CARDIOVASCULAR SYSTEM

Objectives

List the functions of the circulatory systemDescribe the heart

General features, chambers, valvesDifferentiate between the three types of bv’sDescribe the two circulations

Pulmonary vs. SystemicExplain how blood pumps through the heartDefine ECG and what P wave, QRS wave

and T wave represent

Structure and Function

• Functions of the cardiovascular system:Transports nutrients and oxygen to the body Transports waste products from the cells to

the kidneys for excretion Distributes hormones and antibodies

throughout the body Helps control body temperature and

maintain electrolyte balance

Two-sided, double pump Weighs less than a poundSlightly bigger than a fist Located between the lungs in the

thoracic cavityPositioned partially to the left of the

sternum

General features of heart

Heart Anatomy

• Four chambers of the heartAtria

Top two chambersBlood enters the heart through the atria

VentriclesLower two chambersBlood leaves the heart through the ventricles

SeptumDivides the right and left sides of the heart

Heart Anatomy

Two atriaTwo ventricles

Heart Anatomy cont.

• Four valves of the heartPrevent blood from flowing back into heartAtrioventricular

Allow blood to pass from the atria to ventricles

Semilunar valvesAllow blood to pass out of the heartSeparate the ventricles from the pulmonary

artery and aorta

Heart Anatomy cont.

Atrioventricular valves Tricuspid/right AV

valve 3 flaps

Bicuspid/mitral/left AV valve

2 flaps

Semilunar valves

Blood Vessels

The cardiovascular system has three types of blood vessels:

Arteries (and arterioles) – carry blood away from the heart

Capillaries – where nutrient and gas exchange occur

Veins (and venules) – carry blood toward the heart.

Blood Vessels (Continued)

Arteries Carry blood away from the heart

Blood is oxygenated

Have a muscular layer of tissue that helps pump blood out of the body

Aorta is the largest artery in the body, which branches into smaller arteries

ArteriolesSmaller vesselsBlood moves from arterioles to capillaries

Blood Vessels (Continued)

Capillaries Microscopic vessels that carry blood

between the arterial and venous vessels Gases, nutrients, and waste exchanged

Blood gives up oxygen

Blood flows from capillaries into venules

Blood Vessels (Continued)

Veins Venues branch together to form veins Carry blood back to the heart by gravity

Blood is deoxygenated except for pulmonary vein

Contain values that prevent blood from flowing back Have a much thinner muscular layer Superior vena cava and inferior vena cava

Largest veins

Blood Vessels

CirculationPulmonary circulation

Right side of heart pumps deoxygenated blood to the lungs

Systemic circulation Left side of the heart pumps oxygenated blood to rest

of the body Blood returns to the right side of the heart from

the body to complete the cycleHepatic circulation

Path of the blood from the intestines, gallbladder, pancreas, stomach, and spleen through the liver

Passage of Blood Through the Heart

Blood follows this sequence through the heart: superior and inferior vena cava → right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk and arteries to the lungs → pulmonary veins leaving the lungs → left atrium → bicuspid valve → left ventricle → aortic semilunar valve → aorta → to the body.

Structures of the Heart

Path of blood through the heart

Figure 11-1 Blood Flow Through the Cardiovascular System

Internal view of the heart

Cardiac cycle animationBill Nye

The Heartbeat

Each heartbeat is called a cardiac cycle.When the heart beats, the two atria

contract together, then the two ventricles contract; then the whole heart relaxes.

Systole is the contraction of heart chambers; diastole is their relaxation.

The heart sounds, lub-dup, are due to the closing of the atrioventricular valves, followed by the closing of the semilunar valves.

The Heartbeat (Continued)

Heart is the only muscle that can stimulate its own contractionsSinoatrial cells (SA node or pacemaker) in

right atriumInitiates the heartbeat and causes the atria to

contract on average every 0.85 secondsAtrioventricular node (AV node)

Sends impulse into lower portions of the heart (ventricles)

The signal for ventricles to contract travels from AV node to through the atrioventricular bundle to the smaller Purkinje fibers

Intrinsic Control of Heartbeat

The SA node sends out a stimulus, which cause the atria to contract.

When this stimulus reaches the AV node, it signals the ventricles to contract.

Impulses pass down the two branches of the atrioventricular bundle to the Purkinje fibers, and thereafter the ventricles contract

Path of Electrical Current in the Heart

Extrinsic Control of Heartbeat

A cardiac control center in the medulla oblongata speeds up or slows down the heart rate by way of the autonomic nervous system branches: parasympathetic system (slows heart rate) and the sympathetic system (increases heart rate).

Hormones epinephrine and norepinephrine from the adrenal medulla also stimulate faster heart rate.

The Electrocardiogram

An electrocardiogram (ECG) is a recording of the electrical changes that occur in the myocardium during a cardiac cycle.

Atrial depolarization creates the P wave, ventricle depolarization creates the QRS wave, and repolarization of the ventricles produces the T wave.

