structure of cardiovascular system Flashcards
systemic circulation
carries blood between the heart and all organs and tissues
pulmonary circulation
between heart and lungs
where is the heart situated within the body ?
-within the middle mediastinum
- situated obliquely : 2/3rds of the heart to left of the midsternal line
pericardium
fluid filled sac that surrounds the heart and its great vessels
what are the two layers of the pericardium?
fibrous pericardium and serous pericardium
fibrous pericardium
-tough connective tissue
-prevents overfilling
serous pericardium
-Consists of the parietal layer and the visceral layer
-allows movement
what are the three layers of the heart wall ?
1) Epicardium
2) Myocardium
3) Endocardium
Epicardium
outer layer of heart wall
myocardium
middle layer of the heart wall, cardiac muscle
subendochondrial layer
- between endocardium and myocardium
-loose connective tissue containing small blood vessels and nerves and the branches of impulse conducting system
endocardium
inner layer of the heart wall
purkinje fibers
distribute excitatory activity for ventricular contraction
Diastole
heart muscles relax as it fills with blood
what happens to the AV valves during ventricular diastole
they open due to relaxed papillary muscles
systole
heart muscles contact and blood is pumped out
what happen to AV valves during ventricular systole
they close due to contraction of papillary muscles
semilunar valves
prevent backflow into the ventricles
pulmonary valve
semilunar between right ventricle and pulmonary trunk
Aortic valve
semilunar valve between left ventricle and aorta
what does the conducting system of the heart consist of ?
SA node, AV node, AV bundle (bundle of his) and purkinje fibers
conducting system of the heart
generates and transmits impulses to produce coordinated contractions
describe the conducting system of the heart
1)Excitation signal is created by thesinoatrial node.
2)The wave of excitation spreads across theatria,causing them to contract.
3)Upon reaching theatrioventricular node, the signal is delayed.
4) signal is conducted down bundle of His down the intraventricular septum
5)bundle of his and pukinje fibers spread impulses along ventricles causing them to contract
how is the heart drained of deoxygenated blood ?
cardiac veins drain into the coronary sinus which then empties into the right atrium
what are the three layers of the blood vessels ?
1) tunica intima : single layer of endothelium cells
2)tunica media: smooth muscle
3)tunica adventitia: outer connective tissue
