8. Cardiovascular (Incomplete)

What is diastole?

relaxation and filling with blood

What is systole?

contraction and emptying of blood

What is the major role of the cardiovascular system?

Transport of oxygen and removal of metabolic wastes

Which of the following make up the distribution system of the cardiovascular system?

Heart, aorta, aortic branches, smaller arteries, arterioles

Which of these make up the distribution/perfusion system of the cardiovascular system?

Arterioles and capillaries

Which of the following make up the collecting system of the cardiovascular system?

Venules, large veins, vena cava, and heart

Which of the following is the correct pairing regarding vessel diameter and pressure?

Decrease in size causes increase in pressure

List the pathway of blood through the pulmonary and systemic circuits starting with the right atrium.

Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Pulmonary artery → Lungs → Pulmonary vein → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta → Arterioles → Capillaries → Cells → Venules → Veins → Vena cava

Which system is known as the resistance component?

Arterial system

Which system is known as the capacitance component?

Venous system

How are pressure and flow related within the resistance component?

Pressure - directly, Flow - inversely

How are volume and pressure related within the capacitance component?

Volume - directly, Pressure - Inversely

Where are the major resistance sites and why do they occur?

Precapillary beds via the precapillary sphincter

What is a portal system?

When there is a vein separating two capillaries

Where do portal systems occur?

All of these

What do all the portal systems combine to make?

Hepatic portal vein

What does preload describe and what determines it?

incoming blood to the heart; expansibility of the low pressure venous system

What does afterload describe and what determines it?

resistance that the heart encounters to propel the blood out; high pressure of the arterial system

Gravity does not have an effect of the vascular pressure at the level of the heart.

False

Hydrostatic pressure is the same as blood pressure.

True

What determines force of contraction?

Afterload

What percentage of blood moves into the ventricles passively?

70%

What is the relative pressure in veins in mmHg?

0

What percent distribution of blood lies in the pulmonary circulation?

9%

What percent distribution of blood lies in the heart?

7%

What percent distribution of blood lies in the arteries?

13%

What percent distribution of blood lies in the arterioles and capillaries?

7%

What percent distribution of blood lies in the veins, venules, and venous sinuses?

64%

What other name can be given to pulmonary circulation?

Venous

What other name can be given to systemic circulation?

Arterial

What is the special attribute of the SA node that makes it self-excitable enabling it to be self-excitatory?

Constantly open ion channels

Contractile force is directly proportional to the degree of stretching.

True

List the conducting pathway of the heart in order.

1. Bundle of His

2. AV node

3. Purkinje fibers

4. Right and left bundle branches

5. SA node

5, 2, 1, 4, 3

Arrange the following in order of decreasing (fastest → slowest) conduction velocity.

1. Ventricular myocardium

2. AV node

3. Bundle branches

4. Atrial myocardium

5. Purkinje fibers

6. SA node

7. Bundle of His

5, 3, 7, 4, 1, 2, 6

The cardiac muscle of the excited membrane repolarizes immediately after depolarization.

False

What happens in an action potential of cardiac muscle cells after the peak of the spike?

Remains on a plateau for 0.2-0.3 milliseconds before repolarizing

What does the plateau phase in the action potential protect from?

Hyperactivity and out of phase contractions

What is the time of a cardiac action potential where it is insensitive to another stimulus?

Absolute refractory period

What is the time of a cardiac action potential where it has not fully recovered and is highly responsive to another stimulus?

Relative refractory period

What is the time of a cardiac action potential where it is completely ready for a stimulus?

Supernormal period

What is Phase 0 characterized by?

Rapid, relative large influx of sodium ions into the cell

What is Phase 1 characterized by?

Efflux of potassium ions

What is Phase 2 characterized by?

Large, slow, influx of calcium ions with a decreased influx of sodium ions

What is Phase 3 characterized by?

Efflux of potassium ions

What is Phase 4 characterized by?

Normal resting membrane potential

What is the other name given to Phase 1?

Early phase of repolarization

What is the other name given to Phase 2?

Plateau phase

What is the other name given to Phase 3?

Phase of repolarization

What is the other name given to Phase 4?

