chapter 27 the circulatory system

8/13/2019 Chapter 27 the Circulatory System

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2009 The McGraw-Hill Companies, Inc. All rights reserved

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Learning Outcomes27.1 Describe the structure of the heart and the

function of each part.

27.2 Trace the flow of blood through the heart.

27.3 List the most common heart sounds and what

events produce them.

27.4 Explain how heart rate is controlled by the

electrical conduction system of the heart.


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Learning Outcomes (cont.)27.5 List the different types of blood vessels and

describe the functions of each.

27.6 Define blood pressure and tell how it iscontrolled.

27.7 Trace the flow of blood through the pulmonaryand systemic circulation.

27.8 List the major arteries and veins of the body anddescribe their locations.


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Learning Outcomes (cont.)27.9 List and describe the components of blood.

27.10 Give the functions of red blood cells, the different

types of white blood cells, and platelets.

27.11 List the substances normally found in plasma.

27.12 Explain how bleeding is controlled.

27.13 Explain the differences among blood types A, B,AB, and O.


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Learning Outcomes (cont.)27.14 Explain the difference between Rh-positive blood

and Rh-negative blood.

27.15 Explain the importance of blood typing and tellwhich blood types are compatible.

27.16 Describe the causes, signs and symptoms, andtreatments of various diseases and disorders ofthe cardiovascular system.


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Introduction The cardiovascular system consists of heart and

blood vessels

Sends blood to

Lungs for oxygen

Digestive system for nutrients

CV system also circulates waste products tocertain organ systems for removal from the blood


7/53 2009 The McGraw-Hill Companies, Inc. All rights reserved

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The Heart: Structures Cone-shaped organ

about the size of aloose fist

In the mediastinum

Extends from the levelof the second rib to

about the level of thesixth rib

Slightly left of themidline



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The Heart: Structures (cont.) Heart is bordered:

Laterally by the lungs

Posteriorly by the vertebralcolumn

Anteriorly by the sternum

Rests on the diaphragm

inferiorly



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The Heart: Structures (cont.) Heart coverings

Pericardium

Covers theheart and

large blood vesselsattached to the heart

Visceral per icardium

Innermost layer

Directly on the heart

Parietal per icardium

Layer on top of thevisceral pericardium

Heart walls:

Epicardium Outermost layer Fat to cushion heart

Myocardium Middle layer

Primarily cardiac muscle

Endocardium Innermost layer

Thin and smooth

Stretches as the heartpumps

Click for Larger View



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The Heart: Structures (cont.) Four chambers

Two atria

Upper chambers Left and right

Separated by

interatrial septum

Two ventricles

Lower chambers

Left and right

Separated by

interventricular

septum

Click for

View of

Heart

Atrioventricular septum separates the atria

from the ventricles



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The Heart: Structures (cont.) Tricuspid valveprevents blood from flowing back

into the right atrium when the right ventricle

contracts

Bicuspid valveprevents blood from flowing back

into the left atrium when the left ventricle contracts

Pulmonary valveprevents blood from flowing

back into the right ventricle

Aortic valveprevents blood from flowing back

into the left ventricleClick for

View of

Heart



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The Heart:Blood FlowDeoxygenated

blood in from

body

Oxygenated

blood in lungs

Atria Contract Ventricles Contract

Deoxygenatedblood out

to lungs

Oxygenated

blood out to

body

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The Heart:Blood Flow (cont.)

Right

Atrium

Right

Ventricle

Pulmonary

Semilunar

Valve

Left

AtriumBicuspid

Valve

Left

Ventricle

Pulmonary

Valve

Tricuspid

Valve

Aortic

Semilunar

Valve

LungsBody


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The Heart: Cardiac Cycle (cont.) Influenced by

Exercise

Parasympathetic nerves

Sympathetic nerves

Cardiac control center

Body temperature Potassium ions

Calcium ions

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The Heart:Heart Sounds One cardiac cycletwo heart sounds (lubb

and dubb) when valves in the heart snap shut

LubbFirst sound When the ventricles contract, the tricuspid and

bicuspid valves snap shut

DubbSecond sound

When the atria contract and the pulmonary and aortic

valves snap shut

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The Heart: Cardiac Conduction System Group of structures that send electrical impulses through the heart

Sinoatr ial node(SA node)

Wall of right atrium

Generates impulse

Natural pacemaker

Sends impulse to AV node

Atr ioventr icular node(AV

node) Between atria just above ventricles

Atria contract

Sends impulse to the bundle of His

Bundle of H is

Between ventricles

Two branches

Sends impulse to Purkinjefibers

Purkinje fi bers

Lateral walls of ventricles Ventricles contract

Link to

Diagram

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Apply Your KnowledgeMatch the following:

__ Tricuspid valve A. Two branches; sends impulse to Purkinje fibers

__ Bicuspid valve B.Covering of the heart and aorta

__ Pericardium C. Between the right atrium and the right ventricle

__ SA node D. In the lateral walls of ventricles

__ Bundle of His E. Natural pacemaker

__ Purkinje fibers F. Between the left atrium and the left ventricleD

A

E

B

F

C

ANSWER:

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Blood Vessels:Arteries and Arterioles Strongest of the

blood vessels

Carry blood awayfrom the heart

Under high pressure

Vasoconstriction Vasodilation

Arterioles

Small branches ofarteries

Aorta

Takes blood from theheart to the body

Coronary arteries Supply blood to heart

muscle

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Blood Vessels: Veins and Venules Blood under no pressure in

veins

Does not move very easily

Skeletal muscle contractionshelp move blood

Sympathetic nervous systemalso influences pressure

Valves prevent backflow

Venules

Small vessels formed whencapillaries merge

Superior and inferior venacava

Largest veins

Carry blood into right atrium

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Blood Vessels: Capillaries Branches of arterioles

Smallest type of blood vessel

Connect arterioles to venules

Only about one cell layer thick

Oxygen and nutrients can pass out of a capillary into

a body cell

Carbon dioxide and other waste products pass out ofa body cell into a capillary

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Apply Your KnowledgeHow do arteries control blood pressure?

ANSWER: The muscular walls of arteries can constrict to

increase blood pressure or dilate to decrease blood

pressure.

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Blood Pressure Force blood exerts on the inner walls of blood vessels

Highest in arteries

Lowest in veins

Systolic pressure

Ventricles contract

Blood pressure is at its greatest in the arteries

Diastolic pressure Ventricles relax

Blood pressure in arteries is at its lowest

Reported as the systolic number over the diastolic number

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Blood Pressure (cont.) Control is based mainly on the amount of blood pumped out

of the heart

The amount of blood entering should equal the amount

pumped from the heart

Starling's law of the heart

Blood entering the left ventricle stretches the wall of the ventricle

The more the wall is stretched

The harder it will contract and

tTe more blood it will pump out

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Blood Pressure (cont.) Baroreceptors

Also help regulate blood pressure

Located in the aorta and carotid arteries

High blood pressure in aortamessage tocardiac center in braindecreases heart ratelowers blood pressure

Low blood pressure in aortamessage tocardiac center in the brainincreases heart rateincreases blood pressure

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Apply Your KnowledgeWhat 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.

Good Answer!

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Circulation Pulmonary circuit

right atriumright ventriclepulmonary artery

trunk

pulmonary arteries

lungs

pulmonary veinsheart (left atrium)

Systemic circuit

left atriumleft ventricleaortaarteriesarteriolescapillariesvenulesveins

vena cavaheart (right atrium)

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Circulation (cont.) Arterial system

Carry oxygen-rich blood

away from the heart

Pulmonary arteries carry

oxygen-poor blood

Pairedleft and rightartery of the same name

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Circulation (cont.) Venous system

Carries oxygen-poor blood toward

the heart Except pulmonary

veins

Most large veins

have the samenames as thearteries they arenext to

Hepatic portal system

Collection of veins

carrying blood to the

liver

Click for Larger View

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Apply Your Knowledge

ARTERIES: Pulmonary arteries carry oxygen-poor blood.

Do pulmonary arteries carry blood with high levels of

oxygen or low levels of oxygen?


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Blood Components

Hematocrit

The percentage of red blood

cells Normal is about 45%

White cells and

platelets = 1%

Plasma = 55%

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Blood Components:Red Blood Cells Erythrocytes

Transport oxygen throughout the body

Small biconcave-shaped cells

Hemoglobin is a pigment in RBCs

Oxyhemoglobincarries oxygen; bright red

Deoxyhemoglobindoes not carry oxygen; darker red Carries carbon dioxide, so also called carboxyhemoglobin

Anemialow RBC count

Erythropoietinregulates production of RBCs

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Blood Components:Red Blood Cells (cont.)

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Blood Components:White Blood Cells

Granulocytes Neutrophils(55%)destroy bacteria, viruses, and toxins in

the bloodstream (phagocytes)

Eosinophils(3%)get rid of parasitic infections such asworm infections

Basophils(1%)control inflammation and allergicreactions

Agranulocytes Monocytes(8%)destroy bacteria, viruses, and toxins in

blood

Lymphocytes(33%)provide immunity for the body

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Blood Components: White Blood Cells (cont.) WBC count normally 5000 to 10,000 cells per

cubic millimeter of blood

Leukocytosis Elevated WBC count

Usually due to infection

Leukopenia

Low WBC count

Some viral infections and other conditions

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Blood Components:Platelets Fragments of cells found in the bloodstream

Also called thrombocytes

Important in the clotting process of blood

Normal count

130,000 to 360,000 platelets per cubic

millimeter of blood

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Blood Components:Plasma

Liquid portion of blood

composed mostly of water

Proteins

Albumins

Smallest plasma proteins

Pull water in to help

maintain blood pressure

Globulinstransport lipids

and fat-soluble vitamins

Fibrinogenneeded for

blood clotting

Nutrients

Amino acids

Glucose

Nucleotides

Lipids from the digestive

tract

Gasesoxygen, carbon

dioxide, and nitrogen Electrolytes

Waste products

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Blood:Bleeding Control Hemostasisthe control

of bleeding

Three processes ofhemostasis

Blood vessel spasm

Platelet plug formation

Blood coagulation

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Platelet plug

formation:


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Blood Types (cont.)

Blood Type Antigen

Present

Antibody

Present

Blood That Can

Be Received

A A B A and O

B B A B and O

AB AB None A, B, AB, and O

O None A and B O

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Blood Types(cont.)

Rh antigenprotein onRBCs

Rh-positive RBCs contain the

Rh antigen

Rh-negative RBCs do not contain

the Rh antigen

Rh-positive bloodisgiven to Rh-negative

person

Antibodies form

If Rh-negative personreceives more Rh-

positive blood Antibodies bind to the

donor cells

Agglutination occurs

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Apply Your KnowledgeTrue or False:

__ Hematocrit is the percentage of WBCs in the blood.

__ Neutrophils destroy bacteria, viruses, and toxins in the bloodstream.

__ Platelets are important to the clotting process.

__ Albumin is a small plasma protein that pushes water out of the bloodstream.

__ Hemostasis is the control of bleeding.

__ A person with type AB blood can only receive type AB blood.

__ Blood should be matched for Rh factor.

pulls water into

RBCs

can receive any type of blood

T

T

F

T

F

T

F

ANSWER:

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Chest Pain Cardiac

Myocardial infarction

Angina

Pericarditis

Coronary spasm

Non-cardiac

Heartburn

Panic attacks

Pleurisy

Costochondritis

Pulmonary embolism

Sore muscles Broken ribsTake all complaints of

chest pain seriously!

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Chest Pain(cont.)

Determine cause

Electrocardiogram

Stress tests

Blood tests

Chest x-ray

Nuclear scan

Coronary

catheterization Echocardiogram

Endoscopy


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Disease Description

Myocarditis Inflammation of the muscular layer of the heart

Pericarditis Inflammation of the membranes that surroundthe heart (pericardium)

Congestive

Heart Failure

Weakening of the heart over time; heart is

unable to pump enough blood to meet bodys

needs

Coronary Artery

Disease (CAD)

Atherosclerosis; narrowing of coronary arteries

caused by hardening of the fatty plaque deposits

within the arteries

Diseases and Disorders of the

Cardiovascular System (cont.)

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Disease Description

Hypertension High blood pressure; consistent resting blood

pressure equal to or greater than 140/90 mm HgLeukemia Bone marrow produces a large number of

abnormal WBCs

Murmurs Abnormal heart sounds

Myocardial

Infarction

Heart attack; damage to cardiac muscle due to a

lack of blood supply



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Disease Description

Sickle Cell

Anemia

Abnormal hemoglobin causes RBCs to change

to a sickle shape; abnormal cells stick incapillaries

Thalassemia Inherited form of anemia; defective hemoglobin

chain causes, small, pale, and short-lived RBCs

Thrombophlebitis Blood clots and inflammation develops in a vein

Varicose Veins Twisted, dilated veins



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Apply Your Knowledge

ANSWER: Anemia is a condition in which a person does nothave enough red blood cells or hemoglobin in the blood tocarry an adequate amount of oxygen to body cells.

The doctor has told your patient she has anemia. How

would you explain this to the her?

Bravo!

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In Summary

Cardiovascular system

Transport system for body

Heart, arteries, veins, and capillaries

Blood

Transport medium

RBCs, WBCs, platelets, plasma

Medical assistant Assists patients in understanding prevention and

treatments for cardiovascular problems

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End of Chapter

Your work is to discoveryour world and then withall your heart giveyourself to it

~ Buddha

chapter 27 the circulatory system

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