McCance Chapter 32 Structure and Function of the Cardiovascular and Lymphatic Systems

Parietal pericardium

Outer layer of mesothelium that is close to the chest wall

Visceral pericardium

Inner layer of mesothelium that is close to the heart

Epicardium

Outer layer of the heart that provides a smooth surface allowing the heart to contract and relax within the pericardium with a minimal amount of friction

Myocardium

Middle, thick layer of the heart that contains cardiac muscle

Endocardium

Inner layer of the heart composed of simple squamous epithelium that is continuous with the endothelium of blood vessels.

Pulmonary semilunar valve

Valve between the right ventricle and pulmonary arteries that usually has three cusps

Foramen ovale

Opening between the right and left atria in the developing fetus

Left atrioventricular valve

Valve between the left atria and ventricle (mitral valve) that has two cusps

Right atrioventricular valve

Valve between the right atria and ventricle that usually has three cusps

Chordae tendineae

Connect the valves to the papillary muscle in the myocardium

Prolapse

Inverting of the heart valves that causes backflow

Superior vena cava

Enters the right atrium and carries deoxygentaed blood back to the heart

Inferior vena cava

Enters the right atrium and carries deoxygentaed blood back to the heart

Pulmonary veins

Carry oxygenated blood from the lungs to the left side of the heart

Pulmonary arteries

Carries deoxygenated blood to the pulmonary circulation (lungs)

Diastole

Relaxation of the heart

Systole

Contraction of the heart

Left coronary artery

Arises from a single ostium behind the left cusp of the aortic semilunar valve

Left anterior descending artery

Branch of the left coronary artery that supplies blood to portions of the left and right ventricles and much of the interventricular septum

Circumflex artery

Branch of the left coronary artery that supplies blood to the left atrium and the lateral wall of the left ventricle

Right coronary artery

Originates from an ostium behind the right aortic cusp

Conus artery

Branch of the right coronary artery that supplies blood to the upper right ventricle

Marginal branch artery

Branch of the right coronary artery that traverses the right ventricle to the apex

Posterior descending branch artery

Branch of the right coronary artery that supplies both ventricles

Anterior interventricular vein

Drains the anterior surface of the heart

Posterior vein

Drains the posterior surface of the heart

Great cardiac vein

Anterior interventricular and posterior veins come together

Anastomoses

A cross-connection between adjacent channels, tubes, fibers, or other parts of a network

Arteriogenesis

New artery growth branching from pre-existing arteries

Angiogenesis

Growth of new capillaries within a tissue

Shear stress

Increased blood flow velocity creates friction against a blood vessel

Ventricular hypertrophy

Enlargement and thickening of the walls of the heart's main pumping chamber

Connexins

Transmembrane proteins that assemble to form vertebrate gap junctions

Syncytium

Allows rapid, organized, sequential contraction of the atria and then the ventricles through gap junctions

Sinoatrial (SA) node

Contains pacemaker cells of the heart with specialized calcium channels located at the junction of the right atrium and superior vena cava

Atrioventricular (AV) node

Contains pacemaker cells of the heart with specialized calcium channels located in the right atrial wall above the tricuspid valve and anterior to the ostium of the coronary sinus

Bundle of His

Conducting fibers from the AV node converge and transmit depolarizing current to the Bundle branches and then the Purkinjie fibers

Chronotropic

Changes the heart rate

Ionotropic

Change the force or speed of contraction of muscles

P wave

Atrial depolarization

PR interval

Onset of atrial activation to the onset of ventricular activation

QRS complex

Ventricular depolarization

ST interval

Entire ventricular myocardium is depolarized

T wave

Ventricular repolarization

Automaticity

SA and AV nodes generate cardiac action potentials without any stimulus

Rhythmicity

Regular generation of an action potential by the heart's conduction system

Adenosine

Dilate coronary arterioles

Nitric oxide

Dilate coronary arterioles

Prostaglandins

Dilate coronary arterioles

Cardiac Output

Volume of blood flowing through the systemic and pulmonary vessels, calculated by multiplying heart rate (beats per minute) by stroke volume (liters per beat)

Ejection fraction

Percentage of blood that is ejected with each contraction of the atria or ventricles

Preload

Pressure generated at the end of diastole, determined by the ventricular end-diastolic volume

Afterload

Resistance to ejection during systole

Peripheral (or total) vascular resistance

Typically a function of the internal vessel diameter, vessel length, and blood viscosity.

