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