Cardiac Flashcards
Describe the location of the heart in the body
Midline and ventrally in the thorax
Describe the shape & structure of the heart
Conical shape
Wide base - above narrower apex
Ventricular septum separates right & left valves
Upper chambers (=atria) where blood arrives
Lower chambers (=ventricles) pump blood out of heart into arteries
Wall of heart (=myocardium) MUO cardiac muscle tissue
Which muscle is thicker? Left or right of heart? Why?
Left: generates enough pressure to pump blood all around body
Name of double-layered serous sac?
Pericardium
What is the fluid found in pericardium?
Pericardium fluid
What is the pericardium?
Double-layered serous sac surrounding heart
How is back flow back from ventricles to atria prevented?
Atrioventricular valves (tricuspid on right and mitral on left)
What stops the atrioventricular valves everting (flipping inside out) when ventricles contract?
They are attached to the walls of ventricle by fibrous threads (aka chordae tendineae)
When the ventricles relax, what prevents back-flow of blood from the major arteries into the ventricles?
There are semi-lunar valves in the pulmonary artery (pulmonic valve) and aorta (aortic valve) which prevent back-flow to the ventricles.
How are the heart sounds generated?
Closure of the valves within the heart.
When the ventricles contract, the atrioventricular valves close generating the first heart sound, known as lub.
When the ventricles relax, the semilunar valves close generating the second heart sound, known as dub.
Blood flowing from the heart around the body and back to the heart is said to be in which circulation?
Systemic circulation
Blood flowing from the heart to the lungs and back to the heart is said to be in which circulation?
Pulmonary circulation
When the right ventricle contracts, it pumps blood to the …… via the ……
lungs
pulmonary artery
When the left ventricle contracts, it pumps blood to the …….. via the ………
body
aorta
Both the atria contract at the same time and both of the ventricles contract at the same time. When the ventricles are contracted, this period is referred to as ……….. When the ventricles are relaxed, this period is referred to as ……….
systole
diastole
The heart beat is generated by an electrical impulse which begins at the …………………… located in the ……………………..
sinoatrial node
wall of the right atrium
This wave of electrical energy causes the atria to …………. This wave of electrical energy must now pass to a second structure called the ………………….. which is located at the top of the ……………………….
contract
Atrioventricular Node
Interventricular Septum.
The impulse crosses this through a series of fibres called the ……………………..
At the base of the ……………………………….are branches of fibres known as …………..which spread through the ventricular muscle.
Bundle of His
Interventricular septum
Purkinje Fibres
Being arranged in this way ensures that contraction of the ventricles starts at the apex of the heart pushing blood up towards the ………….. and …………………….
pulmonary artery
the aorta.
The myocardium is the muscle of the heart wall. How is this muscle supplied with oxygenated blood?
From coronary arteries (specialised vessels on the surface of the heart)
Why is the cardiovascular system referred to as a double circulation?
Because there is a systemic circulation transferring blood from the heart around the body and back to the heart, whilst there is also a pulmonary circulation transferring blood from the heart, to the lungs and back to the heart.