Heart 1 Flashcards
What is the major function of the cardiovascular system?
Transportation
What does blood do in the cardiovascular system?
It is the transport vehicle that carries oxygen, nutrients, cell wastes, hormones, and many other substances vital for the body homeostasis to and from the cells
What makes blood move around the body?
Provided by the beating heart
How big is the human heart and how much does it weigh?
Adult fist and weighs less than a pound
Where is the heart located?
In the thorax and is flanked on each side by the lungs
What is the position of the heart?
Its more pointed apex is directed towards the left hip and rests on the diaphragm
The apex of the heart is approximately at the level of __________, and what pulse is measured there?
The fifth intercostal space, the apical post
What is the base of the heart also called?
The broader posterosuperior aspect
Where is the base of the heart and what emerge from it?
Points towards the right shoulder and lies beneath the second rib, the great blood vessels of the body
What is the pericardium and what is it made out of?
Encloses the heart, double sac of serous membrane
What is the epicardium also called?
Visceral pericardium
What is the epicardium and what is it a part of?
It is thin and tightly hugs the external surface of the heart, the heart wall
What is serous fluid?
Slippery lubricating fluid
What is serous fluid produced by?
The serous pericardial membranes
What does the serous fluid do?
Allows the heart to beat easily in a relatively frictionless environment as the pericardial layers slide smoothly across each other
What is pericarditis?
Inflammation of the pericardium
What is pericarditis caused by?
A decrease in the amount of serous fluid
What does pericarditis cause?
The pericardial layers bind and stick to each other, resulting in painful adhesions that interfere with heart movements
What does the myocardium consist of thick bundles of?
Cardiac muscle twisted and whorled into ring like arrangements
What layer of the heart contracts?
Myocardium
What is the endocardium?
A thin glistening sheet of endothelium that lines the heart chambers
What else does the endocardium also cover?
The linings of the blood vessels leaving and entering the heart
What is the septum that divides the heart longitudinally?
The interventricular or interatrial septum (depending on which chamber it is seprarting)
What do the pulmonary veins do?
Drains oxygen rich blood from the lungs and returns it to the left side of the heart
How many pulmonary veins are there?
4
What is pulmonary circulation?
Circulation from the right side of the heart to the lungs and back to the left side of the heart
What does pulmonary circulation do?
It caries blood to the lungs for gas exchange and returns it back to the heart
WHat is systemic circulation?
The second circuit, from the left side of the heart through the body tissues and back to the right side of the heart
What does systemic circulation do?
It supplies oxygen and nutrient rich blood to all body organs
Which ventricle walls are thicker and stronger?
Left
Why are the left ventricle walls thicker?
It pumps blood over a much longer pathway through the body
How many valves is the heart equipped with?
4
What do the heart valves do?
Allow blood to flow in only one direction through the heart chambers
What is the mitral valve?
Bicuspid
What does the mitral valve consist of?
Two cusps or flaps of endocardium
How many cusps does the tricuspid have?
3
What are the AV valves?
Separates the Atria from the Ventricle (tricuspid and bicuspid)
What are the chordae tendineae?
Tiny white cords which anchor the cusps to the walls of the ventricles
What are the chordae tendineae sometimes called?
Heart strings
What are the semilunar valves?
Guard the bases of the two large arteries leaving the ventricular chambers.
How many cusps do semilunar valves have?
3
When do each set of valves operate at?
Different times
When are the AV valves open and closed?
Open during heart relaxation and closed when the ventricles are contracting
What does the blood contained in the heart not nourish?
The myocardium
What blood supply nourishes the layers of the heart?
From the right and left coronary arteries
What does the coronary sinus do?
The myocardium is drained here by several cardiac veins and empties into the right atrium
