Flashcards in Internal heart Deck (34):
Name the layers of the heart?
Epicardium (visceral pericardium)
what is the epicardium made up of?
lined with mesothelium externally
What is The myocardium made up of?
Contains cardiac muscles
cardiac (perkje) fibers
What is the endocardium made up of?
inner epithelial layer
inner CT layer
Describe the pumping of blood.
1)atria fill with blood
2)ventricles relax, AV valves open, 80% of blood enters ventricles
3)atria pump at end of cycle, drives rest of 20% into ventricles
4)ventricles contract, pressure increase, AV valves close, semilunar valves open
5) blood leaves ventricles, AV valves open cycle restart
what is the path of blood through the heart?
1) blood enters heart through the IVC,SVC, coronary sinus and interior cardiac veins to the Right atrium
2) goes to the tricuspid valve to right ventricle
3) goes through to the pulmonary valve to pulmonary arteries and enters heart
4) gets oxygenated and leaves lung
5) goes through pulmonary veins to left atrium
6) goes through the bicuspid valve to left ventricle
7)passes through the aortic valve to ascending aorta and enters body
What and where is Crista termanalis?
represents the junction between the sinus venosus and the heart in the developing embryo
smooth muscle found at the opening of the auricle
marks the beginning of the pectinate muscles
externally corresponds with the Sulcus termanalis cordis
What is the interatrial septum?
This represents the area that divides the atria.
during embryo development this is formed from the septa primium and the septa secudum
What is the fossa ovalis?
depression in the right atrium of the heart, the remnant of a thin fibrous sheet that covered the foramen ovale during fetal development
what is the limbus fossa ovalis?
is the prominent oval margin of the fossa ovalis. It is in the right atrium.
What are the pectinate muscle?
Resembling teeth of a comb. They makeup the wal of the atria
What is the tricuspid valve?
A three leafelet valve that stops the back flow of blood from the left ventricle into the right atrium
forms most of the anterior surface of heart
What is the conus arteriosus?
This is a pouch formed from the right ventricle.
from which the pulmonary trunk arises
What are the land marks of the right ventricle?
cardiac conductive fibers (Purkije)
from the external view, identify the right ventricle
Just below the coronary sinus, between the interventricular sulcus
What are the major structures of the left atrium?
forms most o the base of the heart
What are the major structures of the left ventricle?
what is the cardiac skeleton?
Collection of dense, fibrous connective tissue forming four rings in a plane that separates atria and ventricles
Maintains integrity of openings, general structure of heart
Attachment point for valve cusps and cardiac muscles
Serves as an electric isolation of atria and ventricles; no crossed neural pathways
What is the trigone?
fibrocartilage that that connects the Mitral valve, aortic, and the tricuspid rings of the heart.
the pulmonary valve is distinct from the three rings
Describe the A/V valves.
They use the parachute model, where the edges are held in place by the by cardiac skeleton and the cusps are loose.
What prevents the cusps of the A/V valves from collapsing into the Atria?
Explain diastole (ventricular relaxation) from the A/V valves perspective.
valves open passively as arterial pressur exceed vetricular pressure
Explain systole (ventricular contraction) from the A/V valves perspective.
Ventricular pressur is higher than arterial pressure
dont collapse because of strength of chordae tendineae and papillary muscles
Describe the Semilunar valve
three leaflet valve with no ligaments or muscle associated with them
explain the function of the semilunar valves during diastole (ventricular relaxation).
Sinus of leaflet catch blood during increased arterial pressure. keeps the valves closed
explain the function of the semilunar valve during the systole (ventricular contraction)
Valves open due to the increased pressure in the ventricles
Name the cusps of the valves
Tricuspid - Anterior, septal, posterio
Mitral- Anterior, posterior
Aortic - left, right, Posterior
pulmonary- anterior, left, right
Where is the SA node (cardiac pacemaker)?
In the Crista terminalis
the junction of the SVC and the right Atrium
Where is the A/V node?
in the right atrium, near the opening of the coronary sinus
Where is the Atrioventricular bundle?
Continuation of the A/V node, follows the lower border of the interventricular septum (toward the apex)
split into left and right bundles
carries signal to left/right ventricle
What are the Subendocardial plexus of conduction cells (Purkenje fibers)?
terminal branches of the A/V bundle
Describe the contraction of the heart.
Action potential starts in the SA node across the Atria (atria contract)
It reaches the A/V node, travels slowly across the A/V node (time for atria contraction)
travels to A/V bundle, then to purkenje fibers (ventricles contract)