Cardio Flashcards
(25 cards)
Where is the heart?
In the mediastinum behind the body or sternum (between the points of attachment of ribs 2-6)
Posteriorly, rests on the bodies of the thoracic vertebrae five through eight.
What is the purpose of the auricle?
The auricle serves the purpose of increasing the blood holding capacity of the atrium and forms the rough interior part of the atrium
Pericardial cavity
The potential space formed between the two layers of serous pericardium around the heart
Interventricular sulcus
The groves that separate the ventricles of the heart
The anterior inter ventricular sulcus sits where?
The anterior interventricular sulcus is situated on the sternocostal surface of the heart. Close to its left margin
Hemodynamics
The collection of mechanisms that influence the dynamic circulation of blood
What four main structures compose the conduction system of the heart?
- Senoatrial node (SA)
- Atrioventricular node (AV)
- AV bundle (bundle of HIS)
- Subendocardial branches (Purkinje fibres)
What does the SA node do?
Initiated each heartbeat and sets its pace.
What cause the atria to contract?
Impulses generated by the SA nodes travel throughout the muscle fibres of both atria.
What happens after the impulse travels through the muscles fibres of the atria?
The action potential enters the AV nodes from the right atrium. Conduction slows to allow a complete contraction to happen before moving on through to the ventricles
After the AV node, does conduction velocity increase or decrease?
It increases as the impulse is relayed through the AV bundle into the ventricles
What are purkinje fibres?
Subendocardial branches that specialize in conducting the electrical current used in maintaining heart rhythm.
What is an ECG?
An electrocardiogram is a graphic record of the hearts electrical activity
How are ECGs produced?
- Electrodes are attached to a subject
2. Voltage changes that show the hearts electrical activity are sensed by the electrodes and recorded on paper
What do P waves represent?
The depolarization of the atria
What represents the depolarization of the ventricles and repolarization of the atria?
QRS complex
What is the T wave?
It’s a representation of the repolarization of the ventricles
Where is a U wave found and what does it represent?
A u wave is a tiny hump found after the T wave. It represents the repolarization of the papillary muscle
What do intervals between ECG waves tell us?
They can provide information about rate of conduction of an action potential through the heart
What is an action potential?
The change in electrical current potential associated with the passage of an impulse along the membrane of a muscle or nerve cell.
- occurs when the membrane potential of a specific cell location rises and falls.
What condition could a U wave be indicating?
Hyokalemia (the bloods potassium levels are too low) or too much digoxin
What is a cardiac cycle?
A cardiac cycle consists of a contraction (systole) and relaxation (diastole) of both atria and both ventricles
What starts an atrial systole?
atrial systole begins with the P wave of the ECG- which triggers atrial contraction
How is the pressure gradient of the atria affected during atrial systole?
The pressure gradient pushes blood out of the atria and into the relaxed ventricles
