Lecture Medical assisting: Administrative and clinical procedures with anatomy and physiology (4/e) – Chapter 23

Chapter 23 - The cardiovascular system. After studying this chapter you will be able to: Describe the structure of the heart and the function of each part, trace the flow of blood through the heart. list the most common heart sounds and what events produce them, explain how heart rate is controlled by the electrical conduction system of the heart,...

The Cardiovascular

System

Learning Outcomes

23.1 Describe the structure of the heart and the

function of each part.

23.2 Trace the flow of blood through the heart.

23.3 List the most common heart sounds and

what events produce them.

23.4 Explain how heart rate is controlled by the

electrical conduction system of the heart

Learning Outcomes (cont.)

23.5 List the different types of blood vessels and

describe the functions of each.

23.6 Define blood pressure and tell how it is

controlled.

23.7 Trace the flow of blood through the

pulmonary and systemic circulation.

23.8 List the major arteries and veins of the body

and describe their locations

Learning Outcomes (cont.)

23.9 List and describe the components of blood.

23.10 Give the functions of red blood cells, the

different types of white blood cells, and platelets.

23.11 List the substances normally found in

plasma.

23.12 Explain how bleeding is controlled

23.13 Explain the differences among blood types

Learning Outcomes (cont.)

23.14 Explain the difference between Rh-positive

blood and Rh-negative blood.

23.15 Explain the importance of blood typing and

tell which blood types are compatible.

23.16 Describe the causes, signs and symptoms,

and treatments of various diseases and disorders of the cardiovascular system

• The cardiovascular system consists of heart

and blood vessels

• Sends blood to

– Lungs for oxygen

– Digestive system for nutrients

• Also circulates waste products to certain

organ systems for removal from the blood

Structures of the Heart

• Cone-shaped organ

about the size of a

loose fist

• In the mediastinum

• Extends from the

level of the second rib

to about the level of

the sixth rib

• Slightly left of the

midline

Structures of the Heart (cont.)

Structures of the Heart (cont.)

• Heart coverings

– Pericardium

• Covers the heart and large blood vessels attached to the heart

• Visceral pericardium

– Innermost layer – Directly on the heart

• Thin and smooth

• Stretches as the heart

Click for Larger View

Back

Structures of the Heart (cont.)

Click for  View of  Heart

     from the ventricles

Structures of the Heart (cont.)

back into the right atrium when the right ventricle

contracts

flowing back into the left atrium when the left

ventricle contracts

from flowing back into the right ventricle

flowing back into the left ventricle Click for 

View of  Heart

The Heart Labeled

Back

Blood Flow Through the Heart

Deoxygenated

blood in from

body Oxygenated blood in lungs

Atria Contract Ventricles Contract

Deoxygenated blood out

to lungs

Oxygenated blood out to body

Blood Flow Through the Heart (cont.)

Right Atrium

Right Ventricle

Pulmonary Semilunar Valve

Left Atrium

Bicuspid Valve

Left Ventricle

Pulmonary Valve

Tricuspid Valve

Lungs Body

Aortic Semilunar Valve

Cardiac Cycle

• Right atrium contracts

– Tricuspid valve opens

– Blood fills right ventricle

• Right ventricle contracts

– Tricuspid valve closes

– Pulmonary semilunar valve

opens – Blood flows into pulmonary

artery

• Left atrium contracts

– Bicuspid valve opens – Blood fills left ventricle

• Left ventricle contracts

– Bicuspid valve closes – Aortic semilunar valve opens

– Blood pushed into aorta

 One heartbeat = one cardiac cycle

 Atria contract and relax

 Ventricles contract and relax

Cardiac Cycle (cont.)