Electrocardiogram The P wave occurs

just prior to atrial contraction

The QRS complex occurs just prior to ventricular contraction

The T wave occurs when the ventricles are recovering from contraction.

Heart dissection on cadaver

Figure 11-5 Principal Arteries and Veins

Assessment Techniques

Measuring pulse and blood pressureListening to heart soundsDetermining cardiac output

Assessment Techniques (Continued)

Pulse Surge of blood

against the walls of the arteries

Eight pulse points on the body

Normal pulse rate for adults is 60 to 90 beats per minute

Blood pressure Force of blood

against the walls of the arteries

Systolic pressure Ventricles of the heart

contract Diastolic pressure

Ventricles relax Normal blood

pressure 120/80

Blood pressure varies greatly among people

Figure 11-6 Peripheral Pulse

Points

Assessment Techniques (Continued)

Heart soundsHeard through a stethoscopeMurmurs

Abnormal or extra soundClassified by timing, intensity, location,

pitch, and quality of the soundMay be benign or indicate a disorder

ThrillVibration felt by touch over an arteryCaused by an abnormal flow of blood

Assessment Techniques (Continued)

ElectrocardiogramMeasures graphically the pattern of

electrical activity in heart contractionsNormal and abnormal heart activities have

characteristic wave patterns

EchocardiographyUses ultrasonic waves to show the structures

and motions of the heartTransducer plots the sound echoes to produce a

graphic picture

Assessment Techniques (Continued)

Cardiac catheterizationUsed to measure the pressure in the

chambers of the heart, to take blood samples, and to view obstructions in the vessels

A tube is inserted through the blood vessels into the heart

Dye is then released and traced using x-ray

Oxygen transport

Blood

Blood

Essential Life Supportive FluidTransported in Closed System

Throughout Body Through Blood Vessels

Connective Tissue = Cells + Matrix

Physical Characteristics

ViscouspH 7.35 – 7.45Temperature: 38 degrees C; 100.4

degrees F7% - 8% of total body weightMales: 5 – 6 litersFemales: 4 – 5 liters

Functions of Blood

Transportation

Regulation

Protection

Formed Elements

Erythrocytes: (RBCs) – are produced in the red bone marrow.

Leukocytes: (WBCs) – they are formed in the bone marrow and lymph tissue.

Platelets: (Thrombocytes) – are the fragments or pieces of cells because they lack nuclei and vary in shape

General Characteristics of Formed Elements

Living blood cells2 out of 3 are NOT true cellsMost are short livedMost do not divideHematopoiesis occurs in liver,

spleen, thymus, & bone marrow

Plasma

Liquid portion: 90-92% water with fibrous proteins (fibrin)

Straw colored, sticky fluid

Plasma

ProteinsNon-protein nitrogenous

substances:NutrientsElectrolytesRespiratory gases

Functions of Plasma

Suspends blood cells & transports blood cells

Carries metabolic wastes & nutrients

Circulates hormones Maintains water content and body temperature

Maintains acid-base balance of blood

Erythrocytes

Shape: biconcave discSpectrin (fibrous protein)

flexibility to change shapeMature anucleate4 – 5.5 million per cubic

millimeterLifespan: 100 – 120 days97% is hemoglobinErythropoiesis

Leukocytes/WBCsSurveillance, Fighters,

Protectors

5 Types of WBCs

Neutrophils: granulocyteLymphocyte: agranulocyteMonocyte: agranulocyteEosinophil: granulocyteBasophil: granulocyte

Neutrophils

Phagocytize bacteria by secreting an enzyme called lysozyme

Monocytes

Phagocytize bacteria and foreign materials

Eosinophil

Remove toxins and defend the body from allergic reactions by producing antihistamines.

Basophils

Participate in the body’s inflammatory response

Produce histamine (a vasodilator), heparin (an anticoagulant)

Platelets

Platelets

Thrombocytes Involved in blood clottingSmall cytoplasmic fragments from

megakaryocyte250,000 – 400,000 per microliterLifespan: live only 10 daysAspirin inactivates the platelets

Lymphocytes

Provide immunity for the body by developing antibodies

Protect against the formation of cancer cells

Disorders of the Cardiovascular System

Disorders of the Cardiovascular System

AneurysmAn area of a blood vessel that bulges

because of a weakness in the wallAtherosclerosis

A narrowing of blood vessels caused by deposits of fatty material containing calcium and cholesterol

Cardiac arrhythmiaA disturbance of the heart’s rhythm caused

by a defect in the heart’s pacemaker cells or by damage to heart tissue

Disorders of the Cardiovascular System (Continued)

Cardiovascular disease A general term for the combined effects of

arteriosclerosis and related conditions called coronary artery disease

Congenital heart disease A group of disorders that affect about 25,000

newborns each year in the united states Congestive heart failure

The inability of the heart to pump blood adequately to meet the body’s needs

Disorders of the Cardiovascular System (Continued)

Hypertension High blood pressure

Myocardial infarction Known as a heart attack

Phlebitis An inflammation of a vein, often with

formation of a clot

Disorders of the Cardiovascular System (Continued)

Rheumatic heart disease A condition in which the heart muscle and

valves are damaged by a recurrent bacterial infection that usually begins in the throat

Varicose veinsA condition in which veins become enlarged

and ineffective

Health Careers

Health Careers

CardiologistCardiac SurgeonCardiovascular TechnicianEchocardiographerElectrocardiographic TechnicianHematologistPhlebotomistPerfusionist

Medical TermsRoot Word: cardi(o), cardi(a) – denotes

the heart.

Carditis inflammation of the heart Cardiology study of the heart Cardiac pertaining to the heart Cardiograph to record the heart Cardiogram “a” record of the heart Cardiomegaly enlargement of the heart Cardiospasm involuntary contraction of the

heart

Medical TermsRoot Word: cardi(o), cardi(a) – denotes the

heart

Cardiologist specialist of the heartBradycardia slow pace of the heartCardiopathy disease condition of the

heartTachycardia fast pace of the heart

Medical TermsRoot Word: Phleb(o) - denotes the vein

Phlebitis inflammation of the vein

Phleborrhaphy to suture the veinPhleborrhagia excessive flow

discharge in the veinPhlebotomy surgical incision of the

vein

Medical TermsRoot Words: art, arteri(o) - denotes the

artery

Arterio scler osis [age/high BP] of the artery

Arteriopathy disease condition of the artery

Arterial pertaining to the arteryArteritis inflammation in the arteryArthero scler osis disease condition of

hardening of the artery

Medical TermsRoot Words: thromb(o) – denotes the

blood clot

thrombocyte cell tissue of the blood clot Thrombosis disease condition of the

blood clot Thrombogen ic pertaining to the

production/creation of the blood clot Thromboarter itis inflammation of the artery

and blood clot Thromboectomy surgical removal of the

blood clot

Medical TermsRoot Words: thromb(o) – denotes the

blood clot

Thromboid ressembling or like of the blood clot

Thrombolysis destruction or breaking down of the blood clot

Thrombocyto penia decrease of cells of a blood clot

Thrombophleb itis inflammation of the vein of the blood clot

Thrombopathy disease condition of the blood clot

Medical TermsRoot Words: Hemo, Hema, Hemat(o) –

denotes blood

Hemostat stop of the blood Hematocrit measure of the blood Hemolysis destruction or breaking down

of the blood Hematemesis vomit of blood Hemoptysis spit of the blood Hematoma swelling or tumor of the blood Hemo phili ac pertaining to the brotherly

love and blood

Medical TermsRoot Word: emia – denotes blood

Leukemia white blood (cells)Lipemia fat in the bloodHyper glyc emia excessive sugar in the

bloodOligemia few bloodCyanemia blue blood (lack of

oxygen)Anemia without blood (low iron)

Medical TermsRoot Word: erythr(o) – red blood cells

Erythrocyte red blood cellsErythropoiesis creation or

production of red Erythroclasis fracture in the red

cellsErythroblast immature red cells

Medical termsRoot Word: cyt(o) – denotes cell

Cyto bio logy study of the life of the cell

Cyto diagn osis knowledge through the cell

Cyto meta plasia change in the form of cell

Cyto morpho logy study of form/shape of the cell

Cytoma swelling or tumor of the cell

Medical TermsRoot Word: sphygm(o)-denotes pulse or

blood pressureSphygmogram “a” record of the pulse

or blood vesselSphygmoid ressembling or like

pulse or blood vesselSphygmology study of the blood or

blood pressureSphygmopalpation feeling/pulse or

blood pressureSphygmoscopy visual examination of

the pulse or blood pressure

Medical TermsRoot word: vas(o) – denotes blood

vesselsVasomotor produce movement of the

blood vesselVasosection cut of the blood vesselVasorrhaphy to suture the blood vesselVasography to record the blood vesselVasospasm involuntary contraction of

the blood vessel

Medical TermsRoot word: angio – denotes the blood

vessel Angiectasis dilation or opening of the blood

vessel Angiostomy a moth opening of the blood

vessel Angiospasm involuntary contraction of the

blood vessel Angiogram a record of the blood vessel Angiostenosis condition of narrowing of the

blood vessel Angioplasty surgical repair of the blood

vessel

AbbreviationsE-F

E Meaning Ea Each EEG Electroencephalogram EENT Ear, Eye, Nose & Throat EKG or ECG Electrocardiogram EMS Emergency Medical Service EMT Emergency Medical Technician ENT Ear, Nose, Throat EPA Environmental Protection Agency ER Emergency Room EX Exam EXP Exploratory EXC Excision EXT Extract

AbbreviationsE-F

F Meaning F Degrees Farenheit FBS Fasting Blood Sugar FBW Fasting Blood Work FDA Food & Drug Administration Fe Iron FHB Fetal Heart Beat Fl fluids Fx Fracture FUD fever of unknown origin