Chapter 19: The Heart
Terms in this set (86)
Which circuit carries deoxygenated blood to the lungs for gas exchange and returns oxygenated blood to heart?
pulmonary circuit (supplied by right side of heart)
Which circuit pumps oxygenated blood throughout the body and returns deoxygenated blood to the right side of the heart?
systemic circuit (supplied by the left half of the heart)
What does the cardiovascular system consist of?
heart and blood
What exactly is the heart?
a muscular pump that keeps blood flowing through the vessels
Where is the heart located?
in the thoracic cavity in the mediastinum, posterior to the sternum, anterior to the vertebral column, and between the lungs
What is the double-walled sac that surrounds and protects the heart and retains its position in the mediastinum (while allowing for some freedom of movement)?
What is the outer wall that is composed of a tough outer fibrous layer lined by a delicate serous membrane?
What is the fibrous pericardium anchored to?
the diaphragm, the sternum, and the mediastinal tissue posterior to the heart
What is the inner serous pericardium called?
What does the inner layer also do?
forms the outer surface of the heart wall
What does the thin pericardial fluid lubricate?
the pericaridal cavity
The heart is composed of three distinct layers, from superficial to deep what are they?
(outer is pericardium)
What is the simple squamous epithelium that is over a thin layer or areolar tissue that in some places also includes a thick layer of adipose tissue?
Epicardium (visceral pericardium)
What is the thick middle layer composed of cardiac muscle that performs the work of the heart?
What is the simple squamous epithelium over a thin layer of areolar tissue?
What spirals around the heart forming a myocardial vortex?
What is the heart wall made up of?
A fibrous skeleton
What is the fibrous skeleton made up of?
a framework of collagenous and elastin fibers
What do these collagenous and elastin fibers do?
-provide structural support
-anchors the cardiocytes
-acts as an electrical insulator between the atria and ventricles
The heart has how many chambers?
--upper 2 are right and left atria
--lower 2 are the right and left ventricle
Without atrial function, blood flows passively down into the ventricles of the bottom heart--what is only responsible for a 20% increase?
Blood always flows from an area of _____ pressure to an area of ___ pressure.
high to low
The AV valves are tethered to the walls of the ventricles by what?
"heart strings" (chordae tendineae)
What are the cordae tendineae attached to?
What are the major arteries that are attached to the heart?
--aorta (ascending and descending)
--pulmonary trunk (left and right)
What are the major veins that are attached to the heart?
--superior and inferior venae cavae
--4 pulmonary veins
--coronary sinus (back of the heart)
What gets nutrients from the blood flowing through the coronary circulation?
the myocardium (and other tissues of the thick cardiac walls)
The left coronary artery (LCA) travels into the what and divides into the what two branches?
-1. anterior interventricular branch
-2. circuflex branch
What does the anterior interventricular branch (left anterior descending branch) travel in?
anterior interventricular sulcus
Where does the anterior interventricular branch travel to?
the apex, goes around the heart and up the posterior side
What does the interventricular banch supply blood to?
both ventricles and the anterior 2/3 of the interventricular septum
Where does the circumflex branch travel to?
around the left side of the heart in the coronary sulcus and ends on the posterior side
What does the circumflex branch supply blood to?
it supplies blood to the left atrium and posterior wall of the left ventricle
What branches gives off the what?
Left marginal branch
Where does the left marginal branch go?
it passes down the left margin of the heart and supplies the left ventricle
Where does the right coronary artery travel?
around the right side of the heart in the coronary sulcus
What does the right coronary artery (RCA) supply?
te right strium and sinoatrial node
What are the two branches off of the RCA?
1. right marginal branch
2. posterior interventricular branch
Where does the right marginal branch run towards?
the apex and supplies the lateral aspect of the right atrium and ventricle
What does the posterior interventricular branch travel in?
the posterior interventricular sulcus
What is coronary artery disease?