Heart Sounds

(lubb and dubb) when valves in the heart

snap shut

– Lubb – first sound

• When the ventricles contract, the tricuspid and bicuspid valves snap shut

– Dubb – second sound

• When the atria contract and the pulmonary and aortic valves snap shut

Cardiac Conduction System

• Group of structures that send electrical impulses through

the heart

• Sinoatrial node (SA node)

– Wall of right atrium

– Generates impulse

– Natural pacemaker

– Sends impulse to AV node

• Atrioventricular node (AV

Conduction 

System

Back

Apply Your Knowledge

Match 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 fibersD F Between the left atrium and the left ventricle

Blood Vessels

• Closed pathway that

carries blood from the

heart to cells and

back to the heart

Arteries and Arterioles

• Strongest of the

blood vessels

• Carry blood away

from the heart

• Under high pressure

– Vasoconstriction

– Vasodilation

• Arterioles

– Small branches of arteries

Veins and Venules

• Blood under no pressure

• 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 of

a body cell into a capillary

Apply Your Knowledge

How do arteries control blood pressure?

ANSWER: The muscular walls of arteries can

constrict to increase blood pressure or dilate to

decrease blood pressure.

– Blood pressure in arteries is at its lowest

• Reported as the systolic number over the diastolic

number

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

• The more blood it will pump out

Blood Pressure (cont.)

• Baroreceptors

– Also help regulate blood pressure

– Located in the aorta and carotid arteries

– High blood pressure in aorta  message to

cardiac center in brain  decreases heart rate

 lowers blood pressure – Low blood pressure in aorta  message to

cardiac center in the brain  increases heart rate  increases blood pressure

Apply Your Knowledge

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.

Good 

• Pulmonary circuit

right atrium  right ventricle  pulmonary

 pulmonary veins  heart (left atrium)

• Systemic circuit

left atrium  left ventricle  aorta  arteries  arterioles  capillaries  venules  veins  vena cava  heart (right atrium)

– Paired – left and right

artery of the same name

• Except pulmonary veins

– Most large veins

have the same names as the arteries they are next to

 Collection of veins 

carrying blood to the liver  

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?

(leukocytes) – Platelets – cell

fragments – Plasma – fluid part of

Red Blood Cells

• Transport oxygen throughout the body

• Small biconcave-shaped cells

• Hemoglobin is a pigment in RBCs

– Oxyhemoglobin carries oxygen; bright red

– Deoxyhemoglobin does not carry oxygen; darker

red

• Carries carbon dioxide, so also called carboxyhemoglobin

– Anemia – low RBC count

RBCs

Red Blood Cells (cont.)

© Cre8tive StudiosAlamy RF

White Blood Cells

• Granulocytes

– Neutrophils (55%) –destroy bacteria, viruses, and

toxins in the bloodstream (phagocytes)

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

White Blood Cells (cont.)

• WBC count normally 5000 to 10,000 cells

per cubic millimeter of blood

• Fragments of cells found in the

bloodstream

• Important in the clotting process of blood

– 130,000 to 360,000 platelets per cubic

millimeter of blood

• Smallest plasma proteins

• Pull water in to help maintain blood pressure

– Globulins – transport lipids

and fat-soluble vitamins

– Fibrinogen – needed for

blood clotting

• Nutrients

– Amino acids– Glucose

– Nucleotides– Lipids from the digestive tract

• Gases – oxygen, carbon dioxide, and nitrogen

• Electrolytes

• Waste products

Bleeding Control

• Three processes of hemostasis

– Blood vessel spasm

– Platelet plug formation

– Blood coagulation

Platelet plug formation:

RBCs bind to antibodies in plasma

Blood Types (cont.)

Blood Type Antigen

Present Antibody Present Blood That Can Be Received

Blood Types (cont.)

– Antibodies form

• If Rh-negative person receives more

Rh-positive blood

– Antibodies bind to the donor cells

– Agglutination occurs

Apply Your Knowledge

True 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

– Costochondritis – Pulmonary embolism– Sore muscles

– Broken ribs

Take all complaints of  chest pain seriously!

Chest Pain (cont.)

– Endoscopy

Anemia The blood does not have enough red blood

cells or hemoglobin to carry an adequate amount of oxygen to the body’s cells

Aneurysm A ballooned, weakened arterial wall

Arrhythmias Abnormal heart rhythms

Carditis Inflammation of the heart

Endocarditis Inflammation of the innermost lining of the

heart, including valves

System (cont.)

Myocarditis Inflammation of the muscular layer of the

heartPericarditis Inflammation of the membranes that

surround the heart (pericardium)

System (cont.)

