Download Slide 1

Memmler’s
The Human Body in Health and Disease
11th edition
Chapter 14
The Heart and Heart Disease
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Circulation and the Heart
Circulation
•Continuous one-way circuit of the blood vessels
•Propelled by heart
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Location of the Heart
•Between the lungs
•Left of the midline of the body
•In mediastinum
•Apex pointed toward left
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Structure of the Heart
Three tissue layers
•Endocardium lines heart’s interior
•Myocardium is thickest layer; the heart muscle
•Epicardium is thin outermost layer
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The Pericardium
The sac that encloses the heart
•Fibrous pericardium holds heart in place
•Serous membrane
– Parietal layer
– Pericardial cavity
– Visceral layer (epicardium)
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Layers of the
heart wall and
pericardium. The
serous
pericardium
covers the heart
and lines the
fibrous
pericardium.
ZOOMING IN
• Which layer of
the heart wall is
the thickest?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Special Features of the Myocardium
Cardiac muscles
•Are lightly striated (striped)
•Have single nucleus cells
•Are controlled involuntarily
•Have intercalated disks
•Have branching muscle fibers
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Divisions of the Heart
Double pump
•Right side pumps blood low in oxygen to the lungs
– Pulmonary circuit
•Left side pumps oxygenated blood to remainder of body
– Systemic circuit
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Four Chambers
•Right atrium
– Receives low-oxygen blood returning from body tissue
through superior vena cava and inferior vena cava
•Left atrium
– Receives high-oxygen blood from lungs
•Right ventricle
– Pumps blood from right atrium to lungs
•Left ventricle
– Pumps oxygenated blood to body
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The heart as a double
pump. The right side of
the heart pumps blood
through the pulmonary
circuit to the lungs to
be oxygenated; the left
side of the heart
pumps blood through
the systemic circuit to
all other parts of the
body.
ZOOMING IN
• What vessel carries
blood into the systemic
circuit?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The heart and
great vessels.
ZOOMING IN
• Which heart
chamber has the
thickest wall?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Four Valves
•Atrioventricular valves
– Entrance valves
– Right atrioventricular (AV) valve (tricuspid valve)
– Left atrioventricular (AV) valve (bicuspid valve)
•Semilunar valves
– Exit valves
– Pulmonary valve
– Aortic valve
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Valves of the heart (superior view from anterior, atria removed). (A) When the heart is
relaxed (diastole), the AV valves are open and blood flows freely from the atria to the
ventricles. The pulmonary and aortic valves are closed. (B) When the ventricles contract,
the AV valves close and blood pumped out of the ventricles opens the pulmonary and
aortic valves. ZOOMING IN • How many cusps does the right AV valve have? The left?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Pathway of blood through the
heart.
Blood from the systemic circuit
enters the right atrium (1)
through the superior and inferior
venae cavae, flows through the
right AV (tricuspid) valve (2),
and enters the right ventricle
(3). The right ventricle pumps
the blood through the pulmonary
(semilunar) valve (4) into the
pulmonary trunk, which divides
to carry blood to the lungs in the
pulmonary circuit.
Blood returns from the lungs in
the pulmonary veins, enters the
left atrium (5), and flows
through the left AV (mitral)
valve (6) into the left ventricle
(7). The left ventricle pumps the
blood through the aortic
(semilunar) valve (8) into the
aorta, which carries blood into
the systemic circuit.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Blood Supply to the Myocardium
Coronary circulation
•Right coronary artery
•Left coronary artery
•Coronary sinus
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Blood vessels that supply the myocardium. Coronary
arteries and cardiac veins are shown. (A) Anterior
view. (B) Posterior view.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Opening of coronary arteries in the aortic valve (anterior view).
(A) When the left ventricle contracts, the aortic valve opens. The
valve cusps prevent filling of the coronary arteries. (B) When the
left ventricle relaxes, backflow of blood closes the aortic valve
and the coronary arteries fill.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Function of the Heart
Left and right sides of heart work together in cardiac cycle
(heartbeat)
•Systole (active phase, contraction)
•Diastole (resting phase)
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The cardiac cycle.
