Ch 15: Cardiac System
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What are the functions of the cardiac system?
Supply nutrients and O2 to tissues, transport hormones, removes metabolic products from tissues.
How much does the heart weigh?
Less than 500 grams
Where is the heart located?
In the chest in the mediastinum, between the 2nd and 5th ribs anterior to spine posterior to sternum
What is endocarditis?
Inflammation of heart valves
What 3 veins empty into the right atrium?
• Sup vena cava • Inf vena cava • Coronary sinus (receives blood from heart + muscles)
Where do pulmonary veins empty into?
The left atrium.
What are the differences between cardiac and skeletal muscles?
Skeletal: striated, elongated, cylindrical Cardiac: myocardial cells, shorter, wider, more branched and interconnected.
Do cardiac muscles rely on nerve impulses for signals?
No, they create their own signals.
Describe the exitoconductive system of the heart.
• SAN: located in the upper wall of the right atria it is the pacemaker, it depolarises about 70 to 80 times a minute and establishes the sinus rythm. • AVN in the interatrial space, it receives signals from the SAN. • Hiss bundle: receives signals from the AVN, consists of 2 branches. • Purkynje fibres: causes ventricle contraction.
How do sympathetic and parasympathetic nervous systems affect the heart rate?
Sympathetic = increases Parasympathetic = decreases
What results in myocardial infarction?
Myocardial cell death
How many times does the SAN depolarise?
70-80 times per minute
What is endocarditis?
It’s the inflammation of heart valves
What is mitral valve prolapse?
Its when the chordae tendinae is injured and the ventricles retrograde
What is cornonary thrombosis?
It is when the coronary artery has blockages
What is arrhythmia?
It is when the heart is beating irregularly
What is fibrillation how to solve it?
It is when the heart is beating fast and irregularly solving it is through defibrillation/ strong electric shock
How many time per minute does the heart beat?
70-75 times
How long is each cardiac cycle?
1 second
What is the average volume bataie? Define and value.
It is the amount of blood pumped during each systole, 70ml in adults
Whats the average cardiac debit definition and value?
Its the volume de bataie measured per minute, its 5250 ml/min
What is a murmur how can it be determined?
It is an abnormal heart sound, can be a valve disease, diagnosed through a stethoscope.
What is tachycardia?
Its fast pulse and fast heart rate.
Whats bradycardia?
Its low pulse low heart rate