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A 60-year-old woman with a history of obesity and DM II has experienced a…
A 60-year-old woman with a history of obesity and DM II has experienced a myocardial infarction
Mitral valve don't close tightly
Blood to leak backward into the left atrium
result in heart muscle damage.
Irregular heart rhythms in the upper heart chambers (atrial fibrillation)
High blood pressure that affects the blood vessels in the lungs (pulmonary hypertension)
Blood clots
Stroke
Can Affect the:
Nervous System
All functions are regulated by the brain
Heart and fluid function will not work
Urinary System (Kidneys)
Clean the blood
Blood would have water and waste throughout
Respiratory System
circulate blood and oxygen throughout the body
Blood moves through the pulmonary arteries and veins that connect to the heart.
Poor Diet
Poor exercise routine
Stressful Lifestyle
The Anatomy of the Heart
Side-by-Side Pumps
Left Side
Receives oxygenated blood from lungs
Pumps blood into tissues via systemic circuit
Right Side
Receives oxygen-poor blood from tissues
Pumps blood to lungs via pulmonary circuit
Coverings
Pericardium
Double-walled sac
Fibrous Pericardium
Protect, anchor, and prevent overfilling
Visceral layer (epicardium)
External surface
Heart Wall
Cardiac Skeleton: (Connective tissue
Epicardium: AKA visceral pericardium
Myocardium
Bundles of contractile cardiac muscle cells
Cardiac skeleton: crisscrossing, interlacing layer of connective tissue
Anchors cardiac muscle fibers
Supports great vessels and valves
Limits spread of action potentials to specific paths
Heart Valves
(2) Atrioventricular valves
prevent backflow into atria
Tricuspid valve
Mitral valve
Chordae tendineae
Hold valve flaps in closed position during ventricular contraction
Prevent flaps from everting back into atria
(2) Semilunar valves
prevent backflow from major arteries back into ventricles
Pulmonary semilunar
Aortic semilunar
Intercalated discs
Allows heart to be a functional syncytium, a single coordinated unit
The Pathway of blood through the Heart
Right atrium receives oxygen-poor blood from the body
Pumps it to the right ventricle through the tricuspid valve.
Right ventricle pumps the oxygen-poor blood to the lungs through the pulmonary valve.
Reft atrium receives oxygen-rich blood from the lungs
Pumps it to the left ventricle through the mitral valve.
Left ventricle pumps the oxygen-rich blood through the aortic valve out to the rest of the body.
Right Side
SVC, IVC, & Coronary Sinus
Right atrium
Tricuspid valve
Right ventricle
Pulmonary semilunar valve
Pulmonary trunk
Pulmonary arteries
1 more item...
Left Side
Four Pulmonary veins
Left atrium
mitral valve
Left ventricle
Aortic semilunar valve
Aorta
Anatomic circulation
most of coronary blood supply
3x thicker than right
Lub Dub (Heart Sounds)
Presence of gap junctions
Intrinsic cardiac conduction system
Network of noncontractile (autorhythmic) cells
Initiate and distribute impulses to coordinate depolarization and contraction
The Intrinsic Conduction System
Action potential initiation by Pacemaker cells in SA node
Pacemaker potential
K+ channels are closed, but slow Na+ channels are open, causing interior to become more positive
Depolarization at threshold, (-40 mV)
Ca2+ channels open, allowing huge influx of Ca2+, leading to rising phase of action potential
Repolarization
K+ channels open, allowing efflux of K+, and cell becomes more negative
Sinoatrial (SA) node
Generates impulses about 75×/minute (sinus rhythm)
Atrioventricular (AV) node
Delays impulses approximately 0.1 second (lub-dub; pause of 0.1 sec; lub-dub)
Atrioventricular (AV) bundle
The Only electrical connection between atria and ventricles
Purkinje fibers
Complete pathway through interventricular septum into apex and ventricular walls, papillary muscles
Ventricular contraction immediately follows from apex toward atria (wringing mop action)
Sequence of excitation
Sinoatrial node
Atrioventricular node
Atrioventricular bundle
Right and left bundle branches
Subendocardial conducting network (Purkinje fibers)
Cardiac output
amount of blood pumped out by each ventricle in 1 minute
Stroke volume
volume of blood pumped out by one ventricle with each beat
Stroke volume
the amount of blood pumped out by one ventricle each heart beat.
Afterload
pressure that ventricles must overcome to eject blood
Preload
Degree of stretch of heart muscle just before contraction
Electrocardiography
can detect electrical currents generated by heart.
Electrocardiogram (ECG or EKG)
a graphic recording of electrical activity
P wave
depolarization of SA node and atria
QRS complex
ventricular depolarization and atrial repolarization
T wave
ventricular repolarization
P-R interval
beginning of atrial excitation to beginning of ventricular excitation
S-T segment
entire ventricular myocardium depolarized
Q-T interval
beginning of ventricular depolarization through ventricular repolarization
Regulation of Heart Rate
Sympathetic nervous system
activated by emotional or physical stressors
NE and EPI bind to nodal cells and increase their firing rate/ HR
Goal is to maintain CO
Autonomic reflexes
Baroreceptors and chemoreceptors send signals to cardiac center in medulla
Atrial reflex
Protects heart from overfilling
Heart rate increase to move blood through quickly
Baroreceptors in atrial walls stimulated by increased venous return
Chemical regulation of heart rate
Hormones
Epinephrine from adrenal medulla increases heart rate and contractility
Thyroxine increases heart rate; enhances effects of norepinephrine and epinephrine
Ions
Ca2+ and K+ must be maintained for normal heart function
Drugs
Caffeine and Cocaine
Other Factors
Body Temperature
HR increases with increased body temperature
Age
Fetus has fastest HR
Gender
Females have faster HR than males
Exercise
Increases HR
Trained athletes can have slow HR