Heart Physiology Review

Flashcards covering the key terms and concepts from heart physiology, useful for exam preparation.

Cardiac output (CO)

The amount of blood pumped by a single ventricle in one minute.

Stroke volume (SV)

The volume of blood ejected from a ventricle at each beat of the heart.

Positive inotropic agents

Substances that increase the strength of contraction in the myocardium.

Negative inotropic agents

Substances that decrease the strength of contraction in the myocardium.

Pulmonary circulation

The path of deoxygenated blood from the right side of the heart to the lungs and back to the left side of the heart for oxygenation.

Systemic circulation

The flow of oxygenated blood from the left side of the heart to the tissues of the body and back to the right side of the heart.

Coronary circulation

The circulation of blood to and from the tissues of the heart.

Chronotropic agents

Factors that change the heart rate by altering the activity of nodal cells.

Atrioventricular (AV) Node

A cluster of cells that receives the action potential from the sinoatrial node and transmits it to the ventricles.

Pacemaker potential

The gradual depolarization of nodal cells that leads to an action potential.

Myocardial infarction

Death of a region of heart muscle due to loss of blood flow to that area, often caused by a blockage in the coronary arteries.

End diastolic volume (EDV)

The volume of blood in a ventricle just before it contracts.

End systolic volume (ESV)

The volume of blood remaining in a ventricle after it has contracted.

Afterload

The resistance in arteries to the ejection of blood.

Venae cavae

The great veins that carry deoxygenated blood to the right atrium of the heart.

Fibrous pericardium

The tough outer layer that surrounds the heart and provides mechanical protection.

Intercalated discs

Cell structures that connect cardiac muscle cells, allowing electrical signals to be transmitted quickly.

Sinoatrial (SA) node

The heart's natural pacemaker, located in the right atrium.

Cardiac cycle

The sequence of events in the heart from the beginning of one heartbeat to the beginning of the next.

Atrioventricular (AV) valves

Valves that separate the atria from the ventricles.

Papillary muscles

Muscles located in the ventricles that attach to the chordae tendineae and help to prevent the inversion of the AV valves during contraction.

layers of vessels

The three concentric layers found in blood vessels are the tunica intima, tunica media, and tunica externa.

vessels with highest to lowest pressures

arteries, capillaries, veins

types of capillaries

continuous, fenestrated, sinusoidal

Blood flow through capillaries

metarteriole, thoroughfare and true capillaries, venule

vasomotion

blood flow through true capillaries determined by precapillary sphincters

arterial anastomoses

2 arteries supply one capillary bed and one vein

venous anastomoses

one artery to one capillary bed and 2 veins

arterovenous anastamoses

a direct connection between arteries and veins, bypassing capillaries.

Skeletal muscle pump

contractions in skeletal muscle forces blood up veins and valves close to prevent backflow

respiratory pump

diaphragm contracts to make abdominal pressure greater than thoracic pressure to force blood into thoracic cavity and when diaphragm relaxes, pressure equalizes, allowing blood to flow back to the heart.

Total area of vessels vs velocity

inverse relationship, when one is high, other is low

Bulk flow

the movement of fluid driven by pressure differences, essential for distributing nutrients and removing waste.

Filtration

when hydrostatic pressure is greater than osmotic pressure, fluids and solutes are forced out of the capillaries into the surrounding tissue.

reabsorption

when osmotic pressure is greater than hydrostatic pressure, fluids and solutes are drawn back into the capillaries from the surrounding tissue.

myogenic response

response to pressure changes to stabilize blood flow through either vasodilation or vasoconstriction

myogenic response to high blood pressure

stretch causes by high blood pressure stimulates contraction/vasoconstriction

myogenic response for low blood pressure

vasodilation to allow blood flow into tissues

vasodilators

things that increase blood flow to tissues, low oxygen, nutrients, etc

vasoconstrictors

things that reduce blood flow and nutrient exchange, high oxygen, nutrients, low body temp

blood pressure gradient

change in pressure from one end of vessel to the other

pulse pressure

difference in pressure between systolic and diastolic

mean arterial pressure

average pressure throughout entire cardiac cycle, calculated with diastolic + 1/3 pulse pressure

Total blood flow

Pressure gradient from cardiac output/ resistance from vessels

factors that impact resistance in vessels

1. vessel length

2. vessel diameter

3. blood viscosity