Chapter 18: The Heart Flashcards
What are the 2 major divsions of the circulatory system?
Pulmonary and systemic circuit
The pulmonary circuit is on the ____ side of the heart while the systemic circuit is on the ____ side.
Right
Left
What circuit carries blood to lungs for gas exchange and back to the heart?
Pulmonary
t
What does the systemuc circuit do?
Supplies oxygenated blood to all tissues of the body and returns it to the heart.
Fully oxygenated blood arrives from ____ via ______
Lungs
pulmonary veins
What part of the body sends blood to all organs of the body?
The aorta
What sends blood to the lungs?
The pulmonary trunk
The heart is located in the ____, between the ______
Mediastinum, lungs
What is the pericardium?
Double-walled sac that encloses the heart, allowing the heart to beat without friction, providing room to expand and resisting excessive expansion
The heart is anchored to the ____ inferiorly and to the ____ anteriorly.
Diaphraghm and sternum
What is the difference between the parietal and visceral pericardium?
The parietal is an outer tough fiborous layer of connective tissue while the visceral is the inner, thin smooth serous membrane that covers the heart
What can the visceral pericardium also be called?
Epicardium
How much pericardial fluid is in the pericardial cavity?
5 to 30 mL
____ is the painful inflammation of membranes
Pericarditis
What are the 3 layers of the heart?
Epicardium, myocardium and the endocardium
Describe the epicardium (AS A LAYER OF THE HEART)
Outer layer, serous membrane that covers the heart
What is the function of the myocardium?
Provides structural support and attachment for cardiac muscle
Describe the endocardium
Inner layer that lines the heart
What are the 4 heart chambers?
Right and left atria and right and left ventricles
The atrias is ____ while the ventricles are ______.
Superior and inferior
What does the atria do?
Receives blood returning to the heart
What do the ventricles do?
Pump blood into the arteries
What does the atrioventricular (coronary) sulus grooves seperate?
The atria, ventricles
What do the anterior and posterior interventricular sulci grooves seperate?
Ventricles
____ is the wall that seperates atria
Interatrial septum
____ are the internal ridges of myocardium in right atrium and both auricles
Pectinate muscles
____ the muscular wall that seperates ventricles
Interventricular septum
____ is the internal ridges in both ventricles
Trabeculae carnae
What may the trabeculae carneae prevent?
May prevent ventricle walls from sticking together after contraction
What do heart valves do?
They prevent the backflow of blood, ensuring a one-way flow of blood through the heart
What valve controls the blood flow between atrias and ventricles?
Atrioventicular valve
The right AV valve has ____ cusps, so it’s called _____-
3
tricuspid valve
The left AV has ____ cusps, so its called _____
2, mitral valve, used to be bicuspid
What does the chordae tendinae prevent?
It prevents AV valves from flipping or bulging into atria when ventricles contract
Each papillary muscle has ____ attachments to the heart floor.
2 - 3
The ____ valve controls the flow into the great arteries, and open and close because of blood flow and pressure
Semilunar
What are the 2 types of semilunar valves?
Pulmonary and aortic
What causes mitral valve prolapse?
When one or both mitral valve cusps bulge into atria during ventricular contraction
What are some symptoms of mitral valve prolapse?
Chest pain and shortness of breath
When ventricles relax?
When the pressure drops inside the ventricles and AV valves open
When do ventricles contract?
When pressure rises inside the ventricles and AV valves close
____ % of blood pumped by the heart is pumped to the heart itself through the coronary circulation to sustain its strenous workload
5
When does coronary flow peak?
During ventricular relaxation
What is the condition where there is partial obstruction of cornory blood flow, which can cause chest pain?
Agina
____ is complete of coronary blood flow which causes death of cardiac cells in affected area
Myocardial infection
What is venous drainage refered to as?
The route by which blood leaves an organ
Mycardial infection is responsible for about ____ % of deaths in the US
27%
What do the small thesbian veins do?
Drains 5 to 10% of coronary blood directly into the right atrium and ventricle
How does most coronary blood return to the right atrium?
The coronary sinus
What are the 3 main inputs of the coronary sinus?
Great cardiac, posterior interventricular and left marginal veins
Give a brief description of cardiomyoctes?
Striated, short, branched cells with one nucleus
____ join cardiomyocytes end to end
Intercalated discs
What are the 2 types of mechanical junctions that tightly join cardiomyocytes?
Fascia adherens and desmosomes
____ are gap junctions which forms channels that allow ions to flow from the cytoplasm from one cell directly to the next
Electrical junctions
Cardiac muscle depends almost exclusively on ____ to make ATP
aerobic respiration
What is cardiac muscle rich in?
Myoglobin and glycogen
Why is cardiac muscle fatigue resistant?
