Cardiovascular 2 Flashcards
Give the dimensions of the heart
12 cm long
9 cm wide
6 cm thick
Weighs between 250 and 300 grams
Located in the middle mediastinum
What is the mediastinum?
The central compartment of the thoracic cavity
Extends from the sternum to the vertebra column, the first rib to the diaphragm, and between the lungs
What does the mediastinum contain?
The heart, the great vessels, trachea, esophagus, thymus, thoracic duct, phrenic nerve, cardiac nerves, lymph nodes
What is the pericardium?
A membrane that surrounds the heart and the root of the great vessels
The parietal and visceral layers of the pericardium are continuous at the root of the great vessels
What are the components of the pericardium ?
-fibrous: tough connective tissue, forms the outer layer
- serous: thin and contains two parts
- parietal layer: lines the inner surface of fibrous
- visceral layer(epicardium): adheres to the heart and forms its most intimate covering
What is pericardial cavity?
A narrow space between the visceral and parietal layers of the serous pericardium
- Contains a thin film of lubricating fluid
- Collection of excess fluid in the pericardial cavity is known as pericardial effusion
What are the 3 layers of the heart?
Endocardium, myocardium, and pericardium form the three layers of the wall
What does the heart consist of ?
- An apex
- A base or posterior surface
- Sternocostal or Anterior Surface
- Left pulmonary surface
- Right pulmonary surface
- Diaphragmatic or inferior surface
What are the surfaces of the heart?
Anterior surface: formed mainly by the right ventricle, some portions of the right atrium and left ventricle
Inferior surface: formed by both ventricles, mainly left ventricle
Base: formed mainly by the left atrium. Located at the level of the 2nd ICS
Left pulmonary surface: faces the left lung, formed mainly by the LV, and a portion of the left atrium
Right pulmonary surface: faces the right lung. Consists of the right atrium
Apex: formed by the tip of the LV,. Located in the 5th LICS in the MCL
What are the borders (margins) of the heart?
Right border: right atrium
Left border: left ventricle and left auricle
Inferior border: right ventricle and slightly left ventricle
Superior border: both atria
What are the heart chambers?
2 atria- right and left atrium
2 ventricles- right and left ventricles
What are the heart valves?
Semilunar valves:
- Have 3 cusps shaped like half-moons
- Aortic and Pulmonary valves
- Unlike the AV valves, are not attached to the chordae tendinae
Atrioventricular valves:
- Located between the atrium and ventricle
- Tricuspid and Mitrial valve
What is systole?
Ventricular contraction
What is diastole?
Diastole
What are the 3 steps of the cardiac cycle?
- Relaxation period
- Atrial systole
- Ventricular systole
Outline the path of blood through the cardiovascular system
- Right atrium (deoxygenated blood) sends blood through tricuspid valve
- Right ventricle sends blood through pulmonary valve
- Pulmonary trunk and pulmonary arteries send blood to capillaries at lungs where oxygen and CO2 are exchanged
- Pulmonary veins carries oxygenated blood to heart where it is delivered to the left atrium
- Left atrium sends blood through bicuspid valve, and enters the left ventricle
- Aortic valve receives blood and then aorta and systemic arteries. This delivers blood to systemic capillaries
- Deoxygenated blood is delivered to superior vena cava, inferior vena cava, and coronary sinus
What is the position of the tricuspid valve?
Behind the sternum next to right 4th intercostal space
What is the position of the mitrial/bicuspid valve?
Inferior to aortic valve next to 4th left costal cartilage
What position is the aortic valve?
Inferior to the pulmonary valve
What is the position of the pulmonary valve?
At the junction of 3rd left costal cartilage and sternum
Briefly describe the arterial supply of the heart?
The heart is supplied by two coronary arteries
Two coronary arteries, right and left arise from the aortic sinuses in the initial portion of the ascending aorta and supply oxygenated blood to the muscle and other tissues of the heart
What does the right coronary artery supply?
- right atrium and right ventricle
- sino-atrial & atrioventricular nodes
- Interartrial septum
- A portion of the left atrium
- The posteroinferior one-third of the interverntricular septum
- A portion of the posterior part of the left ventricle
What does the left coronary artery supply?
- Most of the left atrium and ventricle
- Anterior two thirds of the inter ventricular septum
- the atrioventricular bundle and its branches
Explain veinous drainage of the heart
Cardiac veins: re,one deoxygenated blood from the heart
Coronary sinus: largest vein of heart (drains to right atrium)
Accept blood from 3 sources:
-Great cardiac
-middle cardiac
-small cardiac
-NOT FROM: anterior cardiac v(drains directly to right atrium)
What is coronary artery disease ?
Accumulation of atherosclerotic plaques in the lumen
Results in:
- Narrowing of the lumen: Myocardial ischemia
- Complete obstruction of lumen: Myocardial Infract
What are the risk factors of coronary artery disease?
Smoking, hypertension, diabetes, high cholesterol
Explain the nerve supply of the heart
Sympathetic- off Sympathetic chain T1-4 post ganglionic—> form cardiopulmonary nerve plexus
Parasympathetic- Vagus CN X preganglionic—> form cardiopulmonary plexus
Sympathetic increase heart rate, dilate cardiac vessels
Parasympathetic decrease heart rate, construct cardiac vessels
Describe the conducting system of the heart
Consists of specialized cardiac muscle fibers
Coordinates the contraction of the heart chambers
Gives the heart its rhythmic beat
Initiate the normal heart beat
