Understanding EKGs (Ch 1-12 Exam)

Myocardium

Thick, middle layer of the heart, composed of cardiac muscle cells, and responsible for ability to contract

Atria

upper chambers of the heart

Coronary Sulcus

surrounds outside of the heart and divides the atria from the ventricles

interatrial septum

The Atria are separated by:

Ventricles

lower chambers of the heart

interventricular septum

The ventricles are separated by

mediastinum

The heart is located in the:

Apex

The ____ of the heart lies just above the diaphragm

Base

The ____ of the heart lies at the level of the third rib.

Closed Fist

The heart matches the size of your:

Pericardium

Closed, two-layered sac, outter most layer of the heart

Parietal Pericardium

Tough, non-elastic, fibrous connective tissue in direct contact with the pleura

Visceral Pericardium

Thin, serous inner layer of pericardium that's contiguous with the epicardium

Pericarditis

inflammation of the serous pericardium

cardiac tamponade

Excess of fluid in pericardial sac

Epicardium

Smooth outer surface of the heart, Coronary arteries are located on this surface

Endocardium

Innermost layer, composed of endothelial tissue

oxygen supply

The endocardium requires constant and uninterrupted:

Atrioventricular Valves

Allow flow from atria into ventricles preventing blood flowing backward from ventricles

Tricuspid valve

Valve located between right atrium and right ventricle, three cusps

Mitral (bicuspid) valve

Valve located between left atrium and left ventricle, two cusps

Semilunar Valves

Prevent backflow of blood into the ventricles

Pulmonic valve

Semi-lunar valve located between right ventricle and pulmonary artery

Aortic valve

Semi-lunar valve located between left ventricle and trunk of the aorta

Ventricular systole

Contraction of ventricles, Atrioventricular valves close and semilunar valves open

Ventricular diastole

Relaxation of ventricles,

Atrioventricular valves open and semilunar valves closed

Blood Vessels

the "container" for fluid or blood

Arteries

Thick wall and muscular vessels, the function under high pressure and carry blood away from the heart. Regulate blood pressure changes in peripheral vascular resistance.

Arterioles

Small arterial vessels

Tunica intima

Innermost layer of the Arterial Wall., made of Connective and elastic tissue.

Tunica media

Middle layer of the Arterial Wall, made of Smooth muscle, elastic, and collagen tissue.

Tunica adventitia

Outermost layer of the Arterial Wall, made of Connective tissue

Coronary Arteries (The right and left)

Provide oxygenated blood throughout the heart muscle

Trunk of the aorta

The right and left Coronary Arteries arise from the:

left anterior descending artery and circumflex artery

Left Coronary Artery divides into the:

Anterior descending artery

supplies most of anterior portion of the heart

Circumflex artery

extends around to the posterior side of the heart and supplies the lateral wall of left ventricle

Right Coronary Artery

Extends around to the posterior portion of the heart, Branches supply blood to lateral wall

Posterior interventricular artery

Branching from the Right Coronary Artery, the ___ ____ ____ supplies posterior and inferior part of left ventricle

Coronary Sinus

Great Cardiac Vein, receives deoxygenated blood from the veins of the myocardium

right atrium

The Coronary Sinus empties into the:

Veins

Vessels that carry blood back to the heart and operate under low pressure

Venules

Smaller vein vessels

Capillaries

Tiny blood vessels with thin walls where the majority of gas exchange occurs

Circulation

Movement through a course (body) that leads back to the initial point (heart)

PULMONARY artery

Blood leaves heart through right ventricle, travels into _____ _____ to the lungs.

PULMONARY veins

Delivers blood from the lungs into the left atrium

Superior Vena Cava

Drains blood from the head and neck

Inferior Vena Cava

A vein that is the largest vein in the human body and collects blood from it.