ZOOMING IN • When the ventricles contract, what valves close? What valves
open?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Output
Calculating cardiac output
•Cardiac output (CO)
•Stroke volume (SV)
•Heart rate (HR)
•CO = HR 3 SV
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The Heart’s Conduction System
Electrical energy stimulates heart muscle
•Nodes
– Sinoatrial (SA) node (pacemaker)
– Atrioventricular (AV) node
•Specialized fibers
– Atrioventricular bundle (bundle of His)
– Purkinje fibers (conduction myofibers)
•Intercalated disks
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Conduction
system of the
heart. The
sinoatrial (SA)
node, the
atrioventricular
(AV) node, and
specialized fibers
conduct the
electrical energy
that stimulates
the heart muscle
to contract.
ZOOMING IN
• What parts of
the conduction
system do the
internodal
pathways connect?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The Conduction Pathway
Sinus rhythm
•Sinoatrial (SA) node
•Atria
•Atrioventricular (AV) node
•Internodal pathways
•Bundle of His
•Bundle branches and Purkinje fibers
•Ventricles
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Control of the Heart Rate
Influences that allow heart to meet changing needs rapidly
•Autonomic nervous system (ANS)
•Sympathetic nervous system
•Parasympathetic system
– Cranial nerve X
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Variations in Heart Rates
•Bradycardia
•Tachycardia
•Sinus arrhythmia
•Premature beat (extrasystole)
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Heart Sounds
•Lub
•Dup
•Murmurs
– Organic
– Functional
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Heart Disease
Most common cause of death in industrialized countries is
heart and circulatory system disease
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Classifications of Heart Disease
•Anatomical classification
–
Endocarditis
–
Myocarditis
–
Pericarditis
•Causative factors classification
–
Congenital heart disease
–
Rheumatic heart disease
–
Coronary artery disease
–
Heart failure
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Congenital Heart Disease
Congenital heart disease often results from fetal
development defects
•Atrial septal defect
•Patent (open) ductus arteriosus
•Ventricular septal defect
•Coarctation of the aorta
•Tetralogy of Fallot
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Rheumatic Heart Disease
•Streptococci release toxins during infection
•Antibodies that combat toxin also attack heart valves
•Heart valves become inflamed
•Valve cusps thicken and harden
•Pulmonary congestion occurs
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Coronary Artery Disease
Coronary arteries can degenerate
•Myocardial infarction
– Creatine kinase released upon any muscle damage.
Tests for certain forms of CK indicate whether an MI
occurred.
•Angina pectoris
•Abnormalities of heart rhythm
•Treatment of heart attacks
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Heart Failure
Heart is unable to pump sufficient blood
•Heart chambers enlarge
•Blood backs up into lungs
•Ventricular muscles have decreased ability
•Fluid accumulates in lungs, liver, abdomen, legs
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The Heart in the Elderly
How the heart can age
•Heart shrinks
•Decreased contraction strength
•Valves become less flexible
•Murmur develops
•Cardiac output decreases
•Abnormal rhythms
•Heart block
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Prevention of Heart Disease
•Risk factors that cannot be
modified
•Risk factors that can be
modified
– Age
– Smoking
– Gender
– Physical inactivity
– Heredity
– Weight
– Body type
– Diet
– Blood pressure
– Diabetes, gout
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Heart Studies
•Stethoscope
•Electrocardiograph (ECG or EKG)
– Electrodes
•Catheterization
– Fluoroscope
•Echocardiography (ultrasound cardiography)
– Oscilloscope
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Treatment of Heart Disease
•Medical approaches
•Surgical approaches
•Combined approaches
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Medications
•Digitalis
•Nitroglycerin
•Beta-adrenergic blocking agents (beta-blockers)
•Antiarrhythmic agents
•Slow calcium-channel blockers
•Anticoagulants
– Aspirin
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Correction of Arrhythmias
•Artificial pacemaker
– Set rate
– Only when heart skips beat
– Adjustable pacing rate
•Implantable cardioverter-defibrillator (ICD)
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Heart Surgery
•Coronary artery bypass graft (CSBG)
•Angioplasty
•Valve replacement
•Surgical transplantation of heart or heart and lungs
•Artificial heart
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
End of Presentation
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins