Chapter 13: Cardiovascular System

Flashcards covering the cardiovascular system, heart structure, function, blood vessels, blood pressure, and blood flow.

Cardiovascular system

A closed circuit consisting of the heart and blood vessels (arteries, capillaries, and veins).

Pulmonary circuit

Transports oxygen-poor blood to the lungs for oxygenation and carbon dioxide removal.

Systemic circuit

Sends oxygen-rich blood to all body cells, delivering oxygen and picking up carbon dioxide.

Pericardium

A membranous sac that encloses the heart.

Fibrous pericardium

Outer, tough, connective tissue layer of the pericardium.

Serous pericardium

Inner, more delicate, double-layered portion of the pericardium.

Parietal pericardium

Outer layer of the serous pericardium, lining the fibrous pericardium.

Visceral pericardium (epicardium)

Inner layer of the serous pericardium, covering the heart.

Pericardial cavity

Space between the visceral and parietal layers, containing serous fluid to reduce friction.

Epicardium (visceral pericardium)

Outermost layer of the heart wall; a serous membrane that decreases friction.

Myocardium

Middle and thickest layer of the heart wall, consisting of cardiac muscle.

Endocardium

Inner layer of the heart wall, continuous with the endothelium of major vessels, containing Purkinje fibers.

Atria

Upper chambers of the heart that receive blood.

Ventricles

Lower chambers of the heart that pump blood out.

Atrioventricular (AV) valve

Ensures one-way blood flow from atria to ventricles on each side of the heart.

Semilunar valve

Valves located between the ventricles and the blood vessels into which blood is pumped.

Skeleton of the heart

Rings of dense connective tissue that provide attachments for heart valves and muscle fibers and prevent dilating of outlets.

Systole

Contraction of a heart chamber.

Diastole

Relaxation of a heart chamber.

Cardiac conduction system

Specialized cardiac muscle tissue that conducts impulses throughout the myocardium.

Sinoatrial (SA) Node

A self-exciting mass of specialized cardiac muscle that serves as the pacemaker, located in the right atrium.

Atrioventricular (AV) Node

Passes impulses to the AV bundle, delaying the signal until atria have finished contracting; located in the interatrial septum.

Electrocardiogram (ECG)

Recording of the electrical changes that occur during a cardiac cycle.

Heart sounds

Heart sounds are due to vibrations in heart tissues as the valves close and

Systolic pressure

maximum arterial pressure reached during ventricular contraction (systole)

Diastolic pressure

minimum arterial pressure reached during ventricular relaxation (diastole), just before the next contraction

Stroke volume

Amount of blood discharged from each ventricle with each contraction (about 70 mL).

Peripheral resistance (PR)

Friction between blood and the walls of blood vessels.

Blood Viscosity

Difficulty with which molecules in a fluid flow past each other.

Baroreceptors

Sense changes in BP; located in aortic arch & carotid arteries

Venous Blood Flow

Blood pressure decreases as distance from the heart increases

Ascending Aorta

First portion of aorta, extending out of the left ventricle

Aortic arch

Bend in the aorta, after ascending aorta

Descending Aorta

Next portion of the aorta, following the arch

Carotid sinuses

Located near the base of the internal carotid artieries and contain baroreceptors to monitor blood pressure