Because it makes little use of anaerobic fermentation or oxygen debt mechanisms and doesn’t fatigue for a lifetime
The ____ controls the route and timing of electrical condunction so all 4 chambers are in sync with eachother
Cardiac conduction system
What does the cardiac conduction system coordinate?
The heartbeat
What is the order in which the cardiac conduction system generates and conducts rhythmic electrical signals?
SA (Sinoatrial) node, AV (atrioventricular) node, AV (atrioventricular) bundle/bundle of histones, right and left bundle branches, Pukinje fibers
What do the cardiomyocytes do in regards to the Purkinje fibers?
They pass signal from cell to cell through gap junctions
Give the steps of the cardiac conduction system.
- SA node fires
- Excitation spreads through the atrial myocardium
- AV node fires
- Excitation spreads down AV bundle - right and left AV bundle branches
- Purkinje fibers distribute excitation through ventricular myocardium
What do sympathetic nerves do?
Increase heart rate and contraction and strength
What do parasympathetic nerves do?
Slow the heart rate
Systole is ____, while diastole is ____-
Contraction and relaxation
Although systole and diastole can refer to contraction and relaxation of either chamber, they usually refer to ______
The action of the ventricles
What is the normal heartbeat triggered by the SA node called?
Sinus rhythm
Adult at rest bpm is typically _____
70 to 80 bpm
What is ectopic foci?
Any region of spontaneous firing other than the SA node like if the SA node is damaged
What are some causes of premature ventricular contraction?
Hypoxia, electroyte imbalance, stress
What is abnormal cardiac rhythm called?
Arrhythmia
What is the major cause of arrhythmia?
Heart block
Each depolarization of the SA node creates ______
One heartbeat
An ____ is a composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes on arms, legs and chest
Electrodiagram/ ECG/EKG
What happens in the P wave?
SA node fires, atria depolarize and contract
Atrial systole occurs in the ____ wave
P
Ventricular depolarization occurs in the ______.
QRS complex
Why is there a complex shape of spikes in the QRS complex?
Different thickness and shape of the two ventricles
Ventrical systole occurs in the ____, which corresponds with _______-
ST segment
Plateau in myocardial action potential
There is ventricular repolarization and relaxation in the ____ wave.
T
What are the steps of the electrical activity of the myocardium?
- Atrial depolarization begins
- Atrial depolarization complete
- Ventricles begin to depolarize at apex; atria reploarizes
- Ventricular depolarization completre
- Ventricles begin to repolarize at apex
- Ventricular repolarization complete
What are some things that could cause deviations of ECG?
Myocardial infections, abnormalities in conduction pathways, heart enlargement, electrolyte and hormone imbalances
____ is serious arrythmia caused by electrical signals traveling randomly
Ventricular fibrilation
What is the strong electrical shock that is used with intent to depolarize entire myocardium and reset heart to sinus rhythm?
Defibrillation
What is ventricular fibrillation a hallmark for?
Heart attacks
____ is listening to sounds made by the body
Auscultation
Describe the first heart sound.
Long and loud ‘lubb’, occuring with closure of AV waves
Describe the second heart sound.
Softer and sharper ‘dupp’, occuring with the closure of semilunar waves
What heart sound is rarely heard in people over 30?
The 3rd heart sound
How long does it take to complete the entire cardiac cycle?
Less than 1 second
The failure of either ventricle to eject blood effectively is called ______
conjestive heart failure
What can cause congestive heart failure?
Myocardial infraction
Chronic hypertension
Valvular insufficiency
Congenital defects in heart structure
What is the average HR of infants?
120 bpm or more
What is the average HR of young adult females?
72 to 80 bpm
What is the average HR of young adult males?
64 to 72
What is tachycardia?
average adult HR above 100 bpm
What is tachycardia caused by?
Stress, anxiety, drugs, heart disease and fever
What is bradycardia?
average HR of less than 60 bpm
Positive chronotropic agents ____ the heartrate while negative chronotropic agents ____ the heartrate
Raise and lower
What does the cardioaccelatory center do?
Stimulates sympathetic cardiac nerves to SA node
The stimulated cardiac nerves in the cardioacceleratory center secrete ______
Noreopinephrine
What does the cardioinhibitory center do?
Stimulates vagus nerves
What does the cardioinbitory center secrete?
Acetylcholine
What are chemoreceptors sensitive to?
Blood pH, CO2 and oxygen
What is a coronary artery?
A constriction of the coronary arteries
____ is usually the result of arherosclerosis.
Coronary artery disease
Give a cause of arteriosclerosis
Inflammation
One major risk factor for coronary artery disease is ____.
Excess of low-density lipoprotein
