Heart Flashcards
What is the heart responsible for maintaining?
constant supply of fresh oxygen and nutrients to the body’s tissue while removing carbon dioxide and waste
Right side of the heart
receives oxygen-poor blood and pumps it to the lungs (pulmonary circuit)
Left side of the heart
receives oxygen-rich blood and pumps it to the body (systemic circuit)
Two Atria
The receiving chambers
“little hallway”
Right Atrium
receives blood returning from the systemic circuit
Left Atrium
receives blood returning from the lungs
Two Ventricles
The pumping Chambers
“little belly”
Right Ventricle
pumps blood into pulmonary circuit
Left Ventricle
pumps blood into the systemic circuit
Location of heart
Size = human fist
Between sternum and vertebral column
Rests on diaphragm
2/3 of the heart’s mass is to the left of the midsternal line
Pericardium
double-walled sac that encloses the heart
Fibrous Pericardium
loose fitting superficial part of the pericardium
- dense connective tissue
- protects heart, keeps it from overfilling, anchors it to the mediastinum
Serous Pericardium
deep to the fibrous pericardium, made of 2 thin layers
- Parietal layer
- Visceral layer
Parietal Layer
lines the internal surface of the fibrous pericardium
Visceral layer
lines the external surface of the heart
Pericardial Cavity
space between the parietal + visceral layers, filled with serous fluid
- reduces friction
Pericarditis
inflammation of the pericardium
- beating heart rubs against the pericardial sac - an audible sound produced
Symptom- pain deep to sternum
- can lead to adhesions, impeded cardiac activity
Cardiac Tamponade
compression of the heart by large amounts of inflammatory fluid in the pericardial cavity
- heart’s ability to pump blood is reduced
- Management_ removal of excess fluid by syringe
Layers of heart
- Epicardium
- Myocardium
- Endocardium
Epicardium
most superficial
Myocardium
middle muscle layer
- composed of contracting, cardiac muscle; bulk of heart
- cardiac muscle cells are arranged in spiral bundles, tethered together by crisscrossing connective tissue (tissue important for sending signals)
Cardiac Skeleton
a reinforcing, dense network formed by the connective tissue fibers
- prevents overstretching from continuous stresses and ensures that action potential only spread along desired pathways
Endocardium
deepest layer, made of endothelium
- line heart chambers, contiguous with the lining of the great vessels
How many chambers, atria, and ventricles are there?
4 chambers
2 superior atria
2 inferior ventricle
Coronary Sulcus (atrioventricular groove)
encircles the junction of the atria and ventricles
Anterior Interventricular Sulcus
carries the anterior interventricular artery, marks the interventricular septum
Posterior Interventricular sulcus
carries the psoterior interventricular artery, marks the interventricular septum
Auricles
small, wrinkled appendages that sit atop each atrium
- expand the volume capacity of the right and left atria as needed
Atria
small, receiving chambers; generate only minimal contraction to push blood into the ventricles
- anterior wall of right atrium is covered with pectinate muscle
- left atrium’s wall are smooth
blood enters the right atrium via…
Coronary Sinus
Superior Vena Cava
Inferior Vena Cava
Blood enter the left atrium via…
Pulmonary veins (4)
Ventricles
makes up most of the volume of the heart
- left ventricle wall is 3x thicker than right ventricles
- left ventricle is circular while right is crescent shaped
slide 15..
Valves
esnures that blood flowd through the ehart in only one direction
atria -> ventricles; ventricles -> great arteries
Atrioventricular valves (AV)
located at each atrial-ventricular junction, prevent backflow of blood into the atria during ventricular contraction
Tricuspid valve
located between the right atrium and ventricle, has 3 flexible cusps
cusps: flap of endocardium
Bicupid valve
located between the left atrium and ventricle, has 2 flexible cusps
chordae tendinae
… slides 16
Functions of valves
blood returning to the atria puts pressure against AV valves; the AV valves are forced opened
as the ventricles fill, AV valve cups hang limply into ventricle
atria contract, forcing additional blood into ventricles
ventricles contract forcing blood against AV valve cusps
AV valve close
chordae tedinae tighten, preventing valve cusps from everting into atria
Simulunar Valves (SL)
- Aortic + Pumonary
guard the bases of the large arteries emerging from each of the ventricle, prevents backflow from vessel to ventricle
Why do SL Valves open and close in response to what
changes in pressure
- forced open as ventricle contact and pressure rises
- close as blood backflows toward the heart and dills the cusps
slide 20
Valve disease/replacement
leaking valves recue the efficiency of pumping heart
incompetent/insufficient valves force heart to repump the same blood multiple times
stenotic valves are stiff/narrowed, constrict heart’s openings (narrowed openings force the heart to contract more forcefully)
faulty valves increases heart’s workload - heart weakens over time
mitral and aortic valves are msot often affected
valves can be replaced with mechanical replicas, chemicallt treated pig or cow valves, or cryopreserved cadaver valves
