CHAPTER 26 The Cardiovascular System 26-2 Learning Outcomes (cont.) 26.1 Describe the structures of...

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CHAPTER

26The Cardiovascular

System

26-2


Learning Outcomes (cont.)

26.1 Describe the structures of the heart and the function of each.

26.2 Explain the cardiac cycle, including the cardiac conduction system.

26.3 Compare pulmonary and systemic circulation.

26-3


Learning Outcomes (cont.)

26.4 Differentiate among the different types of blood vessels and their functions.

26.5 Explain blood pressure and tell how it is controlled.

26.6 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the cardiovascular system.

26-4


Introduction

• The cardiovascular system – Heart – Blood vessels

– Sends blood to• Lungs for oxygen• Digestive system for nutrients

– Also circulates waste products for removal

26-5


The Heart• Cone-shaped organ

• Size of a loose fist

• Slightly left of the midline

• Bordered by– Lungs

– Sternum and vertebral column

– Diaphragm

26-6


Cardiac Membranes

• Pericardium

– Covers the heart and large blood vessels

– Fibrous outer layer

– Visceral pericardium ~ epicardium

– Parietal pericardium

• Pericardial sac

• Pericardial cavity – pericardial fluid Cardiac

Membranes

26-8


The Heart Wall

• Epicardium

• Myocardium

• Endocardium– Thin, smooth layer

– Contains part of electrical conduction systemHeart Wall

26-9


Heart Chambers and Valves

• Four chambers– Two atria

• Upper chambers• Interatrial septum

– Atrioventricular septum separates the atria from the ventricles

– Two ventricles• Lower chambers• Interventricular

septum

Click for View of Heart

26-10


Heart Chambers and Valves (cont.)

• Valves between atria and ventricles

– Tricuspid ~ three cusps

– Bicuspid ~ two cusps

• Valves between ventricles and arteries– Pulmonary semilunar

– Aortic semilunar Click for View of Heart

26-12


Apply Your Knowledge

Match the following:

__ Tricuspid valve A. Outermost layer of the heart wall

__ Bicuspid valve B. Covering of the heart and aorta

__ Intraventricular C. Between the right atrium and the right septum ventricle

Ventricles D. Pump blood into the arteries

Pericardium E. Primarily cardiac muscle

Epicardium F. Between the left atrium and the left ventricle

Myocardium G. Inner most layer of the heart wall

Endocardium H. Separates the ventricles

B

F

C

ANSWER:

A

D

E

G

H

26-13


Cardiac Cycle

One heart beat = one cardiac cycle

1.Right atrium contracts tricuspid valve opens

blood flows into right ventricle

2.Left atrium contracts bicuspid valve closes

blood flows into left ventricle

26-14


Cardiac Cycle (cont.)

3. Right ventricle contracts tricuspid valve

closes pulmonary semilunar valve opens

blood is pushed into pulmonary artery

4. Left ventricle contacts bicuspid valve closes

aortic semilunar valve opens blood is

pushed into aorta

26-15


Cardiac Cycle (cont.)

• Influenced by– Exercise– Parasympathetic nerves– Sympathetic nerves– Cardiac control center– Body temperature– Potassium ions– Calcium ions

26-16


Heart Sounds

• Lubb – First sound– Occurs when ventricles contract and the tricuspid and

bicuspid valves snap shut

• Dubb

– Second sound – Occurs when atria contract and the pulmonary and

aortic valves snap shut

• Murmur – abnormal heart sound

Click for Heart Sounds

26-17


Cardiac Conduction System

• Sinoatrial node – Right atrium– Natural pacemaker– Sends impulse to AV node

• Atrioventricular node – Between atria and just above ventricles– Sends impulse to the bundle of His

Click for Conduction

System

26-18


Cardiac Conduction System (cont.)