Norepinephrine

Positive inotropic agent released primarily by neurons

Epinephrine

Positive inotropic agent released primarily by the adrenal medulla

Thyroid hormone

Positive inotropic agent

Dopamine

Positive inotropic agent

Acetylcholine

Negative inotropic agent released by the vagus nerve

Frank-Starling Law of the Heart

Cardiac muscle increases its strength of contraction when it is stretched

Laplace's Law

The amount of tension generated in the ventricular wall (or any chamber or vessel) to produce a given intraventricular pressure depends on the size (radius and wall thickness) of the ventricle

Hypothalamus

Regulates cardiovascular responses to changes in temperature

Cerebral cortex

Adjusts cardiac reaction to a variety of emotional states

Cardioinhibitory center

Network of interneuorns, parasympathetic nerves are stimulated and the sympathetic nerves are inhibited

Cardioexcitatory center

Network of interneuorns, sympathetic nerves are stimulated and the parasympathetic nerves are inhibited

Sinus arrhythmia

Heart rate varies naturally with respiration, increases with inspiration and decreases with expiration

Baroreceptor reflex

Mediated by stretch receptors (mechanoreceptors) in the aortic arch and carotid arteries, hypotension causes tachycardia and vasoconstriction, hypertension causes bradycardia and vasodilation

Hydrocortisone

Potentiate the effects of the catecholamines

Triiodothyronine

Thyroid hormone increases heart rate, contractility and cardiac output

Growth hormone

Works with insulin-like growth factor 1 (IGF-1) to increase myocardial contractility

Tunica intima

Innermost layer of a blood vessel (squamous epithelium or endothelium)

Tunica media

Middel layer of a blood vessel, smooth muscle fibers mixed with elastic fibers

Tunica externa or adventitia

Outermost layer of a blood vessel, connective tissue containing nerves, lymphatic vessels, fibroblasts, stem/progenitor cells, mast cells, macrophages, B cells, T cells, and dendritic cells

Vasa vasorum

Small vessels located in the tunica externa that nourish larger vessels

Vasculogenesis

Growth of vessels from progenitor or stem-like cells that originate in the bone marrow and other body tissues

Metarterioles

Connective channels with discontinuous smooth muscle cells in their tunica media and branch into capillaries

Sinusoid capillaries

Liver and bone marrow

Fenestrated capillaries

Contain oval windows or pores (renal glomerulus)

Prostacyclin

Vasodilator formed from arachidonic acid

Nitric oxide

Vasodilator, synthesized and released from the endothelium by bradykinin and shear stress

C-type natriuretic hormone

Vasodilator, made throughout the vasculature and works with NO and prostacyclin

Insulin

Increases endothelial cell production of nitric oxide

Estrogen

Triggers enzyme activation and release of NO.

Endothelium-derived relaxing factor

Potent vasodilator made by vascular endothelial cells

Endothelin

Potent endothelium-derived constrictor

Urotensin II

Potent endothelium-derived constrictor

Angiotensin II

Potent vasoconstrictor produced both hormonally via the renin system and locally in vascular tissues

Thromboxane

Produces vasoconstriction and platelet adhesion

Prostaglandins

Produces vasoconstriction especially during chronic inflammation

Laminar flow

Molecules move straight ahead in vessels

Turbulent flow

Flow is obstructed as a vessel makes a turn or blood flow over rough surfaces

Heart murmur

Turbulent blood flow (whorls or eddy currents) produce noise

Viscosity

The state of being thick, sticky, and semifluid in consistency, due to internal friction

Hematocrit

Ratio of the volume of red blood cells to the volume of whole blood

Polycythemia

Increased production of erythrocytes

Mean arterial pressure

Average pressure in the arteries throughout the cardiac cycle, approximated from the measured values of the systolic and diastolic pressures by means of a formula

Baroreceptors

A mechanoreceptor sensitive to changes in pressure in the aortic arches and carotid arteries

Hyperemia

Increase in blood flow

Vasopressin (antidiuretic hormone)

Increases blood volume through reabsorption in the distal tubule and collecting duct of the nephron in the kidney and stimulates thirst

Aldosterone

Stimulates the reabsorption of sodium, chloride, and water in the nephron