Heart 1 Flashcards
The heart is a muscular organ about the size of what?
A fist.
How many chambers does the heart have? What kind of pump is it?
Four-chambered double pump.
At rest, the heart of an adult pumps about _____ L/min of blood.
5.0L/min
How long does it take for blood to be circulated to the most distal extremities and back to the heart?
About ONE minute.
What are the four chambers of the heart called? What two categories are they put into and where are they located?
Atria - Two Upper chambers, sometimes called auricles
Ventricles - Two Lower chambers
- Right/Left Atrium
- Right/Left Ventricle
The right atrioventricular (AV) valve is also known as the ______ valve.
Tricuspid valve
The left atrioventricular (AV) valve is also known as the ______ valve.
Mitral valve
What are the four heart valves and where are they located?
- Pulmonary Valve (Right)
- Right AV Valve (Tricuspid)
- Aortic Valve (Left)
- Left AV Valve (Mitral)
Located between the atria and the ventricles.
The pulmonary valve and the aortic valve are also called the __________ valves because they have 3 cusps which resemble half moons.
Semilunar
What happens to the valve when the pressure is greater behind it?
It opens
What happens when the pressure is greater in front of the valve?
It closes.
Heart valves are considered to be ____-way valves.
One
The heart wall is separated into what three layers? Describe the characteristics of each layer.
- Endocardium - a thin layer of endothelium
- Myocardium - muscle layer (cardiac muscle)
- Epicardium - thin external layer
What is the contraction of the heart muscle stimulated by?
Electrical impulses.
When a specialized system of nodal tissue generates and conducts impulses through the heart, what happens?
Rhythmic contractions of the myocardium.
In the cardiac conduction system, there are four structural and functional portions. What are they? (*Hint - Backup pacemakers in order…)
- Sinoatrial node (SA Node/Pacemaker)
- Atrioventricular node (AV node)
- Atrioventricular bundle (AV bundle or bundle of HIS)
- Purkinje fibers
True or false. When an impulse is created at the top of the heart, it does NOT travel throughout the entire heart.
False.
Impulses DO travel throughout the entire heart.
What are the characteristics of the Sinoatrial node (SA node)? Where is it located and what is the other name for it?
‘Pacemaker’
Located within the posterior wall of the right atrium. Near opening of superior vena cava.
Contracts quicker.
Cells here depolarize quicker than any other cell in heart.
Rhythmical impulses originate in the SA node and spread through atria.
What are the characteristics of the Atrioventricular node (AV node)? Where is it located?
Located within the lower right interatrial septum.
Impulse is delayed in the AV node for 1/10 sec to allow atria contraction BEFORE ventricular contraction.
What are the characteristics of the Atrioventricular bundle (AV bundle or bundle of HIS)? Where is it located?
Originates in the AV node and divides into “two bundle branches” which then extend down the two sides of the interventricular septum.
True or False. When atria muscles contract, they contract with an impulse.
True.
Atria muscles DO contract with an impulse.
How does an electrocardiogram (EKG) operate?
Monitors impulses that initiate rhythmical and ventricular contractions throughout the heart.
Impulses start in the ________ node and spread over the _______ muscle fibers producing _______ contraction.
- SA node
- atrial
- atrial
After an impulse is started in the ____ node. It reaches the ____ node. The impulse then travels through the ____ _______ and ________ __________. This produces coordinated ___________ contraction.
- SA node
- AV node
- AV bundle
- Purkinje fibers
- ventricular
True or False. An EKG records electrical impulse and spread.
True.
An EKG records electrical impulses and spread, not electrical speed or contractions.
What are some of the many factors which may alter the heartbeat rate?
- Sympathetic impulses
- Parasympathetic impulses
- Hormones
- Body temperature
- Exercise
- Emotion
In the cardiac cycle, there are two main functions (*blood pressure). What are they referred to as, and what are their functions?
1. Systole Phase of Contraction Emptying of the atria and ventricles 2. Diastole Phase of Relaxation Filling of the atria and ventricles.
From the two main functions, the cardiac cycle has a total of four processes. What are they? What is their order?
- Mid-diastole
- Atrial systole
- Ventricular systole
- Early diastole
During the ‘Mid-diastole’ process. The _______ and _______ are relaxed.
The _______ and _______ valves are open, the ______ and _______ valves are closed.
- atria
- ventricles
- tricuspid
- mitral
- aortic
- pulmonary
Before the end of the ‘Mid-diastole’ phase, __to__% of ventricular filling occurs.
65 to 85%
During the ‘Atrial systole’ process. The ________ contract and pump the additional __to__% of the blood into the _________. As the _____ contract, the orifices of the ______ ______ and _________ veins narrow; however, there is some regurgitation of blood into the ______.
- atria
- 20 to 35%
- ventricles
- atria
- venae cavae
- pulmonary
- veins
Which valves are closed during isovolumetric contraction?
All four valves are closed
What is considered to be an average PULSE PRESSURE?
40-50 mm Hg
This is the difference between systolic and diastolic(120/80)
What is bradycardia and what are some factors that cause it?
Bradycardia is a decrease in heart rate to less than 60 beats/minute.
It can be caused by expiration, fear (?), and grief
Nerves affect cardiac pumping in two ways: chronotropic and inotropic. What does each of those alter?
Chronotropic- changes the heart rate
Inotropic- changes the strength of contraction
What is the average heart rate in the S.A node?
72-75 beats/minute
What is the heart rate in the A.V node?
50-60 beats/minute
What is the heart rate in the ventricles?
30-40 beats/minute
What is the maximum sympathetic stimulation in the heart?
250 beats/minute
One catecholamine has a significant impact on the permeability of cardiac cells to Na+ and Ca++. Which is it and what is it’s influence?
Norepinephrine; increases the permeability
What is the overall impact of sympathetic control on the cardiac system?
It increases the rate and force of contraction