The Heart

What structures make up the cardiac conduction system? Trace the path of the electrical signals that excite cardiac muscle, starting with the SA node.

1. Sinoatrial(SA) node (aka the pacemaker) 2. Atrioventricular(AV) node 3. Atrioventricular(AV) bundle (bundle of His) 4. Right and left bundle branches 5. Purkinje fibers

Name 5 risk factors for developing coronary artery disease. What is a stent?

Age. Simply getting older increases your risk of damaged and narrowed arteries. Sex. Men are generally at greater risk of coronary artery disease. ... Family history. ... Smoking. ... High blood pressure. ... High blood cholesterol levels. ... Diabetes. ... Obesity. stent- small mesh tube that's used to treat narrow or weak arteries.

Which two vessels branch from the left coronary artery? What tissues do they supply with oxygen?

Anterior interventricular- Supplies anterior portions of both ventricles Circumflex branches-supplies atria and ventricles

What does autorhythmic mean?

Cells that permit the heart to beat spontaneously, without innervationfrom the nervous system

What two layers of the pericardium have fluid between them? What is this fluid-filled space called?

In between two layers of the pericardium is the fluid-filled pericardial cavity. Between the heart and the mediastinum

What valves cause the S1 and S2 heart sounds? What is a heart murmur?

S1- results from mitral and tricuspid valve closure. It is a duller, lower-frequency sound than S2, and occurs at the beginning of ventricular systole.S2 results from aortic and pulmonic valve closure. It is a sharper, louder sound than S1, and occurs at the end of ventricular systole.

The right atrium gets poorly oxygenated blood from three sources. Name these three.

Superior Vena Cava, Inferior Vena Cava, Coronary Sinus

Mediastinum

The heart lies in the middle of the thoracic cavity, in between the lungs

What is the name of the vessel that the coronary veins empty into?

coronary sinus

Where is the cardiovascular center of the brain located? List three types of sensory input to this center

medulla-nerve impulse to pacemaker (or SA node) via sympathetic fibres (to cause faster and stronger cardiac muscle contraction) and the vagus nerve (to cause slower and less strong cardiac muscle contraction). The cardiovascular centre also increases the stroke volume of the heart (that is, the amount of blood it pumps).

Most arteries in the body carry oxygenated blood. Which arteries carry poorly oxygenated blood?

pulmonary arteries

endocardium

simple squamous epithelium

myocardium

thick middle layer composed of cardiac muscle

epicardium

thin outer layer with adipose tissue and blood vessels that supply the heart.

Which valves have chordae tendineae and papillary muscles? What is the function of chordae tendineae and papillary muscles?

• Chordae tendineae- heart strings, are cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart. • Papillary muscles- located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (a.k.a. the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prolapse of these valves.

An ECG is a recording of the electrical activity of the heart. Describe what is happening in the heart during the P-wave, QRS complex, and T wave.

• P-wave- atrio depolarization • QRS complex- ventricular depolarization • T wave-ventricular repolarization

Describe the roles of the SA and AV nodes. What chambers of the heart do the AV bundles and Purkinje fibers excite?

• SA Nodes- group of cells that generates electrical current. It sends out an electrical charge at some set interval (right atrium) • AV Nodes-border between the right atrium and the right ventricle, sets the rhythm of your heart contractions • AV bundles- excite cardiac muscles in the ventricles • Purkinje fibers- excite cardiac muscles in the ventricles

Which nerve increase heart rate, sympathetic or parasympathetic? What is the name of the parasympathetic nerve?

• Sympathetic increase heart rate • The name of the parasympathetic nerve is Vagus Nerve

Define the terms systole and diastole. Do atrial systole and ventricular systole occur at the same time?

• Systole- contraction phase • Diastole-relaxation phase No they do not occur at the same time

Beginning with the vena cavae, trace blood through the right and left heart. You should include 12 structures: 4 chambers, 4 valves, and 4 vessels.

• Vena cavae from body, Right Atrium, Tricuspid valve, Right Ventricle, Pulmonary Valve, Pulmonary trunk, Pulmonary veins, Left Atrium, Bicuspid Valve, Left Ventricle, Aortic Valve, Aorta