Chapter 20 Flashcards
Where is the heart located
Mediastinum
What is the Pericardium
A three layered sac that covers the Heart
What are the two types of pericardiums
Fibrous and Serous Pericardium
What are the 3 layers in the Serous pericardium
Parietal Layer
Visceral Layer
Pericardial cavity (between parietal and visceral layers
What does the endocardium cover
Smooth inner layer of endothelial tissue that covers the heart valves
What is the outer layer of the heart called
Epicardium
What makes up the myocardium and what portion of the heart has myocardium
Cardiac muscle tissue
Makes up a majority of the heart wall
What are upper chambers of the heart called
Atria (sing. Atrium)
Where does the right Atrium receive deoxygenated blood from
Superior and inferior Vena Cava as well as the coronary sinus
Where does the left atrium receive oxygenated blood from
The lungs
What structure separates ventricles
Interventricular septum
Are ventricles superior or inferior to atria
Inferior
Is the myocardium thicker in the left or right ventricle
Left ventricle due to the task of pumping blood back into systemic circulation
What is the main function of heart valves
Insuring blood is flowing in one direction and not back flowing
Where are Atrioventricular Valves (AV Valves) found
Between atria and ventricles so that blood won’t reenter the atria after leaving
What is another name for the right AV valve
Tricuspid Valve which has 3 cusps
What is another name for left AV valve
Bicuspid valve or the Mitral Valve
What are the two type of Semilunar Valves and where are they
Pulmonary Semilunar Valve (next to Rt. Ventricle)
Aortic Semilunar Valve (next to Lt. ventricle)
What is the direct path off blood flow through the heart
14 structures
Vena cava & Coronary sinus
Right Atria
Right AV valve
Right Ventricle
Pulmonary Semilunar Valve
Pulmonary Trunk
Pulmonary Arteries
Lungs
Pulmonary Veins
Left atria
Left AV valve
Left Ventricle
Aortic semilunar valve
Aorta & coronary arteries
What is the RMP of contractile fibers
-90mV
What structures are in between cardiac muscle cells that contain several gap junctions and desmosomes
Intercalated disks
What ion causes depolarization in contractile fibers?
Sodium ions (Na+)
What causes repolarization of contractile fibers
Closure of calcium channels and potassium channels remaining open
What is the definition given to us for the Conduction system
The route used to propagate action potentials throughout the heart muscle
What region in the conduction system is known as the “pacemaker” and where does it pass signals
The Sinoatrial Node (SA Node)
Passes signals throughout both atria via gap junctions located in intercalated disks
Where do Atrioventricular Nodes transport their impulses
To the ventricles
Why does the AV Node bifurcate to the Right and Left Bundle Branches
One branch for each ventricle allowing impulses to pass through the Interventricular septum towards the apex of the heart
What is a Electrocardiogram
A recording of the electrical changes that accompany the Heart beat
What does the P wave represent
Atrial depolarization
What does the QRS complex represent in a heart beat
The onset of Ventricular Depolarization
*Atrial repolarization is hidden in this segment as well
What does the T wave represent
Ventricular Repolarization
What is the P—Q interval
The time it takes for an electrical impulse to travel from SA node through the conduction system
Shows the beginning of Atrial excitation to the beginning of Ventricular excitation
What is the ST segment represent in a heartbeat
The time when the ventricle is fully depolarized
What does Systole mean
Cardiac Contraction
What does diastole mean
Relaxation
What structure does systole and diastole usually refer to
The ventricles
Which systole lasts longer:
Atrial systole or
Ventricle systole
Ventricle systole lasts 0.3 sec @ 75BPM
Atrial systole lasts 0.1sec @ 75BPM
How long is the typical relaxation period during a heartbeat at 75BPM
0.4 seconds
The act of listening to the sounds of the body (usually with a stethoscope) is called
Auscultation
What are the two sounds of the heart
Lubb and Dupp
What disorder is occurring with the heartbeat when the valves of the heart don’t close properly
A murmur
What is the first heart sound to occur
“Lubb”
Associated with the closing of the AV valves @ the beginning of ventricular diastole
What happens during the second heart sound “dupp”
Associated with the closing of semilunar valves at the beginning of ventricular diastole
What is cardiac output (CO)
The volumen of blood ejected Ted by the left ventricle in 1 minute
What is stroke volume
The volume of blood ejected by the ventricle
What does a persons Cardiac Reserve indicate
The ratio between a persons maximum CO and the CO at rest. Usually 4-5 times the resting CO
What 3 factors regulate Stroke Volume
- Stretch (preload): greater stretch = greater contraction
- Contractability: strength of the heartbeat
- Afterload: pressure that must be overcome before semilunar valve can open
What part of the autonomic nervous system is responsible for increasing or decreasing nerve impulses to the heart
The cardiovascular center of the medulla oblongata
What are 3 examples of nerve receptors that have to do with the heart
- Proprioceptors (monitor position of body parts
- Chemoreceptors (monitor chemical changes in the blood)
- Baroreceptors (respond to changes in blood pressure)
What 4 hormones increase heart rate
Epinephrine, norepinephrine, T3 and T4
What is another term for a heart attack
Myocardial Infarction
What is a Myocardial Infarction
A complete obstruction of blood to part of the heart; death of heart muscle
Results in varying degrees of damage which can be repaired by fibrosis
What causes Congestive Heart Failure
Results from a weakened heart that can’t pump blood adequately.
Causes a back-up (pooling) of blood which lead to edema
What disease is defined as the effects of accumulation of atherosclerotic plaques in the Coronary arteries
Coronary Artery Disease
What causes Coronary Artery disease
Diet, genetics, smoking, high BP, Diabetes, life style (I.e. too much fun stuff)
What term describes the hardening of the arteries
Arteriosclerosis
What is atherosclerosis
Development of plaques in the endothelium of arteries. Lipids accumulate along with other material
May cause blockage of the vessel