• Bundle of His– Between ventricles– Right and left bundle branches– Sends impulse to Purkinje fibers

• Purkinje fibers– Lateral walls of ventricles– Ventricles contract

Click for Conduction

System

26-20



Match the following:

__ Right ventricle A. Two branches; sends impulse to Purkinje fibers

__ Left ventricle B. Located in the medulla oblongata

__ Cardiac control C. Contraction pushes blood into the lungs center

__ SA node D. In the lateral walls of ventricles

__ Bundle of His E. Natural pacemaker

__ Purkinje fibers F. Contraction sent blood to the aortaD

A

E

B

F

C

ANSWER:

26-21


Circulation

• Pulmonary circulation– Oxygenates blood– Removes carbon dioxide

• Systemic Circulation– Delivers oxygen and nutrients – Removes carbon dioxide and waste products

26-22


Lungs

Circulation (cont.)

Right Atrium

Right Ventricle

Left Atrium

BicuspidValve

Left Ventricle

Pulmonary Semilunar

Valve

TricuspidValve

Body

AorticSemilunar

Valve

Pulmonary Circulation

Systemic Circulation

26-23



What are the functions of the pulmonary and systemic circulations?

ANSWER: The pulmonary circulation functions to oxygenate the blood and remove carbon dioxide. The systemic circulation delivers oxygen and nutrients to and removes carbon dioxide and waste products from the body’s cells.

26-24


Blood Vessels

• Form a closed pathway that carries blood from the heart to cells and back to the heart

26-25


Arteries and Arterioles

• Thick muscular wall• Carry blood under

high pressure• Arterioles

• Coronary arteries – Supply heart muscle– Coronary sinus

• Pulmonary arteries– Heart to lungs– Deoxygenated blood

• Aorta

26-26


Veins and Venules

• Veins– Deoxygenated blood

– Skeletal muscle contractions move blood

– Valves prevent back flow

– Sympathetic nervous system effect

26-27


Veins and Venules • Venules

• Pulmonary veins – oxygenated blood

• Superior and inferior vena cava

• Hepatic portal system

26-28


Capillaries

• Branches of arterioles

• Connect arterioles to venules

• Exchange vessels

– Oxygen and nutrients

– Carbon dioxide and waste products

– Water

26-29


Apply Your KnowledgeARTERIES:Match the following:

coronary arteries A. exchange vessels

arterioles B. supply blood to the heart tissues

veins C. largest veins in the body

arteries D. supplies the forearm and hand

capillaries E. carry blood toward heart

vena cavae F. drain the knees

radial artery G. strongest blood vessels

popliteal veins H. small branches of arteries

C

A

B

D

E

F

G

H

26-30


Blood Pressure

• The force blood exerts on the inner walls of blood vessels

• Highest in arteries

• Lowest in veins

• Rises and falls as ventricles contract and relax

26-31


Blood Pressure

• Systolic pressure – Systole

– Ventricles contract

– Blood pressure in arteries greatest

• Diastolic pressure– Diastole

– Ventricles relax

– Blood pressure in arteries lowest

• Pulse

26-32


Blood Pressure (cont.)

• Factors affecting blood pressure – Cardiac output

– Blood volume– Vasoconstriction and vasodilation

– Blood viscosity

26-33



• Controlled by the amount of blood pumped out of the heart

• Starling's law of the heart – Blood entering the left ventricle stretches its

wall

– The more the wall is stretched the harder it will contract

26-34



• Baroreceptors – Help regulate blood pressure

– Located in the aorta and carotid arteries

– Send information to cardiac center in the medulla oblongata

26-35



What is the difference between the systolic pressure and diastolic pressure?

ANSWER: Systolic pressure is the result of the contraction of the ventricles increasing the pressure in the arteries. Diastolic pressure is the result of the relaxation of the ventricles lowering the pressure in the arteries.