-plague build up (cholesterol gathers & blocks blood flow to the heart to be able to pump blood)
-fix it by bypass (grafting it to your artery past the blockage point)
What is angioplasty?
stick in a baloon and pushes all of the plague to the side and flattens it
What is a stent?
--small cage and now use better material
--use a balloon to open stent/cage
What does the great cardiac vein drain?
the anterior side of the heart and travels along the anterior interventricular artery
What does the posterior interventricular vein drain?
the posterior aspect of the heart and travels inthe posterior interventricular sulcus
What does cardiac muscle look like?
What are the cells that are short, branched, and have only one (usually centrally located) nucleus?
How do cardiac muscle cells connect to and communicate with neighboring cells?
through gap junctions in intercalated discs
About what percent of all of the muscle cells of the heart form a network or pathway and what is it called?
--cardiac conduction system
What are the specialized group of cells in the cardiac conduction system?
What is the rhythmical electrical activity that the myocytes produce called?
Because heart muscle is autorhythmic, it does not rely on the what to sustain a lifelong heartbeat?
central nervous system
What in the intercalated discs prevent the cardiocytes from pulling apart?
What does the heart depend almost exclusively on to make ATP?
This is why the heart is rich in what?
mitochondira, glycogen, and myoglobin
The autorhythmis myocytes have the 2 important roles of what?
--forming the conduction system of the heart
--acting as pacemakers within that system
What is the normal pacemaker of the heart and why?
the sinoatrial (SA) node
--because it has the fastest rate of depolarization
Where is the SA node located?
in the right atrial wall just below where the superior vena cava enters the chamber
Depolarization of autorhythmic fivers in the SA node firing about once every ____ second or ______ times per minute. This is called what?
What is the second pacemaker by propagating throughout the wall of the atria to the what in the interatrial septum?
atrioventricular (AV) node
What happens at the AV node?
the signal is slowed, allowing ventricles to fill with blood
After the AV node, the signal then passes through what?
the AV bundle (bundle of His) to the interventricular septum
What is the final step in the conduction system?
the purkinje fibers rapidly conduct the action potential throughout the ventricles
What is the role of the autonomic nervous system (ANS) input?
to regulate changes in blood pressure, blood flow, and blood volume to maintain enough cardiac output to provide for all organs at all times (if possible)
Where are the sympathetic nerves present?
throughout the atria (especially in SA node) and ventricles
What does the sympathetic activity do?
increases the heart rate and the strength of myocardiac contraction to increase blood flow out of the heart
Where are the parasympathetic fibers present?
in the CN X or the vagus nerve, exits the skull and continue into the abdomen to innervate structures there
What does the parasympathetic activity do?
-slows the heart from its native rate of 100 bpm to about 70-80 bpm in the average adult
LOOK AT PACEMAKER PHYSIOLOGY
IN YOUR NOTES
Unlike autorhythmic fibers, cardiocytes have a what RMP of -90mV?
The systole is what and makes what sound?
The diastole is what and makes what sound?
Cardiac output is what?
stroke volume times heart rate
--blood pumped per minute
GO BACK TO THE CHART TO
What is cardiac reserve?
the difference between CO at rest and the maximum CO the heart can generate
What is tachycardia?
HR>100 bpm--caused by stress, anxiety, drugs, heart disease, fever
What is bradycardia?
HR<60 bpm--caused by sleep, endurance training, hypothermia
What is a positive chronotropic agent?
factors that raise HR
What is a negative chronotropic agent?
factors that lower HR
Cardiac center in the medulla does what?
lowers or raises the HR based on what the parasympathetic and sympatheic nerves tell it
LOOK AT SLIDE
What are the three important factors that affect SV?
What is CO preload?
the amount of ventricular filling before contraction
What is contractility of the ventricle?
-positive chronotropic-increase contractility
-negative II -decrease II
What is afterload?
the resistance in the blood vessels (aorta) or valves (aortic valve, when damages) the heart is pumping into
LOOK AT CHART OF
STARLINGS LAW OF THE HEART
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