Cardiovascular System, Joanna Barrios, Period:1
Major Functions
Layers of Heart
Structural + functional differences (blood vessels)
Blood flow heart + body
Disorders
Anatomy of the Heart
Pumping chambers of heart
Coverings
Receiving chambers of heart
transport nutrients, gases and waste products around the body
protect the body from infection and blood loss
help maintain fluid balance within the body
circulates oxygen and removes carbon dioxide
help the body maintain a constant body temperature
Right atrium - receives blood returning from systemic circuit
Left atrium- receives blood returning from pulmonary circuit
Right ventricle - most of anterior surface, pumps blood through pulmonary circuit
Left ventricle - posteroinferior surface, pumps blood through systemic circuit
Pericardium
Parietal layer
Visceral layer
Myocardium
Endocardium
semilunar (SL) valves
Aortic semilunar valve - located between left ventricle and aorta
Pulmonary semilunar valve- located between right ventricle and pulmonary trunk
atrioventricular (AV) valves
Mitral valve - made up of two cusps and lies between left atria and ventricle
Chordae tendineae - anchor cusps of AV valves to papillary muscles
Tricuspid valve- made up of three cusps and lieS between right atria and ventricle
located between ventricles and major arteries
prevent back flow from major arteries back into ventricles
prevent back flow into atria when ventricles contract
located between atria and ventricles
Internal features
Interventricular septum - separates ventricles
Four chambers: 2 superior atria, 2 inferior ventricles
Interatrial septum - separates atria
Surface features
Anterior interventricular sulcus - anterior position of interventricular septum
Coronary sulcus (atrioventricular groove)
Posterior interventricular sulcus - landmark on posteroinferior surface
Veins
Inferior vena cava - returns blood from body regions below the diaphragm
Coronary sinus - returns blood from coronary veins
Superior vena cava - returns blood from body regions above the diaphragm
Other
Papillary muscles- project into ventricular cavity
Trabeculae carneae - irregular ridges of muscle on ventricular walls
Apex
Base - posterior surface
Left side of heart
Right side of heart
- Superior vena cava, inferior vena cava, and coronary sinus →
- Right atrium →
- Tricuspid valve →
- Right ventricle →
- Pulmonary semilunar valve →
- Pulmonary trunk →
- Pulmonary arteries →
- Lungs
- Four pulmonary veins →
- Left atrium →
- Mitral valve →
- Left ventricle →
- Aortic semilunar valve →
- Aorta →
- Systemic circulation
Pericardium
double-walled sac that surrounds heart made up of two layers
Parietal layer lines internal surface of fibrous pericardium
Visceral layer (epicardium) on external surface of heart
Two layers separated by fluid-filled pericardial cavity
3 layers
Epicardium - visceral layer of serous pericardium
Myocardium - circular or spiral bundles of contractile cardiac muscle cells
Endocardium - innermost layer; is continuous with endothelial lining of blood vessels
Veins + Arteries
Arteries - carry oxygen-rich blood away from the heart to all of the body's tissues
Arteries run deep, but veins are both deep and superficial
Cardiac Cycle and the ECG
ECG - Electrocardiogram
Phases of Cardiac Cycle
graphic recording of electrical activity
P wave - depolarization of SA node and atria
QRS complex - ventricular depolarization and atrial repolarization
T wave - ventricular repolarization
P-R interval - beginning of atrial excitation to beginning of ventricular excitation
S-T segment - entire ventricular myocardium depolarized
Q-T interval - beginning of ventricular depolarization through ventricular repolarization
Cardiac Cycle: blood flow through heart during one complete heartbeat
- Atrial systole -lasts about 0.1 seconds, both atria contract and force the blood from the atria into the ventricles.
- Ventricular systole- lasts about 0.3 seconds - both ventricles contract, blood is forced to the lungs via the pulmonary trunk, and the rest of the body via the aorta.
- Atrial diastole - lasts about 0.7 seconds, relaxation of the atria, during which the atria fill with blood from the large veins (the vena cavae).
- Ventricular diastole - lasts about 0.5 seconds, begins before atrial systole, allowing the ventricles to fill passively with blood from the atria.
Capillaries
there is less smooth muscle and connective tissue in veins
the walls of veins are thinner than those of arteries,
blood in the veins has less pressure than in the arteries.
Veins - take blood back to the heart
Capillaries surround body cells and tissues to deliver and absorb oxygen, nutrients, and other substances
Capillaries have walls that are only a single cell thick because they exchange materials between blood and tissue
Capillaries have no muscle & elastic fiber like the other blood vessels.
Blood pressure
Covering of the Heart
Heart
Hypotension – Low blood pressure below 90/60 mm Hg
Circulatory shock - blood vessels inadequately fill and cannot circulate blood normally
Hypertension - Sustained elevated arterial pressure of 140/90 mm Hg or higher, heart must work harder; myocardium enlarges, weakens, and becomes flabby
Pericarditis - Inflammation of pericardium
Angina pectoris - Thoracic pain caused by fleeting deficiency in blood delivery to myocardium as a result cells are weakened
Myocardial infarction - Prolonged coronary blockage
intrinsic conduction system
Fibrillation - rapid, irregular contractions
Arrhythmias - irregular heart rhythms
Veins
Varicose veins - dilated and painful veins due to incompetent valves
Heart Rate
Bradycardia - heart rate slower than 60 beats/min
Tachycardia - abnormally fast heart rate (>100 beats/min)
Heart murmurs - abnormal heart sounds heard when blood hits obstructions
Cardiac Output
Coronary atherosclerosis - clogged arteries caused by fat buildup; impairs oxygen delivery to cardiac cells
Congestive heart failure (CHF) – Progressive condition; CO is so low that blood circulation is inadequate to meet tissue needs
Dilated cardiomyopathy (DCM) - ventricles stretch and become flabby, and myocardium deteriorates