AHP117 Chapter 13 Intro to the Cardiovascular System

blood vessels

arteries, veins, capillaries

Where are semilunar valves found?

at the exits from the ventricles

The upper chambers of the heart are called

atria "means chamber"....receive blood returning to the heart, and have thin walls and ear-like auricles projecting from their exterior.

Electrocardiogram (ECG)

recording of the electrical changes that occur in the myocardium during a cardiac cycle

T wave

repolarization of ventricles

vasoconstriction and vasodilation

result from contraction and relaxation of smooth muscle in the arterial walls

Heart chambers

right atrium, right ventricle, left atrium, left ventricle

Myocardium consists of

cardiac muscle nd is the thickest layer of the heart wall

Blood pressure is partially determined by

cardiac output and peripheral resistance.

arteries and arterioles

carry blood away from the heart to the capillaries

veins and venules

carry blood back to the heart

Mechanisms in blood return

contraction of skeletal muscles, one-way valves, pressure changes associated with breathing

regulation of cardiac cycle

controlled by the cardiac center within the medulla oblongata

cardiac conduction system

coordinates the events of the cardiac cycle

P wave

depolarization of the atria

endocardium consists of

endothelium and connective tissue

walls of the heart

epicardium, myocardium, endocardium

AV node

(atrioventricular node) region of the heart between the right atrium and right ventricle from which electrical impulses spread to the ventricles during a heartbeat. Located in the septum.

At the base of the heart, the inner layer folds back to become the

parietal pericardium

Structure of the heart

*Hollow *Cone-shaped *Muscular pump *In the Mediastinum *Rests on the diaphragm *Average adult - 14 cm x 9 cm *Base of the heart lies beneath the 2nd rib *The apex sits between the 4th and 5th rib

Paths of circulation

-Blood vessels can be divided into two major pathways: -The pulmonary circuit -The systemic circuit (includes coronary circulation)

Heart actions

-The heart chambers function in coordinated fashion -Heart actions are regulated so that atria contract (atrial systole) while ventricles relax (ventricular diastole); followed by ventricles contract (ventricular systole) while atria relax (atrial diastole)

The heart muscle requires a continuous supply of

....oxygen-rich blood, so smaller branches of arteries often have _anastomoses_ as alternate pathways for blood, should one pathway become blocked.

Path of Blood Through the Heart

1.superior and inferior vena cava (from the body) 2.right atrium 3.tricuspid valve 4.right ventricle 5.pulmonary valve 6. Pulmonary arteries 7.pulmonary veins (feom lungs) 8. Left atrium 9.mitral valve 10.left ventricle 11.aortic valve 12.descending aorta

cardiovascular system

Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood.

What are the four factors that affect blood pressure

Cardiac output, blood volume, peripheral resistance to blood flow, and viscosity of the blood

Which part of the pathway is systemic?

From the left ventricle, to the body cells through the aorta, systemic arteries, capillaries and veins, and returning to the right atrium through the superior and inferior vena cava

Which part of the pathway is pulmonary?

From the right ventricle, through the pulmonary trunk, arteries, capillaries, and veins, and returning to the left atrium

when the atria fill, pressure in the atria is _____ than that of the ventricles

Higher, which forces the tricuspid and mitral valves open.

endocardium

Inner layer of the heart

heart sounds

Lub-dub. 1st- a-v valves close. 2nd- aortic and pulmonary valves close

The skeleton of the heart consists of

Rings of dense connective tissue surround the pulmonary trunk and aorta to provide attachments for the heart valves and muscle fibers. These tough rings prevent dilating of tissue in this area.

Blood supply to the heart

The first branches off of the aorta, which carry oxygen-rich blood, are the right and left _coronary__ arteries that feed the heart muscle itself. Branches of these arteries feed many capillaries of the myocardium.

SA node

The pacemaker of the heart, located in the right atrium. Generates the impulses for heartbeats

What is the pericardial cavity?

The pericardial cavity is the small space between the visceral surface of the heart and the parietal surface of the pericardial sac. It contains serous fluid, which acts as a lubricant, reducing friction between opposing surfaces.

Capillaries

The smallest blood vessels, and the site of exchange of chemicals and water between the blood and the tissues.

Pericardium consists of

outer fibrous pericardium and inner serous pericardium

Myocardium

Thick middle muscle layer of the heart

What are the semilunar valves functions

To prevent backflow of blood into ventricles as the ventricles relax

epicardium

outermost layer of the heart. It is made up of connective tissue and epithelium, and contains blood and lymph capillaries along with coronary arteries that provide blood to the heart. It is the same as the visceral pericardium.

functional syncytium

a mass of merging cells that act as a unit

heart valves

structures within the heart that open and close with the heartbeat to regulate the one-way flow of blood....The right atrioventricular (AV) valve, called _tricuspid__ valve, and left AV valve, called either bicuspid__ or the _mitral__ valve, have cusps to which strings called _chordae tendineae_ attach. These strings are, in turn, attached to __papillary__ muscles in the inner heart wall, which contract during ventricular contraction to prevent the backflow of blood through the AV valves.

capillary exchange

the movement of substances into and out of capillaries

During the cardiac cycle, pressure within the heart chambers rises and falls...

these pressure changes open and close valves

What is the function of systemic circulation?

to distribute oxygen to tissues throughout the body

What is the function of pulmonary circulation?

to oxygenate the blood and remove carbon dioxide

The heart has four internal chambers

two atria on top and two ventricles below. A septum divides the chambers on the left side from those on the right.

What are the functions of the cardiovascular system?

upplies oxygen and nutrients to tissues and removes wastes from them

The lower chambers of the heart are called

ventricles...he thick-muscled ventricles pump blood to the body and lungs.

QRS wave

ventricular depolarization and atrial repolarization

The inner layer directly covers the heart and is called the

visceral pericardium, or epicardium