Transcript Cellular Biology

Structure and Function of
the Cardiovascular and
Lymphatic Systems
Chapter 29
1
Circulatory System

Heart
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Right heart
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
Pumps blood through the lungs (pulmonary
circulation)
Left heart

Pumps blood through the systemic circulation
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Circulatory System
Pulmonary circuit has
deoxygenated blood,
Systemic circuit has
oxygenated blood.
Veins conduct blood to
the heart and arteries
conduct blood away
from heart
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Circulatory System

Heart
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Mediastinum
Heart wall
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Pericardium
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Parietal and visceral pericardium
Pericardial cavity and fluid – fluid-filled space
Myocardium – the thick contractile muscle layer
Endocardium – inner lining of the heart, smooth
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The Heart Wall
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The Chambers of the Heart
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Right atrium – receiving chamber for blood
from systemic side. No valve between vena
Cava and R atrium
Left atrium – receiving deox blood from lungs
Right ventricle – pumps blood to lungs via
pulmonary arteries
Left ventricle – pumps blood to systemic
circuit via aortia
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The Chambers of the Heart
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The Valves of the Heart
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Atrioventricular valves between A & V
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Tricuspid valve – Right side
Bicuspid valve – left side
Semilunar valves
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Pulmonic semilunar valve
Aortic semilunar valve
Valves and other connective tissue do not conduct
electrical impulses and make up heart skeleton
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The Valves of the Heart
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The Great Vessels
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Superior and inferior venae cavae – bring
blood to R Ventricle from head & body
Pulmonary artery (trunk) - blood to lungs
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Right and left pulmonary arteries
Pulmonary veins – blood from lungs
Aortia – conducts blood to systemic circuit
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Blood Flow
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Cardiac cycle – the electrical and physical
events of an entire heart beat – 0.7 seconds
Diastole – resting phase – no active
contraction
Systole – active muscle contraction and
electrical impulses
Phases of the cardiac cycle
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Blood Flow
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Normal Intracardiac Pressures
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Normal Intracardiac Pressures
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The Coronary Vessels only 2 arteries
with little collateral circulation

Right coronary artery blood flows into artery
only after aortic semilunar valve is closed
otherwise the opening is covered by valve
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Conus
Right marginal branch
Posterior descending branch
Left coronary artery
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Left anterior descending artery
Circumflex artery
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The Coronary Vessels
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Collateral arteries
Coronary capillaries
Coronary veins
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Coronary sinus
Great cardiac vein
Posterior vein of the left ventricle
Coronary lymphatic vessels
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The Coronary Vessels
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Structures That Control Heart
Action
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Cardiac action potentials – electric stimulation of the heart
Conduction system – specialized muscle cells that depolarize
on their own called pacemakers – little muscle actin &
myosin
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Sinoatrial node (SA) – pacemakers depolarize 100 x /minutes due to
leaky membranes to Na
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Intranodal pathways
Atrioventricular node (AV) – only electrical connection between Atria
(top) and Ventricles (bottom) of heart
Bundle of His (AV bundle) – pass through septum of heart to apex
Right and left bundle branches spread out to muscle of ventricles
Purkinje fibers – into the larger muscle mass
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Conduction System of the Heart
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Structures That Control Heart
Action
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Cardiac excitation
Propagation of cardiac action potentials
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Depolarization
Repolarization – long refractory period
Electocardiogram – EKG
Automaticity
Rhythmicity
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Structures That Control Heart
Action
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Cardiac innervation
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Sympathetic nerves
Parasympathetic nerves
Adrenergic receptor function
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α- or β-adrenergic receptors
Norepinephrine or epinephrine
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Autonomic Innervation of the
Cardiovascular System
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Myocardial Cells
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Nearly identical to skeletal muscle cells
Intercalated disks
Actin, myosin, and the troponin-tropomyosin
complex
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Troponin T, I, and C
Myocardial metabolism

Myocardial oxygen consumption
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Myocardial Contraction and
Relaxation
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Cardiac Performance
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Preload
Afterload
Frank-Starling law of the heart – self regulating
mechanism that controls stroke volume and force.
The greater the stretch of the heart muscle the
stronger the force of contraction up to a maximum
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End-diastolic volume – measure of the return flow of
blood and stretch of the ventricles
Laplace law
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Cardiac Performance
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Heart rate
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Cardiovascular control center – in medula
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Neural reflexes
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Cardioexcitatory and cardioinhibitory centers
Bainbridge and baroreceptor reflexes
Atrial receptors – sense the stretch (refill) of heart
Hormones and biochemicals – epinephrine,
digitalis etc…
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Cardiac Performance
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Myocardial contractility
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Stroke volume = SV
Inotropic agents
Oxygen and carbon dioxide levels
Cardiac output CO = SV x HR
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Volume of blood flowing through either the
systemic or pulmonary circuit in liters per minute
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Cardiac Output
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Systemic Circulation
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Arteries
Arterioles
Capillaries
Venules
Veins
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Structure of Blood Vessels
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Lumen
Tunica intima
Tunica media
Tunica externa (adventitia)
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Endothelium
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Structure of Blood Vessels
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Factors Affecting Blood Flow
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Poiseuille law effect of diameter & length of
vessel on resistance
Pressure
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Force exerted on a liquid per unit area
Resistance
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Opposition to force
Diameter and length of the blood vessels
contribute to resistance
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Factors Affecting Blood Flow
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Neural control of total peripheral resistance
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Change in diameter of the vessels
Baroreceptors
Arterial chemoreceptors
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Baroreceptor and Chemoreceptors
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Factors Affecting Blood Flow
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Velocity
Laminar vs. turbulent flow
Vascular compliance
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Laminar vs. Turbulent Flow
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Regulation of Blood Pressure
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Arterial pressure
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Mean arterial pressure (MAP)
Effects of cardiac output
Effects of total peripheral resistance
Effect of hyperemia
Effects of hormones
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Epinephrine and norepinephrine
Antidiuretic hormone, renin-angiotensin system, and
natriuretic peptides
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Regulation of Blood Pressure
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Adrenomedullin
Insulin
Venous pressure
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Regulation of Coronary Circulation
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Coronary perfusion pressure
Autoregulation
Autonomic regulation
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Lymphatic System
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Special vascular system that picks up excess
fluid and returns it to the bloodstream
Lymphatic fluid
Lymphatic veins and venules
Right lymphatic duct
Thoracic duct
Afferent and efferent lymphatic vessels
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Lymphatic System
2 main locations for
fluid return to blood
– R Lymphatic duct
& Thoracic duct on L
subclavian Vein
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Tests of Cardiovascular Function
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Noninvasive assessments
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Sensorium of the individual
Mucous membrane color
Manually palpated pulse
Auscultation of heart sounds
Cardiography
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Tests of Cardiovascular Function
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Noninvasive assessments
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Pulse tracing
Magnetic resonance imaging
Doppler studies
Stress testing
Chest x-ray examinations
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Tests of Cardiovascular Function
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Invasive assessments
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X-ray films with barium
Nuclear imaging with radiolabeled pharmaceuticals
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Hot spot imaging
Cold spot imaging
Tomographic studies
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Tests of Cardiovascular Function
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Invasive assessments
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Atrioventricular bundle electrocardiography
Cardiac catheterization
Coronary angiography
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Aging and the Cardiovascular
System

Arteriosclerosis
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Cross linking of collagen
Increased collagen
Changes in elastin
Atherosclerosis
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Aging and the Cardiovascular
System
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