Cardiology Lecture 1 1/9/12

Front 1

3 functions of the cardiovascular system?

Back 1

1. Transport oxygen and other essential substances to tissues
2. Removal of byproducts of metabolism
3. Helps regulate hemostasis, including body temp and blood pressure

Front 2

What part of the CV system serves as the primary determinant of systemic vascular resistance?

Back 2

Arteries

Front 3

What vessels have the most elastin?

Back 3

Arteries

Front 4

What vessels have the most smooth muscle?

Back 4

Arterioles

Front 5

Which vessels have valves?

Back 5

Veins

Front 6

Are all capillary beds the same?

Back 6

No. Some are "leaky" (renal capillaries), while others are not (pulmonary capillaries)

Front 7

Where is the majority of the body's blood volume?

Back 7

Venous system

Front 8

What regulates regional blood flow?

Back 8

Precapillary sphincters

Front 9

What are three ways that nutrients are exchanged in the capillary beds?

Back 9

1. Diffusion between cells
2. Diffusion through cells
3. Transport via vesicles

Front 10

What is the basic contractile unit of cardiac muscle?

Back 10

Sarcomere

Front 11

What is systole?

Back 11

The time between the first (S1, closure of the AV valves) and second (S2, closure of the semilunar valves) heart sounds.

Front 12

What are the two phases of the cardiac cycle?

Back 12

Systole and diastole

Front 13

What is the path that electrical signals course through the heart?

Back 13

SA node --> atrial myocardium --> AV node --> His-Purkinje system --> ventricular myocardium

Front 14

What ion channels are opened by depolarization of the sarcolemma membrane?

Back 14

L-type calcium channels

Front 15

What do ryanodine receptors do?

Back 15

Calcium binds to ryanodine receptors in the sarcoplasmic reticulum, leading to calcium release from the sarcoplasmic reticulum. (Calcium induced calcium release)

Front 16

What are the contractile proteins of the heart?

Back 16

Myosin (thick filaments), actin (thin filaments), tropomyosin, and troponin I, C, and T

Front 17

What is ventricular diastole?

Back 17

An active, energy requiring process wherein the increased cytosolic calcium concentration achieved during systole results in the reuptake and efflux of calcium out of the cell.

Front 18

What are the mechanisms for restoring the calcium gradient?

Back 18

1. Uptake back into the sarcoplasmic reticulum (85%)
2. Extrusion to the extracellular space via the Na/Ca exchanger (5%)
3. Removal via dedicated Ca pump (1%)
4. In diseased conditions calcium can be sequestered into the mitochondria.

Front 19

What is the blood pressure in each chamber of the heart, the pulmonary artery, and the aorta?

Back 19

Right atrium: 0-3 mmHg
Right ventricle: 25/3 mmHg
Pulmonary artery: 25/12 mmHg
Left atrium: 0-5 mmHg
Left ventricle: 120/5
Aorta: 120/80

Front 20

What are the two fundamental mechanical functions of the heart?

Back 20

Eject Blood
Receive Blood

Front 21

Which side of the heart has greater compliance?

Back 21

Right side

Front 22

What signs of congestion occur in right heart failure?

Back 22

Hepatomegaly and ascites
Occurs when venous pressure exceeds 15 mmHg (normal <5 mmHg)

Front 23

What signs of congestion occur in left heart failure?

Back 23

Cough, labored breathing. Occurs when pulmonary capillary pressure exceeds 25 mmHg (normal <10 mmHg)

Front 24

What are the five determinants of systolic performance and cardiac output?

Back 24

Preload
Afterload
Myocardial contractility
Heart rate
Ventricular synchrony

Front 25

What effect does increased end-diastolic volume have on contractility in a normal heart?

Back 25

Increased contractility, to a point.

Front 26

What are two conditions that impede diastolic filling?

Back 26

Myocardial fibrosis and hypertrophy impede filling because they prevent optimal stretch by the myofibers even when filling pressures are increased.

Front 27

What is afterload?

Back 27

Afterload represents the sum of all those forces that oppose the ejection of blood from the ventricle into the circulation. Also called systolic tension or wall stress.
Afterload is determined by systemic vascular resistance and compliance.

Front 28

What is Ohm's law?

Back 28

Cardiac output (flow) = (P1-P2)/R

Front 29

What is Laplace's Law?

Back 29

Wall stress = (pressure x radius)/(2 x wall thickness)

Front 30

What factors influence contractility?

Back 30

Level of sympathetic nerve activity, the circulating concentration of catecholamines, and to some extent heart rate.
Anoxia, ischemia/fibrosis, and acidemia reduce contractility.

Front 31

What determines heart rate?

Back 31

The automaticity of the SA node, which is subject to autonomic regulation and other environmentsl and metabolic factors.

Front 32

True or False: Ventricular dyssynchrony has little effect on cardiac output.

Back 32

False. Ventricular synchrony is needed to maintain stroke volume.

Front 33

What are the four phases of ventricular diastole?

Back 33

1. Isovolumetric relaxation - begins when the semilunar valves close and lasts until the AV valve opens and filling of the heart begins.
2. Rapid ventricular filling - blood pours in when the AV valves open
3. Diastasis - a period of little/no blood flow that serves as a reserve to be encroached upon when heart rate increases.
4. Late filling period - associated with atrial systole

Front 34

Which of the phases of ventricular diastole can be used as an indicator or diastolic function?

Back 34

Isovolumetric relaxation time (IVRT). A prolonged IVRT suggests impaired relaxation.

Front 35

What is ventricular compliance?

Back 35

The ability of the heart to fill passively. This is determined by the volume and geometry of the chamber as well as the thickness and tissue composition of the walls.

Front 36

What effect does decreased compliance have on end diastolic pressure.

Back 36

Increased pressure is needed to push blood through a non-compliant heart.

Front 37

What conditions could cause decreased contractility?

Back 37

Myocardial fibrosis, hypertrophy

Front 38

True or false: Animals with impaired diastolic function almost always have impaired systolic function as well.

Back 38

False. Animals can have heart failure due to diastolic dysfunction while having normal systolic function.

Front 39

How does calcium interact with the contractile proteins in the sarcomere?

Back 39

Calcium binds to the troponin complex (troponin C). Troponin C interacts with tropomyosin to expose actin binding sites, enabling cross bridges to form between actin and myosin.