Resting phase

What is a standard limb I lead?

Negative electrode - right forelimb ; positive electrode - left forelimb

What is a standard limb II lead?

Negative electrode - right forelimb ; positive electrode - left hindlimb

What is a standard limb III lead?

Negative electrode - left forelimb ; positive electrode - left hindlimb

What is an augmented limb lead?

When two of the standard points are connected to the negative terminal and the other remains by itself on the positive terminal

What are the connections of the AVR lead?

Positive - right forelimb ; Negative - left fore and hindlimb

What are the connections of the AVL lead?

Positive - Left forelimb ; Negative - Right forelimb and left hindlimb

What are the connections of the AVF lead?

Positive - Left hindlimb ; Negative - Right and left forelimb

What does the P wave represent on an ECG?

Atrial depolarization

What does the QRS complex represent on an ECG?

Ventricular depolarization

What does the T wave represent on an ECG?

Ventricular repolarization

What does the U wave represent on an ECG?

Vibration of papillary muscles

Why is atrial repolarization not shown on the ECG?

Ventricular depolarization masks it

What does it mean when the PR interval is prolonged?

Timing is delayed

What does it mean when the whole Q-T interval is shortened?

High frequency of ventricular activity

What does the flattening of the T wave mean?

Volume of blood in ventricles is too low

What does a decrease in R peak mean?

Ventricular contractile force is decreased

What does the PR interval signify?

Atrial depolarization and conduction of impulse through the AV node

What does the QT interval signify?

Ventricular depolarization and repolarization

What does a prolonged PR interval mean?

Bradycardia and first degree heart block

What does a shortened PR interval mean?

Tachycardia

What does a prolonged QT segment mean?

Myocardial infarction, myocarditis, hypocalcemia, and hypothyroidism

What does a shortened QT segment mean?

Hypercalcemia

What does the ST interval represent?

Isoelectric period

What does an elevation in the ST segment mean?

Anterior and inferior myocardial infarction, left bundle branch block, acute pericarditis

What does a depression in the ST segment mean?

Acute myocardial ischemia, posterior myocardial infarction, ventricular hypertrophy, hypokalemia

What does a prolonged ST segment mean?

Hypocalcemia

What does a shortened ST segment mean?

Hypercalcemia

What does the RR interval represent?

One cardiac cycle

What does a prolonged RR interval represent?

Bradycardia

What changes in the ECG do you see with Hypokalemia?

ST depression, flat or inverted T wave, U wave

What changes in the ECG do you see with Hyperkalemia?

Flat P wave, prolonged PR interval, QRS widening, tall peaked T wave

What changes in the ECG do you see with hypocalcemia?

Prolonged ST segment and QT interval

What changes in the ECG do you see with hypercalcemia?

Shortened ST segment and widened T wave

What changes in the ECG do you see with hypomagnesemia?

Tall T wave, ST depression

What changes in the ECG do you see with hypermagnesemia?

Prolonged PR interval, QRS widening

The R-R interval ___1___ during ____2____ and ____3___ during ___4___.

1. decreases, 2. inspiration, 3. increases, 4. expiration

What is the normal variation in RR intervals called?

Respiratory sinus arrhythmia

When lead I is positive and AVF is negative _____ is seen.

Left axis deviation

When lead I and AVF are equally positive _____ is seen.

Normal axis

When lead I and AVF are positive _____ is seen.

Normal axis

When lead I is positive and AVF is almost equiphasic _____ is seen.

Axis approaching 0

When lead I is negative and AVF is positive _____ is seen.

Right axis deviation

When lead I and AVF are negative _____ is seen.

Extreme axis deviation

What are some causes of cardiac arrhythmias?

All of these

What causes abnormal impulse formation?

Problems with the SA node

What causes abnormal impulse conduction?

Problem with the impulse conducting tissues

What causes reentry (or circus) rhythm?

Conduction signal reversal due to necrotic tissue

What can cause altered normal automaticity?

Sympathetic stimulation and decrease in parasympathetic tone

What is a first stage heart block?

No block, just delayed

What is a second degree heart block?

Intermittent block

What is a third degree heart block?

Persistent or complete block