Transcript CRYDER’S cardiovascular

HEART LOCATION & ANATOMY
left lung
right lung
pericardium
apex of heart
diaphragm
MEDIASTINUM
PERICARDIAL LAYERS
pericardial cavity
FIBROUS PERICARDIUM
SEROUS PERICARDIUM (parietal
layer)
SEROUS PERICARDIUM visceral
layer (epicardium)
myocardium
endocardium
heart chamber
HEART MUSCLE
 Three Layers
 Endocardium
 Myocardium
 Epicardium
cardiac muscle
bundles
HEART CHAMBERS
Left atrium
Right atrium
ANTERIOR
Left ventricle
Right ventricle
Interventricular septum
INTERIOR
HEART CHAMBERS: ATRIA
fossa ovalis
(L) pulmonary
veins
pectinate
muscles
tricuspid valve
bicuspid valve
HEART CHAMBERS: VENTRICLES
aorta
pulmonary semilunar
valve
aortic semilunar valve
chordae tendineae
trabeculae carneae
papillary muscles
PULMONARY AND SYSTEMIC
CIRCULATION
CIRCULATION THROUGH THE HEART
Vena cavae
(R) ATRIUM
(R) VENTRICLE
Pulmonary trunk
Pulmonary arteries
LUNGS
(L) ATRIUM
Pulmonary veins
Aorta
(L) VENTRICLE
CORONARY CIRCULATION
(L) coronary
artery
circumflex artery
(R) coronary
artery
marginal artery
posterior interventricular artery
anterior interventricular
artery
CORONARY CIRCULATION
great cardiac
vein
anterior cardiac veins
coronary sinus
middle cardiac vein
small cardiac vein
CORONARY CIRCULATION SUMMARY
Aorta
(R)Coronary artery
Posterior
interventricular
artery
Ventricular
walls
(L)Coronary artery
Circumflex
artery
Marginal
artery
Walls of (R) atrium
& (R) ventricle
Walls of (L) atrium
& (L) ventricle
Cardiac veins
Coronary sinus
(R)atrium
Anterior
interventricular
artery
Ventricular
walls
CARDIAC HISTOLOGY
 Cardiac Muscle Cells
 Striated
 1 to 2 nuclei
 Numerous, large
mitochondria
 Intercalated discs
CARDIAC CONDUCTION SYSTEM
 Nodal System
 Autorhythmic Cells
 1%
of cardiac cells
 Initiate
and conduct and impulse
 Unstable
resting membrane potential
 Continuously
 Trigger
depolarize
contractions of heart muscle
CARDIAC CONDUCTION SYSTEM
 Nodal System
 Sinoatrial (SA) Node
 Mass
of autorhythmic cells
 Near SVC entrance
 Depolarizes 70 to 80 times
a minute (100 if no neural
control)
 Depolarization spreads
through atria
 Atria contract
CARDIAC CONDUCTION SYSTEM
 Nodal System
 Atrioventricular (AV) Node
 Autorhythmic
cells
 Above
tricuspid valve in
interatrial septum
 Passes impulse on to AV
bundle (Bundle of His)
 Bundle of His (AV Bundle)
 Conducts
impulse to
right and left bundle
branches
CARDIAC CONDUCTION SYSTEM
 Nodal System
 Bundle Branches
 Right
and left branches
 Branch
into purkinje
fibers
 Purkinje Fibers
 Enter
myocardium of
ventricle walls and
papillary muscles
 Carry impulse to
ventricles
 Ventricular contraction
CARDIAC CONDUCTION SYSTEM
SUMMARY
Node
AV Node
AV Bundle
Bundle Branches
Purkinje Fibers
EXTRINSIC INNERVATION
 Autonomic Nervous System
 Can slow or accelerate heart
 Cannot initiate a contraction
 Cardiac centers in medulla
 Stimulation by sympathetic
neurons
Increase heart rate
 Increase force of contraction

 Inhibition by parasympathetic
neurons
Via Vagus nerve
 Decrease heart rate
 Decrease force of contraction

