A&P: Cardiovascular system; Heart Flashcards
Pulmonary circuit
Right-Sided pump
Receives oxygen-poor blood from system, then pumps it to lungs
Short, low pressure circulation
Systemic circuit
Left-Sided pump
Receives oxygenated blood from lung, then pumps it to system
Enters left side of heart, exits aorta, then to whole body
Long, high resistance to blood flow
Pericardium
Fibrous pericardium
Serous pericardium
Fibrous pericardium
Outermost layer
Dense CT
Protects, anchors, and prevents overfilling of heart with blood
Serous pericardium
Deep to fibrous
Parietal layer: below/connected to bottom of fibrous
Continous with visceral layer at pulmonary trunk
Pericardial cavity: between 2 layers; film of serous fluid
Visceral layer: (epicardium); layer just on top of heart muscle (integral part of heart wall)
Myocardium
Cardiac muscle
Bulk of heart
Cardiac skeleton: reinforces myocardium and anchors cardiac muscle
Endocardium
Simple squamous epithelial tissue
Lines heart chambers
Touches blood
Continuous with endothelium of all blood vessels
Atria
2 receiving chambers
(Superior)
Right: receives deoxygenated blood from vena cava and coronary sinus
Left: receives oxygenated blood from lungs
Fill simultaneously, then contract
Ventricles
2 heavy duty pumping units Thick myocardial walls (Inferior) Make up most of heart volume Right: receives blood from right atrium Left: received blood from left atrium Fill simultaneously, then contract
Interatrial septum
Separates atrium
Divides heart longitudinally
Interventricular septum
Thicker
Separates ventricles
Blood enters right atrium via 3 veins:
Superior vena cava: returns blood from body regions superior to diaphragm
Inferior vena cava: returns blood from body areas below diaphragm
Coronary sinus: collects blood draining from myocardium
Pulmonary veins
2 right and 2 left
Both carry blood to LEFT atrium
Accessory muscles
Trabecular carnae: muscle projections in wall of ventricles; increase strength of contraction
Papillary muscles: help close AV valves; attached to collagen
Contraction –> closure of valves
Pulmonary trunk
Right side
Blood goes from right ventricle –> pulmonary think –> pulmonary artery
Aorta
Equivalent ot pulmonary trink, except carries oxygen rich blood
Left ventricle –> aorta
Fossa ovalis
In interatrial septum
Between septa
Depression that was once a fetal hole connected to atria
Atrioventricular valves (AV)
2 Between atrium and ventricle Prevent back flow into atria when ventricles contract Right: tricuspid Left: bicuspid (mitral valve)
Chordae tendoneae: collagen cords attached to papillary muscles on AV flaps
Want AV valves closed when ventricles are contracting, to prevent back flow of blood
Semilunar valves (SL)
2 Pulmonary valve -Between right ventricle and pulmonary trunk Aortic valve -Between left ventricle and aorta
When ventricles are contracting, semilunar valves are open
Ventricle –> out
Like AV valves, open and close in response to pressure
Left coronary artery
Circumflex artery: serves lateral side if heart (left atrium and ventricle)
Anterios interventricular artery: runs down center
- Supplies blood to inter ventricular septum and anterior walls of both ventricles
- LAD: left anterior descending artery
Right coronary artery
Marginal artery: serves myocardium of lateral side of ventricle
Posterior interventricular artery: back of heart (posterior ventricle walls)
Coronary veins
Collects venous blood
Coronary sinus
Drains coronary vessels
Sends blood to right atrium
Cardiac output (CO)
Amount of blood pumped out by each ventricle in 1 min
Increases when SV increases and/or heart beats faster
Stroke volume (SV)
Volume of blood pumped out by one ventricle with each beat
Cardiac reserve
Difference between resting and maximal CO
EDV
End diastolic volume
Blood volume when ventricles are at rest (after ventricular filling)
Higher EDV, higher CO
Influenced by:
- Ventricular diastole
- Venous return: amount of blood transported into R&L atria
More return, more blood into ventricles, higher EDV
ESV
End systolic volume
Residual blood; left over after ventricles contract
Influenced by:
- Arterial BP
Higher the BP, the more difficult for ventricles to eject blood, more ESV leftover
-Ventricular systole
Harder the ventricles contract, less ESV
Preload
Degree of stretch just before systole
Increased preload = increased SV
Frank-Startling law
Increase preload via increased venous return
Increased preload, increased EDV, increased strength of contraction
Venous return
Amount of blood returning to the heart and distending its ventricles
Contractility
Contractile strength achieved at a given muscle length
Increased intracellular Ca++ = higher contractility
Sympathetic stimuli = higher contractility
Positive and negative inotropic agents:
+ : epinephrine, thyroxine, glucagon
- ; adidosis, rising K+ levels and calcium channel blockers
Increased contractility = decreased ESV
Afterload
Pressure that the ventricles must overcome to eject blood
Increase after load, increased ESV, decreased CO, increase SV
Arrhythmia
Abnormal heart rate b/c electrical conduction system is out of sync
Bradycardia
Depends on individual
Less then 60 bp (heartbeat slower than normal)
May result from low body them, parasympathetic nervous activation
Seen in extremely trained/elite athletes
Tachycardia
May result from elevated body temp, stress, certain drugs, or heart disease
Resembles someone out of shape
Flutter: 200-33 bpm; electrical current is in sync, just very fast
Fibrillation: high bp; electrical current is chaotic
-Lack of SA node stimulation
Heart valves
Heart murmurs
- Incompetent valve: (not snapping shut): blood regurgitates –> problems with closing
- Stenotic valve: hardening of valve; does not open as wide or close as tight
- Prolapsed valve: slipped forward of down
IE: Infective endocarditis
Fungal infection of the endocardium May be caused by: -Staph -Strept -Candida -Septic blood
Myocardial infraction (MI)
Heart attack
Cell death due to lack of oxygen
Myocardial ischemia
Angina pectoris: blockage with temporary problems
Temporary lack of oxygen (myocardiocytes do not receive blood)
Can turn into an MI
Vascular occlusion
Anything that blocks the flow of blood
Cardiogenic shock
Dead myocardiocytes
Tumor
Myxoma: most common primary cardiac neoplasm
Usually benign
Heart murmur
Incompetent valve: blood regurgitates (problem with valve closing)
Stenoic valve: hardening of valve ( doesnt open as wide or close as tight)
Prolapsed valve: slipped forward or down
