A&P II Chapter 20: The Heart
At a heart rate of 60 beats/min a cardiac cycle lasts
1 second
The heart beats how many times a day
100,000
A heartbeat lasts
370 msec.
How many pulmonary veins are there
4
Order of the conducting system of the heart: 1. Purkinje Fibers 2. AV bundle 3. AV node 4. SA node 5. Bundle branches
4, 3, 2, 5, 1
The Bicuspid (mitral) valve is located
Between the left atrium and left ventricle
David suffers from a prolapsed mitral valve. This condition would cause
Both B & C increased effort by the left ventricle and systolic murmur
The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons
Both parts are true and relate to brainstem control of heart rate
____ is to slow heart rate as ____ is to fast heart rate
Bradycardia; tachycardia
Long plateau phase of the cardiac muscle action potential is due to
Calcium channels remaining open
Angina Pectoris
Heart/chest pain due to ischemia of cardiac vessels & short of O2 in cardiac muscles
What increases heart rate?
Increased sympathetic stimulation of SA node; Decreased parasympathetic stimulation of nodal fibers; Increased levels of epinephrine; Faster depolarization of the pacemaker potential
The foramen oval in the fetal is located in the
Intertribal septum
Blood returning to the heart from the pulmonary circuit first enters the
Left Atrium
The Bicuspid valve prevents backward flow into the
Left atrium
The circumflex branch and the anterior interventricular artery are branches of the
Left coronary artery
The _____ ventricle has a greater workload than the _____
Left; right ventricle
Pulmonary arteries carry blood to the
Lungs
Region in the middle of the thoracic cavity occupied by the heart, great vessels, thymus, esophagus, and trachea
Mediastinum
The AV vales _____ when the semilunar valves close
Open
The hear is innervated by the
Parasympathetic and sympathetic nerves
Contractions of the papillary
Prevent the atrioventricular valves from reversing into the atria
Blood leaves the right ventricle by passing through the pulmonary valve
Pulmonary valve
The left ventricle is the same as the right ventricle EXCEPT that it
Pumps at a greater volume
During the cardiac cycle...
QRS complex precedes the increase in ventricular pressure & the first heart sound coincides with the QRS complex
Blood returning to the heart from the systemic system first enters the
Right Atrium
Right ventricle pumps blood to
Right and left lungs
The marginal branch and posterior interventricular branch are branches of the
Right coronary artery
The Pulmonary semilunar valve prevents backward flow into the
Right ventricle
Heart sounds using stethoscope
S1 (Lubb): AV valves close S2 (Dupp): Semilunar valves close S3: blood flows to ventricles S4: Atrial contraction
Stroke volume = end-diastolic volume - end-systolic volume Cardiac Output = Heart rate * Stroke volume
SV = EDV - ESV in mL CO = HR * SV mL/min = beats/min * ml/beat
Intercalated discs
Serve to transfer ionic currents, action potentials, and the force of contraction from cell to cell
Normal pacemaker of the heart is located in the
Sinoatrial node
Right Atrium receives blood from
Superior/Inferior Vena Cave and Coronary Sinus
____ is to contraction as ____ is to relaxation
Systole; diastole OR Ejection; filling
As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit
Tetany
AV nodal cells are poorly interconnected compared to contractile cells but they have bigger diameters
The 1st part of the statement is TRUE but the 2nd part is FALSE
As blood leaves the right ventricle into the pulmonary trunk, it has to go through
The Conus arteriosus
Blood is supplied to the myocardium by & the first blood vessels to branch from the aorta
The Coronary Arteries
What is near the left 5th intercostal space?
The apex of the heart
If the connection between the SA node and AV node gets blocked
The ventricles will beat more slowly; ECG would have faster P waves than QRS complexes
Stroke volume
The volume of blood ejected from each ventricle during a contraction
Blood flowing into the heart from the venae cavae flows next to the
Tricuspid valve
T wave
Ventricular repolarization (relaxation)
Coronary thrombosis
blood clot forms on a ruptured plaque in a coronary artery
The peak pressure in the VENTRICLE
is greater during the left ventricular systole
Rupture of the papillary muscle in the left ventricle results in
mitral & bicuspid regurgitation/valve prolapse
Cardiac output is increased by
more sympathetic stimulation and increased stroke volume
To perform a CABG, a cardiac surgeon must
open the pericardial sac and visualize the visceral pericardium
Acetylcholine slows the heart because
opens K+ channels in the SA node cells and causes pacemaker potential to depolarize quicker
Foramen Ovale
permits blood flow from the right atrium to the left in fetal circulation
Systolic ejection phase
phase in the cardiac cycle when the bicuspid (mitral) valve is closed and the aortic valve is open
The following list of vessels and structures associated with the heart, put in order for the flow of blood: 1. Right atrium 2. Left atrium 3. Right ventricle 4. Left ventricle 5. Venae cavae 6. Aorta 7. Pulmonary trunk 8. Pulmonary veins
5, 1, 3, 7, 8, 2, 4, 6
Ventricular systole
AV valves are closed
The first heart sound is heard when the
AV valves close
The connective tissues of the myocardium
Add strength and prevent overexpansion of the heart ; Help distribute the forces of contraction; Provide elasticity to help return the heart to its normal size; Provide physical support for cardiac muscle.