26-36


Diseases and Disorders of the Cardiovascular System

• Chest pain – Cardiac causes

• Myocardial infarction• Angina• Pericarditis• Coronary spasm

– Non-cardiac causes• Heartburn• Panic attacks• Pleurisy• Costochondritis • Pulmonary embolism• Sore muscles• Broken ribs

Take all complaints of chest pain seriously!

26-37


Diseases and Disorders of the Cardiovascular System (cont.)

Disease Description

Aneurysm A ballooned, weakened arterial wall

Arrhythmias Abnormal heart rhythms

EndocarditisInflammation of the innermost lining of the heart, including valves

MyocarditisInflammation of the muscular layer of the heart

26-38



Disease Description

Pericarditis Inflammation of the membranes that surround the heart (pericardium)

Congestive heart failure

Weakening of the heart over time; heart is unable to pump enough blood to meet body’s needs

Coronary artery disease (CAD)

Atherosclerosis; narrowing of coronary arteries caused by hardening of the fatty plaque deposits within them

26-39



Disease Description

Hypertension High blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm Hg

Mitral valve prolapse

Valve falls into the left atrium during systole; prevents proper closing

Murmurs Abnormal heart sounds

26-40



Disease Description

Myocardial infarction

Heart attack; damage to cardiac muscle due to a lack of blood supply

Stenosis of the heart valves

The valve does not fully open; aortic stenosis, mitral stenosis

Thrombophlebitis Blood clots and inflammation develop in a vein

Varicose veins Twisted, dilated veins

26-41


Apply Your KnowledgeANSWER:True or false:

A myocardial infarction results from a lack of oxygen to the cardiac muscle

Myocarditis is inflammation of the innermost lining of the heart.

A potentially fatal arrhythmia is ventricular fibrillation.

Murmurs are abnormal heart rhythms.

Bravo!

T

T

F

F

Endocarditis

sounds

26-42


In Summary

26.1 The structures of the heart include the pericardium, epicardium, myocardium, and endocardium.

The chambers of the heart consist of the upper atria and the lower ventricles.

The septa are the interatrial, interventricular, and atrioventricular.

The four valves within the heart are the tricuspid, the bicuspid, the pulmonary semilunar, and the aortic semilunar valves.

26-43


In Summary (cont.)

26.2 One cardiac cycle consists of one complete heartbeat.

The atria contract and relax together, and the ventricles contract and relax together.

As each chamber contracts, associated valves open and close to control the flow of blood through the heart.

Contractions are initiated by the cardiac conduction system.

26-44


In Summary (cont.)

26.3 Pulmonary circulation: Right atrium tricuspid valve right ventricle pulmonary semilunar valve pulmonary trunk pulmonary arteries lungs pulmonary veins left atrium.

Systemic circulation: Left atrium bicuspid valve left ventricle aortic semilunar

valve aorta arteries arterioles capillaries venules veins venae cavae right atrium.

26-45


In Summary (cont.)

26.4 Types of blood vessels include arteries and arterioles, which bring blood from the heart to the body; capillaries, which act as the connectors between the arterioles and venules.

The largest artery in the body is the aorta. Others arteries are listed in the chapter.

The largest veins in the body are the superior and inferior venae cavae. Others veins are listed in the chapter.

26-46


In Summary (cont.)

26.5 Blood pressure is the force exerted on the inner wall of blood vessels by blood as it flows through vessels.

It is highest in arteries and lowest in veins. Clinically, blood pressure refers to the force of blood within the arteries.

Blood pressure is largely controlled by the amount of blood pumped out of the heart, but various other events also may raise and

lower blood pressure.

26-47


In Summary (cont.)

26.6 Many different types of cardiac and blood diseases are described within this chapter.

The signs, symptoms, and treatments are as varied as the diseases themselves.

The last section of this chapter outlines the most common of these diseases, their signs and symptoms, as well as their treatments.

26-48


Your work is to discover your world and then with all your heart give yourself to it.

~ Buddha

End of Chapter 26

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