CARDIAC CYCLE
 Interval from end of one contraction to the
following contraction
 0.8 sec.
 Consists of Two Phases:
 Systole phase
 Diastole phase
CARDIAC CYCLE
 Systole Phase
semilunar valves
(closed)
 Contraction phase
 Blood ejected
 Atrial Systole (0.1 sec.)
LA
 Following
passive filling
with blood
 AV valves open,
semilunar valves closed
 Ventricles fill with blood
bicuspid
(open)
RA
tricuspid
(open)
LV
RV
CARDIAC CYCLE
semilunar valves
(open)
 Systole Phase (cont.)
 Ventricular Systole (0.3
sec.)
 AV
and semilunar
valves closed until
pressure opens
semilunar valves
LA
RA
 Blood
pushed into
pulmonary trunk
 120
mm Hg pressure
 Atria
in diastole
bicuspid
(closed)
LV
tricuspid
(closed)
RV
CARDIAC CYCLE
semilunar valves
(closed)
 Diastole Phase
 Relaxation phase
 Ventricular Diastole
 Follows
ventricular
LA
systole
 AV valves reopen and
filling begins
 80 mm Hg pressure
bicuspid
(open)
RA
LV
tricuspid
(open)
RV
ELECTRICAL EVENTS: ECG
QRS complex
P wave:
atrial depolarization
QRS complex:
ventricular depolarization
T wave:
ventricular repolarization
ECG READINGS
Normal
SA Node Dysfunction
no P waves
2nd Degree Heart Block
(more P waves)
Ventricular Fibrillation
HEART SOUNDS
 Lub-dub
 AV valves closing for ventricular systole
 Semilunar valves closing
 Pause
 Quiescent period (0.4 sec.)
 Ventricles and atria in diastole simultaneously
CARDIAC OUTPUT
Amount of blood pumped out by each ventricle in
1 minute
Sympathetic stimulation needed if CO more than
14 liters/min. is needed
Starling’s Law
The greater the volume of blood returned to the
heart by the veins, the greater the volume of blood
the heart will pump
HEART RATE REGULATION:
Nervous System
 Cardiac Inhibitory Center
 Medulla
 Parasympathetic
 Vagus nerve
 Continually slows heart to
maintain average of 70
beats/min.
 Cardiac Accelerator Center
 Medulla
 Sympathetic
 Increases heart rate and force
of contraction when needed
OTHER REGULATORS
 Hormonal Regulation
 Accelerators
Epinephrine, norepinephrine
 Thyroxine, T3

 Body Temperature
 Increase temp. = increase heart rate
 Decrease temp.= decrease heart rate
 Baroreceptors
 Carotid sinus and aortic arch

Stretch  impulses to inhibitory center  vagus nerve 
decreased heart rate
 Bainbridge (Atrial) Baroreceptors
 Measure intraatrial pressure
Stimulate accelerator center
 Increased heart rate and force of contraction

DISORDERS
 Tachycardia
 Abnormally high heart rate (over 100)
 Bradycardia
 Abnormally low heart rate (under 60)
 Myocardial Infarction
 Death of myocardium
 Replaced with scar tissue
 Arrhythmia
 Uncoordinated pattern of heart contractions
 Fibrillation
 Rapid and out of phase contractions
 Angina Pectoris
 Pain caused by deficiency in blood delivery to the myocardium
DISORDERS
 Pericarditis
 Inflammation of the pericardium
 Can result in cardiac tamponade
 Congestive Heart Failure
 Inadequate pumping of the heart
 Blood back-up in lungs or body
 Excessive fluid in tissues
 Atherosclerosis
 Formation of fatty plaque on artery walls
 Decrease in vessel elasticity and possible blockage
 Ischemic Heart Disease
 Inadequate blood supply to cardiac muscle
 Temporary or chronic
 Heart Murmur
 Defective valve allowing back flow of blood
 Hissing sound from turbulence
BLOOD VESSELS: ARTERIES
 Arteries
 Carry blood away from heart
 high in oxygen
 Branch into arterioles
 Three groups:
Elastic
Arteries
Largest
Elastic fibers in tunica media
Expand and recoil (pulse)
Examples:

Aorta, pulmonary trunk, common iliac arteries
BLOOD VESSELS: ARTERIES
 Three groups (cont.)
 Muscular
arteries
Medium size
Carry blood from elastic arteries to arterioles
Active in vasoconstriction
Examples:
 Femoral,

brachial, axillary arteries
Arterioles
Smallest arteries
Carry blood to capillaries
Regulate blood flow to capillaries
BLOOD VESSELS: VEINS
 Carry blood from body back to heart
 Low in oxygen
 Venules empty into veins
Valve
(open)
 May contain valves
Valve
(closed)
OTHER VESSELS
 Capillaries
 Smallest vessels
 Connect arterioles to venules
 Exchange of nutrients, gases with tissue cells
 Sinusoids
 Vessels in place of capillaries
 In liver, spleen, bone marrow
 Anastomoses
 Connections between vessels such as arteries and veins
without a capillary bed in between
STRUCTURE OF BLOOD VESSELS
 Arteries and Veins
 Three tunics

Tunica interna
(intima)