Starling's law of the heart
An increase in the end-diastolic volume increases the stroke volume
Left ventricle pumps blood to
Aorta
Earlike extension of the atrium
Auricle
Pacemaker cells in the SA node
show a slow spontaneous depolarization and are connected by gap junction to atrial myocytes
Left coronary artery
supplies blood to the left atrium
Compressing the inferior vena cava just below the diaphragm would cause
sympathetic stimulation of the heart would increase
The wall of the left ventricle is thicker than the right because
the left ventricle does more work, and produces a higher pressure than the right
QRS Complex
Depolarization of the ventricle
Viceral Pericardium is the same as
Epicardium
The interventricular sulci and coronary sulcus contain
Fat, arteries, and veins
Pulmonary veins carry blood to the
Heart
How many liters of blood does the heart pump a day
8,000
Pacemaker cells isolated from the SA node generate action potentials at...
80-100 beats per minute
The heart is the size of...
A man's clenched fist
Difference in cardiac muscle cells and skeletal muscle cells
Cardiac muscle cells lack transverse tubules
Most middle layer of the heart wall
Cardiac myocytes
Cusps of atrioventricular valves attach directly to
Chorde tendineae
Lub (1st heart sound)
Closing of the bicuspid (mitral) valve
What is the function of the atrium?
Collects blood & pumps blood to the ventricle
Groove that makes the border between the atria and ventricles
Coronary Sulcus
The great and middle cardiac veins drain blood into the
Coronary sinus
Myocardial infarction (heart attack)
Death of area of heart muscle due to lack of O2; replaced with scar tissue and release hormones like cardiac troponin T & I, and creatinine phosphokinase (CK-MB)
Calcium channel blocker drugs (nifedipine) is used to
Decrease the force of cardiac contraction; Decrease blood pressure; Dilate the coronary arteries; Produce a negative inotropic effect.
When the left ventricle contracts, the distance from the apex to the base & the diameter of the ventricular chamber
Decreases
P wave
Depolarization of the Atria
Which is greater??
The end-diastolic volume that is lower (60 vs. 150; 60 is greater)
Titanic muscle contractions don't occur in a normal cardiac muscle because
The refractory period lasts until the muscle relaxes
Coronary veins empty into
The right atrium
Heart murmur is caused by....
aortic valve stenosis, mitral & pulmonary valve insufficiency
The isovolumetric phase of ventricular systole
atrioventricular valves and semilunar valves are closed
Blood clot
can use clot dissolving drugs like streptokinase or t-PA & heparin; balloon angioplasty
Beta-one receptor activation
causes heart rate to increase
Drugs that block the beta-one adrenergic receptors
decrease heart rate
An increase in the rate of action potentials from baroreceptors lead to
decrease in heart rate and blood pressure
Right/Left coronary arteries
deliver blood to the myocardium
If a patient's tricuspid valve was leaking during systole, what would happen?
diastolic murmur
Treatment of coronary artery disease (CAD) and myocardial infarction (Drug treatment)
drugs that reduce coagulation and risk of thrombosis (aspirin and coumadin); drugs that block sympathetic stimulation (propranolol or metoprolol); drugs that cause vasodilation (nitroglycerin); drugs that block calcium movement into cardiac muscle; and drugs to relieve pain (fibrinolytic agents to help dissolve clots and O2)
The fast depolarization phase of the action potential in cardiac muscle
increased membrane permeability to sodium ions
Arter is to ______ as vein is to ______.
efferent; afferent
Stroke volume depends on...
end diastolic volume, contractility of the ventricle, and the pressure required to pump blood into the aorta
Cardiac tamponade
fluid collecting in the pericardial cavity that restricts the movement of the heart
Medulla oblongata
heart rate is controlled by the neurons located here
If pacemaker cells in the SA node become more permeable to K+ ions
heart rate will decrease, and membrane will hyperpolarize
The atrioventricular valves permit blood flow
in ONE direction only