Med- Surge: Cardiovascular System Flashcards
What side of the body is the heart located?
The heart is located in the left side of the mediastinum.
How many layers are the heart are there?
3 layers.
Epicardium?
The epicardium is the outermost layer of the heart.
Myocardium?
The myocardium is the middle layer and is the actual contracting muscle of the heart.
Endocardium?
The endocardium is the innermost layer and lines the inner chambers and heart valves.
What is the pericardial sac?
Encases and protects the heart from trauma and infection.
How many heart chambers are there?
4
What is the job of the right atrium of the heart?
The right atrium receives deoxygenated blood from the body via the superior and inferior vena cava.
What is the job of the right ventricle?
The right ventricle receives blood from the right atrium and pumps it to the lungs via the pulmonary artery.
What is the job of the left atrium?
The left atrium receives oxygenated blood from the lungs via 4 pulmonary veins.
What is the job of the left ventricle?
The left ventricle is the largest and most muscular chamber; it receives oxygenated blood from the lungs via the left atrium and pumps blood into the systemic circulation via the aorta.
How many valves are in the heart?
4
What are the 4 heart valves?
2 atrioventricular valves, the tricuspid and the mitral.
2 semilunar valves, the pulmonic and the aortic.
What is the job of the atrioventricular valve?
The atrioventricular valves close at the beginning of ventricular contraction and prevent blood from flowing back into the atria from the ventricles; these valves open when the ventricles relax.
What is the job of the semilunar valves?
The semilunar valves prevent blood from flowing back into the ventricles during relaxation; they open during ventricular contraction and close when the ventricles begin to relax.
Sinoatrial (SA) Node: what is it?
The main pacemaker that initiates each heartbeat
Sinoatrial (SA) Node: where is it?
It is located at the junction of the superior vena cava and the right atrium.
Sinoatrial (SA) Node: how does the SA node work?
The SA node generates electrical impulses at 60 to 100 times per minute and is controlled by the sympathetic and parasympathetic nervous systems.
Atrioventricular (AV) node: where is it located?
Located in the lower aspect of the atrial septum
Atrioventricular (AV) node: what does it do?
Receives electrical impulses from the SA node.
Atrioventricular (AV) node: if the SA node fails what happens to the AV node?
If the SA node fails, the AV node can initiate and sustain a heart rate of 40 to 60 beats per minute.
The Bundel of HIS: What is it?
A continuation of the AV node; located at the interventricular septum; it bascially branches out and covers more ground arounfd the heart.
Purkinje fibers: main job?
Purkinje fibers can act as the pacemaker with a rate between 20 and 40 beats per minute when higher pacemakers (such as the SA and AV nodes) fail.
