shortens diastole and reduces blood flow to ventricular myocardium
What is hypotension?
Abnormally low blood pressure that can also reduce blood flow through the ventricular myocardium
What is needed to ensure efficient pumping of blood through heart and blood vessels?
Precise coordinated contractions of heart chambers
What makes contraction of the heart possible?
Conducting system of the heart (properties of cardiac muscle tissue and specialized cells in the heart)
What is audtorhythmicity/intrinsic rhythmicity?
The heart’s ability to initiate the heartbeat itself by specialized cardiac cells
What initiates the heartbeat?
Cardiac fibers of the sinoatrial (SA) node that are located in the posterior wall of the right atrium
Fibers of the SA Node act as the ______, the rhythmic center that establishes pace for cardiac activity
Pacemaker
Under the influence of parasympathetic innervation, the SA node initiates impulses at what rate?
70-80 bpm
Where do muscle impulses travel from the SA Node?
Cardiac muscle of both atria to cause contraction (atrial systole) and then the the atrioventricular (AV) node
What does the fibrous skeleton of the heart do?
Prevent random nerve impulses from spreading between the atria and ventricles
Where can nerve impulses travel through the fibrous skeleton?
At openings in the fibrous skeleton called “Bundle of His”
The AV Node does what to the rate of contraction? Why is this important?
Slows the rate of the impulse to provide a delay between activation and contraction of the upper/lower chambers to allow the atria to contract first and then the ventricles
What is another name for the Bundle of His?
Atrioventricular Bundle
What are purkinje fibers?
Large conduction fibers the recieve the impulse from Bundle of His
Muscles impulses across purkinje fibers are…?
Rapid, consistent with large size of cells, and impulse is spread immediately to stimulate contraction
How is the electrical activity of the heart monitored?
With an electrocardiograph that develops an electrocardiogram