Tunica media

Tunica externa
(adventitia)
tunica
interna
 Vasa vasorum
tunica
media
tunica
externa
ARTERY
VEIN
STRUCTURE OF BLOOD VESSELS
 Capillaries
 Thin walls
 Pre-capillary sphincters
ARTERIOLE
smooth muscle cell
endothelium
CAPILLARY
CAPILLARY STRUCTURE
Pre-capillary sphincters
TERMINAL
ARTERIOLE
CAPILLARIES
POSTCAPILLARY
VENULE
BLOOD PRESSURE
 Pressure exerted on vessel walls
 mm Hg pressure in systemic arteries
 Measured with sphygmomanometer
 Pressure in cuff compresses artery until no pulse heard
 Systolic pressure: taken at first pulse as pressure in cuff released
(ave. 120) = pressure while heart ventricles contracting
 Diastolic pressure: taken when cuff released to point where sound
no longer audible (ave. 80) = pressure when ventricles not
contracting
 Pulse pressure = systolic - diastolic (measure of stress exerted on
small arteries)
INFLUENCES ON B.P.
 Blood Pressure varies directly with the following:
Cardiac Output
 Stroke
volume X heart rate
 Normal is 5.5 liters/min.
Peripheral Resistance
 Opposition
to blood flow
 with blood viscosity
 with length of vessel
 with  in vessel diameter (has the greatest influence
on B.P.)
INFLUENCES ON B.P.
 Blood Pressure varies directly with the following:
Blood Volume
 Mainly
regulated by kidneys

in blood volume =  in B.P.

in blood vol. =  decrease in B.P.
REGULATION OF B.P.
 By nervous system, kidneys and chemical controls
 Nervous Regulation:
 Sympathetic nerve fibers
 Vasoconstriction
of blood vessels
 diameter,  resistance   B.P.
 Vasomotor center in medulla
 Controls
cardiac output
 Controls
degree of vessel constriction
REGULATION OF B.P.
 Nervous Regulation (cont.)
 Baroreceptors
 Pressure sensitive mechanoreceptors
 In aortic arch, carotid sinuses, large elastic arteries of head
and thorax
 Stretching impulses to vasomotor center
 Vasomotor center inhibited  dilation of vessels, decreased
heart rate and output  decreased B.P.
 Chemoreceptors
 Monitor
O2, CO2 levels and pH of blood
 In carotid and aortic bodies
 Send impulses to vasomotor center if O2 or pH drop or CO2
rises
 Vasoconstriction   B.P.
CHEMICAL REGULATION OF B.P.
 Epinephrine and Norepinephrine
 Vasoconstriction
  cardiac output
 ANF (Atrial Natriuretic Factor)
 Release of more sodium and water in urine
  blood volume   B.P.
 ADH (Antidiuretic Hormone)
 Stimulates kidneys to reabsorb water
  blood volume   B.P.
 Renin
 Released from kidneys in response to low B.P.
 Stimulates angiotensin/aldosterone system
 Kidneys reabsorb sodium and water   blood volume and B.P.
RENIN / ANGIOTENSIN / ALDOSTERONE
SYSTEM
CHEMICAL REGULATION OF B.P.
 Other Chemical Controls:
 Endothelin
Nitric oxide
Inflammatory chemicals (histamine)
Alcohol (inhibits ADH release and depresses the
vasomotor center)
RENAL REGULATION OF B.P.
 Kidneys may alter B.P. directly
 Increased B.P. more blood filtered by kidneys
 More urine produced and released
  blood volume   B.P.
 Kidneys may alter B.P. indirectly
 Renin/angiotensin system activated with  B.P.
 Vasoconstriction, water reabsorption due to aldosterone
release
  blood volume   B.P.
DISORDERS
Hypotension
Low B.P. (systolic below 100 mm Hg)
Aging,
poor nutrition, anemia,
hypothyroidism, Addision’s disease, low blood
protein levels or circulatory shock
DISORDERS
Hypertension
Sustained B.P. of 140/90 or higher
“Silent killer”
Higher risk with:
Age
Diet
Obesity
Stress
Smoking
Genetics
DISORDERS
Circulatory Shock
Not enough blood to fill the vessels and
circulate normally
Hypovolemic
shock
Large loss of blood volume
 Diarrhea,
vomiting, hemorrhage, burns
Vasoconstriction, weak pulse, sharp drop in
B.P.
DISORDERS
Circulatory Shock (cont.)
Not enough blood to fill the vessels and circulate
normally
Vascular
shock
Extreme vasodilation
 Poor
circulation, rapidly dropping B.P.
 Normal blood volume
 Problems with vasomotor center, nervous regulation
or bacterial infections
 Cardiogenic
shock
Heart cannot pump adequate blood supply
Usually from myocardial damage
HEAD AND NECK ARTERIES
ABDOMINAL AORTA
CELIAC TRUNK