Hypertension High blood pressure; consistent resting

blood pressure equal to or greater than 140/90 mm Hg

Leukemia Bone marrow produces a large number of

Thalassemia Inherited form of anemia; defective

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

Apply Your Knowledge

ANSWER: Anemia is a condition in which a person does not

have enough red blood cells or hemoglobin in the blood to

carry an adequate amount of oxygen to body cells

The doctor has told your patient she has anemia

How would you explain this to her?

Bravo!

In Summary

23.1 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 septums are interatrial, interventricular, and

atrioventricular

– The four valves within the heart are tricuspid,

bicuspid, pulmonary semilunar valve, and the aortic semilunar valve

In Summary (cont.)

23.2 Superior and inferior vena cavae → right atrium

→ tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → right and left pulmonary arteries → the lungs → pulmonary veins

→ left atrium → bicuspid valve →left ventricle → aortic semilunar valve → aorta → body organs and tissues

23.3 Heart sounds are described as lubb dubb Lubb is

created when the ventricles contact and the tricuspid and bicuspid valves snap shut Dubb occurs when the atria contract and the pulmonary and aortic semilunar valves snap shut

In Summary (cont.)

23.4 The sinoatrial node generates an impulse to the

atrioventricular node The AV node then sends the impulse to the bundle of His The bundle splits into the left and right bundle branches and sends the impulse to the Purkinje fibers in the ventricles

23.5 The arterial system is composed of the aorta, arteries,

and arterioles (largest to smallest) bring blood from the heart to the body The capillaries act as the

connectors between the arterioles and venules From the venules, blood returns to the heart via the veins to the superior and inferior vena cavae

In Summary (cont.)

23.6 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, BP 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 may also raise and lower BP

In Summary (cont.)

23.7 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→vena cavae→right atrium

In Summary (cont.)

23.8 The largest artery in the body is the aorta Other

major arteries include lingual, facial, occipital, maxillary, ophthalmic, axillary, brachial, ulnar, radial, intercostals, lumbar, external iliac, common iliac,

femoral, popliteal, and tibial

The largest veins in the body are the superior and inferior vena cavae Other major veins are jugular, brachiocephalic, axillary, brachial, ulnar, radial,

intercostals, azygos, gastric, splenic, mesenteric, hepatic portal, hepatic, iliac, femoral, popliteal, and saphenous

In Summary (cont.)

23.9 The components of blood are red blood cells (RBC),

white blood cells (WBC), platelets, and plasma

23.10Red blood cells carry oxygen and carbon dioxide

throughout the body White blood cells are divided into two types: granulocytes and agranulocytes

Granulocytes include neutrophils, eosinophils, and basophils Agranulocytes include lymphocytes and monocytes Platelets are essential in the blood

clotting process

23.11Plasma contains three major proteins: albumins,

globulins, and fibrinogen

In Summary (cont.)

23.12Hemostasis is bleeding control When a blood vessel

breaks, the vessel wall spasms and reduces blood loss

Platelets stick to the broken area and to each other, forming a platelet plug

A blood clot occurs when fibrinogen converts to fibrin, which sticks to the damaged area of the blood vessel, creating a meshwork to trap blood cells and platelets, which will remain while tissues repair themselves

In Summary (cont.)

23.13Blood types are named for the antigen present on the

cell surfaces The “opposite” letter is the name of the antibody present Blood type A has antigen A and antibody B; blood type B has antigen B and antibody A; blood type AB has antigens A and B and 0 (zero) antibodies; Blood type O has no antigens present and both A and B antibodies

23.14Rh-positive blood contains the Rh antigen on its

RBCs Rh-negative blood carries no such antigen

In Summary (cont.)

23.15Due to the antibodies present on different blood

types, it is important for blood typing to be done prior

to any transfusion

It is equally important to know if a patient’s blood type

is positive or negative for the same reason

A negative blood type will “fight” the positive antigen found on a positive blood type

An Rh-negative woman carrying an Rh-positive fetus will develop antibodies against the child’s blood type

In Summary (cont.)

23.16Many different types of cardiac and blood diseases

are described in this chapter The signs, symptoms, and treatments are as varied as the diseases

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