Tissue Perfusion

gas exchange in the tissues

From the inferior and superior vena cava, into the right atrium, through the tricuspid valve, into the right ventricle, and through the pulmonic valve

Deoxygenated Blood Flow through the Heart:

From the pulmonary arteries, into the lungs, through the pulmonary alveolar-capillary network, and into the pulmonary veins

Blood Flow through the Pulmonary Circulation:

from the pulmonary veins into the left atrium, through the mitral valve, into the left ventricle, through the aortic valve, and out to the rest of the body

Oxygenated Blood Flow through the Heart:

Cardiac Cycle

the actual time sequence between ventricular contraction and ventricular relaxation

Systole

Simultaneous contraction of the ventricles

Diastole

Synonymous with ventricular relaxation

70%

Ventricles fill with __% of blood passively from atria

0.8 seconds

One normal cardiac cycle occurs every

About 0.2 seconds

Normally systole lasts

About 0.52 seconds

Normally diastole lasts

Ejection Fraction

measurement of the amount of blood pumped out of the ventricles with each cardiac cycle

55-70%

Normal Ejection Fraction value:

40%

An Ejection Fraction less then __% is indicative of heart failure

Stroke volume

Volume of blood pumped out of one ventricle of the heart in single beat or contraction

70 ml

Stroke Volume is estimated at approximately __ ml per beat

Heart rate

Number of contractions or beats per minute

60-100 BPM

Normal heart rate

Cardiac output

Amount of blood pumped by left ventricle in 1 min

Cardiac output = Stroke Volume x Heart Rate

Formula to determine cardiac output

Preload

Pressure in the ventricles at the end of diastole

volume of blood that returns to right atrium

Preload is directly affected by the:

Afterload

Resistance against which the heart must pump

stroke volume and cardiac output

Afterload affects:

Starling's Law

the more the myocardial fibers are stretched, up to a certain point, the more forceful the subsequent contraction will be (Rubber band theory)

Peripheral vascular resistance

Amount of opposition to blood flow offered by arterioles

vasoconstriction and vasodilation

Peripheral vascular resistance is determined by:

Cardiac Output x Peripheral Vascular Resistance

Blood Pressure =

Autonomic Nervous System

Regulates functions of the body that are involuntary or are not under conscious control, HEARTRATE and BLOOD PRESSURE are regulated by this component of nervous system

Sympathetic nervous system

Preparation of body for physical activity (“fight or flight”)

Parasympathetic nervous system

Regulates the calmer (“rest and digest”) functions of our existence

Alpha and beta receptors

Sympathetic nervous system receptors

norepinephrine

Sympathetic nervous system chemical neurotransmitter

adrenergic

Nerve endings that increases the heart rate and contractile forces of cardiac muscle and vasoconstriction

acetylcholine

Parasympathetic nervous system chemical neurotransmitter

cholinergic

Nerve endings that slows the heart rate and the atrioventricular conduction rates

Adrenergic Receptors

Sympathetic nerve fibers that use epinephrine or epinephrine-like substances as neurotransmitters

Cholinergic receptors

Parasympathetic nerve fibers that use acetylcholine as neurotransmitter

Alpha

Receptors that Increase Blood Pressure through Vasoconstriction

Beta 1

Receptors that increase Heart rate and contractility

Beta 2

Receptors that cause bronchial dilation and vasodilation.

Heart and Vessels

Alpha Receptors affect the:

Heart

Beta 1 Receptors affect the:

Lungs and Vessels

Beta 2 Receptors affect the:

Physical Contraction

Myocardial working cells are responsible for generating the _______ __________ of heart cells

Myocardial working cells

Make up the thin muscular layer of atria walls and thicker muscular layer of ventricular walls

Contact and Relax

Myocardial working cells primarily function to both:

Blood Flow

Physical contraction of myocardial tissues generates:

Specialized Pacemaker Cells

Responsible for controlling rate and rhythm by coordinating regular depolarization, found in the electrical conduction system of the heart.

Contract

Unlike Myocardial working cells, Specialized Pacemaker cells cannot:

Generation and Conduction

The primary function of Specialized pacemaker cells is the _________ and ________ of electrical impulses.