CARDIOVASCULAR SYSTEM Flashcards
Location of the heart
- It is midline structure of the thoracic cavity in the mediastinum
- it lies behind the sternum and costal cartilage extending from second to sixth costal cartilage
- about 2/3 of the heart lies in the left and 1/3 of the heart lies in the right of median plane
Size of the heart
Slightly larger then a closed fist
Shape of the heart
- blunt cone shape
- apex ( inferior )
~ blunt round point
~ directed to the left 5th ICS - base ( superior )
~ flat portion
~ directed to the right 2th ICS
Coverings of the heart
1 - Pericardium
1.1 - serous ( inner surface ) , fibrous ( outer surface )
2 - serous —-> parietal + visceral / epicardium
2.1 - between parietal and visceral , there’s pericardial cavity + pericardial fluid in it .
Function of the right atrium
Receives blood from the body
The opening of the right atrium
- superior vena cava
- inferior vena cava
- coronary sinus
Which valve that direct blood from right atrium to right ventricle
Tricuspid valve ( atrioventricular valve )
The function of right ventricle
Pumps the blood to the pulmonary trunk
The function of left atrium
Receives blood from the lungs
Which valve that direct blood from left atrium to left ventricle
Bicuspid valve ( atrioventricular valve )
The function of left ventricle
Pumps the blood to the aorta
Which valve that direct the blood from left ventricle to aorta
Aortic valve ( semi-lunar cusps valve )
Which valve that direct blood to pulmonary trunk
Pulmonary valve ( semi - lunar cusps valve )
What is the inter-ventricular septum
A wall that separates left and right ventricles
The openings of left atrium
The four Pulmonary veins
The function of heart valves
Allows one-way blood flow , prevent back-flow
Types of heart valves
- atrioventricular valves ( direct blood from atrium to ventricle ) ( av - valves open when atrium contract ) ( av - valves close when ventricle contracts )
- semi-lunar cusps valves ( direct blood from , out side to in side the heart and from , in side to out side the heart )
( also this valves has semilunar cusps which has pulmonary sinus + Nodule + Lunule )
What is the chordae tendinae
The chordae tendinae , cords that anchor the cusps to the walls of the ventricles
Function of chordae tendinae
Prevent the valves leaflets from turning inside out
Differences between left ventricle of and right ventricle
- LV : has thicker wall then right ventricle and atria
- LV : must generate greater pressure then right ventricle
What is the cardiac conduction system
Are a specialized cardiac muscle cells , capable of contracting constantly , are divided into sino-atrial node and atrio-ventricle node .
Conduction system pathway
1 - SA node 1.1 - SA node —-> left atrium 2 - AV node 2.1 - AV bundle 2.2 - left and right bundle branches 2.3 - purkinje fibers 3 - relax and repeat 🔁
The function of av node
If SA node is defective , AV node becomes the pacemaker “ but with slower conduction “ ( ectopic beat )
The function of SA node
Initiates the conduction “ the conduction rate , is faster then other areas of the heart “
